1
|
Nef C, Pierella Karlusich JJ, Bowler C. From nets to networks: tools for deciphering phytoplankton metabolic interactions within communities and their global significance. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230172. [PMID: 39034691 DOI: 10.1098/rstb.2023.0172] [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: 10/11/2023] [Revised: 01/26/2024] [Accepted: 03/21/2024] [Indexed: 07/23/2024] Open
Abstract
Our oceans are populated with a wide diversity of planktonic organisms that form complex dynamic communities at the base of marine trophic networks. Within such communities are phytoplankton, unicellular photosynthetic taxa that provide an estimated half of global primary production and support biogeochemical cycles, along with other essential ecosystem services. One of the major challenges for microbial ecologists has been to try to make sense of this complexity. While phytoplankton distributions can be well explained by abiotic factors such as temperature and nutrient availability, there is increasing evidence that their ecological roles are tightly linked to their metabolic interactions with other plankton members through complex mechanisms (e.g. competition and symbiosis). Therefore, unravelling phytoplankton metabolic interactions is the key for inferring their dependency on, or antagonism with, other taxa and better integrating them into the context of carbon and nutrient fluxes in marine trophic networks. In this review, we attempt to summarize the current knowledge brought by ecophysiology, organismal imaging, in silico predictions and co-occurrence networks using 'omics data, highlighting successful combinations of approaches that may be helpful for future investigations of phytoplankton metabolic interactions within their complex communities.This article is part of the theme issue 'Connected interactions: enriching food web research by spatial and social interactions'.
Collapse
Affiliation(s)
- Charlotte Nef
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Université Paris, Paris 75005, France
- Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans, Paris 75016, France
| | | | - Chris Bowler
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Université Paris, Paris 75005, France
- Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans, Paris 75016, France
| |
Collapse
|
2
|
Chowdhury S, Berthelot H, Baudet C, González-Santana D, Reeder CF, L'Helguen S, Maguer JF, Löscher CR, Singh A, Blain S, Cassar N, Bonnet S, Planquette H, Benavides M. Fronts divide diazotroph communities in the Southern Indian Ocean. FEMS Microbiol Ecol 2024; 100:fiae095. [PMID: 38992179 PMCID: PMC11245648 DOI: 10.1093/femsec/fiae095] [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: 01/11/2024] [Revised: 06/20/2024] [Accepted: 07/10/2024] [Indexed: 07/13/2024] Open
Abstract
Dinitrogen (N2) fixation represents a key source of reactive nitrogen in marine ecosystems. While the process has been rather well-explored in low latitudes of the Atlantic and Pacific Oceans, other higher latitude regions and particularly the Indian Ocean have been chronically overlooked. Here, we characterize N2 fixation and diazotroph community composition across nutrient and trace metals gradients spanning the multifrontal system separating the oligotrophic waters of the Indian Ocean subtropical gyre from the high nutrient low chlorophyll waters of the Southern Ocean. We found a sharp contrasting distribution of diazotroph groups across the frontal system. Notably, cyanobacterial diazotrophs dominated north of fronts, driving high N2 fixation rates (up to 13.96 nmol N l-1 d-1) with notable peaks near the South African coast. South of the fronts non-cyanobacterial diazotrophs prevailed without significant N2 fixation activity being detected. Our results provide new crucial insights into high latitude diazotrophy in the Indian Ocean, which should contribute to improved climate model parameterization and enhanced constraints on global net primary productivity projections.
Collapse
Affiliation(s)
- Subhadeep Chowdhury
- Aix Marseille Université, CNRS, Université de Toulon, IRD, OSU Pythéas, Mediterranean Institute of Oceanography (MIO), UM 110, 13288 Marseille, France
- Turing Center for Living Systems, Aix-Marseille University, Marseille, France
| | - Hugo Berthelot
- IFREMER, DYNECO, Pelagos Laboratory, Plouzané, France
- Laboratoire des Sciences de l'Environnement Marin, IUEM, Université de Brest-UMR 6539 CNRS/UBO/IRD, Technopole Brest-Iroise, 29280 Plouzané, France
| | - Corentin Baudet
- Laboratoire des Sciences de l'Environnement Marin, IUEM, Université de Brest-UMR 6539 CNRS/UBO/IRD, Technopole Brest-Iroise, 29280 Plouzané, France
| | - David González-Santana
- Univ Brest, CNRS, IRD, IFREMER, LEMAR, F-29280 Plouzané, France
- Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Christian Furbo Reeder
- Aix Marseille Université, CNRS, Université de Toulon, IRD, OSU Pythéas, Mediterranean Institute of Oceanography (MIO), UM 110, 13288 Marseille, France
- Turing Center for Living Systems, Aix-Marseille University, Marseille, France
| | - Stéphane L'Helguen
- Laboratoire des Sciences de l'Environnement Marin, IUEM, Université de Brest-UMR 6539 CNRS/UBO/IRD, Technopole Brest-Iroise, 29280 Plouzané, France
| | - Jean-François Maguer
- Laboratoire des Sciences de l'Environnement Marin, IUEM, Université de Brest-UMR 6539 CNRS/UBO/IRD, Technopole Brest-Iroise, 29280 Plouzané, France
| | - Carolin R Löscher
- Nordcee, Department of Biology, University of Southern Denmark, Odense 5230, Denmark
| | - Arvind Singh
- Geosciences Division, Physical Research Laboratory, Ahmedabad 380009, India
| | - Stéphane Blain
- Sorbonne Université, CNRS, Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire Océanologique de Banyuls, 66650 Banyuls/mer, France
| | - Nicolas Cassar
- Laboratoire des Sciences de l'Environnement Marin, IUEM, Université de Brest-UMR 6539 CNRS/UBO/IRD, Technopole Brest-Iroise, 29280 Plouzané, France
- Division of Earth and Climate Sciences, Nicholas School of the Environment, Duke University, Durham, NC 27708, United States
| | - Sophie Bonnet
- Aix Marseille Université, CNRS, Université de Toulon, IRD, OSU Pythéas, Mediterranean Institute of Oceanography (MIO), UM 110, 13288 Marseille, France
| | - Hélène Planquette
- Laboratoire des Sciences de l'Environnement Marin, IUEM, Université de Brest-UMR 6539 CNRS/UBO/IRD, Technopole Brest-Iroise, 29280 Plouzané, France
| | - Mar Benavides
- Aix Marseille Université, CNRS, Université de Toulon, IRD, OSU Pythéas, Mediterranean Institute of Oceanography (MIO), UM 110, 13288 Marseille, France
- Turing Center for Living Systems, Aix-Marseille University, Marseille, France
| |
Collapse
|
3
|
Zou C, Yi X, Li H, Bizic M, Berman-Frank I, Gao K. Correlation of methane production with physiological traits in Trichodesmium IMS 101 grown with methylphosphonate at different temperatures. Front Microbiol 2024; 15:1396369. [PMID: 38894967 PMCID: PMC11184136 DOI: 10.3389/fmicb.2024.1396369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 05/20/2024] [Indexed: 06/21/2024] Open
Abstract
The diazotrophic cyanobacterium Trichodesmium has been recognized as a potentially significant contributor to aerobic methane generation via several mechanisms including the utilization of methylphophonate (MPn) as a source of phosphorus. Currently, there is no information about how environmental factors regulate methane production by Trichodesmium. Here, we grew Trichodesmium IMS101 at five temperatures ranging from 16 to 31°C, and found that its methane production rates increased with rising temperatures to peak (1.028 ± 0.040 nmol CH4 μmol POC-1 day-1) at 27°C, and then declined. Its specific growth rate changed from 0.03 ± 0.01 d-1 to 0.34 ± 0.02 d-1, with the optimal growth temperature identified between 27 and 31°C. Within the tested temperature range the Q10 for the methane production rate was 4.6 ± 0.7, indicating a high sensitivity to thermal changes. In parallel, the methane production rates showed robust positive correlations with the assimilation rates of carbon, nitrogen, and phosphorus, resulting in the methane production quotients (molar ratio of carbon, nitrogen, or phosphorus assimilated to methane produced) of 227-494 for carbon, 40-128 for nitrogen, and 1.8-3.4 for phosphorus within the tested temperature range. Based on the experimental data, we estimated that the methane released from Trichodesmium can offset about 1% of its CO2 mitigation effects.
Collapse
Affiliation(s)
- Chuze Zou
- State Key Laboratory of Marine Environmental Science, College of the Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Xiangqi Yi
- Polar and Marine Research Institute, College of Harbor and Coastal Engineering, Jimei University, Xiamen, China
| | - He Li
- Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, China
| | - Mina Bizic
- Department of Environmental Microbiomics, Institute of Environmental Technology, Technical University of Berlin, Berlin, Germany
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Stechlin, Germany
| | - Ilana Berman-Frank
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Kunshan Gao
- State Key Laboratory of Marine Environmental Science, College of the Ocean and Earth Sciences, Xiamen University, Xiamen, China
- Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, China
| |
Collapse
|
4
|
Masuda T, Mareš J, Shiozaki T, Inomura K, Fujiwara A, Prášil O. Crocosphaera watsonii - A widespread nitrogen-fixing unicellular marine cyanobacterium. JOURNAL OF PHYCOLOGY 2024; 60:604-620. [PMID: 38551849 DOI: 10.1111/jpy.13450] [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: 05/05/2023] [Revised: 12/14/2023] [Accepted: 02/08/2024] [Indexed: 06/12/2024]
Abstract
Crocosphaera watsonii is a unicellular N2-fixing (diazotrophic) cyanobacterium observed in tropical and subtropical oligotrophic oceans. As a diazotroph, it can be a source of bioavailable nitrogen (N) to the microbial community in N-limited environments, and this may fuel primary production in the regions where it occurs. Crocosphaera watsonii has been the subject of intense study, both in culture and in field populations. Here, we summarize the current understanding of the phylogenetic and physiological diversity of C. watsonii, its distribution, and its ecological niche. Analysis of the relationships among the individual Crocosphaera species and related free-living and symbiotic lineages of diazotrophs based on the nifH gene have shown that the C. watsonii group holds a basal position and that its sequence is more similar to Rippkaea and Zehria than to other Crocosphaera species. This finding warrants further scrutiny to determine if the placement is related to a horizontal gene transfer event. Here, the nifH UCYN-B gene copy number from a recent synthesis effort was used as a proxy for relative C. watsonii abundance to examine patterns of C. watsonii distribution as a function of environmental factors, like iron and phosphorus concentration, and complimented with a synthesis of C. watsonii physiology. Furthermore, we have summarized the current knowledge of C. watsonii with regards to N2 fixation, photosynthesis, and quantitative modeling of physiology. Because N availability can limit primary production, C. watsonii is widely recognized for its importance to carbon and N cycling in ocean ecosystems, and we conclude this review by highlighting important topics for further research on this important species.
Collapse
Affiliation(s)
- Takako Masuda
- Institute of Microbiology, The Czech Academy of Sciences, Třeboň, Czech Republic
- Japan Fisheries Research and Education Agency, Shiogama, Miyagi, Japan
| | - Jan Mareš
- Institute of Microbiology, The Czech Academy of Sciences, Třeboň, Czech Republic
- Institute of Hydrobiology, Biology Centre, The Czech Academy of Sciences, České Budejovice, Czech Republic
| | - Takuhei Shiozaki
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan
| | - Keisuke Inomura
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA
| | - Amane Fujiwara
- Research Institute for Global Change, JAMSTEC, Yokosuka, Japan
| | - Ondřej Prášil
- Institute of Microbiology, The Czech Academy of Sciences, Třeboň, Czech Republic
| |
Collapse
|
5
|
Deutsch C, Inomura K, Luo YW, Wang YP. Projecting global biological N 2 fixation under climate warming across land and ocean. Trends Microbiol 2024; 32:546-553. [PMID: 38262802 DOI: 10.1016/j.tim.2023.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 12/04/2023] [Accepted: 12/18/2023] [Indexed: 01/25/2024]
Abstract
Biological N2 fixation sustains the global inventory of nitrogenous nutrients essential for the productivity of terrestrial and marine ecosystems. Like most metabolic processes, rates of biological N2 fixation vary strongly with temperature, making it sensitive to climate change, but a global projection across land and ocean is lacking. Here we use compilations of field and laboratory measurements to reveal a relationship between N2 fixation rates and temperature that is similar in both domains despite large taxonomic and environmental differences. Rates of N2 fixation increase gradually to a thermal optimum around ~25°C, and decline more rapidly toward a thermal maximum, which is lower in the ocean than on land. In both realms, the observed temperature sensitivities imply that climate warming this century could decrease N2 fixation rates by ~50% in the tropics while increasing rates by ~50% in higher latitudes. We propose a conceptual framework for understanding the physiological and ecological mechanisms that underpin and modulate the observed temperature dependence of global N2 fixation rates, facilitating cross-fertilization of marine and terrestrial research to assess its response to climate change.
Collapse
Affiliation(s)
- Curtis Deutsch
- Department of Geosciences and High Meadows Environmental Institute, Princeton University, Princeton, NJ, USA.
| | - Keisuke Inomura
- Graduate School of Oceanography, University of Rhode Island, South Kingstown, RI, USA
| | - Ya-Wei Luo
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, China
| | - Ying-Ping Wang
- CSIRO Environment, Private Bag 10, Clayton South, VIC 3169, Australia
| |
Collapse
|
6
|
Deng L, Cheung S, Liu J, Chen J, Chen F, Zhang X, Liu H. Nanoplastics impair growth and nitrogen fixation of marine nitrogen-fixing cyanobacteria. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 350:123960. [PMID: 38608853 DOI: 10.1016/j.envpol.2024.123960] [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: 10/31/2023] [Revised: 03/09/2024] [Accepted: 04/09/2024] [Indexed: 04/14/2024]
Abstract
Nanoplastics pollution is a growing environmental problem worldwide. Recent research has demonstrated the toxic effects of nanoplastics on various marine organisms. However, the influences of nanoplastics on marine nitrogen-fixing cyanobacteria, a critical nitrogen source in the ocean, remained unknown. Here, we report that nanoplastics exposure significantly reduced growth, photosynthetic, and nitrogen fixation rates of Crocosphaera watsonii (a major marine nitrogen-fixing cyanobacterium). Transcriptomic analysis revealed that nanoplastics might harm C. watsonii via downregulation of photosynthetic pathways and DNA damage repair genes, while genes for respiration, cell damage, nitrogen limitation, and iron (and phosphorus) scavenging were upregulated. The number and size of starch grains and electron-dense vacuoles increased significantly after nanoplastics exposure, suggesting that C. watsonii allocated more resources to storage instead of growth under stress. We propose that nanoplastics can damage the cell (e.g., DNA, cell membrane, and membrane-bound transporters), inhibit nitrogen and carbon fixation, and hence lead to nutrient limitation and impaired growth. Our findings suggest the possibility that nanoplastics pollution could reduce the new nitrogen input and hence affect the productivity in the ocean. The impact of nanoplastics on marine nitrogen fixation and productivity should be considered when predicting the ecosystem response and biogeochemical cycling in the changing ocean.
Collapse
Affiliation(s)
- Lixia Deng
- Department of Ocean Science, The Hong Kong University of Science and Technology, China
| | - Shunyan Cheung
- Institute of Marine Biology, National Taiwan Ocean University, Keelung, Taiwan; Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan
| | - Jiaxing Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Jiawei Chen
- Department of Ocean Science, The Hong Kong University of Science and Technology, China
| | - Fengyuan Chen
- Department of Ocean Science, The Hong Kong University of Science and Technology, China; SZU-HKUST Joint PhD Program in Marine Environmental Science, Shenzhen University, Shenzhen, China
| | - Xiaodong Zhang
- Department of Ocean Science, The Hong Kong University of Science and Technology, China
| | - Hongbin Liu
- Department of Ocean Science, The Hong Kong University of Science and Technology, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China; Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), The Hong Kong University of Science and Technology, China.
| |
Collapse
|
7
|
Tschitschko B, Esti M, Philippi M, Kidane AT, Littmann S, Kitzinger K, Speth DR, Li S, Kraberg A, Tienken D, Marchant HK, Kartal B, Milucka J, Mohr W, Kuypers MMM. Rhizobia-diatom symbiosis fixes missing nitrogen in the ocean. Nature 2024; 630:899-904. [PMID: 38723661 PMCID: PMC11208148 DOI: 10.1038/s41586-024-07495-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 04/30/2024] [Indexed: 06/21/2024]
Abstract
Nitrogen (N2) fixation in oligotrophic surface waters is the main source of new nitrogen to the ocean1 and has a key role in fuelling the biological carbon pump2. Oceanic N2 fixation has been attributed almost exclusively to cyanobacteria, even though genes encoding nitrogenase, the enzyme that fixes N2 into ammonia, are widespread among marine bacteria and archaea3-5. Little is known about these non-cyanobacterial N2 fixers, and direct proof that they can fix nitrogen in the ocean has so far been lacking. Here we report the discovery of a non-cyanobacterial N2-fixing symbiont, 'Candidatus Tectiglobus diatomicola', which provides its diatom host with fixed nitrogen in return for photosynthetic carbon. The N2-fixing symbiont belongs to the order Rhizobiales and its association with a unicellular diatom expands the known hosts for this order beyond the well-known N2-fixing rhizobia-legume symbioses on land6. Our results show that the rhizobia-diatom symbioses can contribute as much fixed nitrogen as can cyanobacterial N2 fixers in the tropical North Atlantic, and that they might be responsible for N2 fixation in the vast regions of the ocean in which cyanobacteria are too rare to account for the measured rates.
Collapse
Affiliation(s)
- Bernhard Tschitschko
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- Department of Microbiology, University of Innsbruck, Innsbruck, Austria
| | - Mertcan Esti
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Miriam Philippi
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Abiel T Kidane
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Sten Littmann
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Katharina Kitzinger
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Daan R Speth
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- Centre for Microbiology and Environmental Systems Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
| | - Shengjie Li
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Alexandra Kraberg
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Daniela Tienken
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Hannah K Marchant
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- MARUM - Centre for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Boran Kartal
- Max Planck Institute for Marine Microbiology, Bremen, Germany
- School of Science, Constructor University, Bremen, Germany
| | - Jana Milucka
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | - Wiebke Mohr
- Max Planck Institute for Marine Microbiology, Bremen, Germany
| | | |
Collapse
|
8
|
Zehr JP, Capone DG. Unsolved mysteries in marine nitrogen fixation. Trends Microbiol 2024; 32:532-545. [PMID: 37658011 DOI: 10.1016/j.tim.2023.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 09/03/2023]
Abstract
Biological nitrogen (N2) fixation is critical in global biogeochemical cycles and in sustaining the productivity of the oceans. There remain many unanswered questions, unresolved hypotheses, and unchallenged paradigms. The fundamental balance of N input and losses has not been fully resolved. One of the major N2-fixers, Trichodesmium, remains an enigma with intriguing biological and ecological secrets. Cyanobacterial N2 fixation, once thought to be primarily due to free-living cyanobacteria, now also appears to be dependent on microbial interactions, from microbiomes to unicellular symbioses, which remain poorly characterized. Nitrogenase genes associated with diverse non-cyanobacterial diazotrophs (NCDs) are prevalent, but their significance remains a huge knowledge gap. Answering questions, new and old, such as those discussed here, is needed to understand the ocean's N and C cycles and their responses to environmental change.
Collapse
Affiliation(s)
- Jonathan P Zehr
- Ocean Sciences Department, University of California Santa Cruz, Santa Cruz, CA, USA.
| | - Douglas G Capone
- Marine and Environmental Biology Section of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| |
Collapse
|
9
|
Zhang Z, Zhang Q, Chen B, Yu Y, Wang T, Xu N, Fan X, Penuelas J, Fu Z, Deng Y, Zhu YG, Qian H. Global biogeography of microbes driving ocean ecological status under climate change. Nat Commun 2024; 15:4657. [PMID: 38822036 PMCID: PMC11143227 DOI: 10.1038/s41467-024-49124-0] [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: 10/25/2023] [Accepted: 05/23/2024] [Indexed: 06/02/2024] Open
Abstract
Microbial communities play a crucial role in ocean ecology and global biogeochemical processes. However, understanding the intricate interactions among diversity, taxonomical composition, functional traits, and how these factors respond to climate change remains a significant challenge. Here, we propose seven distinct ecological statuses by systematically considering the diversity, structure, and biogeochemical potential of the ocean microbiome to delineate their biogeography. Anthropogenic climate change is expected to alter the ecological status of the surface ocean by influencing environmental conditions, particularly nutrient and oxygen contents. Our predictive model, which utilizes machine learning, indicates that the ecological status of approximately 32.44% of the surface ocean may undergo changes from the present to the end of this century, assuming no policy interventions. These changes mainly include poleward shifts in the main taxa, increases in photosynthetic carbon fixation and decreases in nutrient metabolism. However, this proportion can decrease significantly with effective control of greenhouse gas emissions. Our study underscores the urgent necessity for implementing policies to mitigate climate change, particularly from an ecological perspective.
Collapse
Affiliation(s)
- Zhenyan Zhang
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, PR China
| | - Qi Zhang
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, PR China
- College of Chemistry & Chemical Engineering, Shaoxing University, Shaoxing, 312000, PR China
| | - Bingfeng Chen
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, PR China
| | - Yitian Yu
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, PR China
| | - Tingzhang Wang
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, 310012, PR China
| | - Nuohan Xu
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, PR China
- College of Chemistry & Chemical Engineering, Shaoxing University, Shaoxing, 312000, PR China
| | - Xiaoji Fan
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, 310012, PR China
| | - Josep Penuelas
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, 08193, Barcelona, Catalonia, Spain
- CREAF, Campus Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Barcelona, Catalonia, Spain
| | - Zhengwei Fu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310032, PR China
| | - Ye Deng
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, 100085, Beijing, PR China
| | - Yong-Guan Zhu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, 100085, Beijing, PR China
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, PR China
| | - Haifeng Qian
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, PR China.
| |
Collapse
|
10
|
Kang W, Mu L, Hu X. Marine Colloids Boost Nitrogen Fixation in Trichodesmium erythraeum by Photoelectrophy. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:9236-9249. [PMID: 38748855 DOI: 10.1021/acs.est.4c01849] [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: 05/29/2024]
Abstract
Nitrogen fixation by the diazotrophic cyanobacterium Trichodesmium contributes up to 50% of the bioavailable nitrogen in the ocean. N2 fixation by Trichodesmium is limited by the availability of nutrients, such as iron (Fe) and phosphorus (P). Although colloids are ubiquitous in the ocean, the effects of Fe limitation on nitrogen fixation by marine colloids (MC) and the related mechanisms are largely unexplored. In this study, we found that MC exhibit photoelectrochemical properties that boost nitrogen fixation by photoelectrophy in Trichodesmium erythraeum. MC efficiently promote photosynthesis in T. erythraeum, thus enhancing its growth. Photoexcited electrons from MC are directly transferred to the photosynthetic electron transport chain and contribute to nitrogen fixation and ammonia assimilation. Transcriptomic analysis revealed that MC significantly upregulates genes related to the electron transport chain, photosystem, and photosynthesis, which is consistent with elevated photosynthetic capacities (e.g., Fv/Fm and carboxysomes). As a result, MC increase the N2 fixation rate by 67.5-89.3%. Our findings highlight a proof-of-concept electron transfer pathway by which MC boost nitrogen fixation, broadening our knowledge on the role of ubiquitous colloids in marine nitrogen biogeochemistry.
Collapse
Affiliation(s)
- Weilu Kang
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Carbon Neutrality Interdisciplinary Science Centre, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Li Mu
- Tianjin Key Laboratory of Agro-Environment and Product Safety, Key Laboratory for Environmental Factors Controlling Agro-Product Quality Safety (Ministry of Agriculture and Rural Affairs), Institute of Agro-Environmental Protection, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
| | - Xiangang Hu
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Carbon Neutrality Interdisciplinary Science Centre, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| |
Collapse
|
11
|
He D, Adachi K, Hashizume D, Nakamura R. Copper sulfide mineral performs non-enzymatic anaerobic ammonium oxidation through a hydrazine intermediate. Nat Chem 2024:10.1038/s41557-024-01537-6. [PMID: 38789556 DOI: 10.1038/s41557-024-01537-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 04/16/2024] [Indexed: 05/26/2024]
Abstract
Anaerobic ammonium oxidation (anammox)-the biological process that activates ammonium with nitrite-is responsible for a significant fraction of N2 production in marine environments. Despite decades of biochemical research, however, no synthetic models capable of anammox have been identified. Here we report that a copper sulfide mineral replicates the entire biological anammox pathway catalysed by three metalloenzymes. We identified a copper-nitrosonium {CuNO}10 complex, formed by nitrite reduction, as the oxidant for ammonium oxidation that leads to heterolytic N-N bond formation from nitrite and ammonium. Similar to the biological process, N2 production was mediated by the highly reactive intermediate hydrazine, one of the most potent reductants in nature. We also found another pathway involving N-N bond heterocoupling for the formation of hybrid N2O, a potent greenhouse gas with a unique isotope composition. Our study represents a rare example of non-enzymatic anammox reaction that interconnects six redox states in the abiotic nitrogen cycle.
Collapse
Affiliation(s)
- Daoping He
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan.
- Biofunctional Catalyst Research Team, RIKEN Center for Sustainable Resource Science, Saitama, Japan.
| | - Kiyohiro Adachi
- Materials Characterization Support Team, RIKEN Center for Emergent Matter Science, Saitama, Japan
| | - Daisuke Hashizume
- Materials Characterization Support Team, RIKEN Center for Emergent Matter Science, Saitama, Japan
| | - Ryuhei Nakamura
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan.
- Biofunctional Catalyst Research Team, RIKEN Center for Sustainable Resource Science, Saitama, Japan.
| |
Collapse
|
12
|
Kim KH, Kim JM, Baek JH, Jeong SE, Kim H, Yoon HS, Jeon CO. Metabolic relationships between marine red algae and algae-associated bacteria. MARINE LIFE SCIENCE & TECHNOLOGY 2024; 6:298-314. [PMID: 38827136 PMCID: PMC11136935 DOI: 10.1007/s42995-024-00227-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 12/28/2023] [Indexed: 06/04/2024]
Abstract
Mutualistic interactions between marine phototrophs and associated bacteria are an important strategy for their successful survival in the ocean, but little is known about their metabolic relationships. Here, bacterial communities in the algal sphere (AS) and bulk solution (BS) of nine marine red algal cultures were analyzed, and Roseibium and Phycisphaera were identified significantly more abundantly in AS than in BS. The metabolic features of Roseibium RMAR6-6 (isolated and genome-sequenced), Phycisphaera MAG 12 (obtained by metagenomic sequencing), and a marine red alga, Porphyridium purpureum CCMP1328 (from GenBank), were analyzed bioinformatically. RMAR6-6 has the genetic capability to fix nitrogen and produce B vitamins (B1, B2, B5, B6, B9, and B12), bacterioferritin, dimethylsulfoniopropionate (DMSP), and phenylacetate that may enhance algal growth, whereas MAG 12 may have a limited metabolic capability, not producing vitamins B9 and B12, DMSP, phenylacetate, and siderophores, but with the ability to produce bacitracin, possibly modulating algal microbiome. P. purpureum CCMP1328 lacks the genetic capability to fix nitrogen and produce vitamin B12, DMSP, phenylacetate, and siderophore. It was shown that the nitrogen-fixing ability of RMAR6-6 promoted the growth of P. purpureum, and DMSP reduced the oxidative stress of P. purpureum. The metabolic interactions between strain RMAR6-6 and P. purpureum CCMP1328 were also investigated by the transcriptomic analyses of their monoculture and co-culture. Taken together, potential metabolic relationships between Roseibium and P. purpureum were proposed. This study provides a better understanding of the metabolic relationships between marine algae and algae-associated bacteria for successful growth. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-024-00227-z.
Collapse
Affiliation(s)
- Kyung Hyun Kim
- Department of Biological Sciences and Biotechnology, Hannam University, Daejon, 34054 Republic of Korea
| | - Jeong Min Kim
- Department of Life Science, Chung-Ang University, Seoul, 06974 Republic of Korea
| | - Ju Hye Baek
- Department of Life Science, Chung-Ang University, Seoul, 06974 Republic of Korea
| | - Sang Eun Jeong
- Department of Life Science, Chung-Ang University, Seoul, 06974 Republic of Korea
| | - Hocheol Kim
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419 Republic of Korea
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419 Republic of Korea
| | - Che Ok Jeon
- Department of Life Science, Chung-Ang University, Seoul, 06974 Republic of Korea
| |
Collapse
|
13
|
Avendaño KA, Ponce-Jahen SJ, Valenzuela EI, Pajares S, Samperio-Ramos G, Camacho-Ibar VF, Cervantes FJ. Nitrogen loss in coastal sediments driven by anaerobic ammonium oxidation coupled to microbial reduction of Mn(IV)-oxide. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 923:171368. [PMID: 38438040 DOI: 10.1016/j.scitotenv.2024.171368] [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: 01/12/2024] [Revised: 02/27/2024] [Accepted: 02/27/2024] [Indexed: 03/06/2024]
Abstract
Coastal sediments play a central role in regulating the amount of land-derived reactive nitrogen (Nr) entering the ocean, and their importance becomes crucial in vulnerable ecosystems threatened by anthropogenic activities. Sedimentary denitrification has been identified as the main sink of Nr in marine environments, while anaerobic ammonium oxidation with nitrite (anammox) has also been pointed out as a key player in controlling the nitrogen pool in these locations. Collected evidence in the present work indicates that the microbial biota in coastal sediments from Baja California (northwestern Mexico) has the potential to drive anaerobic ammonium oxidation linked to Mn(IV) reduction (manganammox). Unamended sediment showed ammonification, but addition of vernadite (δMnO2 with nano-crystal size ∼15 Å) as terminal electron acceptor fueled simultaneous ammonium oxidation (up to ∼400 μM of ammonium removed) and production of Mn(II) with a ratio ∆[Mn(II)]/∆[NH4+] of 1.8, which is very close to the stoichiometric value of manganammox (1.5). Additional incubations spiked with external ammonium also showed concomitant ammonium oxidation and Mn(II) production, accounting for ∼30 % of the oxidized ammonium. Tracer analysis revealed that the nitrogen loss associated with manganammox was 4.2 ± 0.4 μg 30N2/g-day, which is 17-fold higher than that related to the feammox process (anaerobic ammonium oxidation linked to Fe(III) reduction, 0.24 ± 0.02 μg 30N2/g-day). Taxonomic characterization based on 16S rRNA gene sequencing revealed the existence of several clades belonging to Desulfobacterota as potential microorganisms catalyzing the manganammox process. These findings suggest that manganammox has the potential to be an additional Nr sink in coastal environments, whose contribution to total Nr losses remains to be evaluated.
Collapse
Affiliation(s)
- Karen A Avendaño
- Laboratory for Research on Advanced Processes for Water Treatment, Engineering Institute, Campus Juriquilla, Universidad Nacional Autónoma de México, Blvd. Juriquilla 2001, 76230 Querétaro, Mexico
| | - Sergio J Ponce-Jahen
- Laboratory for Research on Advanced Processes for Water Treatment, Engineering Institute, Campus Juriquilla, Universidad Nacional Autónoma de México, Blvd. Juriquilla 2001, 76230 Querétaro, Mexico
| | - Edgardo I Valenzuela
- Escuela de Ingeniería y Ciencias, Tecnológico de Monterrey, Campus Puebla, Atlixcáyotl 5718, Reserva Territorial Atlixcáyotl, Puebla 72453, Mexico
| | - Silvia Pajares
- Unidad Académica de Ecología y Biodiversidad Acuática, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Guillermo Samperio-Ramos
- Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Ensenada, Mexico
| | - Víctor F Camacho-Ibar
- Instituto de Investigaciones Oceanológicas, Universidad Autónoma de Baja California, Ensenada, Mexico
| | - Francisco J Cervantes
- Laboratory for Research on Advanced Processes for Water Treatment, Engineering Institute, Campus Juriquilla, Universidad Nacional Autónoma de México, Blvd. Juriquilla 2001, 76230 Querétaro, Mexico.
| |
Collapse
|
14
|
Sánchez A, Galan-Caamal RJ, Ortiz-Hernández MC, Sánchez-Sánchez J, Camacho-Cruz KA, Anguas-Cabrera D. Ammonium depletion associated with the COVID-19 pandemic in the Mexican Caribbean. MARINE POLLUTION BULLETIN 2024; 202:116347. [PMID: 38608428 DOI: 10.1016/j.marpolbul.2024.116347] [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: 02/25/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 04/14/2024]
Abstract
The Mexican Caribbean contributes significantly to Mexico's gross national product. The number of tourists declined from 16.7 million in 2019 to 8.8 million in 2020 due to the COVID-19 pandemic, with a rapid recovery of 13.5 million in 2021. Wastewater discharge is the primary contamination source associated with the tourism sector's demand for goods and services. Water quality could improve due to fewer tourists arriving during the COVID-19 sanitary emergency. This study aimed to quantify ammonium concentrations at eleven locations to evaluate water quality during the sanitary restriction due to the pandemic in the Mexican Caribbean. The ammonium concentrations were 85 % (Nov-2019), 89 % (Feb-2020), and 86 % (Feb-2021) higher than in Nov-2020, where six of the eleven sampled stations were below the detection limit (0.15 μM). Lower ammonium concentrations coincide with the sanitary restriction period and a decrease in affluent tourists.
Collapse
Affiliation(s)
- A Sánchez
- Centro Interdisciplinario de Ciencias Marinas del Instituto Politécnico Nacional, La Paz, B.C.S., Mexico.
| | - R J Galan-Caamal
- El Colegio de la Frontera Sur, Unidad Chetumal, Chetumal, Quintana Roo, Mexico
| | | | - J Sánchez-Sánchez
- El Colegio de la Frontera Sur, Unidad Chetumal, Chetumal, Quintana Roo, Mexico
| | - K A Camacho-Cruz
- Centro Interdisciplinario de Ciencias Marinas del Instituto Politécnico Nacional, La Paz, B.C.S., Mexico; Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo, Mexico
| | - D Anguas-Cabrera
- El Colegio de la Frontera Sur, Unidad Chetumal, Chetumal, Quintana Roo, Mexico
| |
Collapse
|
15
|
Siriwardana H, Samarasekara RSM, Anthony D, Vithanage M. Measurements and analysis of nitrogen and phosphorus in oceans: Practice, frontiers, and insights. Heliyon 2024; 10:e28182. [PMID: 38560146 PMCID: PMC10979167 DOI: 10.1016/j.heliyon.2024.e28182] [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: 07/05/2023] [Revised: 03/11/2024] [Accepted: 03/13/2024] [Indexed: 04/04/2024] Open
Abstract
Nitrogen and phosphorus concentrations in oceans have been extensively studied, and advancements in associated disciplines have rapidly progressed, enabling the exploration of novel and previously challenging questions. A keyword analysis was conducted using the Scopus database to examine chronological trends and hotspots, offering comprehensive insights into the evolution of marine nitrogen and phosphorus research. For this purpose, author keyword networks were developed for the periods before 1990, 1990 to 2000, 2001 to 2011, and 2012 to 2022. Furthermore, analytical techniques employed in the recent decade to determine nitrogen and phosphorus concentrations in seawater were assessed for their applicability and limitations through a critical review of more than 50 journal articles. Taxonomy and nitrogen biogeochemistry were the prominent research interests for the first two periods, respectively, while stable isotopic tracking of nitrogen and phosphorus processes emerged as the dominant research focus for the last two decades. The integration of macroeconomic factors in research development and the chronological rise of interdisciplinary research were identified. Conventional analytical techniques such as spectrophotometry, colorimetry, fluorometry, and elemental analysis were noted, along with emerging techniques like remote sensing and microfluidic sensors.
Collapse
Affiliation(s)
- Hasitha Siriwardana
- Faculty of Engineering, University of Sri Jayewardenepura, 41, Lumbini Avenue, Ratmalana 10390, Sri Lanka
| | - R S M Samarasekara
- Faculty of Engineering, University of Sri Jayewardenepura, 41, Lumbini Avenue, Ratmalana 10390, Sri Lanka
| | - Damsara Anthony
- Faculty of Engineering, University of Sri Jayewardenepura, 41, Lumbini Avenue, Ratmalana 10390, Sri Lanka
- Department of Civil Engineering, Faculty of Engineering, General Sir John Kotelawala Defence University, Ratmalana, Sri Lanka
| | - Meththika Vithanage
- Ecosphere Resilience Research Center (ERRC), Faculty of Applied Sciences, University of Sri Jayewardenepura, Nugegoda 10250, Sri Lanka
| |
Collapse
|
16
|
Cornejo-Castillo FM, Inomura K, Zehr JP, Follows MJ. Metabolic trade-offs constrain the cell size ratio in a nitrogen-fixing symbiosis. Cell 2024; 187:1762-1768.e9. [PMID: 38471501 DOI: 10.1016/j.cell.2024.02.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 10/06/2023] [Accepted: 02/14/2024] [Indexed: 03/14/2024]
Abstract
Biological dinitrogen (N2) fixation is a key metabolic process exclusively performed by prokaryotes, some of which are symbiotic with eukaryotes. Species of the marine haptophyte algae Braarudosphaera bigelowii harbor the N2-fixing endosymbiotic cyanobacteria UCYN-A, which might be evolving organelle-like characteristics. We found that the size ratio between UCYN-A and their hosts is strikingly conserved across sublineages/species, which is consistent with the size relationships of organelles in this symbiosis and other species. Metabolic modeling showed that this size relationship maximizes the coordinated growth rate based on trade-offs between resource acquisition and exchange. Our findings show that the size relationships of N2-fixing endosymbionts and organelles in unicellular eukaryotes are constrained by predictable metabolic underpinnings and that UCYN-A is, in many regards, functioning like a hypothetical N2-fixing organelle (or nitroplast).
Collapse
Affiliation(s)
- Francisco M Cornejo-Castillo
- Department of Marine Biology and Oceanography, Institut de Ciències del Mar, ICM-CSIC, Barcelona 08003, Spain; Department of Ocean Sciences, University of California, Santa Cruz, CA 95064, USA.
| | - Keisuke Inomura
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, USA.
| | - Jonathan P Zehr
- Department of Ocean Sciences, University of California, Santa Cruz, CA 95064, USA
| | - Michael J Follows
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| |
Collapse
|
17
|
Acosta KG, Juhl AR, Subramaniam A, Duhamel S. Spatial and temporal variation in surface nitrate and phosphate in the Northern Gulf of Mexico over 35 years. Sci Rep 2024; 14:7305. [PMID: 38538688 PMCID: PMC10973365 DOI: 10.1038/s41598-024-58044-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 03/25/2024] [Indexed: 04/01/2024] Open
Abstract
Dissolved inorganic nutrient concentrations in the surface waters (0 to 5 m) of the Northern Gulf of Mexico (NGoM) were analyzed from 1985 to 2019 (> 10,000 observations) to determine spatiotemporal trends and their connection to nutrients supplied from the Mississippi/Atchafalaya River (MAR). In the NGoM, annual mean dissolved inorganic P (DIP) concentrations increased significantly over time, while dissolved inorganic N (DIN) concentrations showed no temporal trend. With greater salinity, mean DIN:DIP decreased from above the Redfield ratio of 16 to below it, reflecting DIN losses and the more conservative behavior of DIP with salinity. Over the same time period, annual mean P (total dissolved P, DIP, dissolved organic P) loading from the MAR to the NGoM significantly increased, annual mean DIN and total dissolved N loading showed no temporal trend, and dissolved organic N loading significantly decreased. Though DIP increased in the MAR, MAR DIP alone was insufficient to explain the surface distribution of DIP with salinity. Therefore, increases in surface DIP in the NGoM are not simply a reflection of increasing MAR DIP, pointing to temporal changes in other DIP sources. The increase in NGoM DIP suggests greater N limitation for phytoplankton, with implications for N fixation and nutrient management.
Collapse
Affiliation(s)
- Kailani G Acosta
- Lamont-Doherty Earth Observatory, Columbia University, 61 Route 9W, Palisades, NY, 10964, USA.
| | - Andrew R Juhl
- Lamont-Doherty Earth Observatory, Columbia University, 61 Route 9W, Palisades, NY, 10964, USA
| | - Ajit Subramaniam
- Lamont-Doherty Earth Observatory, Columbia University, 61 Route 9W, Palisades, NY, 10964, USA
| | - Solange Duhamel
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, 85721, USA
| |
Collapse
|
18
|
Russell SJ, Garcia AK, Kaçar B. A CRISPR interference system for engineering biological nitrogen fixation. mSystems 2024; 9:e0015524. [PMID: 38376168 PMCID: PMC10949490 DOI: 10.1128/msystems.00155-24] [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: 01/31/2024] [Accepted: 01/31/2024] [Indexed: 02/21/2024] Open
Abstract
A grand challenge for the next century is in facing a changing climate through bioengineering solutions. Biological nitrogen fixation, the globally consequential, nitrogenase-catalyzed reduction of atmospheric nitrogen to bioavailable ammonia, is a vital area of focus. Nitrogen fixation engineering relies upon extensive understanding of underlying genetics in microbial models, including the broadly utilized gammaproteobacterium, Azotobacter vinelandii (A. vinelandii). Here, we report the first CRISPR interference (CRISPRi) system for targeted gene silencing in A. vinelandii that integrates genomically via site-specific transposon insertion. We demonstrate that CRISPRi can repress transcription of an essential nitrogen fixation gene by ~60%. Further, we show that nitrogenase genes are suitably expressed from the transposon insertion site, indicating that CRISPRi and engineered nitrogen fixation genes can be co-integrated for combinatorial studies of gene expression and engineering. Our established CRISPRi system fills an important gap for engineering microbial nitrogen fixation for desired purposes.IMPORTANCEAll life on Earth requires nitrogen to survive. About 78% of the atmosphere alone is nitrogen, yet humans cannot use it directly. Instead, we obtain the nitrogen we need for our survival through the food we eat. For more than 100 years, a substantial portion of agricultural productivity has relied on industrial methods for nitrogen fertilizer synthesis, which consumes significant amounts of nonrenewable energy resources and exacerbates environmental degradation and human-induced climate change. Promising alternatives to these industrial methods rely on engineering the only biological pathway for generating bioaccessible nitrogen: microbial nitrogen fixation. Bioengineering strategies require an extensive understanding of underlying genetics in nitrogen-fixing microbes, but genetic tools for this critical goal remain lacking. The CRISPRi gene silencing system that we report, developed in the broadly utilized nitrogen-fixing bacterial model, Azotobacter vinelandii, is an important step toward elucidating the complexity of nitrogen fixation genetics and enabling their manipulation.
Collapse
Affiliation(s)
- Steven J. Russell
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Amanda K. Garcia
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Betül Kaçar
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| |
Collapse
|
19
|
Arévalo S, Pérez Rico D, Abarca D, Dijkhuizen LW, Sarasa-Buisan C, Lindblad P, Flores E, Nierzwicki-Bauer S, Schluepmann H. Genome Engineering by RNA-Guided Transposition for Anabaena sp. PCC 7120. ACS Synth Biol 2024; 13:901-912. [PMID: 38445989 PMCID: PMC10949235 DOI: 10.1021/acssynbio.3c00583] [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: 11/15/2023] [Revised: 01/30/2024] [Accepted: 02/16/2024] [Indexed: 03/07/2024]
Abstract
In genome engineering, the integration of incoming DNA has been dependent on enzymes produced by dividing cells, which has been a bottleneck toward increasing DNA insertion frequencies and accuracy. Recently, RNA-guided transposition with CRISPR-associated transposase (CAST) was reported as highly effective and specific in Escherichia coli. Here, we developed Golden Gate vectors to test CAST in filamentous cyanobacteria and to show that it is effective in Anabaena sp. strain PCC 7120. The comparatively large plasmids containing CAST and the engineered transposon were successfully transferred into Anabaena via conjugation using either suicide or replicative plasmids. Single guide (sg) RNA encoding the leading but not the reverse complement strand of the target were effective with the protospacer-associated motif (PAM) sequence included in the sgRNA. In four out of six cases analyzed over two distinct target loci, the insertion site was exactly 63 bases after the PAM. CAST on a replicating plasmid was toxic, which could be used to cure the plasmid. In all six cases analyzed, only the transposon cargo defined by the sequence ranging from left and right elements was inserted at the target loci; therefore, RNA-guided transposition resulted from cut and paste. No endogenous transposons were remobilized by exposure to CAST enzymes. This work is foundational for genome editing by RNA-guided transposition in filamentous cyanobacteria, whether in culture or in complex communities.
Collapse
Affiliation(s)
- Sergio Arévalo
- Biology
Department, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
- Microbial
Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Lägerhyddsvägen 1, 751
20 Uppsala, Sweden
- Instituto
de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad
de Sevilla, Avenida Americo Vespucio 49, Sevilla 41092, Spain
- Department
of Biological Sciences, Rensselaer Polytechnic
Institute, 110 Eighth
Street, Troy, New York 12180-3590, United
States
| | - Daniel Pérez Rico
- Biology
Department, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Dolores Abarca
- Biology
Department, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Laura W. Dijkhuizen
- Biology
Department, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Cristina Sarasa-Buisan
- Instituto
de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad
de Sevilla, Avenida Americo Vespucio 49, Sevilla 41092, Spain
| | - Peter Lindblad
- Microbial
Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Lägerhyddsvägen 1, 751
20 Uppsala, Sweden
| | - Enrique Flores
- Instituto
de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad
de Sevilla, Avenida Americo Vespucio 49, Sevilla 41092, Spain
| | - Sandra Nierzwicki-Bauer
- Department
of Biological Sciences, Rensselaer Polytechnic
Institute, 110 Eighth
Street, Troy, New York 12180-3590, United
States
| | - Henriette Schluepmann
- Biology
Department, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| |
Collapse
|
20
|
Crump BC, Bowen JL. The Microbial Ecology of Estuarine Ecosystems. ANNUAL REVIEW OF MARINE SCIENCE 2024; 16:335-360. [PMID: 37418833 DOI: 10.1146/annurev-marine-022123-101845] [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: 07/09/2023]
Abstract
Human civilization relies on estuaries, and many estuarine ecosystem services are provided by microbial communities. These services include high rates of primary production that nourish harvests of commercially valuable species through fisheries and aquaculture, the transformation of terrestrial and anthropogenic materials to help ensure the water quality necessary to support recreation and tourism, and mutualisms that maintain blue carbon accumulation and storage. Research on the ecology that underlies microbial ecosystem services in estuaries has expanded greatly across a range of estuarine environments, including water, sediment, biofilms, biological reefs, and stands of seagrasses, marshes, and mangroves. Moreover, the application of new molecular tools has improved our understanding of the diversity and genomic functions of estuarine microbes. This review synthesizes recent research on microbial habitats in estuaries and the contributions of microbes to estuarine food webs, elemental cycling, and interactions with plants and animals, and highlights novel insights provided by recent advances in genomics.
Collapse
Affiliation(s)
- Byron C Crump
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA;
| | - Jennifer L Bowen
- Marine Science Center, Department of Marine and Environmental Sciences, Northeastern University, Nahant, Massachusetts, USA;
| |
Collapse
|
21
|
Mao Y, Lin T, Li H, He R, Ye K, Yu W, He Q. Aerobic methane production by phytoplankton as an important methane source of aquatic ecosystems: Reconsidering the global methane budget. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 907:167864. [PMID: 37866611 DOI: 10.1016/j.scitotenv.2023.167864] [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: 08/10/2023] [Revised: 10/09/2023] [Accepted: 10/13/2023] [Indexed: 10/24/2023]
Abstract
Biological methane, a major source of global methane budget, is traditionally thought to be produced in anaerobic environments. However, the recent reports about methane supersaturation occurring in oxygenated water layer, termed as "methane paradox", have challenged this prevailing paradigm. Significantly, growing evidence has indicated that phytoplankton including prokaryotic cyanobacteria and eukaryotic algae are capable of generating methane under aerobic conditions. In this regard, a systematic review of aerobic methane production by phytoplankton is expected to arouse the public attention, contributing to the understanding of methane paradox. Here, we comprehensively summarize the widespread phenomena of methane supersaturation in oxic layers. The remarkable correlation relationships between methane concentration and several key indicators (depth, chlorophyll a level and organic sulfide concentration) indicate the significance of phytoplankton in in-situ methane accumulation. Subsequently, four mechanisms of aerobic methane production by phytoplankton are illustrated in detail, including photosynthesis-driven metabolism, reactive oxygen species (ROS)-driven demethylation of methyl donors, methanogenesis catalyzed by nitrogenase and demethylation of phosphonates catalyzed by CP lyase. The first two pathways occur in various phytoplankton, while the latter two have been specially discovered in cyanobacteria. Additionally, the effects of four crucial factors on aerobic methane production by phytoplankton are also discussed, including phytoplankton species, light, temperature and crucial nutrients. Finally, the measures to control global methane emissions from phytoplankton, the precise intracellular mechanisms of methane production and a more complete global methane budget model are definitely required in the future research on methane production by phytoplankton. This review would provide guidance for future studies of aerobic methane production by phytoplankton and emphasize the potential contribution of aquatic ecosystems to global methane budget.
Collapse
Affiliation(s)
- Yufeng Mao
- Key Laboratory of Eco-Environment of Three Gorges Region, Ministry of Education, Chongqing University, Chongqing 400044, China; Key Laboratory of Hydraulic and Waterway Engineering, Ministry of Education, Chongqing Jiaotong University, Chongqing 400074, China; Lingzhi Environmental Protection Co., Ltd, Wuxi 214200, China
| | - Tong Lin
- Key Laboratory of Eco-Environment of Three Gorges Region, Ministry of Education, Chongqing University, Chongqing 400044, China
| | - Hong Li
- Key Laboratory of Eco-Environment of Three Gorges Region, Ministry of Education, Chongqing University, Chongqing 400044, China
| | - Ruixu He
- Key Laboratory of Hydraulic and Waterway Engineering, Ministry of Education, Chongqing Jiaotong University, Chongqing 400074, China
| | - Kailai Ye
- Key Laboratory of Hydraulic and Waterway Engineering, Ministry of Education, Chongqing Jiaotong University, Chongqing 400074, China
| | - Weiwei Yu
- Key Laboratory of Hydraulic and Waterway Engineering, Ministry of Education, Chongqing Jiaotong University, Chongqing 400074, China
| | - Qiang He
- Key Laboratory of Eco-Environment of Three Gorges Region, Ministry of Education, Chongqing University, Chongqing 400044, China.
| |
Collapse
|
22
|
Raut Y, Barr CR, Paris ER, Kapili BJ, Dekas AE, Capone DG. Autochthonous carbon loading of macroalgae stimulates benthic biological nitrogen fixation rates in shallow coastal marine sediments. Front Microbiol 2024; 14:1312843. [PMID: 38249476 PMCID: PMC10796445 DOI: 10.3389/fmicb.2023.1312843] [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: 10/10/2023] [Accepted: 11/23/2023] [Indexed: 01/23/2024] Open
Abstract
Macroalgae, commonly known as seaweed, are foundational species in coastal ecosystems and contribute significantly to coastal primary production globally. However, the impact of macroalgal decomposition on benthic biological nitrogen fixation (BNF) after deposition to the seafloor remains largely unexplored. In this study, we measure BNF rates at three different sites at the Big Fisherman's Cove on Santa Catalina Island, CA, USA, which is representative of globally distributed rocky bottom macroalgal habitats. Unamended BNF rates varied among sites (0.001-0.05 nmol N g-1 h -1) and were generally within the lower end of previously reported ranges. We hypothesized that the differences in BNF between sites were linked to the availability of organic matter. Indeed, additions of glucose, a labile carbon source, resulted in 2-3 orders of magnitude stimulation of BNF rates in bottle incubations of sediment from all sites. To assess the impact of complex, autochthonous organic matter, we simulated macroalgal deposition and remineralization with additions of brown (i.e., Macrocystis pyrifera and Dictyopteris), green (i.e., Codium fragile), and red (i.e., Asparagopsis taxiformis) macroalgae. While brown and green macroalgal amendments resulted in 53- to 520-fold stimulation of BNF rates-comparable to the labile carbon addition-red alga was found to significantly inhibit BNF rates. Finally, we employed nifH sequencing to characterize the diazotrophic community associated with macroalgal decomposition. We observed a distinct community shift in potential diazotrophs from primarily Gammaproteobacteria in the early stages of remineralization to a community dominated by Deltaproteobacteria (e.g., sulfate reducers), Bacteroidia, and Spirochaeta toward the latter phase of decomposition of brown, green, and red macroalgae. Notably, the nifH-containing community associated with red macroalgal detritus was distinct from that of brown and green macroalgae. Our study suggests coastal benthic diazotrophs are limited by organic carbon and demonstrates a significant and phylum-specific effect of macroalgal loading on benthic microbial communities.
Collapse
Affiliation(s)
- Yubin Raut
- Marine and Environmental Biology, University of Southern California, Los Angeles, CA, United States
| | - Casey R. Barr
- Marine and Environmental Biology, University of Southern California, Los Angeles, CA, United States
| | - Emily R. Paris
- Earth System Science, Stanford University, Stanford, CA, United States
| | - Bennett J. Kapili
- Earth System Science, Stanford University, Stanford, CA, United States
| | - Anne E. Dekas
- Earth System Science, Stanford University, Stanford, CA, United States
| | - Douglas G. Capone
- Marine and Environmental Biology, University of Southern California, Los Angeles, CA, United States
| |
Collapse
|
23
|
Sun X, Xiao Y, Yong C, Sun H, Li S, Huang H, Jiang H. Interactions between the nitrogen-fixing cyanobacterium Trichodesmium and siderophore-producing cyanobacterium Synechococcus under iron limitation. ISME COMMUNICATIONS 2024; 4:ycae072. [PMID: 38873030 PMCID: PMC11171426 DOI: 10.1093/ismeco/ycae072] [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: 12/06/2023] [Revised: 04/07/2024] [Indexed: 06/15/2024]
Abstract
As diazotrophic cyanobacteria of tremendous biomass, Trichodesmium continuously provide a nitrogen source for carbon-fixing cyanobacteria and drive the generation of primary productivity in marine environments. However, ocean iron deficiencies limit growth and metabolism of Trichodesmium. Recent studies have shown the co-occurrence of Trichodesmium and siderophore-producing Synechococcus in iron-deficient oceans, but whether siderophores secreted by Synechococcus can be used by Trichodesmium to adapt to iron deficiency is not clear. We constructed a mutant Synechococcus strain unable to produce siderophores to explore this issue. Synechococcus filtrates with or without siderophores were added into a Trichodesmium microbial consortium consisting of Trichodesmium erythraeum IMS 101 as the dominant microbe with chronic iron deficiency. By analyzing the physiological phenotype, metagenome, and metatranscriptome, we investigated the interactions between the nitrogen-fixing cyanobacterium Tricodesmium and siderophore-producing cyanobacterium Synechococcus under conditions of iron deficiency. The results indicated that siderophores secreted by Synechococcus are likely to chelate with free iron in the culture medium of the Trichodesmium consortium, reducing the concentration of bioavailable iron and posing greater challenges to the absorption of iron by Trichodesmium. These findings revealed the characteristics of iron-competitive utilization between diazotrophic cyanobacteria and siderophore-producing cyanobacteria, as well as potential interactions, and provide a scientific basis for understanding the regulatory effects of nutrient limitation on marine primary productivity.
Collapse
Affiliation(s)
- Xumei Sun
- School of Marine Sciences, Ningbo University, 818 Fenghua Road, Ningbo, Zhejiang, 315211, People’s Republic of China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), 1 Jintang Road, Zhuhai, Guangdong, 519000, People’s Republic of China
| | - Yan Xiao
- School of Life Sciences, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei, 430079, People’s Republic of China
| | - Chengwen Yong
- School of Marine Sciences, Ningbo University, 818 Fenghua Road, Ningbo, Zhejiang, 315211, People’s Republic of China
| | - Hansheng Sun
- School of Marine Sciences, Ningbo University, 818 Fenghua Road, Ningbo, Zhejiang, 315211, People’s Republic of China
| | - Shuangqing Li
- School of Marine Sciences, Ningbo University, 818 Fenghua Road, Ningbo, Zhejiang, 315211, People’s Republic of China
| | - Hailong Huang
- School of Marine Sciences, Ningbo University, 818 Fenghua Road, Ningbo, Zhejiang, 315211, People’s Republic of China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), 1 Jintang Road, Zhuhai, Guangdong, 519000, People’s Republic of China
| | - Haibo Jiang
- School of Marine Sciences, Ningbo University, 818 Fenghua Road, Ningbo, Zhejiang, 315211, People’s Republic of China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), 1 Jintang Road, Zhuhai, Guangdong, 519000, People’s Republic of China
- School of Life Sciences, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei, 430079, People’s Republic of China
| |
Collapse
|
24
|
Li B, Wang L, Li H, Xue J, Luo W, Xing P, Wu QL. Phosphorus-driven regime shift from heterotrophic to autotrophic diazotrophs in a deep alpine lake. WATER RESEARCH 2024; 248:120848. [PMID: 37976949 DOI: 10.1016/j.watres.2023.120848] [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: 08/15/2023] [Revised: 10/21/2023] [Accepted: 11/07/2023] [Indexed: 11/19/2023]
Abstract
Biological nitrogen fixation plays a critical role in maintaining primary production, particularly in systematic nitrogen deficiency. However, little is known about the dynamics within diazotrophic community facing ongoing nutrient enrichment in freshwater lakes. Here, a consecutive five-year investigation on diazotrophic community was conducted in Lake Fuxian, an oligotrophic deep alpine lake on the trajectory to eutrophic state. Results showed a regime shift from heterotrophic to autotrophic diazotrophs induced by total phosphorus (TP) enrichment. Specifically, heterotrophic diazotrophs dominated the diazotrophic community when TP was lower than 21.8 μg/L, whereas heterotrophic diazotrophs or diazotrophic Cyanobacteria randomly dominated when TP ranged between 21.8 μg/L and 28.8 μg/L. When TP was higher than 28.8 μg/L, diazotrophic Cyanobacteria accounted for 60.4%-97.7% of the total N2-fixers, indicating diazotrophic biodiversity significantly declined under TP enrichment scenario. Moreover, the dominance of diazotrophic Cyanobacteria further facilitated phytoplankton growth, which strengthened positive feedback between phytoplankton and phosphorus under nitrogen deficiency conditions. This is the first report on the threshold-like state responses of freshwater diazotrophs to environmental drivers. Our study expands the knowledge of the diazotrophic dynamics in freshwater ecosystems and contributes quantitative evidence of ecological thresholds for future environmental policymaking.
Collapse
Affiliation(s)
- Biao Li
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; The Fuxianhu Station of Plateau Deep Lake Research, Chinese Academy of Sciences, Yuxi 653100, China
| | - Lina Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Department of Postgraduate Administration, Nanjing University of Information Science and Technology, Nanjing 210044, China
| | - Huabing Li
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; The Fuxianhu Station of Plateau Deep Lake Research, Chinese Academy of Sciences, Yuxi 653100, China
| | - Jingya Xue
- School of Geographical Sciences, Nanjing Normal University, Nanjing 210023, China
| | - Wenlei Luo
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; The Fuxianhu Station of Plateau Deep Lake Research, Chinese Academy of Sciences, Yuxi 653100, China
| | - Peng Xing
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; The Fuxianhu Station of Plateau Deep Lake Research, Chinese Academy of Sciences, Yuxi 653100, China.
| | - Qinglong L Wu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Center for Evolution and Conservation Biology, Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China; Sino-Danish Center for Education and Research, University of Chinese Academy of Sciences, Beijing 100039, China; The Fuxianhu Station of Plateau Deep Lake Research, Chinese Academy of Sciences, Yuxi 653100, China.
| |
Collapse
|
25
|
Hoshino Y, Nettersheim BJ, Gold DA, Hallmann C, Vinnichenko G, van Maldegem LM, Bishop C, Brocks JJ, Gaucher EA. Genetics re-establish the utility of 2-methylhopanes as cyanobacterial biomarkers before 750 million years ago. Nat Ecol Evol 2023; 7:2045-2054. [PMID: 37884688 PMCID: PMC10697835 DOI: 10.1038/s41559-023-02223-5] [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: 10/25/2022] [Accepted: 09/06/2023] [Indexed: 10/28/2023]
Abstract
Fossilized lipids offer a rare glimpse into ancient ecosystems. 2-Methylhopanes in sedimentary rocks were once used to infer the importance of cyanobacteria as primary producers throughout geological history. However, the discovery of hopanoid C-2 methyltransferase (HpnP) in Alphaproteobacteria led to the downfall of this molecular proxy. In the present study, we re-examined the distribution of HpnP in a new phylogenetic framework including recently proposed candidate phyla and re-interpreted a revised geological record of 2-methylhopanes based on contamination-free samples. We show that HpnP was probably present in the last common ancestor of cyanobacteria, while the gene appeared in Alphaproteobacteria only around 750 million years ago (Ma). A subsequent rise of sedimentary 2-methylhopanes around 600 Ma probably reflects the expansion of Alphaproteobacteria that coincided with the rise of eukaryotic algae-possibly connected by algal dependency on microbially produced vitamin B12. Our findings re-establish 2-methylhopanes as cyanobacterial biomarkers before 750 Ma and thus as a potential tool to measure the importance of oxygenic cyanobacteria as primary producers on early Earth. Our study illustrates how genetics can improve the diagnostic value of biomarkers and refine the reconstruction of early ecosystems.
Collapse
Affiliation(s)
- Yosuke Hoshino
- GFZ German Research Centre for Geosciences, Potsdam, Germany.
- Department of Biology, Georgia State University, Atlanta, GA, USA.
| | - Benjamin J Nettersheim
- MARUM Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Bremen, Germany.
| | - David A Gold
- Department of Earth and Planetary Sciences, University of California Davis, Davis, CA, USA
| | | | - Galina Vinnichenko
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Lennart M van Maldegem
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Caleb Bishop
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Jochen J Brocks
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Eric A Gaucher
- Department of Biology, Georgia State University, Atlanta, GA, USA
| |
Collapse
|
26
|
Fernández-Juárez V, Hallstrøm S, Pacherres CO, Wang J, Coll-Garcia G, Kühl M, Riemann L. Biofilm formation and cell plasticity drive diazotrophy in an anoxygenic phototrophic bacterium. Appl Environ Microbiol 2023; 89:e0102723. [PMID: 37882569 PMCID: PMC10686084 DOI: 10.1128/aem.01027-23] [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: 06/23/2023] [Accepted: 09/14/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE The contribution of non-cyanobacterial diazotrophs (NCDs) to total N2 fixation in the marine water column is unknown, but their importance is likely constrained by the limited availability of dissolved organic matter and low O2 conditions. Light could support N2 fixation and growth by NCDs, yet no examples from bacterioplankton exist. In this study, we show that the phototrophic NCD, Rhodopseudomonas sp. BAL398, which is a member of the diazotrophic community in the surface waters of the Baltic Sea, can utilize light. Our study highlights the significance of biofilm formation for utilizing light and fixing N2 under oxic conditions and the role of cell plasticity in regulating these processes. Our findings have implications for the general understanding of the ecology and importance of NCDs in marine waters.
Collapse
Affiliation(s)
- Víctor Fernández-Juárez
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Søren Hallstrøm
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark
| | - Cesar O. Pacherres
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jiaqi Wang
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Guillem Coll-Garcia
- Microbiology, Biology Department, University of the Balearic Islands, Palma de Mallorca, Spain
- Environmental Microbiology Group, Mediterranean Institute for Advanced Studies (CSIC-UIB), Esporles, Spain
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Lasse Riemann
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
27
|
Zhang W, Li H, Cao H, Zhao X. Small ponds have stronger potential for net nitrogen removal: Insight from direct dissolved N 2 measurement. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 900:165765. [PMID: 37506899 DOI: 10.1016/j.scitotenv.2023.165765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 07/20/2023] [Accepted: 07/22/2023] [Indexed: 07/30/2023]
Abstract
Growing demands for watershed nitrogen (N) removal have called attention to abundant small bodies of water such as ponds, which have long been heralded as efficient storage and processing systems. Although pond conservation, restoration, and creation have been widely implemented to mitigate N pollution, information is limited regarding the impact of size-that is, whether N removal potential and efficiency are dependent upon pond size. We investigated the dynamics of N removal rates in 56 ponds from a hilly watershed by studying their bimonthly N2 concentrations and fluxes. Our results showed that smaller ponds performed better in net N removal. This can be discerned from the areal N2 fluxes, which were the highest in small ponds (< 4, 000 m2). The corresponding N2 fluxes (4.73 ± 4.53 mmol N2 m-2 d-1) were 2 to 14 times greater than those observed in larger ponds. The N removal efficiency, a metric used to describe the portions of the substrates released as N2, was also significantly higher in the small ponds (∼8.7 %) than in the larger ponds (∼5.0 %). Further regression analysis showed that both areal N2 flux and N removal efficiency were negatively correlated with pond area. The underlying mechanisms behind the size effects of N removal could be attributed to small ponds having larger sediment contact area to water volume ratios. Thus, smaller ponds allow more opportunities for N to interact with bioactive sediments than larger ponds. Overall, our findings contribute to the understanding of the distal role of pond size in affecting N removal. This research also provides a strong rationale for considering the effects of system size when implementing management practices dedicated to maximizing N removal.
Collapse
Affiliation(s)
- Wangshou Zhang
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
| | - Hengpeng Li
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
| | - Heng Cao
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; College of Water Conservancy Engineering, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Xiaofan Zhao
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; College of Water Conservancy Engineering, Zhengzhou University, Zhengzhou, Henan 450001, China
| |
Collapse
|
28
|
Chen S, Meng Y, Lin S, Yu Y, Xi J. Estimation of sea surface nitrate from space: Current status and future potential. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 899:165690. [PMID: 37487888 DOI: 10.1016/j.scitotenv.2023.165690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 07/26/2023]
Abstract
Sea surface nitrate (SSN) plays an important role in assessing phytoplankton growth and new production in the ocean. Field sampling of SSN data is important, but limited by data quantity both spatially and temporally. Satellite remote sensing can contribute through providing spatial and temporal data to such assessments. During the past 30 years many studies have been published focusing on SSN retrievals from satellites to a greater or less extent. In this study, we reviewed the progresses of SSN estimation from satellites in both open ocean and coastal waters. Because of the lack of electromagnetic properties of SSN, satellite retrievals of SSN were most realized by developing relationships between SSN and related environmental variables (e.g., sea surface temperature, chlorophyll-a concentration, sea surface salinity), using traditional empirical regressions and novel machine learning techniques. We synthesized most of the peer-reviewed studies for both open and coastal oceans, in terms of study areas, model inputs, regression formulas, and model uncertainties. In general, regional SSN algorithms were most developed in coastal oceans with upwelling or river discharges. The published SSN algorithms had varying uncertainties with a wide range of 0.83-6.87 μmol/L, and the uncertainties were significantly reduced in recent studies, with more field measurements available and better understanding of the physical and biogeochemical processes in driving nitrate dynamics.
Collapse
Affiliation(s)
- Shuangling Chen
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China.
| | - Yu Meng
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
| | - Sheng Lin
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
| | - Yi Yu
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
| | - Jingyuan Xi
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
| |
Collapse
|
29
|
Niu Y, An Z, Gao D, Chen F, Zhou J, Liu B, Qi L, Wu L, Lin Z, Yin G, Liang X, Dong H, Liu M, Hou L, Zheng Y. Tidal dynamics regulates potential coupling of carbon‑nitrogen‑sulfur cycling microbes in intertidal flats. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 899:165663. [PMID: 37474052 DOI: 10.1016/j.scitotenv.2023.165663] [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: 05/05/2023] [Revised: 07/17/2023] [Accepted: 07/17/2023] [Indexed: 07/22/2023]
Abstract
Tide-driven hydrodynamic process causes significant geochemical gradients that influence biogeochemical cycling and ecological functioning of estuarine and coastal ecosystems. However, the effects of tidal dynamics on microbial communities, particularly at the functional gene level, remain unclear even though microorganisms play critical roles in biogeochemical carbon (C), nitrogen (N) and sulfur (S) cycling. Here, we used 16S rRNA gene amplicon sequencing and microarray-based approach to reveal the stratification of microorganisms related to C, N and S cycles along vertical redox gradients in intertidal wetlands. Alpha-diversity of bacteria and archaea was generally higher at the deep groundwater-sediment interface. Microbial compositions were markedly altered along the sediment profile, and these shifts were largely due to changes in nutrient availability and redox potential. Furthermore, functional genes exhibited redox partitioning between interfaces and transition layer, with abundant genes involved in C decomposition, methanogenesis, heterotrophic denitrification, sulfite reduction and sulfide oxidation existed in the middle anoxic zone. The influence of tidal dynamics on sediment function was highly associated with redox state, sediment texture, and substrates availability, leading to distinct distribution pattern of metabolic coupling of microbes involved in energy flux and elemental cycling in intertidal wetlands. These results indicate that tidal cycles are critical in determining microbial community and functional structure, and they provide new insights into sediment microbe-mediated biogeochemical cycling in intertidal habitats.
Collapse
Affiliation(s)
- Yuhui Niu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China; Shanghai Academy of Landscape Architecture Science and Planning, Shanghai 200232, China
| | - Zhirui An
- School of Geographic Sciences, East China Normal University, Shanghai 200241, China; Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, Shanghai 200241, China
| | - Dengzhou Gao
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| | - Feiyang Chen
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| | - Jie Zhou
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| | - Bolin Liu
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| | - Lin Qi
- School of Geographic Sciences, East China Normal University, Shanghai 200241, China; Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, Shanghai 200241, China
| | - Li Wu
- School of Geographic Sciences, East China Normal University, Shanghai 200241, China; Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, Shanghai 200241, China
| | - Zhuke Lin
- School of Geographic Sciences, East China Normal University, Shanghai 200241, China; Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, Shanghai 200241, China
| | - Guoyu Yin
- School of Geographic Sciences, East China Normal University, Shanghai 200241, China; Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, Shanghai 200241, China
| | - Xia Liang
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| | - Hongpo Dong
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| | - Min Liu
- School of Geographic Sciences, East China Normal University, Shanghai 200241, China; Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, Shanghai 200241, China
| | - Lijun Hou
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| | - Yanling Zheng
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China; School of Geographic Sciences, East China Normal University, Shanghai 200241, China; Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, Shanghai 200241, China.
| |
Collapse
|
30
|
Robicheau BM, Tolman J, Rose S, Desai D, LaRoche J. Marine nitrogen-fixers in the Canadian Arctic Gateway are dominated by biogeographically distinct noncyanobacterial communities. FEMS Microbiol Ecol 2023; 99:fiad122. [PMID: 37951299 PMCID: PMC10656255 DOI: 10.1093/femsec/fiad122] [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: 02/28/2023] [Revised: 07/30/2023] [Accepted: 11/09/2023] [Indexed: 11/13/2023] Open
Abstract
We describe diazotrophs present during a 2015 GEOTRACES expedition through the Canadian Arctic Gateway (CAG) using nifH metabarcoding. In the less studied Labrador Sea, Bradyrhizobium sp. and Vitreoscilla sp. nifH variants were dominant, while in Baffin Bay, a Stutzerimonas stutzeri variant was dominant. In comparison, the Canadian Arctic Archipelago (CAA) was characterized by a broader set of dominant variants belonging to Desulfobulbaceae, Desulfuromonadales, Arcobacter sp., Vibrio spp., and Sulfuriferula sp. Although dominant diazotrophs fell within known nifH clusters I and III, only a few of these variants were frequently recovered in a 5-year weekly nifH times series in the coastal NW Atlantic presented herein, notably S. stutzeri and variants belonging to Desulfobacterales and Desulfuromonadales. In addition, the majority of dominant Arctic nifH variants shared low similarity (< 92% nucleotide identities) to sequences in a global noncyanobacterial diazotroph catalog recently compiled by others. We further detected UCYN-A throughout the CAG at low-levels using quantitative-PCR assays. Temperature, depth, salinity, oxygen, and nitrate were most strongly correlated to the Arctic diazotroph diversity observed, and we found a stark division between diazotroph communities of the Labrador Sea versus Baffin Bay and the CAA, hence establishing that a previously unknown biogeographic community division can occur for diazotrophs in the CAG.
Collapse
Affiliation(s)
- Brent M Robicheau
- Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Jennifer Tolman
- Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Sonja Rose
- Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Dhwani Desai
- Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, Nova Scotia, B3H 4R2, Canada
- Department of Pharmacology, Dalhousie University, 5850 College Street, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Julie LaRoche
- Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, Nova Scotia, B3H 4R2, Canada
| |
Collapse
|
31
|
Liu X, Li P, Wang H, Han LL, Yang K, Wang Y, Jiang Z, Cui L, Kao SJ. Nitrogen fixation and diazotroph diversity in groundwater systems. THE ISME JOURNAL 2023; 17:2023-2034. [PMID: 37715043 PMCID: PMC10579273 DOI: 10.1038/s41396-023-01513-x] [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: 04/19/2023] [Revised: 09/03/2023] [Accepted: 09/05/2023] [Indexed: 09/17/2023]
Abstract
Biological nitrogen fixation (BNF), the conversion of N2 into bioavailable nitrogen (N), is the main process for replenishing N loss in the biosphere. However, BNF in groundwater systems remains poorly understood. In this study, we examined the activity, abundance, and community composition of diazotrophs in groundwater in the Hetao Plain of Inner Mongolia using 15N tracing methods, reverse transcription qPCR (RT-qPCR), and metagenomic/metatranscriptomic analyses. 15N2 tracing incubation of near in situ groundwater (9.5-585.4 nmol N L-1 h-1) and N2-fixer enrichment and isolates (13.2-1728.4 nmol N g-1 h-1, as directly verified by single-cell resonance Raman spectroscopy), suggested that BNF is a non-negligible source of N in groundwater in this region. The expression of nifH genes ranged from 3.4 × 103 to 1.2 × 106 copies L-1 and was tightly correlated with dissolved oxygen (DO), Fe(II), and NH4+. Diazotrophs in groundwater were chiefly aerobes or facultative anaerobes, dominated by Stutzerimonas, Pseudomonas, Paraburkholderia, Klebsiella, Rhodopseudomonas, Azoarcus, and additional uncultured populations. Active diazotrophs, which prefer reducing conditions, were more metabolically diverse and potentially associated with nitrification, sulfur/arsenic mobilization, Fe(II) transport, and CH4 oxidation. Our results highlight the importance of diazotrophs in subsurface geochemical cycles.
Collapse
Affiliation(s)
- Xiaohan Liu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, PR China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China
| | - Ping Li
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, PR China.
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China.
| | - Helin Wang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, PR China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China
| | - Li-Li Han
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, PR China
| | - Kai Yang
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, PR China
| | - Yanhong Wang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, PR China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China
| | - Zhou Jiang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, PR China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074, PR China
| | - Li Cui
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, PR China
| | - Shuh-Ji Kao
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, PR China
| |
Collapse
|
32
|
Turk-Kubo KA, Gradoville MR, Cheung S, Cornejo-Castillo FM, Harding KJ, Morando M, Mills M, Zehr JP. Non-cyanobacterial diazotrophs: global diversity, distribution, ecophysiology, and activity in marine waters. FEMS Microbiol Rev 2023; 47:fuac046. [PMID: 36416813 PMCID: PMC10719068 DOI: 10.1093/femsre/fuac046] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 09/15/2022] [Accepted: 11/17/2022] [Indexed: 12/17/2023] Open
Abstract
Biological dinitrogen (N2) fixation supplies nitrogen to the oceans, supporting primary productivity, and is carried out by some bacteria and archaea referred to as diazotrophs. Cyanobacteria are conventionally considered to be the major contributors to marine N2 fixation, but non-cyanobacterial diazotrophs (NCDs) have been shown to be distributed throughout ocean ecosystems. However, the biogeochemical significance of marine NCDs has not been demonstrated. This review synthesizes multiple datasets, drawing from cultivation-independent molecular techniques and data from extensive oceanic expeditions, to provide a comprehensive view into the diversity, biogeography, ecophysiology, and activity of marine NCDs. A NCD nifH gene catalog was compiled containing sequences from both PCR-based and PCR-free methods, identifying taxa for future studies. NCD abundances from a novel database of NCD nifH-based abundances were colocalized with environmental data, unveiling distinct distributions and environmental drivers of individual taxa. Mechanisms that NCDs may use to fuel and regulate N2 fixation in response to oxygen and fixed nitrogen availability are discussed, based on a metabolic analysis of recently available Tara Oceans expedition data. The integration of multiple datasets provides a new perspective that enhances understanding of the biology, ecology, and biogeography of marine NCDs and provides tools and directions for future research.
Collapse
Affiliation(s)
- Kendra A Turk-Kubo
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
| | - Mary R Gradoville
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
- Columbia River Inter-Tribal Fish Commission, Portland, OR, United States
| | - Shunyan Cheung
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
| | - Francisco M Cornejo-Castillo
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
- Department of Marine Biology and Oceanography, Institute of Marine Sciences (ICM-CSIC), Pg. Marítim Barceloneta, 37-49 08003 Barcelona, Spain
| | - Katie J Harding
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
- Marine Biology Research Division, Scripps Institute of Oceanography, 9500 Gilman Drive, La Jolla, CA 92093, United States
| | - Michael Morando
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
| | - Matthew Mills
- Department of Earth System Science, Stanford University, 473 Via Ortega, Stanford, CA 94305, United States
| | - Jonathan P Zehr
- Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
| |
Collapse
|
33
|
Robicheau BM, Tolman J, Desai D, LaRoche J. Microevolutionary patterns in ecotypes of the symbiotic cyanobacterium UCYN-A revealed from a Northwest Atlantic coastal time series. SCIENCE ADVANCES 2023; 9:eadh9768. [PMID: 37774025 PMCID: PMC10541017 DOI: 10.1126/sciadv.adh9768] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 08/28/2023] [Indexed: 10/01/2023]
Abstract
UCYN-A is a globally important nitrogen-fixing symbiotic microbe often found in colder regions and coastal areas where nitrogen fixation has been overlooked. We present a 3-year coastal Northwest Atlantic time series of UCYN-A by integrating oceanographic data with weekly nifH and16S rRNA gene sequencing and quantitative PCR assays for UCYN-A ecotypes. High UCYN-A relative abundances dominated by A1 to A4 ecotypes reoccurred annually in the coastal Northwest Atlantic. Although UCYN-A was detected every summer/fall, the ability to observe separate ecotypes may be highly dependent on sampling time given intense interannual and weekly variability of ecotype-specific occurrences. Additionally, much of UCYN-A's rarer diversity was populated by short-lived neutral mutational variants, therefore providing insight into UCYN-A's microevolutionary patterns. For instance, rare ASVs exhibited community composition restructuring annually, while also sharing a common connection to a dominant ASV within each ecotype. Our study provides additional perspectives for interpreting UCYN-A intraspecific diversity and underscores the need for high-resolution datasets when deciphering spatiotemporal ecologies within UCYN-A.
Collapse
Affiliation(s)
- Brent M. Robicheau
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jennifer Tolman
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Dhwani Desai
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
- Integrated Microbiome Resource, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Julie LaRoche
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| |
Collapse
|
34
|
von Friesen LW, Paulsen ML, Müller O, Gründger F, Riemann L. Glacial meltwater and seasonality influence community composition of diazotrophs in Arctic coastal and open waters. FEMS Microbiol Ecol 2023; 99:fiad067. [PMID: 37349965 DOI: 10.1093/femsec/fiad067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 04/29/2023] [Accepted: 06/20/2023] [Indexed: 06/24/2023] Open
Abstract
The Arctic Ocean is particularly affected by climate change with unknown consequences for primary productivity. Diazotrophs-prokaryotes capable of converting atmospheric nitrogen to ammonia-have been detected in the often nitrogen-limited Arctic Ocean but distribution and community composition dynamics are largely unknown. We performed amplicon sequencing of the diazotroph marker gene nifH from glacial rivers, coastal, and open ocean regions and identified regionally distinct Arctic communities. Proteobacterial diazotrophs dominated all seasons, epi- to mesopelagic depths and rivers to open waters and, surprisingly, Cyanobacteria were only sporadically identified in coastal and freshwaters. The upstream environment of glacial rivers influenced diazotroph diversity, and in marine samples putative anaerobic sulphate-reducers showed seasonal succession with highest prevalence in summer to polar night. Betaproteobacteria (Burkholderiales, Nitrosomonadales, and Rhodocyclales) were typically found in rivers and freshwater-influenced waters, and Delta- (Desulfuromonadales, Desulfobacterales, and Desulfovibrionales) and Gammaproteobacteria in marine waters. The identified community composition dynamics, likely driven by runoff, inorganic nutrients, particulate organic carbon, and seasonality, imply diazotrophy a phenotype of ecological relevance with expected responsiveness to ongoing climate change. Our study largely expands baseline knowledge of Arctic diazotrophs-a prerequisite to understand underpinning of nitrogen fixation-and supports nitrogen fixation as a contributor of new nitrogen in the rapidly changing Arctic Ocean.
Collapse
Affiliation(s)
- Lisa W von Friesen
- Department of Biology, University of Copenhagen, Strandpromenaden 5, DK-3000 Helsingør, Denmark
| | - Maria L Paulsen
- Department of Biology, Aarhus University, Ny Munkegade 114-116, DK-8000 Aarhus, Denmark
| | - Oliver Müller
- Department of Biological Sciences, University of Bergen, Thormøhlens gate 53A, NO-5006 Bergen, Norway
| | - Friederike Gründger
- Department of Biology, Aarhus University, Ny Munkegade 114-116, DK-8000 Aarhus, Denmark
| | - Lasse Riemann
- Department of Biology, University of Copenhagen, Strandpromenaden 5, DK-3000 Helsingør, Denmark
| |
Collapse
|
35
|
Luo W, Luo YW. Diurnally dynamic iron allocation promotes N 2 fixation in marine dominant diazotroph Trichodesmium. Comput Struct Biotechnol J 2023; 21:3503-3512. [PMID: 37484493 PMCID: PMC10362294 DOI: 10.1016/j.csbj.2023.07.006] [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: 02/14/2023] [Revised: 06/15/2023] [Accepted: 07/04/2023] [Indexed: 07/25/2023] Open
Abstract
Trichodesmium is the dominant photoautotrophic dinitrogen (N2) fixer (diazotroph) in the ocean. Iron is an important factor limiting growth of marine diazotrophs including Trichodesmium mainly because of high iron content of its N2-fixing enzyme, nitrogenase. However, it still lacks a quantitative understanding of how dynamic iron allocation among physiological processes acts to regulate growth and N2 fixation in Trichodesmium. Here, we constructed a model of Trichodesmium trichome in which intracellular iron could be dynamically re-allocated in photosystems and nitrogenase during the daytime. The results demonstrate that the dynamic iron allocation enhances modeled N2 fixation and growth rates of Trichodesmium, especially in iron-limited conditions, albeit having a marginal impact under high iron concentrations. Although the reuse of iron during a day is an apparent cause that dynamic iron allocation can benefit Trichodesmium under iron limitation, our model reveals two important mechanisms. First, the release of iron from photosystems downregulates the intracellular oxygen (O2) production and reduces the demand of respiratory protection, a process that Trichodesmium wastefully respires carbohydrates to create a lower O2 window for N2 fixation. Hence, more carbohydrates can be used in growth. Second, lower allocation of iron to nitrogenase during early daytime, a period when photosynthesis is active and intracellular O2 is high, reduces the amount of iron that is trapped in the inactivated nitrogenase induced by O2. This mechanism further increases the iron use efficiency in Trichodesmium. Overall, our study provides mechanistic and quantitative insight into the diurnal iron allocation that can alleviate iron limitation to Trichodesmium.
Collapse
|
36
|
Fletcher-Hoppe C, Yeh YC, Raut Y, Weissman JL, Fuhrman JA. Symbiotic UCYN-A strains co-occurred with El Niño, relaxed upwelling, and varied eukaryotes over 10 years off Southern California. ISME COMMUNICATIONS 2023; 3:63. [PMID: 37355737 PMCID: PMC10290647 DOI: 10.1038/s43705-023-00268-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 05/05/2023] [Accepted: 06/12/2023] [Indexed: 06/26/2023]
Abstract
Biological nitrogen fixation, the conversion of N2 gas into a bioavailable form, is vital to sustaining marine primary production. Studies have shifted beyond traditionally studied tropical diazotrophs. Candidatus Atelocyanobacterium thalassa (or UCYN-A) has emerged as a focal point due to its streamlined metabolism, intimate partnership with a haptophyte host, and broad distribution. Here, we explore the environmental parameters that govern UCYN-A's presence at the San Pedro Ocean Time-series (SPOT), its host specificity, and statistically significant interactions with non-host eukaryotes from 2008-2018. 16S and 18S rRNA gene sequences were amplified by "universal primers" from monthly samples and resolved into Amplicon Sequence Variants, allowing us to observe multiple UCYN-A symbioses. UCYN-A1 relative abundances increased following the 2015-2016 El Niño event. This "open ocean ecotype" was present when coastal upwelling declined, and Ekman transport brought tropical waters into the region. Network analyses reveal all strains of UCYN-A co-occur with dinoflagellates including Lepidodinium, a potential predator, and parasitic Syndiniales. UCYN-A2 appeared to pair with multiple hosts and was not tightly coupled to its predominant host, while UCYN-A1 maintained a strong host-symbiont relationship. These biological relationships are particularly important to study in the context of climate change, which will alter UCYN-A distribution at regional and global scales.
Collapse
Affiliation(s)
- Colette Fletcher-Hoppe
- Marine & Environmental Biology, Department of Biological Sciences, University of Southern California (USC), Los Angeles, CA, USA
| | - Yi-Chun Yeh
- Marine & Environmental Biology, Department of Biological Sciences, University of Southern California (USC), Los Angeles, CA, USA
- Department of Global Ecology, Carnegie Institution for Science, Stanford University, Stanford, CA, USA
| | - Yubin Raut
- Marine & Environmental Biology, Department of Biological Sciences, University of Southern California (USC), Los Angeles, CA, USA
| | - J L Weissman
- Marine & Environmental Biology, Department of Biological Sciences, University of Southern California (USC), Los Angeles, CA, USA
- Schmid College of Science and Technology, Chapman University, Orange, CA, USA
| | - Jed A Fuhrman
- Marine & Environmental Biology, Department of Biological Sciences, University of Southern California (USC), Los Angeles, CA, USA.
| |
Collapse
|
37
|
Zheng M, Xu M, Li D, Deng Q, Mo J. Negative responses of terrestrial nitrogen fixation to nitrogen addition weaken across increased soil organic carbon levels. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 877:162965. [PMID: 36948308 DOI: 10.1016/j.scitotenv.2023.162965] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 03/15/2023] [Accepted: 03/16/2023] [Indexed: 05/06/2023]
Abstract
The traditional view holds that biological nitrogen (N) fixation is energetically expensive and thus, facultative N fixers reduce N fixation rates while obligate N fixers are excluded by non-N fixers as soil N becomes rich. This view, however, contradicts the phenomenon that N fixation does not decline in many terrestrial ecosystems under N enrichment. To address this paradoxical phenomenon, we conducted a meta-analysis of N fixation and diazotroph (N-fixing microorganism) community structure in response to N addition across terrestrial ecosystems. N addition inhibited N fixation, but the inhibitory effect weakened across increased soil organic carbon (SOC) concentrations. The response ratios of N fixation (including free-living, plant-associated, and symbiotic types) to N addition were lower in the ecosystems with low SOC concentrations (<10 mg/g) than in those with medium or high SOC concentrations (10-20 and > 20 mg/g, respectively). The negative N-addition effects on diazotroph abundance and diversity also weakened across increased SOC levels. Among the climatic and soil factors, SOC was the most important predictor regarding the responses of N fixation and diazotroph community structure to N addition. Overall, our study reveals the role of SOC in affecting the responses of N fixation to N addition, which helps understand the relationships of biological N fixation and N enrichment as well as the mechanisms of terrestrial C and N coupling.
Collapse
Affiliation(s)
- Mianhai Zheng
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; South China National Botanical Garden, Guangzhou, China.
| | - Meichen Xu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; South China National Botanical Garden, Guangzhou, China; College of Resource and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Dejun Li
- Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
| | - Qi Deng
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; South China National Botanical Garden, Guangzhou, China
| | - Jiangming Mo
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China; South China National Botanical Garden, Guangzhou, China.
| |
Collapse
|
38
|
Alleman AB, Peters JW. Mechanisms for Generating Low Potential Electrons across the Metabolic Diversity of Nitrogen-Fixing Bacteria. Appl Environ Microbiol 2023; 89:e0037823. [PMID: 37154716 PMCID: PMC10231201 DOI: 10.1128/aem.00378-23] [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] [Indexed: 05/10/2023] Open
Abstract
The availability of fixed nitrogen is a limiting factor in the net primary production of all ecosystems. Diazotrophs overcome this limit through the conversion of atmospheric dinitrogen to ammonia. Diazotrophs are phylogenetically diverse bacteria and archaea that exhibit a wide range of lifestyles and metabolisms, including obligate anaerobes and aerobes that generate energy through heterotrophic or autotrophic metabolisms. Despite the diversity of metabolisms, all diazotrophs use the same enzyme, nitrogenase, to reduce N2. Nitrogenase is an O2-sensitive enzyme that requires a high amount of energy in the form of ATP and low potential electrons carried by ferredoxin (Fd) or flavodoxin (Fld). This review summarizes how the diverse metabolisms of diazotrophs utilize different enzymes to generate low potential reducing equivalents for nitrogenase catalysis. These enzymes include substrate-level Fd oxidoreductases, hydrogenases, photosystem I or other light-driven reaction centers, electron bifurcating Fix complexes, proton motive force-driven Rnf complexes, and Fd:NAD(P)H oxidoreductases. Each of these enzymes is critical for generating low potential electrons while simultaneously integrating the native metabolism to balance nitrogenase's overall energy needs. Understanding the diversity of electron transport systems to nitrogenase in various diazotrophs will be essential to guide future engineering strategies aimed at expanding the contributions of biological nitrogen fixation in agriculture.
Collapse
Affiliation(s)
- Alexander B. Alleman
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - John W. Peters
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
| |
Collapse
|
39
|
Bonnet S, Guieu C, Taillandier V, Boulart C, Bouruet-Aubertot P, Gazeau F, Scalabrin C, Bressac M, Knapp AN, Cuypers Y, González-Santana D, Forrer HJ, Grisoni JM, Grosso O, Habasque J, Jardin-Camps M, Leblond N, Le Moigne FAC, Lebourges-Dhaussy A, Lory C, Nunige S, Pulido-Villena E, Rizzo AL, Sarthou G, Tilliette C. Natural iron fertilization by shallow hydrothermal sources fuels diazotroph blooms in the ocean. Science 2023; 380:812-817. [PMID: 37228198 DOI: 10.1126/science.abq4654] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 04/21/2023] [Indexed: 05/27/2023]
Abstract
Iron is an essential nutrient that regulates productivity in ~30% of the ocean. Compared with deep (>2000 meter) hydrothermal activity at mid-ocean ridges that provide iron to the ocean's interior, shallow (<500 meter) hydrothermal fluids are likely to influence the surface's ecosystem. However, their effect is unknown. In this work, we show that fluids emitted along the Tonga volcanic arc (South Pacific) have a substantial impact on iron concentrations in the photic layer through vertical diffusion. This enrichment stimulates biological activity, resulting in an extensive patch of chlorophyll (360,000 square kilometers). Diazotroph activity is two to eight times higher and carbon export fluxes are two to three times higher in iron-enriched waters than in adjacent unfertilized waters. Such findings reveal a previously undescribed mechanism of natural iron fertilization in the ocean that fuels regional hotspot sinks for atmospheric CO2.
Collapse
Affiliation(s)
- Sophie Bonnet
- Aix Marseille University, Université de Toulon, CNRS, IRD, MIO Marseille, France
| | - Cécile Guieu
- Laboratoire d'Océanographie de Villefranche (LOV), Institut de la Mer de Villefranche, CNRS, Sorbonne Université, 06230 Villefranche-sur-Mer, France
| | - Vincent Taillandier
- Laboratoire d'Océanographie de Villefranche (LOV), Institut de la Mer de Villefranche, CNRS, Sorbonne Université, 06230 Villefranche-sur-Mer, France
| | - Cédric Boulart
- Adaptation et Diversité en Milieu Marin, UMR 7144 AD2M CNRS-Sorbonne Université, Station Biologique de Roscoff, 29680 Roscoff, France
| | - Pascale Bouruet-Aubertot
- Laboratoire d'Océanographie et du Climat: Expérimentation et Approches Numériques (LOCEAN-IPSL), Sorbonne University, CNRS-IRD-MNHN, 75005 Paris, France
| | - Frédéric Gazeau
- Laboratoire d'Océanographie de Villefranche (LOV), Institut de la Mer de Villefranche, CNRS, Sorbonne Université, 06230 Villefranche-sur-Mer, France
| | - Carla Scalabrin
- Ifremer, Univ Brest, CNRS, UMR 6538 Geo-Ocean, F-29280 Plouzané, France
| | - Matthieu Bressac
- Laboratoire d'Océanographie de Villefranche (LOV), Institut de la Mer de Villefranche, CNRS, Sorbonne Université, 06230 Villefranche-sur-Mer, France
| | - Angela N Knapp
- Department of Earth, Ocean, and Atmospheric Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Yannis Cuypers
- Laboratoire d'Océanographie et du Climat: Expérimentation et Approches Numériques (LOCEAN-IPSL), Sorbonne University, CNRS-IRD-MNHN, 75005 Paris, France
| | - David González-Santana
- CNRS, Univ Brest, IRD, Ifremer, UMR 6539, LEMAR, Plouzané, France
- Instituto de Oceanografía y Cambio Global (IOCAG), Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas, Spain
| | - Heather J Forrer
- Department of Earth, Ocean, and Atmospheric Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Jean-Michel Grisoni
- Institut de la Mer de Villefranche, IMEV, Sorbonne Université, Villefranche-sur-Mer, France
| | - Olivier Grosso
- Aix Marseille University, Université de Toulon, CNRS, IRD, MIO Marseille, France
| | - Jérémie Habasque
- CNRS, Univ Brest, IRD, Ifremer, UMR 6539, LEMAR, Plouzané, France
| | | | - Nathalie Leblond
- Institut de la Mer de Villefranche, IMEV, Sorbonne Université, Villefranche-sur-Mer, France
| | - Frédéric A C Le Moigne
- Aix Marseille University, Université de Toulon, CNRS, IRD, MIO Marseille, France
- CNRS, Univ Brest, IRD, Ifremer, UMR 6539, LEMAR, Plouzané, France
| | | | - Caroline Lory
- Aix Marseille University, Université de Toulon, CNRS, IRD, MIO Marseille, France
| | - Sandra Nunige
- Aix Marseille University, Université de Toulon, CNRS, IRD, MIO Marseille, France
| | | | - Andrea L Rizzo
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Milano, Via Alfonso Corti 12, 20133 Milano, Italy
- Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 4, 20126 Milan, Italy
| | | | - Chloé Tilliette
- Laboratoire d'Océanographie de Villefranche (LOV), Institut de la Mer de Villefranche, CNRS, Sorbonne Université, 06230 Villefranche-sur-Mer, France
| |
Collapse
|
40
|
Takuhei S, Nishimura Y, Yoshizawa S, Takami H, Hamasaki K, Fujiwara A, Nishino S, Harada N. Distribution and survival strategies of endemic and cosmopolitan diazotrophs in the Arctic Ocean. THE ISME JOURNAL 2023:10.1038/s41396-023-01424-x. [PMID: 37217593 DOI: 10.1038/s41396-023-01424-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 04/18/2023] [Accepted: 04/25/2023] [Indexed: 05/24/2023]
Abstract
Dinitrogen (N2) fixation is the major source of reactive nitrogen in the ocean and has been considered to occur specifically in low-latitude oligotrophic oceans. Recent studies have shown that N2 fixation also occurs in the polar regions and thus is a global process, although the physiological and ecological characteristics of polar diazotrophs are not yet known. Here, we successfully reconstructed diazotroph genomes, including that of cyanobacterium UCYN-A (Candidatus 'Atelocyanobacterium thalassa'), from metagenome data corresponding to 111 samples isolated from the Arctic Ocean. These diazotrophs were highly abundant in the Arctic Ocean (max., 1.28% of the total microbial community), suggesting that they have important roles in the Arctic ecosystem and biogeochemical cycles. Further, we show that diazotrophs within genera Arcobacter, Psychromonas, and Oceanobacter are prevalent in the <0.2 µm fraction in the Arctic Ocean, indicating that current methods cannot capture their N2 fixation. Diazotrophs in the Arctic Ocean were either Arctic-endemic or cosmopolitan species from their global distribution patterns. Arctic-endemic diazotrophs, including Arctic UCYN-A, were similar to low-latitude-endemic and cosmopolitan diazotrophs in genome-wide function, however, they had unique gene sets (e.g., diverse aromatics degradation genes), suggesting adaptations to Arctic-specific conditions. Cosmopolitan diazotrophs were generally non-cyanobacteria and commonly had the gene that encodes the cold-inducible RNA chaperone, which presumably makes their survival possible even in deep, cold waters of global ocean and polar surface waters. This study shows global distribution pattern of diazotrophs with their genomes and provides clues to answering the question of how diazotrophs can inhabit polar waters.
Collapse
Affiliation(s)
- Shiozaki Takuhei
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, 277-8564, Japan.
| | - Yosuke Nishimura
- Research Centre for Bioscience and Nanoscience, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, 237-0061, Japan
| | - Susumu Yoshizawa
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, 277-8564, Japan
| | - Hideto Takami
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, 277-8564, Japan
- Center for Mathematical Science and Advanced Technology, JAMSTEC, Yokohama, 236-0001, Japan
| | - Koji Hamasaki
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, 277-8564, Japan
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 277-8564, Kashiwa, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 113-8657, Bunkyo-ku, Japan
| | - Amane Fujiwara
- Research Institute for Global Change, JAMSTEC, Yokosuka, 237-0061, Japan
| | - Shigeto Nishino
- Research Institute for Global Change, JAMSTEC, Yokosuka, 237-0061, Japan
| | - Naomi Harada
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, 277-8564, Japan
- Research Institute for Global Change, JAMSTEC, Yokosuka, 237-0061, Japan
| |
Collapse
|
41
|
Sun S, Hu X, Kang W, Yao M. Combined effects of microplastics and warming enhance algal carbon and nitrogen storage. WATER RESEARCH 2023; 233:119815. [PMID: 36881974 DOI: 10.1016/j.watres.2023.119815] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/21/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
Algae dominate primary production in groundwater and oceans and play a critical role in global carbon dioxide fixation and climate change but are threatened by ongoing global warming events (such as heatwaves) and increasing microplastic (MP) pollution. However, whether and how ecologically important phytoplankton respond to the combined effects of warming and MPs remain poorly understood. We thus investigated the combined effects of these factors on carbon and nitrogen storage and the mechanisms underlying the alterations in the physiological performance of a model diatom, Phaeodactylum tricornutum, exposed to a warming stressor (25 °C compared with 21 °C) and polystyrene MP acclimation. Although warmer conditions decreased the cell viability, the diatoms subjected to the synergistic effects of MPs and warming showed significant increases in the growth rate (1.10-fold) and nitrogen uptake rate (1.26-fold). Metabolomics and transcriptomic analyses revealed that MPs and warming mainly promoted fatty acid metabolism, the urea cycle, glutamine and glutamate production, and the tricarboxylic acid (TCA) cycle due to an increased level of 2-oxoglutarate, which is the hub of carbon and nitrogen metabolism and accounts for the acquisition and utilization of carbon and nitrogen. Our findings emphasize the nonnegligible effects of MPs and HWs on the algal carbon and nitrogen cycles in waters.
Collapse
Affiliation(s)
- Shan Sun
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education)/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Xiangang Hu
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education)/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
| | - Weilu Kang
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education)/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| | - Mingqi Yao
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education)/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China
| |
Collapse
|
42
|
Lu J, Shu Y, Zhang H, Zhang S, Zhu C, Ding W, Zhang W. The Landscape of Global Ocean Microbiome: From Bacterioplankton to Biofilms. Int J Mol Sci 2023; 24:ijms24076491. [PMID: 37047466 PMCID: PMC10095273 DOI: 10.3390/ijms24076491] [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: 03/08/2023] [Revised: 03/26/2023] [Accepted: 03/27/2023] [Indexed: 04/01/2023] Open
Abstract
The development of metagenomics has opened up a new era in the study of marine microbiota, which play important roles in biogeochemical cycles. In recent years, the global ocean sampling expeditions have spurred this research field toward a deeper understanding of the microbial diversities and functions spanning various lifestyles, planktonic (free-living) or sessile (biofilm-associated). In this review, we deliver a comprehensive summary of marine microbiome datasets generated in global ocean expeditions conducted over the last 20 years, including the Sorcerer II GOS Expedition, the Tara Oceans project, the bioGEOTRACES project, the Micro B3 project, the Bio-GO-SHIP project, and the Marine Biofilms. These datasets have revealed unprecedented insights into the microscopic life in our oceans and led to the publication of world-leading research. We also note the progress of metatranscriptomics and metaproteomics, which are confined to local marine microbiota. Furthermore, approaches to transforming the global ocean microbiome datasets are highlighted, and the state-of-the-art techniques that can be combined with data analyses, which can present fresh perspectives on marine molecular ecology and microbiology, are proposed.
Collapse
Affiliation(s)
- Jie Lu
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266100, China
| | - Yi Shu
- MOE Key Laboratory of Marine Genetics and Breeding, Ocean University of China, Qingdao 266100, China;
| | - Heng Zhang
- College of Marine Life Sciences, Ocean University of China, Qingdao 266100, China
| | - Shangxian Zhang
- Haide College, Ocean University of China, Qingdao 266100, China
| | - Chengrui Zhu
- Haide College, Ocean University of China, Qingdao 266100, China
| | - Wei Ding
- MOE Key Laboratory of Marine Genetics and Breeding, Ocean University of China, Qingdao 266100, China;
- College of Marine Life Sciences, Ocean University of China, Qingdao 266100, China
- Haide College, Ocean University of China, Qingdao 266100, China
- Correspondence: (W.D.); (W.Z.)
| | - Weipeng Zhang
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266100, China
- College of Marine Life Sciences, Ocean University of China, Qingdao 266100, China
- Haide College, Ocean University of China, Qingdao 266100, China
- Correspondence: (W.D.); (W.Z.)
| |
Collapse
|
43
|
Webb EA, Held NA, Zhao Y, Graham ED, Conover AE, Semones J, Lee MD, Feng Y, Fu FX, Saito MA, Hutchins DA. Importance of mobile genetic element immunity in numerically abundant Trichodesmium clades. ISME COMMUNICATIONS 2023; 3:15. [PMID: 36823453 PMCID: PMC9950141 DOI: 10.1038/s43705-023-00214-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/13/2022] [Accepted: 01/12/2023] [Indexed: 02/25/2023]
Abstract
The colony-forming cyanobacteria Trichodesmium spp. are considered one of the most important nitrogen-fixing genera in the warm, low nutrient ocean. Despite this central biogeochemical role, many questions about their evolution, physiology, and trophic interactions remain unanswered. To address these questions, we describe Trichodesmium pangenomic potential via significantly improved genomic assemblies from two isolates and 15 new >50% complete Trichodesmium metagenome-assembled genomes from hand-picked, Trichodesmium colonies spanning the Atlantic Ocean. Phylogenomics identified ~four N2 fixing clades of Trichodesmium across the transect, with T. thiebautii dominating the colony-specific reads. Pangenomic analyses showed that all T. thiebautii MAGs are enriched in COG defense mechanisms and encode a vertically inherited Type III-B Clustered Regularly Interspaced Short Palindromic Repeats and associated protein-based immunity system (CRISPR-Cas). Surprisingly, this CRISPR-Cas system was absent in all T. erythraeum genomes, vertically inherited by T. thiebautii, and correlated with increased signatures of horizontal gene transfer. Additionally, the system was expressed in metaproteomic and transcriptomic datasets and CRISPR spacer sequences with 100% identical hits to field-assembled, putative phage genome fragments were identified. While the currently CO2-limited T. erythraeum is expected to be a 'winner' of anthropogenic climate change, their genomic dearth of known phage resistance mechanisms, compared to T. thiebautii, could put this outcome in question. Thus, the clear demarcation of T. thiebautii maintaining CRISPR-Cas systems, while T. erythraeum does not, identifies Trichodesmium as an ecologically important CRISPR-Cas model system, and highlights the need for more research on phage-Trichodesmium interactions.
Collapse
Affiliation(s)
- Eric A Webb
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA.
| | - Noelle A Held
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Environmental Systems Science, ETH, Zurich, Switzerland
| | - Yiming Zhao
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Elaina D Graham
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Asa E Conover
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Jake Semones
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Michael D Lee
- Blue Marble Space Institute of Science, NASA Ames Research Center, Mountain View, CA, 94035, USA
| | - Yuanyuan Feng
- College of Marine and Environmental Sciences, Tianjin University of Science and Technology, Tianjin, 300457, China
| | - Fei-Xue Fu
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Mak A Saito
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
| | - David A Hutchins
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| |
Collapse
|
44
|
Structure-Function Covariation of Phycospheric Microorganisms Associated with the Typical Cross-Regional Harmful Macroalgal Bloom. Appl Environ Microbiol 2023; 89:e0181522. [PMID: 36533927 PMCID: PMC9888261 DOI: 10.1128/aem.01815-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Unravelling the structure-function variation of phycospheric microorganisms and its ecological correlation with harmful macroalgal blooms (HMBs) is a challenging research topic that remains unclear in the natural dynamic process of HMBs. During the world's largest green tide bloom, causative macroalgae Ulva prolifera experienced dramatic changes in growth state and environmental conditions, providing ideal scenarios for this investment. Here, we assess the phycospheric physicochemical characteristics, the algal host's biology, the phycospheric bacterial constitutive patterns, and the functional potential during the U. prolifera green tide. Our results indicated that (i) variation in the phycosphere nutrient structure was closely related to the growth state of U. prolifera; (ii) stochastic processes govern phycospheric bacterial assembly, and the contribution of deterministic processes to assembly varied among phycospheric seawater bacteria and epiphytic bacteria; (iii) phycospheric seawater bacteria and epiphytic bacteria exhibited significant heterogeneity variation patterns in community composition, structure, and metabolic potential; and (iv) phycospheric bacteria with carbon or nitrogen metabolic functions potentially influenced the nutrient utilization of U. prolifera. Furthermore, the keystone genera play a decisive role in the structure-function covariation of phycospheric bacterial communities. Our study reveals complex interactions and linkages among environment-algae-bacterial communities which existed in the macroalgal phycosphere and highlights the fact that phycospheric microorganisms are closely related to the fate of the HMBs represented by the green tide. IMPORTANCE Harmful macroalgal blooms represented by green tides have become a worldwide marine ecological problem. Unraveling the structure-function variation of phycospheric microorganisms and their ecological correlation with HMBs is challenging. This issue is still unclear in the natural dynamics of HMBs. Here, we revealed the complex interactions and linkages among environment-algae-bacterial communities in the phycosphere of the green macroalgae Ulva prolifera, which causes the world's largest green tides. Our study provides new ideas to increase our understanding of the variation patterns of macroalgal phycospheric bacterial communities and the formation mechanisms and ecological effects of green tides and highlights the importance of phycospheric microorganisms as a robust tool to help understand the fate of HMBs.
Collapse
|
45
|
Bonnet S, Benavides M, Le Moigne FAC, Camps M, Torremocha A, Grosso O, Dimier C, Spungin D, Berman-Frank I, Garczarek L, Cornejo-Castillo FM. Diazotrophs are overlooked contributors to carbon and nitrogen export to the deep ocean. THE ISME JOURNAL 2023; 17:47-58. [PMID: 36163270 PMCID: PMC9750961 DOI: 10.1038/s41396-022-01319-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 08/25/2022] [Accepted: 09/06/2022] [Indexed: 11/09/2022]
Abstract
Diazotrophs are widespread microorganisms that alleviate nitrogen limitation in 60% of our oceans, thereby regulating marine productivity. Yet, the group-specific contribution of diazotrophs to organic matter export has not been quantified, which so far has impeded an accurate assessment of their impact on the biological carbon pump. Here, we examine the fate of five groups of globally-distributed diazotrophs by using an original combination of mesopelagic particle sampling devices across the subtropical South Pacific Ocean. We demonstrate that cyanobacterial and non-cyanobacterial diazotrophs are exported down to 1000 m depth. Surprisingly, group-specific export turnover rates point to a more efficient export of small unicellular cyanobacterial diazotrophs (UCYN) relative to the larger and filamentous Trichodesmium. Phycoerythrin-containing UCYN-B and UCYN-C-like cells were recurrently found embedded in large (>50 µm) organic aggregates or organized into clusters of tens to hundreds of cells linked by an extracellular matrix, presumably facilitating their export. Beyond the South Pacific, our data are supported by analysis of the Tara Oceans metagenomes collected in other ocean basins, extending the scope of our results globally. We show that, when diazotrophs are found in the euphotic zone, they are also systematically present in mesopelagic waters, suggesting their transport to the deep ocean. We thus conclude that diazotrophs are a significant part of the carbon sequestered in the deep ocean and, therefore, they need to be accounted in regional and global estimates of export.
Collapse
Affiliation(s)
- Sophie Bonnet
- Aix Marseille University, Université de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France.
| | - Mar Benavides
- Aix Marseille University, Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France ,grid.5399.60000 0001 2176 4817Turing Center for Living Systems, Aix-Marseille University, 13009 Marseille, France
| | - Frédéric A. C. Le Moigne
- Aix Marseille University, Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France ,grid.463763.30000 0004 0638 0577LEMAR, Laboratoire des sciences de l’environnement marin, UMR6539, CNRS, UBO, IFREMER, IRD, 29280 Plouzané, Technopôle Brest-Iroise France
| | - Mercedes Camps
- Aix Marseille University, Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France
| | - Antoine Torremocha
- Aix Marseille University, Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France
| | - Olivier Grosso
- Aix Marseille University, Université de Toulon, CNRS, IRD, MIO UM 110, 13288 Marseille, France
| | - Céline Dimier
- grid.499565.20000 0004 0366 8890Laboratoire d’Océanographie de Villefranche (LOV), Sorbonne Université, CNRS, 06230 Villefranche sur mer, France
| | - Dina Spungin
- grid.18098.380000 0004 1937 0562University of Haifa, The Leon H. Charney School of Marine Sciences, Haifa, 3498838 Israel
| | - Ilana Berman-Frank
- grid.18098.380000 0004 1937 0562University of Haifa, The Leon H. Charney School of Marine Sciences, Haifa, 3498838 Israel
| | - Laurence Garczarek
- grid.464101.60000 0001 2203 0006Sorbonne Université, CNRS, UMR 7144 Adaptation and Diversity in the Marine Environment (AD2M), Station Biologique de Roscoff (SBR), Roscoff, France
| | - Francisco M. Cornejo-Castillo
- grid.464101.60000 0001 2203 0006Sorbonne Université, CNRS, UMR 7144 Adaptation and Diversity in the Marine Environment (AD2M), Station Biologique de Roscoff (SBR), Roscoff, France ,grid.418218.60000 0004 1793 765XInstitut de Ciènces del Mar (ICM-CSIC), E08003 Barcelona, Spain
| |
Collapse
|
46
|
Salas K, Cabello AM, Turk-Kubo KA, Zehr JP, Cornejo-Castillo FM. Primer design for the amplification of the ammonium transporter genes from the uncultured haptophyte algal species symbiotic with the marine nitrogen-fixing cyanobacterium UCYN-A1. Front Microbiol 2023; 14:1130695. [PMID: 37138636 PMCID: PMC10150950 DOI: 10.3389/fmicb.2023.1130695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 03/21/2023] [Indexed: 05/05/2023] Open
Abstract
The multiple symbiotic partnerships between closely related species of the haptophyte algae Braarudosphaera bigelowii and the nitrogen-fixing cyanobacteria Candidatus Atelocyanobacterium thalassa (UCYN-A) contribute importantly to the nitrogen and carbon cycles in vast areas of the ocean. The diversity of the eukaryotic 18S rDNA phylogenetic gene marker has helped to identify some of these symbiotic haptophyte species, yet we still lack a genetic marker to assess its diversity at a finer scale. One of such genes is the ammonium transporter (amt) gene, which encodes the protein that might be involved in the uptake of ammonium from UCYN-A in these symbiotic haptophytes. Here, we designed three specific PCR primer sets targeting the amt gene of the haptophyte species (A1-Host) symbiotic with the open ocean UCYN-A1 sublineage, and tested them in samples collected from open ocean and near-shore environments. Regardless of the primer pair used at Station ALOHA, which is where UCYN-A1 is the pre-dominant UCYN-A sublineage, the most abundant amt amplicon sequence variant (ASV) was taxonomically classified as A1-Host. In addition, two out of the three PCR primer sets revealed the existence of closely-related divergent haptophyte amt ASVs (>95% nucleotide identity). These divergent amt ASVs had higher relative abundances than the haptophyte typically associated with UCYN-A1 in the Bering Sea, or co-occurred with the previously identified A1-Host in the Coral Sea, suggesting the presence of new diversity of closely-related A1-Hosts in polar and temperate waters. Therefore, our study reveals an overlooked diversity of haptophytes species with distinct biogeographic distributions partnering with UCYN-A, and provides new primers that will help to gain new knowledge of the UCYN-A/haptophyte symbiosis.
Collapse
Affiliation(s)
- Krystal Salas
- Department of Ocean Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Ana M. Cabello
- Department of Ocean Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
- Centro Oceanográfico de Málaga, Instituto Español de Oceanografía, IEO-CSIC, Málaga, Spain
| | - Kendra A. Turk-Kubo
- Department of Ocean Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
| | - Jonathan P. Zehr
- Department of Ocean Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
- *Correspondence: Jonathan P. Zehr,
| | - Francisco M. Cornejo-Castillo
- Department of Ocean Sciences, University of California, Santa Cruz, Santa Cruz, CA, United States
- Department of Marine Biology and Oceanography, Institute of Marine Sciences (ICM-CSIC), Barcelona, Spain
- Francisco M. Cornejo-Castillo,
| |
Collapse
|
47
|
Quantitative Analysis of the Trade-Offs of Colony Formation for Trichodesmium. Microbiol Spectr 2022; 10:e0202522. [PMID: 36374046 PMCID: PMC9769814 DOI: 10.1128/spectrum.02025-22] [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] [Indexed: 11/16/2022] Open
Abstract
There is considerable debate about the benefits and trade-offs for colony formation in a major marine nitrogen fixer, Trichodesmium. To quantitatively analyze the trade-offs, we developed a metabolic model based on carbon fluxes to compare the performance of Trichodesmium colonies and free trichomes under different scenarios. Despite reported reductions in carbon fixation and nitrogen fixation rates for colonies relative to free trichomes, we found that model colonies can outperform individual cells in several cases. The formation of colonies can be advantageous when respiration rates account for a high proportion of the carbon fixation rate. Negative external influence on vital rates, such as mortality due to predation or micronutrient limitations, can also create a net benefit for colony formation relative to individual cells. In contrast, free trichomes also outcompete colonies in many scenarios, such as when respiration rates are equal for both colonies and individual cells or when there is a net positive external influence on rate processes (i.e., optimal environmental conditions regarding light and temperature or high nutrient availability). For both colonies and free trichomes, an increase in carbon fixation relative to nitrogen fixation rates would increase their relative competitiveness. These findings suggest that the formation of colonies in Trichodesmium might be linked to specific environmental and ecological circumstances. Our results provide a road map for empirical studies and models to evaluate the conditions under which colony formation in marine phytoplankton can be sustained in the natural environment. IMPORTANCE Trichodesmium is a marine filamentous cyanobacterium that fixes nitrogen and is an important contributor to the global nitrogen cycle. In the natural environment, Trichodesmium can exist as individual cells (trichomes) or as colonies (puffs and tufts). In this paper, we try to answer a longstanding question in marine microbial ecology: how does colony formation benefit the survival of Trichodesmium? To answer this question, we developed a carbon flux model that utilizes existing published rates to evaluate whether and when colony formation can be sustained. Enhanced respiration rates, influential external factors such as environmental conditions and ecological interactions, and variable carbon and nitrogen fixation rates can all create scenarios for colony formation to be a viable strategy. Our results show that colony formation is an ecologically beneficial strategy under specific conditions, enabling Trichodesmium to be a globally significant organism.
Collapse
|
48
|
Emerging Trends of Nanotechnology and Genetic Engineering in Cyanobacteria to Optimize Production for Future Applications. LIFE (BASEL, SWITZERLAND) 2022; 12:life12122013. [PMID: 36556378 PMCID: PMC9781209 DOI: 10.3390/life12122013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 11/20/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022]
Abstract
Nanotechnology has the potential to revolutionize various fields of research and development. Multiple nanoparticles employed in a nanotechnology process are the magic elixir that provides unique features that are not present in the component's natural form. In the framework of contemporary research, it is inappropriate to synthesize microparticles employing procedures that include noxious elements. For this reason, scientists are investigating safer ways to produce genetically improved Cyanobacteria, which has many novel features and acts as a potential candidate for nanoparticle synthesis. In recent decades, cyanobacteria have garnered significant interest due to their prospective nanotechnological uses. This review will outline the applications of genetically engineered cyanobacteria in the field of nanotechnology and discuss its challenges and future potential. The evolution of cyanobacterial strains by genetic engineering is subsequently outlined. Furthermore, the recombination approaches that may be used to increase the industrial potential of cyanobacteria are discussed. This review provides an overview of the research undertaken to increase the commercial avenues of cyanobacteria and attempts to explain prospective topics for future research.
Collapse
|
49
|
Zhang W, Li H, Cao H. Strong variability in nitrogen (N) removal rates in typical agricultural pond from hilly catchment: Evidence from diel and monthly dissolved N 2 measurement. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 314:120196. [PMID: 36126768 DOI: 10.1016/j.envpol.2022.120196] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/23/2022] [Accepted: 09/13/2022] [Indexed: 06/15/2023]
Abstract
Ponds, depressional submerged landscapes that can store and process nitrogen (N)-enriched runoff from surrounding uplands, are recognized as biogeochemical hotspots for N removal. Despite their strong potential for N removal, information is limited concerning the specifics of their changing nature. Here, we investigated the dynamics of N removal rate in a typical agricultural pond from a hilly catchment, by unraveling the monthly and diel patterns of N2 concentrations and fluxes. Our observations showed that the N pollution in the pond was severe. Its averaged total N level reached 3.6 mg L-1, of which ∼72% consisted of NO3-N. Meanwhile, the water samples were supersaturated with N2, demonstrating N removal occurring in the pond. Further estimates of net N2 fluxes indicated that N removal rates exhibited obvious day-and-night and monthly differences. On the diel scale, N removal rates exhibited a distinct diurnal cycle, with nocturnal rates around 20% higher than during the day. Such a diel pattern can be mainly explained by the fluctuation in DO levels, showing that at nighttime when photosynthesis is absent, low DO environments are conducive to N removal. On a monthly scale, the monthly rates ranged from 0.02 to 0.49 mmol N2 m-2 h-1 (mean: 0.23 mmol N2 m-2 h-1), with generally higher removal rates in the warmer and concurrently rainy months (June-September). N levels in the pond were the corresponding primary explanatory variables. Assembled data from both monthly and hourly scales provided a more complete picture of the changing nature of N removal in ponds. Future work should carefully consider the effects of altered environmental conditions triggered by hydrological events to better reveal the control mechanisms behind the time-immediate N removal from lowland ponds.
Collapse
Affiliation(s)
- Wangshou Zhang
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
| | - Hengpeng Li
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
| | - Heng Cao
- Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| |
Collapse
|
50
|
Gradoville MR, Dugenne M, Hynes AM, Zehr JP, White AE. Empirical relationship between nifH gene abundance and diazotroph cell concentration in the North Pacific Subtropical Gyre. JOURNAL OF PHYCOLOGY 2022; 58:829-833. [PMID: 36266252 DOI: 10.1111/jpy.13289] [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: 06/17/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
Cyanobacterial N2 -fixing microorganisms (diazotrophs) play a critical role in nitrogen and carbon cycling in the oceans; hence, accurate measurements of diazotroph abundance are imperative for understanding ocean biogeochemistry. Marine diazotroph abundances are often assessed using qPCR of the nifH gene, a sensitive, taxa-specific, and time/cost-efficient method. However, the validity of nifH abundance as a proxy for cell concentration has recently been questioned. Here, we compare nifH gene abundances to cell counts for four diazotroph taxa (Trichodesmium, Crocosphaera, Richelia, and Calothrix) on two cruises to the North Pacific Subtropical Gyre, one of the largest habitats for marine diazotrophs. nifH:cell relationships were strong and significant for Crocosphaera, Richelia, and Calothrix (nifH:cell 1.51-2.58; R2 = 0.89-0.96) but were not significant for Trichodesmium, despite previous studies reporting significant nifH:cell relationships for this organism. Limited available data suggest that empirical nifH:cell can vary among studies but that relationships are usually significantly linear and >1:1. Our study indicates that nifH gene abundance, while not a direct measure of cells, is a useful quantitative proxy for diazotroph abundance.
Collapse
Affiliation(s)
- Mary R Gradoville
- Ocean Sciences Department, University of California Santa Cruz, Santa Cruz, California, 95064, USA
| | - Mathilde Dugenne
- Department of Oceanography, University of Hawai'i at Mānoa, Honolulu, Hawaii, 96822, USA
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawai'i at Mānoa, Honolulu, Hawaii, 96822, USA
| | - Annette M Hynes
- School of Oceanography, University of Washington, Seattle, Washington, 98195, USA
| | - Jonathan P Zehr
- Ocean Sciences Department, University of California Santa Cruz, Santa Cruz, California, 95064, USA
| | - Angelicque E White
- Department of Oceanography, University of Hawai'i at Mānoa, Honolulu, Hawaii, 96822, USA
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, University of Hawai'i at Mānoa, Honolulu, Hawaii, 96822, USA
| |
Collapse
|