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Liu S, Hou C, Dong C, Zhao D, Chen Q, Terence Yang JY, Tang K. Integrated multi-omics analyses reveal microbial community resilience to fluctuating low oxygen in the East China sea. ENVIRONMENTAL RESEARCH 2024; 261:119764. [PMID: 39122162 DOI: 10.1016/j.envres.2024.119764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 07/31/2024] [Accepted: 08/07/2024] [Indexed: 08/12/2024]
Abstract
Climate change and eutrophication are accelerating ocean deoxygenation, leading to a global decline in oxygen levels. The East China Sea, frequently experiencing deoxygenation events, harbors diverse microbial communities. However, the response of these communities to the changing deoxygenation dynamics remains poorly understood. Here, we explored the composition and function of microbial communities inhabiting seawaters of the Changjiang Estuary and offshore areas. Our findings suggested that neutral processes significantly influenced the assembly of these communities. The overall bacterial composition demonstrated remarkable high stability across the oxygen gradient. Salinity exhibited a significantly stronger correlation with bacterial community structure than dissolved oxygen. Both metagenomics and metaproteomics revealed that all of the samples exhibited similar functional community structures. Heterotrophic metabolism dominated these sites, as evidenced by a diverse array of transporters and metabolic enzymes for organic matter uptake and utilization, which constituted a significant portion of the expressed proteins. O2 was the primary electron acceptor in bacteria even under hypoxic conditions, evidenced by expression of low- and high-affinity cytochrome oxidases. Proteins associated with anaerobic processes, such as dissimilatory sulfite reductases, were virtually undetectable. Untargeted liquid chromatography with tandem mass spectrometry analysis of seawater samples revealed a diverse range of dissolved organic matter (DOM) components in amino acids, lipids, organic acids, peptides, and carbohydrates, potentially fueling dominant taxa growth. Despite fluctuations in the abundance of specific genera, the remarkable similarity in community structure, function, and DOM suggests that this ecosystem possesses robust adaptive mechanisms that buffer against abrupt changes, even below the well-defined hypoxic threshold in marine ecosystem.
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Affiliation(s)
- Shujing Liu
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, China
| | - Congcong Hou
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, China
| | - Changjie Dong
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, China
| | - Duo Zhao
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, China
| | - Quanrui Chen
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, China
| | - Jin-Yu Terence Yang
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, China
| | - Kai Tang
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, China.
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2
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Huang Z, Shu L, He Z, Yan Q. Community coalescence under variable hydrochemical conditions of the Chesapeake Bay shaped bacterial diversity and functional traits. ENVIRONMENTAL RESEARCH 2024; 257:119272. [PMID: 38823613 DOI: 10.1016/j.envres.2024.119272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Revised: 05/27/2024] [Accepted: 05/28/2024] [Indexed: 06/03/2024]
Abstract
Community coalescence related to bacterial mixing events regulates community characteristics and affects the health of estuary ecosystems. At present, bacterial coalescence and its driving factors are still unclear. The present study used a dataset from the Chesapeake Bay (2017) to address how bacterial community coalescence in response to variable hydrochemistry in estuarine ecosystems. We determined that variable hydrochemistry promoted the deterioration of water quality. Temperature, orthophosphate, dissolved oxygen, chlorophyll a, Secchi disk depth, and dissolved organic phosphorus were the key environmental factors driving community coalescence. Bacteria with high tolerance to environmental change were the primary taxa accumulated in community coalescence, and the significance of deterministic processes to communities was revealed. Community coalescence was significantly correlated with the pathways of metabolism and organismal systems, and promoted the co-occurrence of antibiotic resistance and virulence factor genes. Briefly, community coalescence under variable hydrochemical conditions shaped bacterial diversity and functional traits, to optimise strategies for energy acquisition and lay the foundation for alleviating environmental pressures. However, potential pathogenic bacteria in community coalescence may be harmful to human health and environmental safety. The present study provides a scientific reference for ecological management of estuaries.
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Affiliation(s)
- Zhenyu Huang
- School of Environmental Science and Engineering, Marine Synthetic Ecology Research Center, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Observation and Research Station for Marine Ranching in Lingdingyang Bay, China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou, 510006, China
| | - Longfei Shu
- School of Environmental Science and Engineering, Marine Synthetic Ecology Research Center, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Observation and Research Station for Marine Ranching in Lingdingyang Bay, China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou, 510006, China
| | - Zhili He
- School of Environmental Science and Engineering, Marine Synthetic Ecology Research Center, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Observation and Research Station for Marine Ranching in Lingdingyang Bay, China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou, 510006, China
| | - Qingyun Yan
- School of Environmental Science and Engineering, Marine Synthetic Ecology Research Center, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Observation and Research Station for Marine Ranching in Lingdingyang Bay, China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou, 510006, China.
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3
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Liu S, Chen Q, Hou C, Dong C, Qiu X, Tang K. Recovery of 1559 metagenome-assembled genomes from the East China Sea's low-oxygen region. Sci Data 2024; 11:994. [PMID: 39266528 DOI: 10.1038/s41597-024-03850-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Accepted: 09/02/2024] [Indexed: 09/14/2024] Open
Abstract
The Changjiang Estuary and adjacent East China Sea are well-known hypoxic aquatic environments. Eutrophication-driven hypoxia frequently occurs in coastal areas, posing a major threat to the ecological environment, including altering community structure and metabolic processes of marine organisms, and enhancing diversion of energy shunt into microbial communities. However, the responses of microbial communities and their metabolic pathways to coastal hypoxia remain poorly understood. Here, we studied the microbial communities collected from spatiotemporal samplings using metagenomic sequencing in the Changjiang Estuary and adjacent East China Sea. This generated 1.31 Tbp of metagenomics data, distributed across 103 samples corresponding to 8 vertical profiles. We further reported 1,559 metagenome-assembled genomes (MAGs), of which 508 were high-quality MAGs (Completeness > 90% and Contamination < 10%). Phylogenomic analysis classified them into 181 archaeal and 1,378 bacterial MAGs. These results provided a valuable metagenomic dataset available for further investigation of the effects of hypoxia on marine microorganisms.
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Affiliation(s)
- Shujing Liu
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, Fujian, China
| | - Quanrui Chen
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, Fujian, China
| | - Congcong Hou
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, Fujian, China
| | - Changjie Dong
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, Fujian, China
| | - Xuanyun Qiu
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, Fujian, China
| | - Kai Tang
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, Fujian, China.
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4
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Park Y, Song B, Cha J, An S. Microbiome signature of different stages of hypoxia event in Wonmun Bay. MARINE ENVIRONMENTAL RESEARCH 2024; 202:106673. [PMID: 39216437 DOI: 10.1016/j.marenvres.2024.106673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 06/24/2024] [Accepted: 08/08/2024] [Indexed: 09/04/2024]
Abstract
We investigated how microbial communities associated with different hypoxic stages respond to environmental changes across three water depths in Wonmun Bay, South Korea. Analysis of temperature, salinity, dissolved oxygen (DO), and nutrient concentrations revealed prominent seasonal shifts and strong stratification during summer hypoxia. Metabarcoding of prokaryotic 16 S rRNA genes and phototrophic eukaryotic chloroplasts along with quantitative PCR (qPCR) revealed variations in the abundance and composition of these communities. Chloroplast 16 S sequences in May were dominated by land plants (93% of Embryophyta), contrasting with the diverse phytoplankton taxa detected in other months. The water communities in May also had higher total microbial abundance than other months but significantly lower alpha diversity. These results suggest a major influence of freshwater discharge on water communities, pre-conditioning for hypoxia events by promoting organic matter decomposition coupled with DO consumption in bottom water. Subsequently, distinct microbial communities were observed across depths during hypoxia in June and July, while less variability was detected among different depths in September and later months when hypoxia events disappeared. Principal Coordinate analysis (PCoA) demonstrated the distinct patterns of microbial communities in May, June, and July from other months. Both sulfur-oxidizing and sulfate-reducing bacteria (SRB) were prevalent in June while the increase of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) was observed in mid and bottom water in July. This data suggests the intricate interaction between sulfur and nitrogen-cycling microbes during the hypoxia events in Wonmun Bay. In conclusion, this study provides valuable insights into the microbial community responses to the varying environmental conditions at different stages of hypoxia events in eutrophic coastal ecosystems.
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Affiliation(s)
- Yunjung Park
- Research Institute for Basic Sciences, College of Natural Sciences, Pusan National University, Busan, 46241, Republic of Korea
| | - Bongkeun Song
- Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA, 23062, United States
| | - Jaeho Cha
- Department of Microbiology, College of Natural Sciences, Pusan National University, Busan, 46241, Republic of Korea
| | - Soonmo An
- Department of Oceanography and Marine Research Institute, Pusan National University, Busan, 46241, Republic of Korea.
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Liu Z, Cao F, Wan J, Chen X, Kong B, Li D, Zhang XH, Jiang Y, Shi X. Stable microbial community diversity across large-scale Antarctic water masses. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 947:174559. [PMID: 38992373 DOI: 10.1016/j.scitotenv.2024.174559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 07/04/2024] [Accepted: 07/04/2024] [Indexed: 07/13/2024]
Abstract
The distinctive environmental attributes of the Southern Ocean underscore the indispensability of microorganisms in this region. We analyzed 208 samples obtained from four separate layers (Surface, Deep Chlorophyll Maximum, Middle, and Bottom) in the neighboring seas of the Antarctic Peninsula and the Cosmonaut Sea to explore variations in microbial composition, interactions and community assembly processes. The results demonstrated noteworthy distinctions in alpha and beta diversity across diverse communities, with the increase in water depth, a gradual rise in community diversity was observed. In particular, the co-occurrence network analysis exposed pronounced microbial interactions within the same water mass, which are notably stronger than those observed between different water masses. Co-occurrence network complexity was higher in the surface water mass than in the bottom water mass. Yet, the surface water mass exhibited greater network stability. Moreover, in the phylogenetic-based β-nearest taxon distance analyses, deterministic processes were identified as the primary factors influencing community assembly in Antarctic microorganisms. This study contributes to exploring diversity and assembly processes under the complex hydrological conditions of Antarctica.
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Affiliation(s)
- Zhengang Liu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, China; Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Furong Cao
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Jiyuan Wan
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Xing Chen
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, China; Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Bin Kong
- First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China
| | - Dong Li
- Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
| | - Xiao-Hua Zhang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, China; Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Yong Jiang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, China; Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.
| | - Xiaochong Shi
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, and College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao 266237, China; Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.
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Jiao N, Luo T, Chen Q, Zhao Z, Xiao X, Liu J, Jian Z, Xie S, Thomas H, Herndl GJ, Benner R, Gonsior M, Chen F, Cai WJ, Robinson C. The microbial carbon pump and climate change. Nat Rev Microbiol 2024; 22:408-419. [PMID: 38491185 DOI: 10.1038/s41579-024-01018-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2024] [Indexed: 03/18/2024]
Abstract
The ocean has been a regulator of climate change throughout the history of Earth. One key mechanism is the mediation of the carbon reservoir by refractory dissolved organic carbon (RDOC), which can either be stored in the water column for centuries or released back into the atmosphere as CO2 depending on the conditions. The RDOC is produced through a myriad of microbial metabolic and ecological processes known as the microbial carbon pump (MCP). Here, we review recent research advances in processes related to the MCP, including the distribution patterns and molecular composition of RDOC, links between the complexity of RDOC compounds and microbial diversity, MCP-driven carbon cycles across time and space, and responses of the MCP to a changing climate. We identify knowledge gaps and future research directions in the role of the MCP, particularly as a key component in integrated approaches combining the mechanisms of the biological and abiotic carbon pumps for ocean negative carbon emissions.
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Affiliation(s)
- Nianzhi Jiao
- Innovation Research Center for Carbon Neutralization, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, China.
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China.
| | - Tingwei Luo
- Innovation Research Center for Carbon Neutralization, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, China
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China
| | - Quanrui Chen
- Innovation Research Center for Carbon Neutralization, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, China
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China
| | - Zhao Zhao
- Innovation Research Center for Carbon Neutralization, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, China
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China
| | - Xilin Xiao
- Innovation Research Center for Carbon Neutralization, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen, China
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China
| | - Jihua Liu
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China
- Institute of Marine Science and Technology, Shandong University, Qingdao, China
| | - Zhimin Jian
- State Key Laboratory of Marine Geology, Tongji University, Shanghai, China
| | - Shucheng Xie
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Helmuth Thomas
- Institute of Carbon Cycles, Helmholtz-Zentrum Hereon, Geesthacht, Germany
- Institut für Chemie und Biologie des Meeres (ICBM), Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Gerhard J Herndl
- Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
| | - Ronald Benner
- Department of Biological Sciences, School of the Earth, Ocean and Environment, University of South Carolina, Columbia, SC, USA
| | - Micheal Gonsior
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China
- Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, MD, USA
| | - Feng Chen
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science, Baltimore, MD, USA
| | - Wei-Jun Cai
- School of Marine Science and Policy, University of Delaware, Newark, DE, USA
| | - Carol Robinson
- UN Global ONCE joint focal points at Shandong University, University of East Anglia, University of Maryland Center for Environmental Science, and Xiamen University, Xiamen, China.
- Centre for Ocean and Atmospheric Sciences (COAS), School of Environmental Sciences, University of East Anglia, Norwich, UK.
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Huang H, Zan S, Shao K, Chen H, Fan J. Spatial distribution characteristics and interaction effects of DOM and microbial communities in kelp cultivation areas. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 920:170511. [PMID: 38309352 DOI: 10.1016/j.scitotenv.2024.170511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 01/17/2024] [Accepted: 01/26/2024] [Indexed: 02/05/2024]
Abstract
The influence of macroalgae cultivation on aquaculture carbon sinks is significant, with microbial carbon (C) pumps contributing to a stable inert dissolved carbon pool in this context. Concurrently, dissolved organic matter (DOM) exchange at the marine sediment-water interface profoundly affects global ecosystem element cycling. However, the interactions between DOM and bacterial communities at the sediment-water interface in kelp cultivation areas, especially regarding microbial function prediction, have not been fully explored. This study analyzed the DOM characteristics, environmental factors, and bacterial community structure in the Tahewan kelp--Saccharina japonica cultivated area and compared them with those in non-cultivated areas. The results indicated significantly higher dissolved organic carbon (DOC) concentrations in the kelp culture area, particularly in surface seawater and overlying water. The dominant bacterial phyla in both regions included Pseudomonadota, Actinomycetota, and Bacteroidota in both regions, while Desulfobacterota was more prevalent in the sediment environment of the cultivated region. Parallel factor analysis (EEM-PARAFAC) was used to identify DOM components, among which component C2 (a microbial humic-like substance DOM) was highly resistant to microbial degradation. We infer that C2 has similar properties to recalcitrant dissolved organic matter (RDOM). Analysis of the predicted functional genes based on 16S rRNA gene data showed that methanol oxidation, methylotrophy, and methanotrophy were significant in the bottom seawater of the cultivation area. The carbon (C), nitrogen (N), and sulfur (S) cycle functional genes in the sediment environment of the kelp cultivation area were more active than those in other areas, especially in which sulfate reduction and denitrification were the two main processes. Furthermore, a DOM priming effect was identified in the cultivated sediment environment, where kelp-released labile dissolved organic matter (LDOM) stimulates rapid degradation of the original RDOM, potentially enhancing C sequestration.
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Affiliation(s)
- Huiling Huang
- College of Oceanography and Ecological Science, Shanghai Ocean University, Shanghai, China; State Environmental Protection Key Laboratory of Coastal Ecosystem, National Marine Environmental Monitoring Center, Dalian, China
| | - Shuaijun Zan
- Groundwater Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Shenzhen International Graduate School, Tsinghua University, Shenzhen, China
| | - Kuishuang Shao
- State Environmental Protection Key Laboratory of Coastal Ecosystem, National Marine Environmental Monitoring Center, Dalian, China
| | - Hanjun Chen
- State Environmental Protection Key Laboratory of Coastal Ecosystem, National Marine Environmental Monitoring Center, Dalian, China; College of Marine Technology and Environment, Dalian Ocean University, Dalian, China
| | - Jingfeng Fan
- College of Oceanography and Ecological Science, Shanghai Ocean University, Shanghai, China; State Environmental Protection Key Laboratory of Coastal Ecosystem, National Marine Environmental Monitoring Center, Dalian, China; College of Marine Technology and Environment, Dalian Ocean University, Dalian, China.
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8
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Xu Z, Sun Q, Miao Y, Li H, Wang B, Jin H, Zhu Z, Chen J. Ecosystem dynamics and hypoxia control in the East China Sea: A bottom-up and top-down perspective. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 918:170729. [PMID: 38325445 DOI: 10.1016/j.scitotenv.2024.170729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/25/2024] [Accepted: 02/03/2024] [Indexed: 02/09/2024]
Abstract
Decades of overfishing have greatly altered the community structure in the East China Sea (ECS). The decrease of top predators in the food web has weakened the control exerted from higher trophic levels. As a result, the biomass of benthic crustaceans, representing the third trophic level, has increased. This has probably led to a restriction of the second trophic level, diminishing its ability to control primary producer biomass. Consequently, the ecological pyramid of trophic levels in the ECS has been altered, reducing the top-down control on the first trophic level. This has made algal blooms more susceptible to occur under nutrient loads, temperate temperatures, and light availability. The reduced abundance of the fourth trophic levels has caused a larger portion of primary productivity to sink directly to the benthic community, bypassing the food web. This influx of sinking organic matter has resulted in organic enrichment in the bottom waters, impacting the biomass and diversity of benthic organisms. Furthermore, it has intensified anthropogenic carbon storage in the sediment. Subsequently, intense decomposition processes occur, leading to the development of anoxia and even hypoxia. The seasonal hypoxia off the Changjiang Estuary can be attributed to the combined influence of top-down control and bottom-up control related to nutrient loading, and terrestrial inputs. In order to mitigate extreme hypoxia events, it is necessary to implement comprehensive fisheries policies that prioritize the maintenance of a healthy and functional ecosystem. This approach should go beyond relying solely on watershed management strategies to regulate riverine inputs. PLAIN LANGUAGE SUMMARY: Decades of overfishing changed the food web in the East China Sea and weaken the resistance of ecosystem to hypoxia. Commercial fishing on top predators decreases the fourth trophic level while relatively increases the third trophic represented by crab and shrimp, which enhances grazing on the zooplankton. The decrease of the second trophic level fails to control the biomass of phytoplankton, thus more primary productivities directly sink to the benthic community and cause organic enrichment. The elevated flux of organic matters to the bottom waters causes the thrive of the carbs and shrimps, as well as more remineralization processes and eventually low oxygen level. Unlike the bottom-up perspective of hypoxia mechanism off the Changjiang Estuary, which is from the nutrient load, phytoplankton bloom, quick sink, effective decomposition and eventually hypoxia, the top-down control focuses on the changes of ecosystem structure and thus derived hindered energy transfer, changed community structure, enhanced carbon sink, elevated remineralization and ultimately hypoxia. These two mechanisms combine with each other and control the seasonal hypoxia off the Changjiang Estuary and even other coastal regions around the world.
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Affiliation(s)
- Zhongsheng Xu
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources, Second Institute of Oceanography, MNR, Hangzhou 310012, China.
| | - Qianwen Sun
- Ocean College, Zhejiang University, Zhoushan 316000, China.
| | - Yanyi Miao
- School of Oceanography, Shanghai Jiao Tong University, Shanghai 200030, China.
| | - Hongliang Li
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources, Second Institute of Oceanography, MNR, Hangzhou 310012, China.
| | - Bin Wang
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources, Second Institute of Oceanography, MNR, Hangzhou 310012, China.
| | - Haiyan Jin
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources, Second Institute of Oceanography, MNR, Hangzhou 310012, China.
| | - Zuhao Zhu
- Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources, Fourth Institute of Oceanography, MNR, Beihai 536015, China.
| | - Jianfang Chen
- Key Laboratory of Marine Ecosystem Dynamics, Ministry of Natural Resources, Second Institute of Oceanography, MNR, Hangzhou 310012, China.
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9
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Sarkar J, Mondal M, Bhattacharya S, Dutta S, Chatterjee S, Mondal N, N S, Peketi A, Mazumdar A, Ghosh W. Extremely oligotrophic and complex-carbon-degrading microaerobic bacteria from Arabian Sea oxygen minimum zone sediments. Arch Microbiol 2024; 206:179. [PMID: 38498215 DOI: 10.1007/s00203-024-03875-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/23/2024] [Accepted: 01/26/2024] [Indexed: 03/20/2024]
Abstract
Sediments underlying marine hypoxic zones are huge sinks of unreacted complex organic matter, where despite acute O2 limitation, obligately aerobic bacteria thrive, and steady depletion of organic carbon takes place within a few meters below the seafloor. However, little knowledge exists about the sustenance and complex carbon degradation potentials of aerobic chemoorganotrophs in these sulfidic ecosystems. We isolated and characterized a number of aerobic bacterial chemoorganoheterotrophs from across a ~ 3 m sediment horizon underlying the perennial hypoxic zone of the eastern Arabian Sea. High levels of sequence correspondence between the isolates' genomes and the habitat's metagenomes and metatranscriptomes illustrated that the strains were widespread and active across the sediment cores explored. The isolates catabolized several complex organic compounds of marine and terrestrial origins in the presence of high or low, but not zero, O2. Some of them could also grow anaerobically on yeast extract or acetate by reducing nitrate and/or nitrite. Fermentation did not support growth, but enabled all the strains to maintain a fraction of their cell populations over prolonged anoxia. Under extreme oligotrophy, limited growth followed by protracted stationary phase was observed for all the isolates at low cell density, amid high or low, but not zero, O2 concentration. While population control and maintenance could be particularly useful for the strains' survival in the critically carbon-depleted layers below the explored sediment depths (core-bottom organic carbon: 0.5-1.0% w/w), metagenomic data suggested that in situ anoxia could be surmounted via potential supplies of cryptic O2 from previously reported sources such as Nitrosopumilus species.
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Affiliation(s)
- Jagannath Sarkar
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India.
| | - Mahamadul Mondal
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India
| | - Sabyasachi Bhattacharya
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India
- National Institute of Biomedical Genomics, Kalyani, West Bengal, India
| | - Subhajit Dutta
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India
| | - Sumit Chatterjee
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India
| | - Nibendu Mondal
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India
- International Institute of Innovation and Technology, Kolkata, West Bengal, India
| | - Saran N
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India
| | - Aditya Peketi
- Geological Oceanography, CSIR National Institute of Oceanography, Dona Paula, Goa, 403004, India
| | - Aninda Mazumdar
- Geological Oceanography, CSIR National Institute of Oceanography, Dona Paula, Goa, 403004, India
| | - Wriddhiman Ghosh
- Department of Biological Sciences, Bose Institute, Kolkata, 700091, West Bengal, India.
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10
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Moncada C, Arnosti C, Brüwer JD, de Beer D, Amann R, Knittel K. Niche separation in bacterial communities and activities in porewater, loosely attached, and firmly attached fractions in permeable surface sediments. THE ISME JOURNAL 2024; 18:wrae159. [PMID: 39115410 PMCID: PMC11368169 DOI: 10.1093/ismejo/wrae159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 07/26/2024] [Accepted: 08/07/2024] [Indexed: 09/04/2024]
Abstract
Heterotrophic microbes are central to organic matter degradation and transformation in marine sediments. Currently, most investigations of benthic microbiomes do not differentiate between processes in the porewater and on the grains and, hence, only show a generalized picture of the community. This limits our understanding of the structure and functions of sediment microbiomes. To address this problem, we fractionated sandy surface sediment microbial communities from a coastal site in Isfjorden, Svalbard, into cells associated with the porewater, loosely attached to grains, and firmly attached to grains; we found dissimilar bacterial communities and metabolic activities in these fractions. Most (84%-89%) of the cells were firmly attached, and this fraction comprised more anaerobes, such as sulfate reducers, than the other fractions. The porewater and loosely attached fractions (3% and 8%-13% of cells, respectively) had more aerobic heterotrophs. These two fractions generally showed a higher frequency of dividing cells, polysaccharide (laminarin) hydrolysis rates, and per-cell O2 consumption than the firmly attached cells. Thus, the different fractions occupy distinct niches within surface sediments: the firmly attached fraction is potentially made of cells colonizing areas on the grain that are protected from abrasion, but might be more diffusion-limited for organic matter and electron acceptors. In contrast, the porewater and loosely attached fractions are less resource-limited and have faster growth. Their cell numbers are kept low possibly through abrasion and exposure to grazers. Differences in community composition and activity of these cell fractions point to their distinct roles and contributions to carbon cycling within surface sediments.
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Affiliation(s)
- Chyrene Moncada
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany
| | - Carol Arnosti
- Department of Earth, Marine, and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Jan D Brüwer
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany
| | - Dirk de Beer
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany
| | - Rudolf Amann
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany
| | - Katrin Knittel
- Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany
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11
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Li P, Liang W, Zhou Y, Yi Y, He C, Shi Q, He D. Hypoxia diversifies molecular composition of dissolved organic matter and enhances preservation of terrestrial organic carbon in the Yangtze River Estuary. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167661. [PMID: 37813254 DOI: 10.1016/j.scitotenv.2023.167661] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 10/11/2023]
Abstract
Dissolved organic matter (DOM) is an essential component of the global carbon cycle, and estuaries link the rivers and the oceans, thus playing important roles in land-ocean DOM transformation and transport. However, the effects of hypoxia on DOM transport and fate in estuaries and coastal oceans remains poorly understood. To address this gap, we characterized the molecular composition of DOM in bottom water (BW) and sediment porewater (PW) at hypoxic and non-hypoxic sites in the Yangtze River Estuary (YRE) using ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry. Our results showed significant differences in DOM molecular composition between hypoxic and non-hypoxic areas for both BW and PW. Specifically, DOM in hypoxic sites was more recalcitrant than that in non-hypoxic areas for both BW and PW, with lower H/C, and higher O/C, double bond equivalent, and modified aromaticity index. The presence of higher polyphenols, and black carbon in hypoxic areas suggested that hypoxic conditions could facilitate the preservation of terrestrial organic matter. Furthermore, we identified a much higher number of hypoxia-unique formulas than ocean-non-hypoxia-unique formulas, indicating that hypoxia could diversify the DOM pool. Within hypoxia-unique formulas for PW, both biologically labile (unsaturated aliphatic compounds and peptides) and recalcitrant formulas (carboxyl-rich alicyclic molecules) were found, suggesting that hypoxia could facilitate the preservation of labile formulas and the production of recalcitrant formulas. In addition, we formulated that the sulfurization is more important in PW than BW in hypoxic areas based on the higher dissolved organic sulfur (DOS) abundance and larger number of hypoxia-only formulas in hypoxic PW, and also the precursor analysis results. Overall, our study provides insights into the effect of hypoxia on the molecular characteristics and preservation of DOM in estuaries and coastal oceans, highlighting the importance of considering hypoxia in understanding the biogeochemical processes of these ecosystems.
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Affiliation(s)
- Penghui Li
- School of Marine Sciences, Sun Yat-sen University, Zhuhai 519082, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai 519082, China
| | - Wenzhao Liang
- Department of Ocean Science, Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yuping Zhou
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, China
| | - Yuanbi Yi
- Department of Ocean Science, Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Chen He
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Changping District, Beijing 102249, China
| | - Quan Shi
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Changping District, Beijing 102249, China
| | - Ding He
- Department of Ocean Science, Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong, China; State Key Laboratory of Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
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12
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Parsons RJ, Liu S, Longnecker K, Yongblah K, Johnson C, Bolaños LM, Comstock J, Opalk K, Kido Soule MC, Garley R, Carlson CA, Temperton B, Bates NR. Suboxic DOM is bioavailable to surface prokaryotes in a simulated overturn of an oxygen minimum zone, Devil's Hole, Bermuda. Front Microbiol 2023; 14:1287477. [PMID: 38179459 PMCID: PMC10765504 DOI: 10.3389/fmicb.2023.1287477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 11/17/2023] [Indexed: 01/06/2024] Open
Abstract
Oxygen minimum zones (OMZs) are expanding due to increased sea surface temperatures, subsequent increased oxygen demand through respiration, reduced oxygen solubility, and thermal stratification driven in part by anthropogenic climate change. Devil's Hole, Bermuda is a model ecosystem to study OMZ microbial biogeochemistry because the formation and subsequent overturn of the suboxic zone occur annually. During thermally driven stratification, suboxic conditions develop, with organic matter and nutrients accumulating at depth. In this study, the bioavailability of the accumulated dissolved organic carbon (DOC) and the microbial community response to reoxygenation of suboxic waters was assessed using a simulated overturn experiment. The surface inoculated prokaryotic community responded to the deep (formerly suboxic) 0.2 μm filtrate with cell densities increasing 2.5-fold over 6 days while removing 5 μmol L-1 of DOC. After 12 days, the surface community began to shift, and DOC quality became less diagenetically altered along with an increase in SAR202, a Chloroflexi that can degrade recalcitrant dissolved organic matter (DOM). Labile DOC production after 12 days coincided with an increase of Nitrosopumilales, a chemoautotrophic ammonia oxidizing archaea (AOA) that converts ammonia to nitrite based on the ammonia monooxygenase (amoA) gene copy number and nutrient data. In comparison, the inoculation of the deep anaerobic prokaryotic community into surface 0.2 μm filtrate demonstrated a die-off of 25.5% of the initial inoculum community followed by a 1.5-fold increase in cell densities over 6 days. Within 2 days, the prokaryotic community shifted from a Chlorobiales dominated assemblage to a surface-like heterotrophic community devoid of Chlorobiales. The DOM quality changed to less diagenetically altered material and coincided with an increase in the ribulose-1,5-bisphosphate carboxylase/oxygenase form I (cbbL) gene number followed by an influx of labile DOM. Upon reoxygenation, the deep DOM that accumulated under suboxic conditions is bioavailable to surface prokaryotes that utilize the accumulated DOC initially before switching to a community that can both produce labile DOM via chemoautotrophy and degrade the more recalcitrant DOM.
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Affiliation(s)
- Rachel J. Parsons
- Microbial Ecology Laboratory, Bermuda Institute of Ocean Sciences, St. George’s, Bermuda
- Julie Ann Wrigley Global Futures Laboratory, School of Ocean Futures, Arizona State University, Tempe, AZ, United States
| | - Shuting Liu
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, California, CA, United States
- Department of Environmental and Sustainability Sciences, Kean University, Union, NJ, United States
| | - Krista Longnecker
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Kevin Yongblah
- Microbial Ecology Laboratory, Bermuda Institute of Ocean Sciences, St. George’s, Bermuda
- Department of Biology, University of Syracuse, Syracuse, NY, United States
| | - Carys Johnson
- Microbial Ecology Laboratory, Bermuda Institute of Ocean Sciences, St. George’s, Bermuda
| | - Luis M. Bolaños
- School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Jacqueline Comstock
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, California, CA, United States
| | - Keri Opalk
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, California, CA, United States
| | - Melissa C. Kido Soule
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States
| | - Rebecca Garley
- Microbial Ecology Laboratory, Bermuda Institute of Ocean Sciences, St. George’s, Bermuda
- Julie Ann Wrigley Global Futures Laboratory, School of Ocean Futures, Arizona State University, Tempe, AZ, United States
| | - Craig A. Carlson
- Department of Ecology, Evolution and Marine Biology, Marine Science Institute, University of California, Santa Barbara, California, CA, United States
| | - Ben Temperton
- School of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Nicholas R. Bates
- Microbial Ecology Laboratory, Bermuda Institute of Ocean Sciences, St. George’s, Bermuda
- Julie Ann Wrigley Global Futures Laboratory, School of Ocean Futures, Arizona State University, Tempe, AZ, United States
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13
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Li H, Feng X, Xiong T, Shao W, Wu W, Zhang Y. Particulate Organic Carbon Released during Macroalgal Growth Has Significant Carbon Sequestration Potential in the Ocean. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:19723-19731. [PMID: 37963337 DOI: 10.1021/acs.est.3c04959] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
Substantial amounts of particulate organic carbon (POC) are released during macroalgal growth; however, the fate of these POCs and their carbon sequestration effects remain unclear. Here, field investigations found that Ulva prolifera caused a significant increase of POC in seawater below the surface during a macroalgal bloom. However, laboratory simulations revealed that 77.6% of these POC was easily degraded by microorganisms in a short period of time, concurrently resulting in the production of dissolved organic carbon (DOC) from POC transformation. Over a period of 3 months, the bioavailable components of macroalgae-released POC and POC-transformed DOC were degraded, leaving 39.6% of the antibiodegradable substances composed of biorecalcitrant POC and biorecalcitrant DOC. However, although the biorecalcitrant POC was rich in humic-like components resisting biodegradation, the biorecalcitrant POC exhibited greater sensitivity to photodegradation than biorecalcitrant DOC. The photodegradation removal rate of biorecalcitrant POC (14.1%) was more than 10 times that of biorecalcitrant DOC (1.2%). Ultimately, a substantial portion (36.3%) of the POC released by growing macroalgae could potentially perform long-term carbon sequestration after conversion to recalcitrant POC and recalcitrant DOC, and these inert carbons derived from macroalgal POC have been previously ignored and should also be included in macroalgal carbon sequestration accounting.
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Affiliation(s)
- Hongmei Li
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
| | - Xiuting Feng
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tianqi Xiong
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
| | - Wei Shao
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
| | - Wangchi Wu
- Qingdao Municipal Bureau of Ecology and Environment, Qingdao 266003, China
| | - Yongyu Zhang
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
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14
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Kontoyiannis H, Pavlidou A, Zeri C, Krasakopoulou E, Simboura N, Hatzianestis I, Papadopoulos VP, Rousselaki E, Asimakopoulou G, Siokou I. Thirty years of a bottom oxygen depletion-renewal cycle in the coastal yet deep environment of the West Saronikos Gulf (Greece): Its drivers and the impact on the benthic communities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 902:166025. [PMID: 37562620 DOI: 10.1016/j.scitotenv.2023.166025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 08/01/2023] [Accepted: 08/01/2023] [Indexed: 08/12/2023]
Abstract
In the period 1987-2017, a series of physical and chemical measurements related to oxygen variability at a trough area with a maximum depth of ~420 m in the West Saronikos Gulf, reveal the following: In the early 90s, deep winter mixing occurred resulting in an oxygenation down to ~420 m followed by an oxygen decline. This decline reached near-bottom hypoxic conditions (O2 < ~62 μM (μmol/L)) after 1998, while a denitrification phase occurred after 2000 and a complete bottom anoxia in 2005. In June 2012, an oxygenation down to ~350 m was detected that most likely occurred in winter 2012. The 2012 oxygenation raised the until-then anoxic bottom concentrations to hypoxic ones in the years towards 2017 via vertical diffusive oxygen transfer. Observations of the benthic communities during the hypoxia, severe hypoxia (O2 < ~15 μM) and oxygen recovery phases showed a peak of opportunists in the hypoxia and a long faunal depletion in the severe hypoxia phases. A reversal in the benthic community structure appeared after the oxygenation of 2012 with the (re)appearance of opportunists while, in 2017, the community showed signs of retreat to earlier stages. The main anthropogenic pressure that could tentatively affect the oxygen concentration in the study area is posed by the Athens treated-sewage outfall at ~40 km away from the trough, which inputs organic matter into the Saronikos Gulf through effluent water of reduced salinity that, in addition, may alter the stratification opposing the vertical mixing. We show that the treated sewage output had no influence on a) the stratification, b) the particulate and dissolved organic carbon and c) the sewage-derived organic matter. Instead, the long-term dissolved oxygen variability with the deep renewal events was mostly driven by the large-scale atmosphere-ocean conditions (heat exchange and evaporation-minus-precipitation budget) that determine the hydrographic characteristics and the winter mixing.
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Affiliation(s)
| | - Alexandra Pavlidou
- Hellenic Centre for Marine Research, Institute of Oceanography, Anavyssos, Greece.
| | - Christina Zeri
- Hellenic Centre for Marine Research, Institute of Oceanography, Anavyssos, Greece
| | | | - Nomiki Simboura
- Hellenic Centre for Marine Research, Institute of Oceanography, Anavyssos, Greece
| | - Ioannis Hatzianestis
- Hellenic Centre for Marine Research, Institute of Oceanography, Anavyssos, Greece
| | | | - Eleni Rousselaki
- Hellenic Centre for Marine Research, Institute of Oceanography, Anavyssos, Greece
| | | | - Ioanna Siokou
- Hellenic Centre for Marine Research, Institute of Oceanography, Anavyssos, Greece
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15
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Jin H, Xu J, Peng Y, Xin J, Peng N, Li Y, Huang J, Zhang R, Li C, Wu Y, Gong B, Wang R. Impacts of landscape patterns on plant species diversity at a global scale. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 896:165193. [PMID: 37406683 DOI: 10.1016/j.scitotenv.2023.165193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/07/2023]
Abstract
Landscape patterns are important drivers of biodiversity. Owing to differences in vegetation types, sampling methods, diversity measures, spatial scales, and landscape levels, the impact of landscape patterns on biodiversity remains widely debated. Using a global standardized plant community database and land use and land cover maps at 30-m resolution, for the period 1990-2017, we calculated plant species α- and β-diversity, and landscape metrics at patch- and landscape-levels, and discerned the direct and indirect impacts of landscape patterns on plant species diversity based on environmental factors, namely climate, spatial features, and human disturbance. We found that landscape patterns exhibited the main indirect effects, whereas climate factors exhibited dominant direct effects on plant α-diversity via the direct effects of patch patterns and functional traits. With respect to β-diversity, landscape-level patterns exerted more direct than indirect effects. These effects are strongly dependent on scale. Landscape- and patch-level patterns had opposite effects on plant diversity, depending on their composition and spatial structure, demonstrating that their effects could be mediated by one another. The adaptation of plants to landscape patterns is mainly through variations in leaf area, plant height, specific leaf area, stem density, seed biomass, and other seed-dispersal traits, which vary across vegetation types. Our findings highlight the importance of functional traits and diversity in understanding the mechanism by which landscape patterns influence plant species diversity; accordingly, we recommend balancing the spatial structure of patch- and landscape-level patterns to enhance variation in functional traits, and, ultimately, to maintain global plant diversity.
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Affiliation(s)
- Hanni Jin
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Jing Xu
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Yu Peng
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China.
| | - Jiaxun Xin
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Nanyi Peng
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Yanyi Li
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Jijiao Huang
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Ruiqiang Zhang
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Chen Li
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Yimeng Wu
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Bingzhang Gong
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Ronghui Wang
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
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16
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George AB, Wang T, Maslov S. Functional convergence in slow-growing microbial communities arises from thermodynamic constraints. THE ISME JOURNAL 2023; 17:1482-1494. [PMID: 37380829 PMCID: PMC10432562 DOI: 10.1038/s41396-023-01455-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 05/15/2023] [Accepted: 06/12/2023] [Indexed: 06/30/2023]
Abstract
The dynamics of microbial communities is complex, determined by competition for metabolic substrates and cross-feeding of byproducts. Species in the community grow by harvesting energy from chemical reactions that transform substrates to products. In many anoxic environments, these reactions are close to thermodynamic equilibrium and growth is slow. To understand the community structure in these energy-limited environments, we developed a microbial community consumer-resource model incorporating energetic and thermodynamic constraints on an interconnected metabolic network. The central element of the model is product inhibition, meaning that microbial growth may be limited not only by depletion of metabolic substrates but also by accumulation of products. We demonstrate that these additional constraints on microbial growth cause a convergence in the structure and function of the community metabolic network-independent of species composition and biochemical details-providing a possible explanation for convergence of community function despite taxonomic variation observed in many natural and industrial environments. Furthermore, we discovered that the structure of community metabolic network is governed by the thermodynamic principle of maximum free energy dissipation. Our results predict the decrease of functional convergence in faster growing communities, which we validate by analyzing experimental data from anaerobic digesters. Overall, the work demonstrates how universal thermodynamic principles may constrain community metabolism and explain observed functional convergence in microbial communities.
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Affiliation(s)
- Ashish B George
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Tong Wang
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Sergei Maslov
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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17
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Chen X, Cai R, Zhuo X, Chen Q, He C, Sun J, Zhang Y, Zheng Q, Shi Q, Jiao N. Niche differentiation of microbial community shapes vertical distribution of recalcitrant dissolved organic matter in deep-sea sediments. ENVIRONMENT INTERNATIONAL 2023; 178:108080. [PMID: 37429058 DOI: 10.1016/j.envint.2023.108080] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 06/29/2023] [Accepted: 06/29/2023] [Indexed: 07/12/2023]
Abstract
Sedimentary organic matter provides carbon substrates and energy sources for microorganisms, which drive benthic biogeochemical processes and in turn modify the quantity and quality of dissolved organic matter (DOM). However, the molecular composition and distribution of DOM and its interactions with microbes in deep-sea sediments remain poorly understood. Here, molecular composition of DOM and its relationship with microbes were analyzed in samples collected from two sediment cores (∼40 cm below the sea floor), at depths of 1157 and 2253 m from the South China Sea. Results show that niche differentiation was observed on a fine scale in different sediment layers, with Proteobacteria and Nitrososphaeria dominating the shallow sediments (0-6 cm) and Chloroflexi and Bathyarchaeia prevailing in deeper sediments (6-40 cm), indicating correspondence of microbial community composition with both geographical isolation and the availability of organic matter. An intimate link between the DOM composition and microbial community further indicates that, microbial mineralization of fresh organic matter in the shallow layer potentially resulted in the accumulation of recalcitrant DOM (RDOM), while relatively low abundance of RDOM was linked to anaerobic microbial utilization in deeper sediment layers. In addition, higher RDOM abundance in the overlying water, as compared to that in the surface sediment, suggests that sediment might be a source of deep-sea RDOM. These results emphasize the close relation between the distribution of sediment DOM and different microbial community, laying a foundation for understanding the complex dynamics of RDOM in deep-sea sediment and water column.
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Affiliation(s)
- Xiaoxia Chen
- College of Ocean and Earth Sciences and State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China; Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen 361005, China
| | - Ruanhong Cai
- College of Ocean and Earth Sciences and State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China; Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen 361005, China.
| | - Xiaocun Zhuo
- State Key Laboratory of Heavy Oil Processing, Research Centre for Geomicrobial Resources and Application, China University of Petroleum, Beijing 102249, China
| | - Quanrui Chen
- College of Ocean and Earth Sciences and State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China; Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen 361005, China
| | - Chen He
- State Key Laboratory of Heavy Oil Processing, Research Centre for Geomicrobial Resources and Application, China University of Petroleum, Beijing 102249, China
| | - Jia Sun
- College of Ocean and Earth Sciences and State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China; Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen 361005, China
| | - Yao Zhang
- College of Ocean and Earth Sciences and State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China; Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen 361005, China
| | - Qiang Zheng
- College of Ocean and Earth Sciences and State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China; Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen 361005, China
| | - Quan Shi
- State Key Laboratory of Heavy Oil Processing, Research Centre for Geomicrobial Resources and Application, China University of Petroleum, Beijing 102249, China
| | - Nianzhi Jiao
- College of Ocean and Earth Sciences and State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China; Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen 361005, China; Carbon Neutral Innovation Research Center, Xiamen University, Xiamen 361005, China.
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18
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Liu J, Wang Y, Jaccard SL, Wang N, Gong X, Fang N, Bao R. Pre-aged terrigenous organic carbon biases ocean ventilation-age reconstructions in the North Atlantic. Nat Commun 2023; 14:3788. [PMID: 37355680 DOI: 10.1038/s41467-023-39490-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 06/15/2023] [Indexed: 06/26/2023] Open
Abstract
Changes in ocean ventilation have been pivotal in regulating carbon sequestration and release on centennial to millennial timescales. However, paleoceanographic reconstructions documenting changes in deep-ocean ventilation using 14C dating, may bear multidimensional explanations, obfuscating the roles of ocean ventilation played on climate evolution. Here, we show that previously inferred poorly ventilated conditions in the North Atlantic were linked to enhanced pre-aged organic carbon (OC) input during Heinrich Stadial 1 (HS1). The 14C age of sedimentary OC was approximately 13,345 ± 692 years older than the coeval foraminifera in the central North Atlantic during HS1, which is coupled to a ventilation age of 5,169 ± 660 years. Old OC was mainly of terrigenous origin and exported to the North Atlantic by ice-rafting. Remineralization of old terrigenous OC in the ocean may have contributed to, at least in part, the anomalously old ventilation ages reported for the high-latitude North Atlantic during HS1.
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Affiliation(s)
- Jingyu Liu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, PR China
- Laboratory for Marine Ecology and Environmental Science, Pilot Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, PR China
| | - Yipeng Wang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, PR China
- Laboratory for Marine Ecology and Environmental Science, Pilot Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, PR China
| | - Samuel L Jaccard
- Institute of Earth Sciences, University of Lausanne, Lausanne, CH-1015, Switzerland
- Oeschger Center for Climate Change Research, University of Bern, Bern, CH-3012, Switzerland
| | - Nan Wang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Lab of Submarine Geosciences and Prospecting Techniques, Ministry of Education and College of Marine Geosciences, Ocean University of China, Qingdao, 266100, PR China
| | - Xun Gong
- Institute for Advanced Marine Research, China University of Geosciences, Guangzhou, PR China
- Shandong Provincial Key Laboratory of Computer Networks, Qilu University of Technology (Shandong Academy of Sciences), Jinan, PR China
| | - Nianqiao Fang
- School of Ocean Sciences, China University of Geosciences (Beijing), 100083, Beijing, PR China
| | - Rui Bao
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, PR China.
- Laboratory for Marine Ecology and Environmental Science, Pilot Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, PR China.
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19
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Simonović N, Dominović I, Marguš M, Matek A, Ljubešić Z, Ciglenečki I. Dynamics of organic matter in the changing environment of a stratified marine lake over two decades. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 865:161076. [PMID: 36565878 DOI: 10.1016/j.scitotenv.2022.161076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/16/2022] [Accepted: 12/16/2022] [Indexed: 06/17/2023]
Abstract
The marine lake (Rogoznica Lake), which fluctuates between stratified and holomictic conditions, is a unique environment on the eastern Adriatic coast affected by environmental changes. These changes are reflected in the warming of the water column, the apparent deoxygenation of the epilimnion, and the accumulation of organic matter (OM), toxic sulfide, and ammonium in the anoxic hypolimnion. Since the early 1990s, the volume of anoxic water has increased as the chemocline has moved to the surface water layer. A trend toward enrichment of refractory dissolved organic carbon (DOC) was observed in the anoxic hypolimnion, while a decreasing trend was observed in the oxic epilimnion in the spring DOC. At the same time, the most reactive surface-active fraction of DOC showed the opposite trend. In addition, there is evidence of accumulation of particulate organic carbon (POC) in the water column, followed by an increase in the fraction of POC in total organic carbon (TOC). On a multi-year scale (1996-2020), this work presents a unique time series of the dynamics of OM in the stratified marine system, showing a significant change in its quantity and quality due to climate and environmental variability. DOC-normalized surfactant activity is shown to be a good indicator of environmental change.
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Affiliation(s)
- Niki Simonović
- Laboratory for Physical Oceanography and Chemistry of Aquatic Systems, Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia
| | - Iva Dominović
- Laboratory for Physical Oceanography and Chemistry of Aquatic Systems, Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia
| | - Marija Marguš
- Laboratory for Physical Oceanography and Chemistry of Aquatic Systems, Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia
| | - Antonija Matek
- Department of Biology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000 Zagreb, Croatia
| | - Zrinka Ljubešić
- Department of Biology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000 Zagreb, Croatia
| | - Irena Ciglenečki
- Laboratory for Physical Oceanography and Chemistry of Aquatic Systems, Division for Marine and Environmental Research, Ruđer Bošković Institute, Zagreb, Croatia.
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20
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Stüeken EE, Kirsimäe K, Lepland A, Prave AR. Hydrothermal Regeneration of Ammonium as a Basin-Scale Driver of Primary Productivity. ASTROBIOLOGY 2023; 23:195-212. [PMID: 36577019 DOI: 10.1089/ast.2021.0203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Hydrothermal vents are important targets in the search for life on other planets due to their potential to generate key catalytic surfaces and organic compounds for biogenesis. Less well studied, however, is the role of hydrothermal circulation in maintaining a biosphere beyond its origin. In this study, we explored this question with analyses of organic carbon, nitrogen abundances, and isotopic ratios from the Paleoproterozoic Zaonega Formation (2.0 Ga), NW Russia, which is composed of interbedded sedimentary and mafic igneous rocks. Previous studies have documented mobilization of hydrocarbons, likely associated with magmatic intrusions into unconsolidated sediments. The igneous bodies are extensively hydrothermally altered. Our data reveal strong nitrogen enrichments of up to 0.6 wt % in these altered igneous rocks, suggesting that the hydrothermal fluids carried ammonium concentrations in the millimolar range, which is consistent with some modern hydrothermal vents. Furthermore, large isotopic offsets of ∼10‰ between organic-bound and silicate-bound nitrogen are most parsimoniously explained by partial biological uptake of ammonium from the vent fluid. Our results, therefore, show that hydrothermal activity in ancient marine basins could provide a locally high flux of recycled nitrogen. Hydrothermal nutrient recycling may thus be an important mechanism for maintaining a large biosphere on anoxic worlds.
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Affiliation(s)
- Eva E Stüeken
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, United Kingdom
| | - Kalle Kirsimäe
- Department of Geology, University of Tartu, Tartu, Estonia
| | - Aivo Lepland
- Department of Geology, University of Tartu, Tartu, Estonia
- Geological Survey of Norway, Trondheim, Norway
- Institute of Geology, Tallinn University of Technology, Tallinn, Estonia
| | - Anthony R Prave
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, United Kingdom
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21
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Seasonal Hypoxia Enhances Benthic Nitrogen Fixation and Shapes Specific Diazotrophic Community in the Eutrophic Marine Ranch. Processes (Basel) 2023. [DOI: 10.3390/pr11010138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Recently, a growing number of studies have confirmed that biological nitrogen fixation is also an important reactive nitrogen source in coastal regions. However, how benthic nitrogen fixation and diazotrophic community in coastal regions respond to seasonal hypoxia remains largely unknown. In this study, we investigated the spatiotemporal pattern of potential nitrogen fixation rate and diazotrophic abundance and community in sediments of a eutrophic marine ranch experiencing summer hypoxia using 15N tracing and high throughput sequencing techniques. The results showed that potential nitrogen fixation rates ranged from 0.013 to 10.199 μmol kg−1 h−1, and were significantly enhanced by summer hypoxia (ANOVA, p < 0.05). However, nifH gene abundance peaked in June. The diazotrophic community was dominated by Geobacteraceae (>60%), followed by Desulfobulbaceae (13.61%). Bottom water oxygen, pH, Chl-a concentration, and sediment NH4+ significantly regulated benthic nitrogen fixation, while the variation of diazotrophic community was explained by sediment TOC, TN, and Fe content (p < 0.05). This study highlighted that hypoxia stimulated benthic nitrogen fixation, which counteracted the nitrogen removal by denitrification and anammox, and could further aggregate eutrophication of the coastal marine ranch. Moreover, the result emphasized the importance of nitrogen fixation in coastal regions for the global N budget.
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22
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Guo Y, Wu C, Sun J. Pathogenic bacteria significantly increased under oxygen depletion in coastal waters: A continuous observation in the central Bohai Sea. Front Microbiol 2022; 13:1035904. [DOI: 10.3389/fmicb.2022.1035904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 10/19/2022] [Indexed: 11/22/2022] Open
Abstract
The spread of pathogenic bacteria in coastal waters endangers the health of the local people and jeopardizes the safety of the marine environment. However, their dynamics during seasonal hypoxia in the Bohai Sea (BHS) have not been studied. Here, pathogenic bacteria were detected from the 16S rRNA gene sequencing database and were used to explore their dynamics and driving factors with the progressively deoxygenating in the BHS. Our results showed that pathogenic bacteria were detected in all samples, accounting for 0.13 to 24.65% of the total number of prokaryotic sequences in each sample. Pathogenic Proteobacteria was dominated in all samples, followed by Firmicutes, Actinobacteria, Tenericutes, and Bacteroidetes, etc. β-diversity analysis showed that pathogenic bacteria are highly temporally heterogeneous and regulated by environmental factors. According to RDA analysis, these variations may be influenced by salinity, ammonia, DO, phosphate, silicate, and Chl a. Additionally, pathogenic bacteria in surface water and hypoxia zone were found to be significantly separated in August. The vertical distribution of pathogenic bacterial communities is influenced by several variables, including DO and nutrition. It is noteworthy that the hypoxia zones increase the abundance of certain pathogenic genera, especially Vibrio and Arcobacter, and the stability of the pathogenic bacterial community increased from May to August. These phenomena indicate that the central Bohai Sea is threatened by an increasingly serious pathogenic community from May to August. And the developing hypoxia zone in the future may intensify this phenomenon and pose a more serious threat to human health. This study provides new insight into the changes of pathogenic bacteria in aquatic ecosystems and may help to make effective policies to control the spread of pathogenic bacteria.
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23
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M K VS, Joseph S, P S A, Ghermandi A, Kumar A. A coastal Ramsar site on transition to hypoxia and tracking pollution sources: a case study of south-west coast of India. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 195:45. [PMID: 36305948 DOI: 10.1007/s10661-022-10602-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
Coastal lakes and estuaries are considered economic drivers for coastal communities by delivering invaluable economic and ecosystem services. The coastal ecosystems are facing recurrent hypoxia events (dissolved oxygen; DO < 2.0 mg L-1) and are emerging as a major threat to ecosystem structure and functioning. The Ashtamudi Lake, (area = 56 km2), is one of the Ramsar sites in the State of Kerala and located on the SW coast of India. The waterways are extensively used for backwater tourism and for fishery activities. This paper discusses the spatio-temporal variation of water quality attributes with emphasis on hypoxia during non-monsoon and monsoon seasons. The extent of hypoxia on fishery diversity was discussed. The Southern Zone, adjacent to the urban area, shows the hypoxic condition with higher concentration of BOD, NO3-N, and NH4-N. The hypoxic condition is largely limited to the Southern Zone in both seasons. The occurrence of low DO in the lake is highly related to salinity and organic load in the lake system. The tracking of pollution sources in the lake system was also done through identification of pollution potential zones and found that catchments adjacent to Southern and Western Zones (urban regions) are the major source of pollution. The study suggests that hypoxia is chiefly attributed to anthropogenic interventions in the form of discharge of wastes into the lake causing overloading of nutrients and organic effluents, decrease in the freshwater supply, the absence of proper freshwater mixing or dilution, and effluent discharge from nearby urban centers.
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Affiliation(s)
- Vishnu Sagar M K
- Department of Environmental Sciences, University of Kerala, Thiruvananthapuram, Kerala, India, 695581
| | - Sabu Joseph
- Department of Environmental Sciences, University of Kerala, Thiruvananthapuram, Kerala, India, 695581.
| | - Arunkumar P S
- Department of Environmental Sciences, University of Kerala, Thiruvananthapuram, Kerala, India, 695581
| | - Andrea Ghermandi
- Department of Natural Resources and Environmental Management, University of Haifa, Haifa, Israel
| | - Amit Kumar
- School of Hydrology and Water Resources, Nanjing University of Information Science and Technology, Nanjing, 210044, China
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24
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Fonseca A, Espinoza C, Nielsen LP, Marshall IPG, Gallardo VA. Bacterial community of sediments under the Eastern Boundary Current System shows high microdiversity and a latitudinal spatial pattern. Front Microbiol 2022; 13:1016418. [PMID: 36246233 PMCID: PMC9561620 DOI: 10.3389/fmicb.2022.1016418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 09/16/2022] [Indexed: 11/13/2022] Open
Abstract
The sediments under the Oxygen Minimum Zone of the Eastern Boundary Current System (EBCS) along Central-South Peru and North-Central Chile, known as Humboldt Sulfuretum (HS), is an organic-matter-rich benthic habitat, where bacteria process a variety of sulfur compounds under low dissolved-oxygen concentrations, and high sulfide and nitrate levels. This study addressed the structure, diversity and spatial distribution patterns of the HS bacterial community along Northern and South-Central Chile using 16S rRNA gene amplicon sequencing. The results show that during the field study period, the community was dominated by sulfur-associated bacteria. Indeed, the most abundant phylum was Desulfobacterota, while Sva0081 sedimentary group, of the family Desulfosarcinaceae (the most abundant family), which includes sulfate-reducer and H2 scavenger bacteria, was the most abundant genus. Furthermore, a spatial pattern was unveiled along the study area to which the family Desulfobulbaceae contributed the most to the spatial variance, which encompasses 42 uncharacterized amplicon sequence variants (ASVs), three assigned to Ca. Electrothrix and two to Desulfobulbus. Moreover, a very high microdiversity was found, since only 3.7% of the ASVs were shared among localities, reflecting a highly diverse and mature community.
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Affiliation(s)
- Alexis Fonseca
- Center for Electromicrobiology, Department of Biology, Aarhus University, Aarhus, Denmark
- *Correspondence: Alexis Fonseca,
| | - Carola Espinoza
- Department of Oceanography, University of Concepción, Concepción, Chile
| | - Lars Peter Nielsen
- Center for Electromicrobiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Ian P. G. Marshall
- Center for Electromicrobiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Victor A. Gallardo
- Department of Oceanography, University of Concepción, Concepción, Chile
- Victor A. Gallardo,
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25
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Deng L, Meile C, Fiskal A, Bölsterli D, Han X, Gajendra N, Dubois N, Bernasconi SM, Lever MA. Deposit-feeding worms control subsurface ecosystem functioning in intertidal sediment with strong physical forcing. PNAS NEXUS 2022; 1:pgac146. [PMID: 36714871 PMCID: PMC9802194 DOI: 10.1093/pnasnexus/pgac146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 07/25/2022] [Indexed: 06/18/2023]
Abstract
Intertidal sands are global hotspots of terrestrial and marine carbon cycling with strong hydrodynamic forcing by waves and tides and high macrofaunal activity. Yet, the relative importance of hydrodynamics and macrofauna in controlling these ecosystems remains unclear. Here, we compare geochemical gradients and bacterial, archaeal, and eukaryotic gene sequences in intertidal sands dominated by subsurface deposit-feeding worms (Abarenicola pacifica) to adjacent worm-free areas. We show that hydrodynamic forcing controls organismal assemblages in surface sediments, while in deeper layers selective feeding by worms on fine, algae-rich particles strongly decreases the abundance and richness of all three domains. In these deeper layers, bacterial and eukaryotic network connectivity decreases, while percentages of clades involved in degradation of refractory organic matter, oxidative nitrogen, and sulfur cycling increase. Our findings reveal macrofaunal activity as the key driver of biological community structure and functioning, that in turn influence carbon cycling in intertidal sands below the mainly physically controlled surface layer.
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Affiliation(s)
| | - Christof Meile
- Department of Marine Sciences, University of Georgia, 325 Sanford Drive, Athens, GA 30602, USA
| | | | - Damian Bölsterli
- Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology, Zurich (ETH Zurich), Universitätstrasse 16, 8092 Zurich, Switzerland
| | | | - Niroshan Gajendra
- Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology, Zurich (ETH Zurich), Universitätstrasse 16, 8092 Zurich, Switzerland
| | - Nathalie Dubois
- Department of Surface Waters - Research and Management, Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Überlandstrasse 133, 8600 Dübendorf, Switzerland
- Department of Earth Sciences, Swiss Federal Institute of Technology, Zurich (ETH Zurich), Sonneggstrasse 5, 8092 Zürich, Switzerland
| | - Stefano M Bernasconi
- Department of Earth Sciences, Swiss Federal Institute of Technology, Zurich (ETH Zurich), Sonneggstrasse 5, 8092 Zürich, Switzerland
| | - Mark A Lever
- Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology, Zurich (ETH Zurich), Universitätstrasse 16, 8092 Zurich, Switzerland
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26
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Wang J, Guo X, Li Y, Song G, Zhao L. Understanding the Variation of Bacteria in Response to Summertime Oxygen Depletion in Water Column of Bohai Sea. Front Microbiol 2022; 13:890973. [PMID: 35756048 PMCID: PMC9221365 DOI: 10.3389/fmicb.2022.890973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/05/2022] [Indexed: 11/14/2022] Open
Abstract
Aiming to reveal the variation in bacteria community under oxygen depletion formed every summer in water column of central Bohai Sea, a time-scenario sampling from June to August in 2018 at a 20-day interval along one inshore-offshore transect was settled. Water samples were collected at the surface, middle, and bottom layer and then analyzed by high-throughput sequencing targeting both 16S rRNA and nosZ genes. Compared to the surface and middle water, oxygen depletion occurred at bottom layer in August. In top two layers, Cyanobacteria dominated the bacterial community, whereas heterotrophic bacteria became dominant in bottom water of Bohai Sea. Based on the time scenario, distinct community separation was observed before (June and July) and after (August) oxygen depletion (p = 0.003). Vertically, strict stratification of nosZ gene was stably formed along 3 sampling layers. As a response to oxygen depletion, the diversity indices of both total bacteria (16S rRNA) and nosZ gene-encoded denitrification bacteria all increased, which indicated the intense potential of nitrogen lose when oxygen depleted. Dissolved oxygen (DO) was the key impacting factor on the community composition of total bacteria in June, whereas nutrients together with DO play the important roles in August for both total and denitrifying bacteria. The biotic impact was revealed further by strong correlations which showed between Cyanobacteria and heterotrophic bacteria in June from co-occurrence network analysis, which became weak in August when DO was depleted. This study discovered the variation in bacteria community in oxygen-depleted water with further effort to understand the potential role of denitrifying bacteria under oxygen depletion in Bohai Sea for the first time, which provided insights into the microbial response to the world-wide expanding oxygen depletion and their contributions in the ocean nitrogen cycling.
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Affiliation(s)
- Jing Wang
- Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity, Tianjin Normal University, Tianjin, China
| | - Xiaoxiao Guo
- Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity, Tianjin Normal University, Tianjin, China
| | - Yanying Li
- Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Key Laboratory of Conservation and Utilization of Animal Diversity, Tianjin Normal University, Tianjin, China
| | - Guisheng Song
- School of Marine Science and Technology, Tianjin University, Tianjin, China
| | - Liang Zhao
- College of Marine and Environmental Sciences, Tianjin University of Science and Technology, Tianjin, China
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27
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Han Y, Zhang M, Chen X, Zhai W, Tan E, Tang K. Transcriptomic evidences for microbial carbon and nitrogen cycles in the deoxygenated seawaters of Bohai Sea. ENVIRONMENT INTERNATIONAL 2022; 158:106889. [PMID: 34619534 DOI: 10.1016/j.envint.2021.106889] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 09/19/2021] [Accepted: 09/20/2021] [Indexed: 06/13/2023]
Abstract
Eutrophication-induced water deoxygenation occurs continually in coastal oceans, and alters community structure, metabolic processes, and the energy shunt, resulting in a major threat to the ecological environment. Seasonal deoxygenation events have occurred in the Bohai Sea (China), however, how these affect the functional activity of microorganisms remains unclear. Here, through the use of absolute quantification of 16S rRNA genes amplicon sequencing and metatranscriptomics approaches, we investigated the structure of the microbial community and the patterns of transcriptional activity in deoxygenated seawaters. The dominant phyla were Proteobacteria (average value, 1.4 × 106 copies ml-1), Cyanobacteria (3.7 × 105 copies ml-1), Bacteroidetes (2.7 × 105 copies ml-1), and the ammonia-oxidizing archaea Thaumarchaeota (1.9 × 105 copies ml-1). Among the various environmental factors, dissolved oxygen, pH and temperature displayed the most significant correlation with microbial community composition and functional activity. Metatranscriptomic data showed high transcriptional activity of Thaumarchaeota in the deoxygenated waters, with a significant increase in the expression of core genes representing ammonia oxidation, ammonia transport, and carbon fixation (3-hydroxypropionic acid/4-hydroxybutyric acid cycle) pathways. The transcripts of Cyanobacteria involved in photosynthesis and carbon fixation (Calvin-Benson-Bassham cycle) significantly decreased in low oxygen waters. Meanwhile, the transcripts for the ribulose bisphosphate carboxylase-encoding gene shifted from being assigned to photoautotrophic to chemoautotrophic organisms in surface and bottom waters, respectively. Moreover, the transcription profile indicated that heterotrophs play a critical role in transforming low-molecular-weight dissolved organic nitrogen. Elevated abundances of transcripts related to microbial antioxidant activity corresponded to an enhanced aerobic metabolism of Thaumarchaeota in the low oxygen seawater. In general, our transcriptional evidences showed a population increase of Thaumarchaeota, especially the coastal ecotype of ammonia oxidizers, in low oxygen aquatic environments, and indicated an enhanced contribution of chemolithoautotrophic carbon fixation to carbon flow.
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Affiliation(s)
- Yu Han
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, Fujian, PR China
| | - Mu Zhang
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, Fujian, PR China
| | - Xiaofeng Chen
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, Fujian, PR China
| | - Weidong Zhai
- Institute of Marine Science and Technology, Shandong University, Qingdao 266000, Shandong, PR China
| | - Ehui Tan
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou 570228, Hainan, PR China
| | - Kai Tang
- State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, Fujian, PR China.
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28
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Zhao D, Gao P, Xu L, Qu L, Han Y, Zheng L, Gong X. Disproportionate responses between free-living and particle-attached bacteria during the transition to oxygen-deficient zones in the Bohai Seawater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 791:148097. [PMID: 34412405 DOI: 10.1016/j.scitotenv.2021.148097] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/19/2021] [Accepted: 05/24/2021] [Indexed: 06/13/2023]
Abstract
The Bohai Sea has recently suffered several seasonal oxygen-deficiency, even hypoxia events during the summer. To better understand effects of dissolved oxygen (DO) concentration on the bacterial composition in particle attached (PA) and free living (FL) fractions during the transition from oxic water to low oxygen conditions, the bacterial communities under three different oxygen levels, i.e., high oxygen (HO, close to 100% O2 saturation), medium oxygen (MO, close to 75% O2 saturation), and low oxygen (LO, close to 50% O2 saturation) in the Bohai Sea were investigated using 16S rRNA amplicon sequencing. Fourteen water samples from 5 stations were collected during a cruise from August to September in 2018. The results showed that the sequences of Proteobacteria and Actinobacteriota jointly accounted for up to 74% across all 14 samples. The Shannon index in HO samples were significantly higher than in LO samples (P < 0.05), especially in PA communities. The composition of bacterial communities varied by oxygen concentration in all samples, and the effect was more pronounced in the PA fraction, which indicates that the PA fraction was more sensitive to the change in oxygen concentration, possibly due to the tighter interactions in this community than in the FL fraction. This study provides novel insights into the distribution of bacterial communities, and clues for understanding the responses of bacterial communities in the Bohai Sea during the transition from the oxic to oxygen-deficient zones.
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Affiliation(s)
- Duo Zhao
- Institute of Marine Science and Technology, Shandong University, Qingdao, Shandong 266237, China
| | - Ping Gao
- MNR Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China
| | - Le Xu
- Institute of Marine Science and Technology, Shandong University, Qingdao, Shandong 266237, China
| | - Lingyun Qu
- MNR Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China
| | - Yajing Han
- Institute of Marine Science and Technology, Shandong University, Qingdao, Shandong 266237, China
| | - Liwen Zheng
- Institute of Marine Science and Technology, Shandong University, Qingdao, Shandong 266237, China
| | - Xianzhe Gong
- Institute of Marine Science and Technology, Shandong University, Qingdao, Shandong 266237, China.
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29
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Zárate A, Dorador C, Valdés J, Molina V, Icaza G, Pacheco AS, Castillo A. Benthic microbial diversity trends in response to heavy metals in an oxygen-deficient eutrophic bay of the Humboldt current system offshore the Atacama Desert. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 286:117281. [PMID: 33992902 DOI: 10.1016/j.envpol.2021.117281] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/25/2021] [Accepted: 04/27/2021] [Indexed: 06/12/2023]
Abstract
Mejillones Bay is a coastal ecosystem situated in an oxygen-deficient upwelling area impacted by mining activities in the coastal desert region of northern Chile, where conspicuous microbial life develops in the sediments. Herein, heavy metal (loid)s (HMs) such as Cu, Pb, As, Zn, Al, Fe, Cd, Mo, Ni and V as well as benthic microbial communities were studied using spectrometry and iTag-16 S rRNA sequencing. Samples were taken from two contrasting sedimentary localities in the Bay named Punta Rieles (PR) and Punta Chacaya (PC) within 10-50 m water-depth gradient. PR sediments were organic matter rich (21.1% of TOM at 50 m) and overlaid with low-oxygen waters (<0.06 ml O2/L bottom layer) compared with PC. In general, HMs like Al, Ni, Cd, As and Pb tended to increase in concentration with depth in PR, while the opposite pattern was observed in PC. In addition, PR presented a higher number of unique families (72) compared to PC (35). Among the top ten microbial families, Desulfobulbaceae (4.6% vs. 3.2%), Flavobacteriaceae (2.8% vs. 2.3%) and Anaerolineaceae (3.3% vs. 2.3%) dominated in PR, meanwhile Actinomarinales_Unclassified (8.1% vs. 4.2%) and Sandaracinaceae (4.4% vs. 2.0%) were more abundant in PC. Multivariate analyses confirmed that water depth-related variation was a good proxy for oxygen conditions and metal concentrations, explaining the structure of benthic microbial assemblages. Cd, Ni, As and Pb showed uniformly positive associations with communities that represented the keystone taxa in the co-occurrence network, including Anaerolineaceae, Thiotrichaceae, Desulfobulbaceae, Desulfarculaceae and Bacteroidales_unclassified communities. Collectively, these findings provide new insights for establishing the ecological interconnections of benthic microorganisms in response to metal contamination in a coastal upwelling environment.
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Affiliation(s)
- Ana Zárate
- Doctorado en Ciencias Aplicadas Mención Sistemas Marinos Costeros, Universidad de Antofagasta, Antofagasta, Chile; Laboratorio de Complejidad Microbiana y Ecología Funcional, Instituto Antofagasta & Centro de Bioingeniería y Biotecnología (CeBiB), Universidad de Antofagasta, Antofagasta, Chile; Humedales Del Caribe Colombiano, Universidad Del Atlántico, Barranquilla, Colombia.
| | - Cristina Dorador
- Laboratorio de Complejidad Microbiana y Ecología Funcional, Instituto Antofagasta & Centro de Bioingeniería y Biotecnología (CeBiB), Universidad de Antofagasta, Antofagasta, Chile; Departamento de Biotecnología, Facultad de Ciencias Del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile
| | - Jorge Valdés
- Laboratorio de Sedimentología y Paleoambientes, Instituto de Ciencias Naturales A. von Humboldt, Facultad de Ciencias Del Mar y de Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile
| | - Verónica Molina
- Departamento de Biología, Observatorio de Ecología Microbiana, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha, Valparaíso, Chile; HUB Ambiental UPLA, Universidad de Playa Ancha, Valparaíso, Chile
| | - Gonzalo Icaza
- Laboratorio de Complejidad Microbiana y Ecología Funcional, Instituto Antofagasta & Centro de Bioingeniería y Biotecnología (CeBiB), Universidad de Antofagasta, Antofagasta, Chile
| | - Aldo S Pacheco
- Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos, Lima, Peru
| | - Alexis Castillo
- Centro de Investigación y Estudios Avanzados Del Maule. Vicerrectoría de Investigación de Investigación y Posgrado. Universidad Católica Del Maule, Campus San Miguel. Talca, Chile
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Tardy V, Etienne D, Masclaux H, Essert V, Millet L, Verneaux V, Lyautey E. Spatial distribution of sediment archaeal and bacterial communities relates to the source of organic matter and hypoxia - a biogeographical study on Lake Remoray (France). FEMS Microbiol Ecol 2021; 97:6362600. [PMID: 34472595 DOI: 10.1093/femsec/fiab126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 08/31/2021] [Indexed: 11/15/2022] Open
Abstract
Bottom waters hypoxia spreads in many lakes worldwide causing severe consequences on whole lakes trophic network. Here, we aimed at understanding the origin of organic matter stored in the sediment compartment and the related diversity of sediment microbial communities in a lake with deoxygenated deep water layers. We used a geostatistical approach to map and compare both the variation of organic matter and microbial communities in sediment. Spatialisation of C/N ratio and δ13C signature of sediment organic matter suggested that Lake Remoray was characterized by an algal overproduction which could be related to an excess of nutrient due to the close lake-watershed connectivity. Three spatial patterns were observed for sediment microbial communities after the hypoxic event, each characterized by specific genetic structure, microbial diversity and composition. The relative abundance variation of dominant microbial groups across Lake Remoray such as Cyanobacteria, Gammaproteobacteria, Deltaproteobacteria and Chloroflexi provided us important information on the lake areas where hypoxia occurs. The presence of methanogenic species in the deeper part of the lake suggests important methane production during hypoxia period. Taken together, our results provide an extensive picture of microbial communities' distribution related to quantity and quality of organic matter in a seasonally hypoxic lake.
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Affiliation(s)
- Vincent Tardy
- Pôle R&D 'ECLA', 73376 Le Bourget-du-Lac, France.,Université Savoie Mont Blanc, INRAE, CARRTEL, 74200 Thonon-les-Bains, France
| | - David Etienne
- Pôle R&D 'ECLA', 73376 Le Bourget-du-Lac, France.,Université Savoie Mont Blanc, INRAE, CARRTEL, 74200 Thonon-les-Bains, France
| | - Hélène Masclaux
- Laboratoire Chrono-Environnement, UMR CNRS 6249, Univ. Bourgogne Franche-Comté, F-25000 Besançon, France
| | - Valentin Essert
- Laboratoire Chrono-Environnement, UMR CNRS 6249, Univ. Bourgogne Franche-Comté, F-25000 Besançon, France
| | - Laurent Millet
- Laboratoire Chrono-Environnement, UMR CNRS 6249, Univ. Bourgogne Franche-Comté, F-25000 Besançon, France
| | - Valérie Verneaux
- Laboratoire Chrono-Environnement, UMR CNRS 6249, Univ. Bourgogne Franche-Comté, F-25000 Besançon, France
| | - Emilie Lyautey
- Pôle R&D 'ECLA', 73376 Le Bourget-du-Lac, France.,Université Savoie Mont Blanc, INRAE, CARRTEL, 74200 Thonon-les-Bains, France
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Raven MR, Keil RG, Webb SM. Rapid, concurrent formation of organic sulfur and iron sulfides during experimental sulfurization of sinking marine particles. GLOBAL BIOGEOCHEMICAL CYCLES 2021; 35:e2021GB007062. [PMID: 35756156 PMCID: PMC9231689 DOI: 10.1029/2021gb007062] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Organic matter (OM) sulfurization can enhance the preservation and sequestration of carbon in anoxic sediments, and it has been observed in sinking marine particles from marine O2-deficient zones. The magnitude of this effect on carbon burial remains unclear, however, because the transformations that occur when sinking particles encounter sulfidic conditions remain undescribed. Here, we briefly expose sinking marine particles from the eastern tropical North Pacific O2-deficient zone to environmentally relevant sulfidic conditions (20°C, 0.5 mM [poly]sulfide, two days) and then characterize the resulting solid-phase organic and inorganic products in detail. During these experiments, the abundance of organic sulfur in both hydrolyzable and hydrolysis-resistant solids roughly triples, indicating extensive OM sulfurization. Lipids also sulfurize on this timescale, albeit less extensively. In all three pools, OM sulfurization produces organic monosulfides, thiols, and disulfides. Hydrolyzable sulfurization products appear within ≤ 200-μm regions of relatively homogenous composition that are suggestive of sulfurized extracellular polymeric substances (EPS). Concurrently, reactions with particulate iron oxyhydroxides generate low and fairly uniform concentrations of iron sulfide (FeS) within these same EPS-like materials. Iron oxyhydroxides were not fully consumed during the experiment, which demonstrates that organic materials can be competitive with reactive iron for sulfide. These experiments support the hypothesis that sinking, OM- and EPS-rich particles in a sulfidic water mass can sulfurize within days, potentially contributing to enhanced sedimentary carbon sequestration. Additionally, sulfur-isotope and chemical records of organic S and iron sulfides in sediments have the potential to incorporate signals from water column processes.
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Affiliation(s)
- M R Raven
- Department of Earth Science, University of California, Santa Barbara, Santa Barbara CA 93117, USA
| | - R G Keil
- School of Oceanography, University of Washington, Seattle WA 98195, USA
| | - S M Webb
- Stanford Synchrotron Radiation Lightsource, Stanford University, Menlo Park CA 94025, USA
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Unique chemical parameters and microbial activity lead to increased archaeological preservation at the Roman frontier site of Vindolanda, UK. Sci Rep 2021; 11:15837. [PMID: 34349140 PMCID: PMC8338975 DOI: 10.1038/s41598-021-94853-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 07/16/2021] [Indexed: 02/07/2023] Open
Abstract
Waterlogged burial conditions impact upon artefact preservation. One major determinant of preservation is presence and behaviour of microorganisms, however, unravelling the mechanisms, especially in waterlogged conditions is challenging. In this study, we analysed elemental composition, bacterial diversity and community structure from excavation trenches at the Roman Site of Vindolanda, Northumberland, UK, using pXRF and 16S rRNA gene amplicon sequencing. Excavation trenches provide information of different occupation periods. The results indicated that microbial communities were dominated by Firmicutes, Bacteroidetes and Proteobacteria at a phylum level. Samples which also had visible vivianite presence showed that there were marked increases in Methylophilus. Methylophilus might be associated with favourable preservation in these anaerobic conditions. More research is needed to clearly link the presence of Methylophilus with vivianite production. The study emphasises the need for further integration of chemical and microbiome approaches, especially in good preservation areas, to explore microbial and chemical degradation mechanisms.
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Gomez-Saez GV, Dittmar T, Holtappels M, Pohlabeln AM, Lichtschlag A, Schnetger B, Boetius A, Niggemann J. Sulfurization of dissolved organic matter in the anoxic water column of the Black Sea. SCIENCE ADVANCES 2021; 7:7/25/eabf6199. [PMID: 34134989 PMCID: PMC8208715 DOI: 10.1126/sciadv.abf6199] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 05/04/2021] [Indexed: 05/05/2023]
Abstract
Today's oceans store as much dissolved organic carbon (DOC) in the water column as there is CO2 in the atmosphere, and as such dissolved organic matter (DOM) is an important component of the global carbon cycle. It was shown that in anoxic marine sediments, reduced sulfur species (e.g., H2S) abiotically react with organic matter, contributing to carbon preservation. It is not known whether such processes also contribute to preserving DOM in ocean waters. Here, we show DOM sulfurization within the sulfidic waters of the Black Sea, by combining elemental, isotopic, and molecular analyses. Dissolved organic sulfur (DOS) is formed largely in the water column and not derived from sediments or allochthonous nonmarine sources. Our findings suggest that during large-scale anoxic events, DOM may accumulate through abiotic reactions with reduced sulfur species, having long-lasting effects on global climate by enhancing organic carbon sequestration.
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Affiliation(s)
- Gonzalo V Gomez-Saez
- Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Oldenburg, Germany.
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Sciences (AWI), Bremerhaven, Germany
| | - Thorsten Dittmar
- Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Oldenburg, Germany
- Helmholtz Institute for Functional Marine Biodiversity (HIFMB), University of Oldenburg, Oldenburg, Germany
| | - Moritz Holtappels
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Sciences (AWI), Bremerhaven, Germany
- Max Planck Institute for Marine Microbiology (MPI), Bremen, Germany
- MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Anika M Pohlabeln
- Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Oldenburg, Germany
| | - Anna Lichtschlag
- Max Planck Institute for Marine Microbiology (MPI), Bremen, Germany
- National Oceanography Centre, Southampton, UK
| | - Bernhard Schnetger
- Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Oldenburg, Germany
| | - Antje Boetius
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Sciences (AWI), Bremerhaven, Germany
- Max Planck Institute for Marine Microbiology (MPI), Bremen, Germany
- MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Jutta Niggemann
- Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, Oldenburg, Germany
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Abstract
Cyanophages are viruses that target cyanobacteria and directly control their abundance via viral lysis. Cyanobacteria are known to cause large blooms in water bodies, substantially contributing to oxygen depletion in bottom waters resulting in areas called dead zones. Up to 20% of prokaryotic organisms in the oceans are estimated to die every day due to viral infection and lysis. Viruses can therefore alter microbial diversity, community structure, and biogeochemical processes driven by these organisms. Cyanophages are viruses that infect and lyse cyanobacterial cells, adding bioavailable carbon and nutrients into the environment. Cyanobacteria are photosynthesizing bacteria, with some species capable of N2 fixation, which are known to form large blooms as well as resistant resting cells known as akinetes. Here, we investigated cyanophage diversity and community structure plus cyanobacteria in dead zone sediments. We sampled surface sediments and sequenced DNA and RNA, along an oxygen gradient—representing oxic, hypoxic, and anoxic conditions—in one of the world’s largest dead zones located in the Baltic Sea. Cyanophages were detected at all stations and, based on partial genome contigs, had a higher alpha diversity and different beta diversity in the hypoxic-anoxic sediments, suggesting that cyanobacteria in dead zone sediments and/or environmental conditions select for specific cyanophages. Some of these cyanophages can infect cyanobacteria with potential consequences for gene expression related to their photosystem and phosphate regulation. Top cyanobacterial genera detected in the anoxic sediment included Dolichospermum/Anabaena, Synechococcus, and Cyanobium. RNA transcripts classified to cyanobacteria were associated with numerous pathways, including anaerobic carbon metabolism and N2 fixation. Cyanobacterial blooms are known to fuel oxygen-depleted ecosystems with phosphorus (so-called internal loading), and our cyanophage data indicate the potential for viral lysis of cyanobacteria which might explain the high nutrient turnover in these environments. IMPORTANCE Cyanophages are viruses that target cyanobacteria and directly control their abundance via viral lysis. Cyanobacteria are known to cause large blooms in water bodies, substantially contributing to oxygen depletion in bottom waters resulting in areas called dead zones. Our knowledge of cyanophages in dead zones is very scarce, and so far, no studies have assembled partial cyanophage genomes and investigated their associated cyanobacteria in these dark and anoxic sediments. Here, we present the first study using DNA and RNA sequencing to investigate in situ diversity of cyanophages and cyanobacteria in dead zones. Our study shows that dead zone sediments contain different cyanophages compared to oxic sediments and suggest that these viruses are able to affect cyanobacterial photosystem and phosphate regulation. Furthermore, cyanophage-controlled lysis of cyanobacteria might also increase the turnover of carbon, phosphorus, and nitrogen in these oxygen-free environments at the bottom of the sea.
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Mohd-Din M, Abdul-Wahab MF, Mohamad SE, Jamaluddin H, Shahir S, Ibrahim Z, Hii KS, Tan SN, Leaw CP, Gu H, Lim PT. Prolonged high biomass diatom blooms induced formation of hypoxic-anoxic zones in the inner part of Johor Strait. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:42948-42959. [PMID: 32725555 DOI: 10.1007/s11356-020-10184-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 07/17/2020] [Indexed: 06/11/2023]
Abstract
The Johor Strait has experienced rapid development of various human activities and served as the main marine aquaculture area for the two countries that bordered the strait. Several fish kill incidents in 2014 and 2015 have been confirmed, attributed to the algal blooms of ichthyotoxic dinoflagellates; however, the cause of fish kill events after 2016 was not clarified and the causative organisms remained unknown. To clarify the potential cause of fish kills along the Johor Strait, a 1-year field investigation was conducted with monthly sampling between May 2018 and April 2019. Monthly vertical profiles of physical water parameters (temperature, salinity, and dissolved oxygen levels) were measured in situ at different depths (subsurface, 1 m, 5 m, and 8 m) depending on the ambient depth of the water column at the sampling stations. The spatial-temporal variability of macronutrients and chlorophyll a content was analyzed. Our results showed that high chlorophyll a concentration (up to 48.8 μg/L) and high biomass blooms of Skeletonema, Chaetoceros, Rhizosolenia, and Thalassiosira were observed seasonally at the inner part of the strait. A hypoxic to anoxic dead zone, with the dissolved oxygen levels ranging from 0.19 to 1.7 mg/L, was identified in the inner Johor Strait, covering an estimated area of 10.3 km2. The occurrence of high biomass diatom blooms and formation of the hypoxic-anoxic zone along the inner part Johor Strait were likely the culprits of some fish kill incidents after 2016.
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Affiliation(s)
- Monaliza Mohd-Din
- Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia
| | - Mohd Firdaus Abdul-Wahab
- Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia
- Taiwan-Malaysia Innovation Center for Clean Water and Sustainable Energy (WISE Centre), Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia
| | - Shaza Eva Mohamad
- Department of Environmental and Green Technology (EGT), Malaysia-Japan International Institute of Technology (MJIIT), Universiti Teknologi Malaysia, 54100, Kuala Lumpur, Malaysia
| | - Haryati Jamaluddin
- Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia
| | - Shafinaz Shahir
- Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia
| | - Zaharah Ibrahim
- Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia
| | - Kieng Soon Hii
- Bachok Marine Research Station, Institute of Ocean and Earth Sciences, University of Malaya, 16310, Bachok, Kelantan, Malaysia
| | - Suh Nih Tan
- Institute of Oceanography and Environment, University Malaysia Terengganu, 21030, Kuala Nerus, Terengganu, Malaysia
| | - Chui Pin Leaw
- Bachok Marine Research Station, Institute of Ocean and Earth Sciences, University of Malaya, 16310, Bachok, Kelantan, Malaysia
| | - Haifeng Gu
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen City, China
| | - Po Teen Lim
- Bachok Marine Research Station, Institute of Ocean and Earth Sciences, University of Malaya, 16310, Bachok, Kelantan, Malaysia.
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Bhattacharya S, Roy C, Mandal S, Sarkar J, Rameez MJ, Mondal N, Mapder T, Chatterjee S, Pyne P, Alam M, Haldar PK, Roy R, Fernandes S, Peketi A, Chakraborty R, Mazumdar A, Ghosh W. Aerobic microbial communities in the sediments of a marine oxygen minimum zone. FEMS Microbiol Lett 2020; 367:5911577. [PMID: 32975580 PMCID: PMC7568448 DOI: 10.1093/femsle/fnaa157] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 09/23/2020] [Indexed: 12/20/2022] Open
Abstract
The ecology of aerobic microorganisms is never explored in marine oxygen minimum zone (OMZ) sediments. Here we reveal aerobic bacterial communities along ∼3 m sediment-horizons of the eastern Arabian Sea OMZ. Sulfide-containing sediment-cores retrieved from 530 mbsl (meters beneath the sea-level) and 580 mbsl were explored at 15–30 cm intervals, using metagenomics, pure-culture-isolation, genomics and metatranscriptomics. Genes for aerobic respiration, and oxidation of methane/ammonia/alcohols/thiosulfate/sulfite/organosulfur-compounds, were detected in the metagenomes from all 25 sediment-samples explored. Most probable numbers for aerobic chemolithoautotrophs and chemoorganoheterotrophs at individual sample-sites were up to 1.1 × 107 (g sediment)-1. The sediment-sample collected from 275 cmbsf (centimeters beneath the seafloor) of the 530-mbsl-core yielded many such obligately aerobic isolates belonging to Cereibacter, Guyparkeria, Halomonas, Methylophaga, Pseudomonas and Sulfitobacter which died upon anaerobic incubation, despite being provided with all possible electron acceptors and fermentative substrates. High percentages of metatranscriptomic reads from the 275 cmbsf sediment-sample, and metagenomic reads from all 25 sediment-samples, matched the isolates’ genomic sequences including those for aerobic metabolisms, genetic/environmental information processing and cell division, thereby illustrating the bacteria's in-situ activity, and ubiquity across the sediment-horizons, respectively. The findings hold critical implications for organic carbon sequestration/remineralization, and inorganic compounds oxidation, within the sediment realm of global marine OMZs.
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Affiliation(s)
| | - Chayan Roy
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Subhrangshu Mandal
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Jagannath Sarkar
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Moidu Jameela Rameez
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Nibendu Mondal
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Tarunendu Mapder
- Department of Chemistry, Bose Institute, 93/1 APC Road, Kolkata 700009, India
| | - Sumit Chatterjee
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Prosenjit Pyne
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Masrure Alam
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Prabir Kumar Haldar
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Rimi Roy
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
| | - Svetlana Fernandes
- Gas Hydrate Research Group, Geological Oceanography, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India
| | - Aditya Peketi
- Gas Hydrate Research Group, Geological Oceanography, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India
| | - Ranadhir Chakraborty
- Department of Biotechnology, University of North Bengal, Raja Rammohanpur, District - Darjeeling, West Bengal 734013, India
| | - Aninda Mazumdar
- Gas Hydrate Research Group, Geological Oceanography, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India
| | - Wriddhiman Ghosh
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata 700054, India
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Microbial Origin of the Organic Matter Preserved in the Cayo Coco Lagoonal Network, Cuba. MINERALS 2020. [DOI: 10.3390/min10020143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The southern part of the tropical Cayo Coco Island (Cuba) hosts a complex, highly evaporative and marine-fed lagoonal network. In the easternmost lagoon of this network, hypersaline conditions favour the development of complex sedimentary microbial ecosystems within the water column at the bottom water-sediment interface and on the shore. Some of these ecosystems are producing microbial mats and biofilms with variable mineralisation rates, depending on their location. Since the mineralisation of these microbial deposits is rare, the sedimentary record does not provide a direct window on the evolution of these ecosystems or their distribution through space and time. However, microbial deposits also produce copious amounts of organic matter, which may be used to decipher any microbial-related origin within the sedimentary record. Microbial mats and biofilms were identified as the potential source of organic material in addition to the surrounding mangrove, soils and suspended particulate matter (SPM). The origin and evolution of the sedimentary organic matter preserved within the lagoonal sediments has been analysed using geochemical parameters such as elemental (TOC, TN and [C/N]atomic ratio) and isotopic (δ13Corg and δ15NTN) signals on four sedimentary cores retrieved from different locations in the lagoon and compared with the geochemical signatures of the potential sources. Despite the high potential for organic matter accumulation in the studied lagoon, the TOC and TN downcore values in sediments that were analysed (i.e., micritic muds and bioclastic sands) remain very low compared to the sediment-water interface. The relative contributions of the different potential sources of organic matter were estimated using [C/N]atomic ratios and δ13Corg values. The δ15NTN signature was discarded as a source signature as it records synsedimentary, early diagenetic, secondary evolution of the nitrogen signal associated with OM remineralisation (i.e., denitrification). Finally, among the microbial deposits, the slime recognised in the permanently submersed zone of the waterbody appears to be the main contributor to the organic matter preserved within the sediments of the lagoon. SPM, mainly composed of microbial-rich particles, also contribute and cannot be ruled out as a source.
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Ravaglioli C, Bulleri F, Rühl S, McCoy SJ, Findlay HS, Widdicombe S, Queirós AM. Ocean acidification and hypoxia alter organic carbon fluxes in marine soft sediments. GLOBAL CHANGE BIOLOGY 2019; 25:4165-4178. [PMID: 31535452 DOI: 10.1111/gcb.14806] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 07/26/2019] [Accepted: 07/27/2019] [Indexed: 06/10/2023]
Abstract
Anthropogenic stressors can alter the structure and functioning of infaunal communities, which are key drivers of the carbon cycle in marine soft sediments. Nonetheless, the compounded effects of anthropogenic stressors on carbon fluxes in soft benthic systems remain largely unknown. Here, we investigated the cumulative effects of ocean acidification (OA) and hypoxia on the organic carbon fate in marine sediments, through a mesocosm experiment. Isotopically labelled macroalgal detritus (13 C) was used as a tracer to assess carbon incorporation in faunal tissue and in sediments under different experimental conditions. In addition, labelled macroalgae (13 C), previously exposed to elevated CO2 , were also used to assess the organic carbon uptake by fauna and sediments, when both sources and consumers were exposed to elevated CO2 . At elevated CO2 , infauna increased the uptake of carbon, likely as compensatory response to the higher energetic costs faced under adverse environmental conditions. By contrast, there was no increase in carbon uptake by fauna exposed to both stressors in combination, indicating that even a short-term hypoxic event may weaken the ability of marine invertebrates to withstand elevated CO2 conditions. In addition, both hypoxia and elevated CO2 increased organic carbon burial in the sediment, potentially affecting sediment biogeochemical processes. Since hypoxia and OA are predicted to increase in the face of climate change, our results suggest that local reduction of hypoxic events may mitigate the impacts of global climate change on marine soft-sediment systems.
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Affiliation(s)
| | - Fabio Bulleri
- Dipartimento di Biologia, Università di Pisa, CoNISMa, Pisa, Italy
| | - Saskia Rühl
- Plymouth Marine Laboratory, Plymouth, UK
- Southampton University, Southampton, UK
| | - Sophie J McCoy
- Department of Biological Sciences, Florida State University, Tallahassee, FL, USA
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39
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Rastelli E, Corinaldesi C, Dell'Anno A, Tangherlini M, Lo Martire M, Nishizawa M, Nomaki H, Nunoura T, Danovaro R. Drivers of Bacterial α- and β-Diversity Patterns and Functioning in Subsurface Hadal Sediments. Front Microbiol 2019; 10:2609. [PMID: 31798555 PMCID: PMC6868121 DOI: 10.3389/fmicb.2019.02609] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 10/28/2019] [Indexed: 12/28/2022] Open
Abstract
Oceanic trenches at hadal (>6,000 m) depths are hot spots of organic matter deposition and mineralization and can host abundant and active bacterial assemblages. However, the factors able to shape their biodiversity and functioning remain largely unexplored, especially in subsurface sediments. Here, we investigated the patterns and drivers of benthic bacterial α- and β-diversity (i.e., OTU richness and turnover diversity) along the vertical profile down to 1.5 m sediment depth in the Izu-Bonin Trench (at ~10,000 m water depth). The protease and glucosidase enzymatic activity rates were also determined, as a proxy of organic matter degradation potential in the different sediment layers. Molecular fingerprinting based on automated ribosomal intergenic spacer analysis (ARISA) indicated that the α-diversity of bacterial assemblages remained high throughout the vertical profile and that the turnover (β-) diversity among sediment horizons reached values up to 90% of dissimilarity. Multivariate distance-based linear modeling (DISTLM) pointed out that the diversity and functioning of the hadal bacterial assemblages were influenced by the variability of environmental conditions (including the availability of organic resources and electron donors/acceptors) and of viral production rates along the sediment vertical profile. Based on our results, we can argue that the heterogeneity of physical-chemical features of the hadal sediments of the Izu-Bonin Trench contribute to increase the niches availability for different bacterial taxa, while viruses contribute to maintain high levels of bacterial turnover diversity and to enhance organic matter cycling in these extremely remote and isolated ecosystems.
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Affiliation(s)
- Eugenio Rastelli
- Department of Marine Biotechnology, Stazione Zoologica Anton Dohrn, Naples, Italy
| | - Cinzia Corinaldesi
- Department of Materials, Environmental Sciences and Urban Planning, Polytechnic University of Marche, Ancona, Italy
| | - Antonio Dell'Anno
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Michael Tangherlini
- Department of Research Infrastructures for Marine Biological Resources, Stazione Zoologica Anton Dohrn, Naples, Italy
| | - Marco Lo Martire
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Manabu Nishizawa
- Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-star), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
| | - Hidetaka Nomaki
- Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-star), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
| | - Takuro Nunoura
- Research Center for Bioscience and Nanoscience (CeBN), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
| | - Roberto Danovaro
- Department of Marine Biotechnology, Stazione Zoologica Anton Dohrn, Naples, Italy.,Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
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40
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Increasing oxygen deficiency changes rare and moderately abundant bacterial communities in coastal soft sediments. Sci Rep 2019; 9:16341. [PMID: 31704947 PMCID: PMC6841974 DOI: 10.1038/s41598-019-51432-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 09/25/2019] [Indexed: 11/20/2022] Open
Abstract
Coastal hypoxia is a major environmental problem worldwide. Hypoxia-induced changes in sediment bacterial communities harm marine ecosystems and alter biogeochemical cycles. Nevertheless, the resistance of sediment bacterial communities to hypoxic stress is unknown. We investigated changes in bacterial communities during hypoxic-anoxic disturbance by artificially inducing oxygen deficiency to the seafloor for 0, 3, 7, and 48 days, with subsequent molecular biological analyses. We further investigated relationships between bacterial communities, benthic macrofauna and nutrient effluxes across the sediment-water-interface during hypoxic-anoxic stress, considering differentially abundant operational taxonomic units (OTUs). The composition of the moderately abundant OTUs changed significantly after seven days of oxygen deficiency, while the abundant and rare OTUs first changed after 48 days. High bacterial diversity maintained the resistance of the communities during oxygen deficiency until it dropped after 48 days, likely due to anoxia-induced loss of macrofaunal diversity and bioturbation. Nutrient fluxes, especially ammonium, correlated positively with the moderate and rare OTUs, including potential sulfate reducers. Correlations may reflect bacteria-mediated nutrient effluxes that accelerate eutrophication. The study suggests that even slightly higher bottom-water oxygen concentrations, which could sustain macrofaunal bioturbation, enable bacterial communities to resist large compositional changes and decrease the harmful consequences of hypoxia in marine ecosystems.
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41
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Matys ED, Mackey T, Grettenberger C, Mueller E, Jungblut A, Sumner DY, Hawes I, Summons RE. Environmental controls on bacteriohopanepolyol profiles of benthic microbial mats from Lake Fryxell, Antarctica. GEOBIOLOGY 2019; 17:551-563. [PMID: 31325234 DOI: 10.1111/gbi.12353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 04/20/2019] [Accepted: 05/04/2019] [Indexed: 06/10/2023]
Abstract
Bacteriohopanepolyols (BHPs) are pentacyclic triterpenoid lipids that contribute to the structural integrity and physiology of some bacteria. Because some BHPs originate from specific classes of bacteria, BHPs have potential as taxonomically and environmentally diagnostic biomarkers. For example, a stereoisomer of bacteriohopanetetrol (informally BHT II) has been associated with anaerobic ammonium oxidation (anammox) bacteria and suboxic to anoxic marine environments where anammox is active. As a result, the detection of BHT II in the sedimentary record and fluctuations in the relative abundance of BHT II may inform reconstructions of nitrogen cycling and ocean redox changes through the geological record. However, there are uncertainties concerning the sources of BHT II and whether or not BHT II is produced in abundance in non-marine environments, both of which are pertinent to interpretations of BHT II signatures in sediments. To address these questions, we investigate the BHP composition of benthic microbial mats from Lake Fryxell, Antarctica. Lake Fryxell is a perennially ice-covered lake with a sharp oxycline in a density-stabilized water column. We describe the diversity and abundance of BHPs in benthic microbial mats across a transect from oxic to anoxic conditions. Generally, BHP abundances and diversity vary with the morphologies of microbial mats, which were previously shown to reflect local environmental conditions, such as irradiance and oxygen and sulfide concentrations. BHT II was identified in mats that exist within oxic to anoxic portions of the lake. However, anammox bacteria have yet to be identified in Lake Fryxell. We examine our results in the context of BHPs as biomarkers in modern and ancient environments.
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Affiliation(s)
- Emily D Matys
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Tyler Mackey
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | | | - Elliott Mueller
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Anne Jungblut
- Department of Life Sciences, The Natural History Museum, London, UK
| | - Dawn Y Sumner
- Department of Earth and Planetary Sciences, University of California, Davis, California
| | - Ian Hawes
- University of Waikato, Tauranga, New Zealand
| | - Roger E Summons
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts
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42
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Peoples LM, Grammatopoulou E, Pombrol M, Xu X, Osuntokun O, Blanton J, Allen EE, Nunnally CC, Drazen JC, Mayor DJ, Bartlett DH. Microbial Community Diversity Within Sediments from Two Geographically Separated Hadal Trenches. Front Microbiol 2019; 10:347. [PMID: 30930856 PMCID: PMC6428765 DOI: 10.3389/fmicb.2019.00347] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 02/11/2019] [Indexed: 11/13/2022] Open
Abstract
Hadal ocean sediments, found at sites deeper than 6,000 m water depth, are thought to contain microbial communities distinct from those at shallower depths due to high hydrostatic pressures and higher abundances of organic matter. These communities may also differ from one other as a result of geographical isolation. Here we compare microbial community composition in surficial sediments of two hadal environments—the Mariana and Kermadec trenches—to evaluate microbial biogeography at hadal depths. Sediment microbial consortia were distinct between trenches, with higher relative sequence abundances of taxa previously correlated with organic matter degradation present in the Kermadec Trench. In contrast, the Mariana Trench, and deeper sediments in both trenches, were enriched in taxa predicted to break down recalcitrant material and contained other uncharacterized lineages. At the 97% similarity level, sequence-abundant taxa were not trench-specific and were related to those found in other hadal and abyssal habitats, indicating potential connectivity between geographically isolated sediments. Despite the diversity of microorganisms identified using culture-independent techniques, most isolates obtained under in situ pressures were related to previously identified piezophiles. Members related to these same taxa also became dominant community members when native sediments were incubated under static, long-term, unamended high-pressure conditions. Our results support the hypothesis that there is connectivity between sediment microbial populations inhabiting the Mariana and Kermadec trenches while showing that both whole communities and specific microbial lineages vary between trench of collection and sediment horizon depth. This in situ biodiversity is largely missed when incubating samples within pressure vessels and highlights the need for revised protocols for high-pressure incubations.
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Affiliation(s)
- Logan M Peoples
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States
| | - Eleanna Grammatopoulou
- Oceanlab, The Institute of Biological and Environmental Sciences, King's College, The University of Aberdeen, Aberdeen, United Kingdom
| | - Michelle Pombrol
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States
| | - Xiaoxiong Xu
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States
| | - Oladayo Osuntokun
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States
| | - Jessica Blanton
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States
| | - Eric E Allen
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States
| | - Clifton C Nunnally
- Louisiana Universities Marine Consortium (LUMCON), Chauvin, LA, United States
| | - Jeffrey C Drazen
- Department of Oceanography, University of Hawai'i at Ma-noa, Honolulu, HI, United States
| | - Daniel J Mayor
- Oceanlab, The Institute of Biological and Environmental Sciences, King's College, The University of Aberdeen, Aberdeen, United Kingdom.,National Oceanography Centre, University of Southampton Waterfront Campus European Way, Southampton, United Kingdom
| | - Douglas H Bartlett
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States
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43
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Mori F, Umezawa Y, Kondo R, Wada M. Dynamics of Sulfate-Reducing Bacteria Community Structure in Surface Sediment of a Seasonally Hypoxic Enclosed Bay. Microbes Environ 2018; 33:378-384. [PMID: 30449831 PMCID: PMC6308007 DOI: 10.1264/jsme2.me18092] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We herein report on the dynamics of a sulfate-reducing bacteria (SRB) community structure in the surface sediment of a seasonally hypoxic enclosed bay for two consecutive years (2012 and 2013). The uppermost (0–5 mm) and subsurface (5–10 mm) layers of sediment were examined with a terminal-restriction fragment length polymorphism (T-RFLP) analysis based on the dissimilatory sulfite reductase (dsrA) gene. The SRB community significantly differed between the two sediment layers over the sampling period. This difference was mainly attributed to operational taxonomic units (OTUs) that were unique to either of the sediment layers. However, nearly 70% of total OTUs were shared between the two layers, with a few predominating. Therefore, no significant shift was observed in the SRB community structure under varying dissolved oxygen (DO) conditions in bottom water overlying the sediment surface. An additional analysis of 16S rRNA gene amplicon sequences, conducted for three uppermost sediment samples (July, August, and September in 2012), revealed that Desulfococcus, a member of SRB with high tolerance to oxygen, was the predominant Deltaproteobacteria across the uppermost sediment samples. Based on the predominance of shared OTUs across the SRB community in the sediment (0–10 mm) regardless of bottom-water DO, some SRB that are physiologically tolerant of a wide range of DO conditions may have dominated and masked changes in responsive SRB to DO concentrations. These results suggest that the SRB community structure in the enclosed bay became stable under repeated cycles of seasonal hypoxia, but may be compromised if the severity of hypoxia increases in the future.
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Affiliation(s)
- Fumiaki Mori
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University
| | - Yu Umezawa
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University
| | - Ryuji Kondo
- Department of Marine Science and Technology, Fukui Prefectural University
| | - Minoru Wada
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University
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44
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Caswell BA, Paine M, Frid CLJ. Seafloor ecological functioning over two decades of organic enrichment. MARINE POLLUTION BULLETIN 2018; 136:212-229. [PMID: 30509801 DOI: 10.1016/j.marpolbul.2018.08.041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 06/13/2018] [Accepted: 08/20/2018] [Indexed: 05/27/2023]
Abstract
Climate change and anthropogenic nutrient enrichment are driving rapid increases in ocean deoxygenation. These changes cause biodiversity loss and have severe consequences for marine ecosystem functioning and in turn the delivery of ecosystem services upon which humanity depends (e.g. fisheries). We seek to understand how such changes will impact seafloor functioning using biological traits analysis. Results from a sewage-sludge disposal site in the Firth of Clyde, UK spanning 26 years of monitoring showed that substantial changes in macrobenthic nutrient cycling and the provision of food for predators occurred, with elevated functioning on the margins 1-2 km from the centre of the disposal grounds. Thus, changes in food-web dynamics are expected, that weaken benthic pelagic coupling and lower secondary production (such as fisheries). Generally, functioning was conserved, but declined below a ~6% total organic carbon threshold. Similar to other severely deoxygenated systems, the recovery was slow and hysteresis was apparent.
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Affiliation(s)
- Bryony A Caswell
- Environmental Futures Research Institute, Griffith University, Gold Coast Campus, Parklands Drive, Qld 4222, Australia; School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK.
| | - Miranda Paine
- School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK
| | - Christopher L J Frid
- School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP, UK; School of Environment and Science, Griffith University, Gold Coast Campus, Parklands Drive, Qld 4222, Australia
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45
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Torti A, Jørgensen BB, Lever MA. Preservation of microbial DNA in marine sediments: insights from extracellular DNA pools. Environ Microbiol 2018; 20:4526-4542. [PMID: 30198168 DOI: 10.1111/1462-2920.14401] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 07/04/2018] [Accepted: 09/05/2018] [Indexed: 01/15/2023]
Abstract
Marine sediments harbour extracellular DNA (exDNA) not associated with currently living organisms. Including this exDNA in genetic surveys may distort abundance and diversity estimates of living prokaryotic communities. We separately extract exDNA and intracellular DNA (inDNA) from 11 horizons in a 10-m deep sediment core from Aarhus Bay (Denmark) that spans > 9000 years of Holocene sedimentation. We compare depth profiles of bacterial and archaeal 16S rRNA gene compositions to those of macrofaunal activity (bioturbation), sulfate and methane concentrations, sediment age and lithology. Among these variables, bioturbation shows the strongest relationship with the two DNA pools. In bioturbated surface sediments, the majority of Operational Taxonomic Units (OTUs) present in exDNA is absent from inDNA, thus belonging to microorganisms that were not alive at the time of sampling. Below the bioturbation zone, the two DNA pools display a much higher phylogenetic similarity. At all depths, the majority of exDNA and inDNA sequences show highest sequence similarities to sediment microorganisms, a finding that is additionally supported by separate analyses on low- and high-molecular weight exDNA. Our results indicate that in Aarhus Bay the vast majority of prokaryotic exDNA is turned over, thus not contributing to a genetic archive of past environmental change.
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Affiliation(s)
- Andrea Torti
- Department of Bioscience, Center for Geomicrobiology, Aarhus University, Aarhus, Denmark
| | - Bo Barker Jørgensen
- Department of Bioscience, Center for Geomicrobiology, Aarhus University, Aarhus, Denmark
| | - Mark Alexander Lever
- Department of Bioscience, Center for Geomicrobiology, Aarhus University, Aarhus, Denmark.,Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich, Switzerland
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46
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Raven MR, Fike DA, Gomes ML, Webb SM, Bradley AS, McClelland HLO. Organic carbon burial during OAE2 driven by changes in the locus of organic matter sulfurization. Nat Commun 2018; 9:3409. [PMID: 30143628 PMCID: PMC6109118 DOI: 10.1038/s41467-018-05943-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 07/23/2018] [Indexed: 11/15/2022] Open
Abstract
Ocean Anoxic Event 2 (OAE2) was a period of dramatic disruption to the global carbon cycle when massive amounts of organic matter (OM) were buried in marine sediments via complex and controversial mechanisms. Here we investigate the role of OM sulfurization, which makes OM less available for microbial respiration, in driving variable OM preservation in OAE2 sedimentary strata from Pont d’Issole (France). We find correlations between the concentration, S:C ratio, S-isotope composition, and sulfur speciation of OM suggesting that sulfurization facilitated changes in carbon burial at this site as the chemocline moved in and out of the sediments during deposition. These patterns are reproduced by a simple model, suggesting that small changes in primary productivity could drive large changes in local OM burial in environments poised near a critical redox threshold. This amplifying mechanism may be central to understanding the magnitude of global carbon cycle response to environmental perturbations. The mechanisms responsible for the burial of vast quantities of organic matter during Ocean Anoxic Event remain unclear. Here, the authors combine biogeochemical analysis and modeling and show that sulfurization could play a critical role in facilitating globally elevated burial of organic matter.
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Affiliation(s)
- Morgan Reed Raven
- Department of Earth and Planetary Sciences, Washington University in St Louis, St Louis, MO, 63130, USA.
| | - David A Fike
- Department of Earth and Planetary Sciences, Washington University in St Louis, St Louis, MO, 63130, USA
| | - Maya L Gomes
- Department of Earth and Planetary Sciences, Washington University in St Louis, St Louis, MO, 63130, USA.,Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Samuel M Webb
- Stanford Synchrotron Radiation Lightsource, Stanford University, Menlo Park, CA, 94025, USA
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47
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Fernandes S, Mazumdar A, Bhattacharya S, Peketi A, Mapder T, Roy R, Carvalho MA, Roy C, Mahalakshmi P, Da Silva R, Rao PLS, Banik SK, Ghosh W. Enhanced carbon-sulfur cycling in the sediments of Arabian Sea oxygen minimum zone center. Sci Rep 2018; 8:8665. [PMID: 29875466 PMCID: PMC5989202 DOI: 10.1038/s41598-018-27002-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/21/2018] [Indexed: 01/04/2023] Open
Abstract
Biogeochemistry of oxygen minimum zone (OMZ) sediments, which are characterized by high input of labile organic matter, have crucial bearings on the benthic biota, gas and metal fluxes across the sediment-water interface, and carbon-sulfur cycling. Here we couple pore-fluid chemistry and comprehensive microbial diversity data to reveal the sedimentary carbon-sulfur cycle across a water-depth transect covering the entire thickness of eastern Arabian Sea OMZ, off the west coast of India. Geochemical data show remarkable increase in average total organic carbon content and aerial sulfate reduction rate (JSO42-) in the sediments of the OMZ center coupled with shallowing of sulfate methane transition zone and hydrogen sulfide and ammonium build-up. Total bacterial diversity, including those of complex organic matter degraders, fermentative and exoelectrogenic bacteria, and sulfate-reducers (that utilize only simple carbon compounds) were also found to be highest in the same region. The above findings indicate that higher organic carbon sequestration from the water-columns (apparently due to lower benthic consumption, biodegradation and biotransformation) and greater bioavailability of simple organic carbon compounds (apparently produced by fermetative microflora of the sediments) are instrumental in intensifying the carbon-sulfur cycle in the sediments of the OMZ center.
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Affiliation(s)
| | - Aninda Mazumdar
- CSIR-National Institute of Oceanography, Dona Paula, Goa, 403004, India.
| | | | - Aditya Peketi
- CSIR-National Institute of Oceanography, Dona Paula, Goa, 403004, India
| | - Tarunendu Mapder
- Department of Chemistry, Bose Institute, 93/1 APC Road, Kolkata, 700009, India
- Indian Institute of Engineering Science and Technology, Shibpur, Howrah, 711103, West Bengal, India
| | - Rimi Roy
- Department of Microbiology, Bose Institute, Kolkata, 700054, West Bengal, India
| | - Mary Ann Carvalho
- CSIR-National Institute of Oceanography, Dona Paula, Goa, 403004, India
| | - Chayan Roy
- Department of Microbiology, Bose Institute, Kolkata, 700054, West Bengal, India
| | | | - Rheane Da Silva
- CSIR-National Institute of Oceanography, Dona Paula, Goa, 403004, India
| | - P L Srinivasa Rao
- Gujarat Energy Research and Management Institute, Gujarat, 382421, India
| | - Suman Kumar Banik
- Department of Chemistry, Bose Institute, 93/1 APC Road, Kolkata, 700009, India
| | - Wriddhiman Ghosh
- Department of Microbiology, Bose Institute, Kolkata, 700054, West Bengal, India.
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48
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Helm I, Karina G, Jalukse L, Pagano T, Leito I. Comparative validation of amperometric and optical analyzers of dissolved oxygen: a case study. ENVIRONMENTAL MONITORING AND ASSESSMENT 2018; 190:313. [PMID: 29705878 DOI: 10.1007/s10661-018-6692-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 04/16/2018] [Indexed: 05/27/2023]
Abstract
A comprehensive comparative validation for two different types of dissolved oxygen (DO) analyzers, amperometric and optical, is presented on two representative commercial DO analyzers. A number of performance characteristics were evaluated including drift, intermediate precision, accuracy of temperature compensation, accuracy of reading (under different measurement conditions), linearity, flow dependence of the reading, repeatability (reading stability), and matrix effects of dissolved salts. The matrix effects on readings in real samples were evaluated by analyzing the dependence of the reading on salt concentration (at saturation concentration of DO). The analyzers were also assessed in DO measurements of a number of natural waters. The uncertainty contributions of the main influencing parameters were estimated under different experimental conditions. It was found that the uncertainties of results for both analyzers are quite similar but the contributions of the uncertainty sources are different. Our results imply that the optical analyzer might not be as robust as is commonly assumed; however, it has better reading stability, lower stirring speed dependence, and typically requires less maintenance. On the other hand, the amperometric analyzer has a faster response and wider linear range. Both analyzers seem to have issues with the accuracy of temperature compensation. The approach described in this work will be useful to practitioners carrying out DO measurements for ensuring reliability of their measurements.
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Affiliation(s)
- Irja Helm
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
| | - Gerli Karina
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
- Estonian Veterinary and Food Laboratory, Kreutzwaldi 30, 51006, Tartu, Estonia
| | - Lauri Jalukse
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia
- Estonian Veterinary and Food Laboratory, Kreutzwaldi 30, 51006, Tartu, Estonia
| | - Todd Pagano
- Department of Science & Mathematics, Rochester Institute of Technology, Rochester, NY, 14623, USA
| | - Ivo Leito
- Institute of Chemistry, University of Tartu, Ravila 14a, 50411, Tartu, Estonia.
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49
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Mori F, Umezawa Y, Kondo R, Wada M. Effects of bottom-water hypoxia on sediment bacterial community composition in a seasonally hypoxic enclosed bay (Omura Bay, West Kyushu, Japan). FEMS Microbiol Ecol 2018; 94:4951600. [DOI: 10.1093/femsec/fiy053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 03/21/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Fumiaki Mori
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Bunkyo 1-14, Nagasaki, Nagasaki 852-8521, Japan
| | - Yu Umezawa
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Bunkyo 1-14, Nagasaki, Nagasaki 852-8521, Japan
- Department of Environmental Science on Biosphere, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan
| | - Ryuji Kondo
- Department of Marine Science and Technology, Fukui Prefectural University, Fukui 917-0003, Japan
| | - Minoru Wada
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Bunkyo 1-14, Nagasaki, Nagasaki 852-8521, Japan
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50
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Stigebrandt A. On the response of the Baltic proper to changes of the total phosphorus supply. AMBIO 2018; 47:31-44. [PMID: 28726128 PMCID: PMC5709262 DOI: 10.1007/s13280-017-0933-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 03/31/2017] [Accepted: 06/29/2017] [Indexed: 06/07/2023]
Abstract
Using a time-dependent phosphorus (P) budget model for the Baltic proper, describing sources and sinks at the external borders of the water column, one may compute the e-folding time T of the adjustment of the winter surface water P concentration c 1 to abruptly changed total P supply. The restoration time TR = 3T is introduced as a practical measure of the time it takes to achieve 95% of the change of c 1 towards the final, equilibrium, state c 1e. The P budget model, including an internal source emanating from deep anoxic bottoms, also shows that c 1e is proportional to the total P supply to the water column. About 70% of present time total P supply to the Baltic proper comes from deep anoxic bottoms. If deep bottoms were kept oxygenated, this internal P supply would be turned off and the equilibrium concentration c1e would be reduced by about 70%. This should imply that the Baltic proper may be restored to a state determined by the external P supplies from land-based and oceanic sources. According to the model, restoration would take 10-15 years. Thereafter most of the equipment used for oxygenation may be shut off since also the deepwater oxygen demand by decomposition of fresh organic matter, would have decreased by about 70% implying that the deepwater would be kept oxic by the natural vertical circulation. The model presented in this paper provides a new science-based solution of the eutrophication problem of the Baltic proper, which is of great interest from a management point of view.
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Affiliation(s)
- Anders Stigebrandt
- Department of Marine Sciences, University of Gothenburg, Box 461, SE-40530, Gothenburg, Sweden.
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