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Te Velde K, Mairo A, Peeters ET, Winter HV, Tudorache C, Slabbekoorn H. Natural soundscapes of lowland river habitats and the potential threat of urban noise pollution to migratory fish. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 359:124517. [PMID: 39002749 DOI: 10.1016/j.envpol.2024.124517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 06/18/2024] [Accepted: 07/07/2024] [Indexed: 07/15/2024]
Abstract
Migratory fish populations have experienced great declines, and considerable effort have been put into reducing stressors, such as chemical pollution and physical barriers. However, the importance of natural sounds as an information source and potential problems caused by noise pollution remain largely unexplored. The spatial distribution of sound sources and variation in propagation characteristics could provide migratory fish with acoustic cues about habitat suitability, predator presence, food availability and conspecific presence. We here investigated the relationship between natural soundscapes and local river conditions and we explored the presence of human-related sounds in these natural soundscapes. We found that 1a) natural river sound profiles vary with river scale and cross-sectional position, and that 1b) depth, width, water velocity, and distance from shore were all significant factors in explaining local soundscape variation. We also found 2a) audible human activities in almost all our underwater recordings and urban and suburban river parts had elevated sound levels relative to rural river parts. Furthermore, 2b) daytime levels were louder than night time sound levels, and bridges and nearby road traffic were much more prominent with diurnal and weekly patterns of anthropogenic noise in the river systems. We believe our data show high potential for natural soundscapes of low-land river habitat to serve as important environmental cues to migratory fish. However, anthropogenic noise may be particularly problematic due to the omnipresence, and relatively loud levels relative to the modest dynamic range of the natural sound sources, in these slow-flowing freshwater systems.
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Affiliation(s)
- Kees Te Velde
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333, BE, Leiden, the Netherlands.
| | - Amy Mairo
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333, BE, Leiden, the Netherlands
| | - Edwin Thm Peeters
- Aquatic Ecology and Water Quality Management Group, Wageningen University, PO Box 47, 6700AA, Wageningen, the Netherlands
| | - Hendrik V Winter
- Wageningen Marine Research, PO Box 68, 1970AB, IJmuiden, the Netherlands
| | - Christian Tudorache
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333, BE, Leiden, the Netherlands
| | - Hans Slabbekoorn
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333, BE, Leiden, the Netherlands
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2
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Zhang Q, Xiong Y, Zhang J, Liu B, Chen T, Liu S, Dang C, Xu WD, Ahmad HA, Liu T. Eutrophication impacts the distribution and functional traits of viral communities in lakes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 946:174339. [PMID: 38960155 DOI: 10.1016/j.scitotenv.2024.174339] [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: 05/04/2024] [Revised: 06/25/2024] [Accepted: 06/26/2024] [Indexed: 07/05/2024]
Abstract
Viruses play a crucial role in aquatic ecosystems by regulating microbial composition and impacting biogeochemical cycling. While the response of viral diversity to the trophic status has been preliminarily explored in lake ecosystems, there is limited integrated exploration of the biogeography of viruses, host associations, and the auxiliary metabolic genes (AMGs), particularly for plateau lakes. Therefore, this research investigated the viral biogeography, virus-host association, and AMGs in the surface waters of 11 lakes varying in trophic levels (eutrophic and oligo-mesotrophic) in the Yunnan-Guizhou plateau region of China. A total of 73,105 viral operational taxonomic units were obtained from 11 samples, with 84.8 % remaining unannotated at the family level, indicating a predominance of novel viruses within these lakes. The most abundant viral family was Kyanoviridae (24.4 %), recognized as a common cyanophage. The vast majority of cyanobacteria and several eukaryotic algae were predicted as hosts for the viruses, with a lytic lifestyle predominating the life strategy of these cyanophages, implying the potential influence of the virus on algae. The viral community structure significantly correlated with both trophic status and the bacterial community. The structure equation model analysis revealed chlorophyll a was the primary factor affecting viral communities. Moreover, numerous AMGs linked to carbon metabolism, phosphorus metabolism, sulfur metabolism, and photosynthesis were found in these lakes, some of which showed virus preference for the trophic statuses, suggesting a vital role of the virus in driving biogeochemical cycling in the lake crossing different nutrient levels. In addition, a restricted presence of viruses was found to infect humans or harbor antibiotic resistance genes in the lakes, suggesting a subtle yet potential link to human health. Overall, these findings offer insights into the response of viral communities to eutrophication and their potential role in biogeochemical cycling and controlling algal propagation.
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Affiliation(s)
- Qiue Zhang
- Environmental Microbiome Engineering and Innovative Genomics Laboratory, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China
| | - Yanxuan Xiong
- Environmental Microbiome Engineering and Innovative Genomics Laboratory, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China
| | - Jinhong Zhang
- Environmental Microbiome Engineering and Innovative Genomics Laboratory, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China
| | - Boya Liu
- Environmental Microbiome Engineering and Innovative Genomics Laboratory, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China
| | - Tianyi Chen
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, PR China
| | - Shufeng Liu
- College of Resources and Environmental Sciences, China Agricultural University, Beijing 100083, PR China
| | - Chenyuan Dang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Wei D Xu
- Changjiang Institute of Survey, Planning, Design and Research, Wuhan, Hubei 430010, PR China
| | - Hafiz Adeel Ahmad
- Environmental Microbiome Engineering and Innovative Genomics Laboratory, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China; School of Biomedical Engineering, Shenzhen University, Shenzhen 518060, PR China.
| | - Tang Liu
- Environmental Microbiome Engineering and Innovative Genomics Laboratory, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China.
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3
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Jiang X, Wang M, Yang S, He D, Fang F, Yang L. The response of structure and nitrogen removal function of the biofilm on submerged macrophytes to high ammonium in constructed wetlands. J Environ Sci (China) 2024; 142:129-141. [PMID: 38527879 DOI: 10.1016/j.jes.2023.07.004] [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: 05/28/2023] [Revised: 06/27/2023] [Accepted: 07/04/2023] [Indexed: 03/27/2024]
Abstract
The ammonium exceedance discharge from sewage treatment plants has a great risk to the stable operation of subsequent constructed wetlands (CWs). The effects of high ammonium shocks on submerged macrophytes and epiphytic biofilms on the leaves of submerged macrophytes in CWs were rarely mentioned in previous studies. In this paper, the 16S rRNA sequencing method was used to investigate the variation of the microbial communities in biofilms on the leaves of Vallisneria natans plants while the growth characteristics of V. natans plants were measured at different initial ammonium concentrations. The results demonstrated that the total chlorophyll and soluble sugar synthesis of V. natans plants decreased by 51.45% and 57.16%, respectively, and malondialdehyde content increased threefold after 8 days if the initial NH4+-N concentration was more than 5 mg/L. Algal density, bacterial quantity, dissolved oxygen, and pH increased with high ammonium shocks. The average removal efficiencies of total nitrogen and NH4+-N reached 73.26% and 83.94%, respectively. The heat map and relative abundance analysis represented that the relative abundances of phyla Proteobacteria, Cyanobacteria, and Bacteroidetes increased. The numbers of autotrophic nitrifiers and heterotrophic nitrification aerobic denitrification (HNAD) bacteria expanded in biofilms. In particular, HNAD bacteria of Flavobacterium, Hydrogenophaga, Acidovorax, Acinetobacter, Pseudomonas, Aeromonas, and Azospira had higher abundances than autotrophic nitrifiers because there were organic matters secreted from declining leaves of V. natans plants. The analysis of the nitrogen metabolic pathway showed aerobic denitrification was the main nitrogen removal pathway. Thus, the nitrification and denitrification bacterial communities increased in epiphytic biofilms on submerged macrophytes in constructed wetlands while submerged macrophytes declined under ammonium shock loading.
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Affiliation(s)
- Xue Jiang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Mengmeng Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Shunqing Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Di He
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Fei Fang
- School of Resources and Environment, Anqing Normal University, Anqing 246133, China
| | - Liuyan Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
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Mugnai S, Derossi N, Hendlin Y. Algae communication, conspecific and interspecific: the concepts of phycosphere and algal-bacteria consortia in a photobioreactor (PBR). PLANT SIGNALING & BEHAVIOR 2023; 18:2148371. [PMID: 36934349 PMCID: PMC10026891 DOI: 10.1080/15592324.2022.2148371] [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: 08/24/2022] [Revised: 11/12/2022] [Accepted: 11/12/2022] [Indexed: 06/18/2023]
Abstract
Microalgae in the wild often form consortia with other species promoting their own health and resource foraging opportunities. The recent application of microalgae cultivation and deployment in commercial photobioreactors (PBR) so far has focussed on single species of algae, resulting in multi-species consortia being largely unexplored. Reviewing the current status of PBR ecological habitat, this article argues in favor of further investigation into algal communication with conspecifics and interspecifics, including other strains of microalgae and bacteria. These mutualistic species form the 'phycosphere': the microenvironment surrounding microalgal cells, potentiating the production of certain metabolites through biochemical interaction with cohabitating microorganisms. A better understanding of the phycosphere could lead to novel PBR configurations, capable of incorporating algal-microbial consortia, potentially proving more effective than single-species algal systems.
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Affiliation(s)
| | | | - Yogi Hendlin
- Erasmus School of Philosophy, Erasmus University, Rotterdam, Netherlands
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Ozanich E, Thode A, Gerstoft P, Freeman LA, Freeman S. Deep embedded clustering of coral reef bioacoustics. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 149:2587. [PMID: 33940892 DOI: 10.1121/10.0004221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
Deep clustering was applied to unlabeled, automatically detected signals in a coral reef soundscape to distinguish fish pulse calls from segments of whale song. Deep embedded clustering (DEC) learned latent features and formed classification clusters using fixed-length power spectrograms of the signals. Handpicked spectral and temporal features were also extracted and clustered with Gaussian mixture models (GMM) and conventional clustering. DEC, GMM, and conventional clustering were tested on simulated datasets of fish pulse calls (fish) and whale song units (whale) with randomized bandwidth, duration, and SNR. Both GMM and DEC achieved high accuracy and identified clusters with fish, whale, and overlapping fish and whale signals. Conventional clustering methods had low accuracy in scenarios with unequal-sized clusters or overlapping signals. Fish and whale signals recorded near Hawaii in February-March 2020 were clustered with DEC, GMM, and conventional clustering. DEC features demonstrated the highest accuracy of 77.5% on a small, manually labeled dataset for classifying signals into fish and whale clusters.
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Affiliation(s)
- Emma Ozanich
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92037, USA
| | - Aaron Thode
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92037, USA
| | - Peter Gerstoft
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92037, USA
| | - Lauren A Freeman
- Naval Undersea Warfare Center Newport, Newport, Rhode Island 02841, USA
| | - Simon Freeman
- Naval Undersea Warfare Center Newport, Newport, Rhode Island 02841, USA
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6
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Ferrier-Pagès C, Leal MC, Calado R, Schmid DW, Bertucci F, Lecchini D, Allemand D. Noise pollution on coral reefs? - A yet underestimated threat to coral reef communities. MARINE POLLUTION BULLETIN 2021; 165:112129. [PMID: 33588103 DOI: 10.1016/j.marpolbul.2021.112129] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 05/08/2023]
Abstract
Noise pollution is an anthropogenic stressor that is increasingly recognized for its negative impact on the physiology, behavior and fitness of marine organisms. Driven by the recent expansion of maritime shipping, artisanal fishing and tourism (e.g., motorboats used for recreational purpose), underwater noise increased greatly on coral reefs. In this review, we first provide an overview on how reef organisms sense and use sound. Thereafter we review the current knowledge on how underwater noise affects different reef organisms. Although the majority of available examples are limited to few fish species, we emphasize how the impact of noise differs based on an organisms' acoustic sensitivity, mobility and developmental stage, as well as between noise type, source and duration. Finally, we highlight measures available to governments, the shipping industry and individual users and provide directions for polices and research aimed to manage this global issue of noise emission on coral reefs.
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Affiliation(s)
- Christine Ferrier-Pagès
- Centre Scientifique de Monaco, Coral Ecophysiology Team, 8 Quai Antoine 1er, MC-98000, Monaco.
| | - Miguel C Leal
- ECOMARE, Centre for Environmental and Marine Studies (CESAM), Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Ricardo Calado
- ECOMARE, Centre for Environmental and Marine Studies (CESAM), Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | | | - Frédéric Bertucci
- Functional and Evolutionary Morphology Lab, University of Liege, Belgium; PSL University, EPHE-UPVD-CNRS, USR 3278 CRIOBE, 98729 Moorea, French Polynesia
| | - David Lecchini
- PSL University, EPHE-UPVD-CNRS, USR 3278 CRIOBE, 98729 Moorea, French Polynesia; Laboratoire d'Excellence "CORAIL", Perpignan, France
| | - Denis Allemand
- Centre Scientifique de Monaco, Coral Ecophysiology Team, 8 Quai Antoine 1er, MC-98000, Monaco
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7
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Peck M, Tapilatu RF, Kurniati E, Rosado C. Rapid coral reef assessment using 3D modelling and acoustics: acoustic indices correlate to fish abundance, diversity and environmental indicators in West Papua, Indonesia. PeerJ 2021; 9:e10761. [PMID: 33614275 PMCID: PMC7877240 DOI: 10.7717/peerj.10761] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 12/22/2020] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Providing coral reef systems with the greatest chance of survival requires effective assessment and monitoring to guide management at a range of scales from community to government. The development of rapid monitoring approaches amenable to collection at community level, yet recognised by policymakers, remains a challenge. Technologies can increase the scope of data collection. Two promising visual and audio approaches are (i) 3D habitat models, generated through photogrammetry from video footage, providing assessment of coral cover structural metrics and (ii) audio, from which acoustic indices shown to correlate to vertebrate and invertebrate diversity, can be extracted. METHODS We collected audio and video imagery using low cost underwater cameras (GoPro Hero7™) from 34 reef samples from West Papua (Indonesia). Using photogrammetry one camera was used to generate 3D models of 4 m2 reef, the other was used to estimate fish abundance and collect audio to generate acoustic indices. We investigated relationships between acoustic metrics, fish abundance/diversity/functional groups, live coral cover and reef structural metrics. RESULTS Generalized linear modelling identified significant but weak correlations between live coral cover and structural metrics extracted from 3D models and stronger relationships between live coral and fish abundance. Acoustic indices correlated to fish abundance, species richness and reef functional metrics associated with overfishing and algal control. Acoustic Evenness (1,200-11,000 Hz) and Root Mean Square RMS (100-1,200 Hz) were the best individual predictors overall suggesting traditional bioacoustic indices, providing information on sound energy and the variability in sound levels in specific frequency bands, can contribute to reef assessment. CONCLUSION Acoustics and 3D modelling contribute to low-cost, rapid reef assessment tools, amenable to community-level data collection, and generate information for coral reef management. Future work should explore whether 3D models of standardised transects and acoustic indices generated from low cost underwater cameras can replicate or support 'gold standard' reef assessment methodologies recognised by policy makers in marine management.
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Affiliation(s)
- Mika Peck
- School of Life Sciences, University of Sussex, Brighton, East Sussex, UK
| | - Ricardo F. Tapilatu
- Marine Science Department and Research Centre of Pacific Marine Resources, University of Papua, Manokwari, West Papua, Indonesia
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Frongia F, Forti L, Arru L. Sound perception and its effects in plants and algae. PLANT SIGNALING & BEHAVIOR 2020; 15:1828674. [PMID: 33048612 PMCID: PMC7671032 DOI: 10.1080/15592324.2020.1828674] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Life evolved in an acoustic world. Sound is perceived in different ways by the species that inhabit the Planet. Among organisms, also some algal species seem to respond to sound stimuli with increased cell growth and productivity. The purpose of this Short Communication is to provide an overview of the current literature about various organisms and sound, with particular attention to algal organisms, which, when subjected to sound applications, can change their metabolism accordingly.
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Affiliation(s)
- Francesca Frongia
- Department of Life Science, University of Modena and Reggio Emilia, Modena/Reggio Emilia, Italy
| | - Luca Forti
- Department of Life Science, University of Modena and Reggio Emilia, Modena/Reggio Emilia, Italy
| | - Laura Arru
- Department of Life Science, University of Modena and Reggio Emilia, Modena/Reggio Emilia, Italy
- CONTACT Laura Arru Department of Life Science, University of Modena and Reggio Emilia, Modena/Reggio Emilia, Italy
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9
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Papale E, Prakash S, Singh S, Batibasaga A, Buscaino G, Piovano S. Soundscape of green turtle foraging habitats in Fiji, South Pacific. PLoS One 2020; 15:e0236628. [PMID: 32756577 PMCID: PMC7406084 DOI: 10.1371/journal.pone.0236628] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 07/10/2020] [Indexed: 11/18/2022] Open
Abstract
The soundscape features of the marine environment provide crucial information about ecosystem health for many species, and they are defined by the local biological, geophysical, and anthropogenic components. In this study, we investigated the soundscape at green turtle neritic foraging habitats in Fiji, South Pacific, with the aims of characterizing the contribution of each component and of comparing the levels of acoustic pressure among sites with different abundances of sea turtles. Four sites were selected at two islands, and one hydrophone was deployed at each site. Generalized additive models highlighted that sound pressure levels (SPLs) at low frequencies (125–250 Hz) were especially affected by wind conditions, while at higher frequencies (>250 Hz) SPLs were mostly influenced by fish and crustacean acoustic activity. Higher abundances of green turtles were found at sites with the highest levels of SPLs and the highest number of acoustic emissions by fishes and crustaceans but were not related to maximum seagrass and macroalgae coverage, or the highest number of fish. The selected coastal habitats have negligible anthropogenic noise, thus this study informs physiological and behavioral studies of the acoustic signatures that sea turtles might target and provides a baseline against which potential impact of soundscape changes on sea turtle spatial abundance and distribution can be evaluated.
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Affiliation(s)
- Elena Papale
- BioacousticsLab, IAS Capo Granitola, National Research Council, Torretta Granitola, Italy
- Department of Life Science and Systems Biology, University of Torino, Torino, Italy
- * E-mail: (EP); (SP)
| | - Shritika Prakash
- School of Marine Studies, The University of the South Pacific, Suva, Fiji
| | - Shubha Singh
- School of Marine Studies, The University of the South Pacific, Suva, Fiji
| | | | - Giuseppa Buscaino
- BioacousticsLab, IAS Capo Granitola, National Research Council, Torretta Granitola, Italy
| | - Susanna Piovano
- School of Marine Studies, The University of the South Pacific, Suva, Fiji
- * E-mail: (EP); (SP)
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Silveira CB, Luque A, Roach TN, Villela H, Barno A, Green K, Reyes B, Rubio-Portillo E, Le T, Mead S, Hatay M, Vermeij MJ, Takeshita Y, Haas A, Bailey B, Rohwer F. Biophysical and physiological processes causing oxygen loss from coral reefs. eLife 2019; 8:49114. [PMID: 31793432 PMCID: PMC6890468 DOI: 10.7554/elife.49114] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 10/27/2019] [Indexed: 12/25/2022] Open
Abstract
The microbialization of coral reefs predicts that microbial oxygen consumption will cause reef deoxygenation. Here we tested this hypothesis by analyzing reef microbial and primary producer oxygen metabolisms. Metagenomic data and in vitro incubations of bacteria with primary producer exudates showed that fleshy algae stimulate incomplete carbon oxidation metabolisms in heterotrophic bacteria. These metabolisms lead to increased cell sizes and abundances, resulting in bacteria consuming 10 times more oxygen than in coral incubations. Experiments probing the dissolved and gaseous oxygen with primary producers and bacteria together indicated the loss of oxygen through ebullition caused by heterogenous nucleation on algae surfaces. A model incorporating experimental production and loss rates predicted that microbes and ebullition can cause the loss of up to 67% of gross benthic oxygen production. This study indicates that microbial respiration and ebullition are increasingly relevant to reef deoxygenation as reefs become dominated by fleshy algae. Rising water temperatures, pollution and other factors are increasingly threatening corals and the entire reef ecosystems they build. The potential for corals to resist and recover from the stress these factors cause ultimately depends on their ability to compete against fast-growing fleshy algae that can rapidly take over the reefs. Living on the fleshy algae, the coral and in the surrounding water are communities of bacteria and other microbes that help maintain the health of the coral reef. Both corals and algae modify the chemical and physical environment of the reef to alter the composition of the microbial communities for their own benefit. Algae, for instance, release large amounts of sugars and other molecules of organic carbon into the water. These carbon molecules are then taken up by the bacteria, along with oxygen, to produce chemical energy via a process called respiration. This could cause the levels of oxygen in the water to decrease, potentially damaging the corals and creating more open space for the algae. Previous studies have revealed how communities of microbes on coral reefs use organic carbon, but it remains unclear how they affect the levels of oxygen in the reefs. To address this question, Silveira et al. used an approach called metagenomics to analyze the bacteria in samples of water from 87 reefs across the Pacific and the Caribbean, and also performed experiments with reef bacteria grown in the laboratory. The experiments showed that bacteria growing in the presence of fleshy algae became larger and more abundant than bacteria growing near corals, resulting in the water containing lower levels of oxygen. Furthermore, the fleshy algae produced bubbles of oxygen that were released from the water. Silveira et al. developed a mathematical model that predicted that these bubbles, combined with the respiration of bacteria that live near algae, caused the loss of 67% of the oxygen in the water surrounding the reef. These findings represent a fundamental step towards understanding how changes in the levels of oxygen in water affect the ability of coral reefs to resist and recover from stress.
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Affiliation(s)
- Cynthia B Silveira
- Department of Biology, San Diego State University, San Diego, United States.,Viral Information Institute, San Diego State University, San Diego, United States
| | - Antoni Luque
- Viral Information Institute, San Diego State University, San Diego, United States.,Computational Science Research Center, San Diego State University, San Diego, United States.,Department of Mathematics and Statistics, San Diego State University, San Diego, United States
| | - Ty Nf Roach
- Hawaii Institute of Marine Biology, University of Hawaii at Mānoa, Kāneohe, United States
| | - Helena Villela
- Department of Microbiology, Rio de Janeiro Federal University, Rio de Janeiro, Brazil
| | - Adam Barno
- Department of Microbiology, Rio de Janeiro Federal University, Rio de Janeiro, Brazil
| | - Kevin Green
- Department of Biology, San Diego State University, San Diego, United States
| | - Brandon Reyes
- Department of Biology, San Diego State University, San Diego, United States
| | - Esther Rubio-Portillo
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Tram Le
- Department of Biology, San Diego State University, San Diego, United States
| | - Spencer Mead
- Department of Biology, San Diego State University, San Diego, United States
| | - Mark Hatay
- Department of Biology, San Diego State University, San Diego, United States.,Viral Information Institute, San Diego State University, San Diego, United States
| | - Mark Ja Vermeij
- CARMABI Foundation, Willemstad, Curaçao.,Department of Freshwater and Marine Ecology, Institute for Biodiversity andEcosystem Dynamics, University of Amsterdam, Amsterdam, Netherlands
| | | | - Andreas Haas
- NIOZ Royal Netherlands Institute for Sea Research, Utrecht University, Texel, Netherlands
| | - Barbara Bailey
- Department of Mathematics and Statistics, San Diego State University, San Diego, United States
| | - Forest Rohwer
- Department of Biology, San Diego State University, San Diego, United States.,Viral Information Institute, San Diego State University, San Diego, United States
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