1
|
Voolstra CR, Raina JB, Dörr M, Cárdenas A, Pogoreutz C, Silveira CB, Mohamed AR, Bourne DG, Luo H, Amin SA, Peixoto RS. The coral microbiome in sickness, in health and in a changing world. Nat Rev Microbiol 2024; 22:460-475. [PMID: 38438489 DOI: 10.1038/s41579-024-01015-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2024] [Indexed: 03/06/2024]
Abstract
Stony corals, the engines and engineers of reef ecosystems, face unprecedented threats from anthropogenic environmental change. Corals are holobionts that comprise the cnidarian animal host and a diverse community of bacteria, archaea, viruses and eukaryotic microorganisms. Recent research shows that the bacterial microbiome has a pivotal role in coral biology. A healthy bacterial assemblage contributes to nutrient cycling and stress resilience, but pollution, overfishing and climate change can break down these symbiotic relationships, which results in disease, bleaching and, ultimately, coral death. Although progress has been made in characterizing the spatial-temporal diversity of bacteria, we are only beginning to appreciate their functional contribution. In this Review, we summarize the ecological and metabolic interactions between bacteria and other holobiont members, highlight the biotic and abiotic factors influencing the structure of bacterial communities and discuss the impact of climate change on these communities and their coral hosts. We emphasize how microbiome-based interventions can help to decipher key mechanisms underpinning coral health and promote reef resilience. Finally, we explore how recent technological developments may be harnessed to address some of the most pressing challenges in coral microbiology, providing a road map for future research in this field.
Collapse
Affiliation(s)
| | - Jean-Baptiste Raina
- Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales, Australia.
| | - Melanie Dörr
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Anny Cárdenas
- Department of Biology, American University, Washington, DC, USA
| | - Claudia Pogoreutz
- PSL Université Paris: EPHE-UPVD-CNRS, UAR 3278 CRIOBE, Université de Perpignan, Perpignan, France
| | | | - Amin R Mohamed
- Marine Microbiomics Laboratory, Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - David G Bourne
- Australian Institute of Marine Science, Townsville, Queensland, Australia
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Haiwei Luo
- Simon F.S. Li Marine Science Laboratory, School of Life Sciences, State Key Laboratory of Agrobiotechnology and Institute of Environment, Energy and Sustainability, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Shady A Amin
- Marine Microbiomics Laboratory, Biology Program, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
- Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Raquel S Peixoto
- Red Sea Research Center (RSRC) and Computational Biology Research Center (CBRC), Biological, Environmental Sciences, and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
| |
Collapse
|
2
|
Yang Q, Ling J, Zhang Y, Zhou W, Wei Z, Li J, Zhang Y, Dong J, Qian P. Microbial nitrogen removal in reef-building corals: A light-sensitive process. CHEMOSPHERE 2024; 359:142394. [PMID: 38777199 DOI: 10.1016/j.chemosphere.2024.142394] [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: 12/18/2023] [Revised: 05/10/2024] [Accepted: 05/20/2024] [Indexed: 05/25/2024]
Abstract
Scleractinian corals are the main framework-building groups in tropical coral reefs. In the coral holobiont, nitrogen-cycling mediated by microbes is fundamental for sustaining the coral reef ecosystems. However, little direct evidence characterizing the activities of microbial nitrogen removal via complete denitrification and anaerobic ammonium oxidation (anammox) in stony corals has been presented. In this study, multiple incubation experiments using 15N-tracer were conducted to identify and characterize N2 production by denitrification and anammox in the stony coral Pocillopora damicornis. The rates of denitrification and anammox were recorded up to 0.765 ± 0.162 and 0.078 ± 0.009 nmol N2 cm-2 h-1 respectively. Denitrification contributed the majority (∼90%) of N2 production by microbial nitrogen removal in stony corals. The microbial nitrogen removal activities showed diel rhythms, which might correspond to photosynthetic oxygen production. The N2 production rates of anammox and denitrification increased with incubation time. To the authors' knowledge, this study is the first to confirm and characterize the activities of complete denitrification and anammox in stony corals via stable isotope techniques. This study extends the understanding on nitrogen-cycling in coral reefs and how it participates in corals' resilience to environmental stressors.
Collapse
Affiliation(s)
- Qingsong Yang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China; University of Chinese Academy of Sciences, Beijing, China; Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Juan Ling
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China; Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China
| | - Ying Zhang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; University of Chinese Academy of Sciences, Beijing, China
| | - Weiguo Zhou
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Zhangliang Wei
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Jie Li
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Yanying Zhang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; Ocean School, Yantai University, Yantai, China.
| | - Junde Dong
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China; Tropical Marine Biological Research Station in Hainan, CAS-HKUST Sanya Joint Laboratory of Marine Science Research, Chinese Academy of Sciences and Hainan Key Laboratory of Tropical Marine Biotechnology, Sanya, China; Shantou Marine Plants Experiment Station, Chinese Academy of Sciences, Shantou, China.
| | - Peiyuan Qian
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China; Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China; Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China
| |
Collapse
|
3
|
Tilstra A, Braxator L, Thobor B, Mezger SD, Hill CEL, El-Khaled YC, Caporale G, Kim S, Wild C. Short-term ocean acidification decreases pulsation and growth of the widespread soft coral Xenia umbellata. PLoS One 2023; 18:e0294470. [PMID: 37967066 PMCID: PMC10651030 DOI: 10.1371/journal.pone.0294470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 10/31/2023] [Indexed: 11/17/2023] Open
Abstract
Coral reefs may experience lower pH values as a result of ocean acidification (OA), which has negative consequences, particularly for calcifying organisms. Thus far, the effects of this global factor have been mainly investigated on hard corals, while the effects on soft corals remain relatively understudied. We therefore carried out a manipulative aquarium experiment for 21 days to study the response of the widespread pulsating soft coral Xenia umbellata to simulated OA conditions. We gradually decreased the pH from ambient (~8.3) to three consecutive 7-day long pH treatments of 8.0, 7.8, and 7.6, using a CO2 dosing system. Monitored response variables included pulsation rate, specific growth rate, visual coloration, survival, Symbiodiniaceae cell densities and chlorophyll a content, photosynthesis and respiration, and finally stable isotopes of carbon (C) and nitrogen (N) as well as CN content. Pulsation decreased compared to controls with each consecutive lowering of the pH, i.e., 17% at pH 8.0, 26% at pH 7.8 and 32% at pH 7.6, accompanied by an initial decrease in growth rates of ~60% at pH 8.0, not decreasing further at lower pH. An 8.3 ‰ decrease of δ13C confirmed that OA exposed colonies had a higher uptake and availability of atmospheric CO2. Coral productivity, i.e., photosynthesis, was not affected by higher dissolved inorganic C availability and none of the remaining response variables showed any significant differences. Our findings suggest that pulsation is a phenotypically plastic mechanism for X. umbellata to adjust to different pH values, resulting in reduced growth rates only, while maintaining high productivity. Consequently, pulsation may allow X. umbellata to inhabit a broad pH range with minimal effects on its overall health. This resilience may contribute to the competitive advantage that soft corals, particularly X. umbellata, have over hard corals.
Collapse
Affiliation(s)
- Arjen Tilstra
- Department of Marine Ecology, University of Bremen, Bremen, Germany
| | - Lorena Braxator
- Department of Marine Ecology, University of Bremen, Bremen, Germany
| | - Bianca Thobor
- Department of Marine Ecology, University of Bremen, Bremen, Germany
| | - Selma D. Mezger
- Department of Marine Ecology, University of Bremen, Bremen, Germany
| | | | | | - Giulia Caporale
- Department of Marine Ecology, University of Bremen, Bremen, Germany
| | - Sohyoung Kim
- Department of Marine Ecology, University of Bremen, Bremen, Germany
| | - Christian Wild
- Department of Marine Ecology, University of Bremen, Bremen, Germany
| |
Collapse
|
4
|
Exploring the Potential Molecular Mechanisms of Interactions between a Probiotic Consortium and Its Coral Host. mSystems 2023; 8:e0092122. [PMID: 36688656 PMCID: PMC9948713 DOI: 10.1128/msystems.00921-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Beneficial microorganisms for corals (BMCs) have been demonstrated to be effective probiotics to alleviate bleaching and mitigate coral mortality in vivo. The selection of putative BMCs is traditionally performed manually, using an array of biochemical and molecular tests for putative BMC traits. We present a comprehensive genetic survey of BMC traits using a genome-based framework for the identification of alternative mechanisms that can be used for future in silico selection of BMC strains. We identify exclusive BMC traits associated with specific strains and propose new BMC mechanisms, such as the synthesis of glycine betaine and ectoines. Our roadmap facilitates the selection of BMC strains while increasing the array of genetic targets that can be included in the selection of putative BMC strains to be tested as coral probiotics. IMPORTANCE Probiotics are currently the main hope as a potential medicine for corals, organisms that are considered the marine "canaries of the coal mine" and that are threatened with extinction. Our experiments have proved the concept that probiotics mitigate coral bleaching and can also prevent coral mortality. Here, we present a comprehensive genetic survey of probiotic traits using a genome-based framework. The main outcomes are a roadmap that facilitates the selection of coral probiotic strains while increasing the array of mechanisms that can be included in the selection of coral probiotics.
Collapse
|
5
|
Xiang N, Rädecker N, Pogoreutz C, Cárdenas A, Meibom A, Wild C, Gärdes A, Voolstra CR. Presence of algal symbionts affects denitrifying bacterial communities in the sea anemone Aiptasia coral model. ISME COMMUNICATIONS 2022; 2:105. [PMID: 37938763 PMCID: PMC9723753 DOI: 10.1038/s43705-022-00190-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 09/28/2022] [Accepted: 10/10/2022] [Indexed: 11/09/2023]
Abstract
The coral-algal symbiosis is maintained by a constant and limited nitrogen availability in the holobiont. Denitrifiers, i.e., prokaryotes reducing nitrate/nitrite to dinitrogen, could contribute to maintaining the nitrogen limitation in the coral holobiont, however the effect of host and algal identity on their community is still unknown. Using the coral model Aiptasia, we quantified and characterized the denitrifier community in a full-factorial design combining two hosts (CC7 and H2) and two strains of algal symbionts of the family Symbiodiniaceae (SSA01 and SSB01). Strikingly, relative abundance of denitrifiers increased by up to 22-fold in photosymbiotic Aiptasia compared to their aposymbiotic (i.e., algal-depleted) counterparts. In line with this, while the denitrifier community in aposymbiotic Aiptasia was largely dominated by diet-associated Halomonas, we observed an increasing relative abundance of an unclassified bacterium in photosymbiotic CC7, and Ketobacter in photosymbiotic H2, respectively. Pronounced changes in denitrifier communities of Aiptasia with Symbiodinium linucheae strain SSA01 aligned with the higher photosynthetic carbon availability of these holobionts compared to Aiptasia with Breviolum minutum strain SSB01. Our results reveal that the presence of algal symbionts increases abundance and alters community structure of denitrifiers in Aiptasia. Thereby, patterns in denitrifier community likely reflect the nutritional status of aposymbiotic vs. symbiotic holobionts. Such a passive regulation of denitrifiers may contribute to maintaining the nitrogen limitation required for the functioning of the cnidarian-algal symbiosis.
Collapse
Affiliation(s)
- Nan Xiang
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, 28359, Bremen, Germany.
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, 27570, Bremerhaven, Germany.
| | - Nils Rädecker
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Claudia Pogoreutz
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Anny Cárdenas
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Anders Meibom
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
- Center for Advanced Surface Analysis (CASA), Institute of Earth Science, University of Lausanne, 1015, Lausanne, Switzerland
| | - Christian Wild
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, 28359, Bremen, Germany
| | - Astrid Gärdes
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, 27570, Bremerhaven, Germany
- Hochschule Bremerhaven, Fachbereich 1, An der Karlstadt 8, 27568, Bremerhaven, Germany
| | | |
Collapse
|
6
|
Kim S, Wild C, Tilstra A. Effective asexual reproduction of a widespread soft coral: comparative assessment of four different fragmentation methods. PeerJ 2022; 10:e12589. [PMID: 35111389 PMCID: PMC8783554 DOI: 10.7717/peerj.12589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 11/12/2021] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Many coral reefs worldwide are experiencing declines in hard corals, resulting in other benthic organisms, e.g., soft corals, becoming more dominant. As such, more studies on the ecophysiology of soft corals are needed. Despite many methods for asexual reproduction of hard corals, effective methods for soft corals, i.e., without a hard skeleton, are scarce. This study, thus, assessed four fragmentation methods, the glue, rubber band, tunnel mesh, and plug mesh method for the pulsating soft coral Xenia umbellata that is widely distributed in the tropical Indo-Pacific. METHODS Methods were comparatively assessed by determining the required time and labor for the fragmentation plus the health status of the fragmented corals by measuring their oxygen fluxes and pulsation rates, i.e., a special feature of this soft coral that can be used as a proxy for its health. RESULTS There were no significant health status differences between methods. This was indicated by similar gross photosynthesis (between 7.4 to 9.7 μg O2 polyp-1 h-1) and pulsating rates (between 35 and 44 pulses min-1) among methods. In terms of time/labor intensity and success rates, i.e., the percentage of fragments attached to the desired surface, the plug mesh method was the most efficient method with a significantly higher success rate (95 ± 5%), while the others had a success rate between 5 ± 5 and 45 ± 15%. The time needed for fragmentation, though not significant, was also the shortest (78 ± 11 s fragment-1), while other methods required between 84 ± 14 and 126 ± 8 s frag-1. The plug mesh method may thus be a valuable tool related to the reproduction of soft corals for use in subsequent experimental work.
Collapse
|
7
|
Glaze TD, Erler DV, Siljanen HMP. Microbially facilitated nitrogen cycling in tropical corals. THE ISME JOURNAL 2022; 16:68-77. [PMID: 34226659 PMCID: PMC8692614 DOI: 10.1038/s41396-021-01038-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 06/04/2021] [Accepted: 06/08/2021] [Indexed: 02/06/2023]
Abstract
Tropical scleractinian corals support a diverse assemblage of microbial symbionts. This 'microbiome' possesses the requisite functional diversity to conduct a range of nitrogen (N) transformations including denitrification, nitrification, nitrogen fixation and dissimilatory nitrate reduction to ammonium (DNRA). Very little direct evidence has been presented to date verifying that these processes are active within tropical corals. Here we use a combination of stable isotope techniques, nutrient uptake calculations and captured metagenomics to quantify rates of nitrogen cycling processes in a selection of tropical scleractinian corals. Denitrification activity was detected in all species, albeit with very low rates, signifying limited importance in holobiont N removal. Relatively greater nitrogen fixation activity confirms that corals are net N importers to reef systems. Low net nitrification activity suggests limited N regeneration capacity; however substantial gross nitrification activity may be concealed through nitrate consumption. Based on nrfA gene abundance and measured inorganic N fluxes, we calculated significant DNRA activity in the studied corals, which has important implications for coral reef N cycling and warrants more targeted investigation. Through the quantification and characterisation of all relevant N-cycling processes, this study provides clarity on the subject of tropical coral-associated biogeochemical N-cycling.
Collapse
Affiliation(s)
- Thomas D Glaze
- Centre for Coastal Biogeochemistry Research, School of Environment Science and Engineering, Southern Cross University, Lismore, NSW, Australia.
| | - Dirk V Erler
- Centre for Coastal Biogeochemistry Research, School of Environment Science and Engineering, Southern Cross University, Lismore, NSW, Australia
| | - Henri M P Siljanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
- Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria
| |
Collapse
|
8
|
Moynihan MA, Goodkin NF, Morgan KM, Kho PYY, Lopes Dos Santos A, Lauro FM, Baker DM, Martin P. Coral-associated nitrogen fixation rates and diazotrophic diversity on a nutrient-replete equatorial reef. THE ISME JOURNAL 2022; 16:233-246. [PMID: 34294880 PMCID: PMC8692400 DOI: 10.1038/s41396-021-01054-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 06/23/2021] [Accepted: 06/30/2021] [Indexed: 02/07/2023]
Abstract
The role of diazotrophs in coral physiology and reef biogeochemistry remains poorly understood, in part because N2 fixation rates and diazotrophic community composition have only been jointly analyzed in the tissue of one tropical coral species. We performed field-based 15N2 tracer incubations during nutrient-replete conditions to measure diazotroph-derived nitrogen (DDN) assimilation into three species of scleractinian coral (Pocillopora acuta, Goniopora columna, Platygyra sinensis). Using multi-marker metabarcoding (16S rRNA, nifH, 18S rRNA), we analyzed DNA- and RNA-based communities in coral tissue and skeleton. Despite low N2 fixation rates, DDN assimilation supplied up to 6% of the holobiont's N demand. Active coral-associated diazotrophs were chiefly Cluster I (aerobes or facultative anaerobes), suggesting that oxygen may control coral-associated diazotrophy. Highest N2 fixation rates were observed in the endolithic community (0.20 µg N cm-2 per day). While the diazotrophic community was similar between the tissue and skeleton, RNA:DNA ratios indicate potential differences in relative diazotrophic activity between these compartments. In Pocillopora, DDN was found in endolithic, host, and symbiont compartments, while diazotrophic nifH sequences were only observed in the endolithic layer, suggesting a possible DDN exchange between the endolithic community and the overlying coral tissue. Our findings demonstrate that coral-associated diazotrophy is significant, even in nutrient-rich waters, and suggest that endolithic microbes are major contributors to coral nitrogen cycling on reefs.
Collapse
Affiliation(s)
- Molly A Moynihan
- Earth Observatory of Singapore, Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Singapore.
- Asian School of the Environment, Nanyang Technological University, Singapore, Singapore.
| | - Nathalie F Goodkin
- Asian School of the Environment, Nanyang Technological University, Singapore, Singapore
- Earth Observatory of Singapore, Nanyang Technological University, Singapore, Singapore
- American Museum of Natural History, New York, NY, USA
| | - Kyle M Morgan
- Asian School of the Environment, Nanyang Technological University, Singapore, Singapore
| | - Phyllis Y Y Kho
- Asian School of the Environment, Nanyang Technological University, Singapore, Singapore
| | | | - Federico M Lauro
- Asian School of the Environment, Nanyang Technological University, Singapore, Singapore
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, Singapore
| | - David M Baker
- Division for Ecology and Biodiversity, School of Biological Sciences, University of Hong Kong, Hong Kong, PR China
- The Swire Institute of Marine Science, University of Hong Kong, Hong Kong, PR China
| | - Patrick Martin
- Asian School of the Environment, Nanyang Technological University, Singapore, Singapore
| |
Collapse
|
9
|
Barreto MM, Ziegler M, Venn A, Tambutté E, Zoccola D, Tambutté S, Allemand D, Antony CP, Voolstra CR, Aranda M. Effects of Ocean Acidification on Resident and Active Microbial Communities of Stylophora pistillata. Front Microbiol 2021; 12:707674. [PMID: 34899619 PMCID: PMC8656159 DOI: 10.3389/fmicb.2021.707674] [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: 05/10/2021] [Accepted: 10/28/2021] [Indexed: 12/12/2022] Open
Abstract
Ocean warming and ocean acidification (OA) are direct consequences of climate change and affect coral reefs worldwide. While the effect of ocean warming manifests itself in increased frequency and severity of coral bleaching, the effects of ocean acidification on corals are less clear. In particular, long-term effects of OA on the bacterial communities associated with corals are largely unknown. In this study, we investigated the effects of ocean acidification on the resident and active microbiome of long-term aquaria-maintained Stylophora pistillata colonies by assessing 16S rRNA gene diversity on the DNA (resident community) and RNA level (active community). Coral colony fragments of S. pistillata were kept in aquaria for 2 years at four different pCO2 levels ranging from current pH conditions to increased acidification scenarios (i.e., pH 7.2, 7.4, 7.8, and 8). We identified 154 bacterial families encompassing 2,047 taxa (OTUs) in the resident and 89 bacterial families including 1,659 OTUs in the active communities. Resident communities were dominated by members of Alteromonadaceae, Flavobacteriaceae, and Colwelliaceae, while active communities were dominated by families Cyclobacteriacea and Amoebophilaceae. Besides the overall differences between resident and active community composition, significant differences were seen between the control (pH 8) and the two lower pH treatments (7.2 and 7.4) in the active community, but only between pH 8 and 7.2 in the resident community. Our analyses revealed profound differences between the resident and active microbial communities, and we found that OA exerted stronger effects on the active community. Further, our results suggest that rDNA- and rRNA-based sequencing should be considered complementary tools to investigate the effects of environmental change on microbial assemblage structure and activity.
Collapse
Affiliation(s)
- Marcelle Muniz Barreto
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Maren Ziegler
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany
| | | | | | | | | | | | - Chakkiath Paul Antony
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Christian R Voolstra
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Manuel Aranda
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| |
Collapse
|
10
|
Rädecker N, Pogoreutz C, Gegner HM, Cárdenas A, Perna G, Geißler L, Roth F, Bougoure J, Guagliardo P, Struck U, Wild C, Pernice M, Raina JB, Meibom A, Voolstra CR. Heat stress reduces the contribution of diazotrophs to coral holobiont nitrogen cycling. THE ISME JOURNAL 2021; 16:1110-1118. [PMID: 34857934 PMCID: PMC8941099 DOI: 10.1038/s41396-021-01158-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 11/11/2021] [Accepted: 11/16/2021] [Indexed: 12/22/2022]
Abstract
Efficient nutrient cycling in the coral-algal symbiosis requires constant but limited nitrogen availability. Coral-associated diazotrophs, i.e., prokaryotes capable of fixing dinitrogen, may thus support productivity in a stable coral-algal symbiosis but could contribute to its breakdown when overstimulated. However, the effects of environmental conditions on diazotroph communities and their interaction with other members of the coral holobiont remain poorly understood. Here we assessed the effects of heat stress on diazotroph diversity and their contribution to holobiont nutrient cycling in the reef-building coral Stylophora pistillata from the central Red Sea. In a stable symbiotic state, we found that nitrogen fixation by coral-associated diazotrophs constitutes a source of nitrogen to the algal symbionts. Heat stress caused an increase in nitrogen fixation concomitant with a change in diazotroph communities. Yet, this additional fixed nitrogen was not assimilated by the coral tissue or the algal symbionts. We conclude that although diazotrophs may support coral holobiont functioning under low nitrogen availability, altered nutrient cycling during heat stress abates the dependence of the coral host and its algal symbionts on diazotroph-derived nitrogen. Consequently, the role of nitrogen fixation in the coral holobiont is strongly dependent on its nutritional status and varies dynamically with environmental conditions.
Collapse
Affiliation(s)
- Nils Rädecker
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia. .,Department of Biology, University of Konstanz, Konstanz, Germany. .,Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - Claudia Pogoreutz
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Hagen M Gegner
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Metabolomics Core Technology Platform, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Anny Cárdenas
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Gabriela Perna
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Laura Geißler
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Florian Roth
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Baltic Sea Centre, Stockholm University, Stockholm, Sweden.,Faculty of Biological and Environmental Sciences, Tvärminne Zoological Station, University of Helsinki, Helsinki, Finland
| | - Jeremy Bougoure
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Perth, WA, Australia
| | - Paul Guagliardo
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Perth, WA, Australia
| | - Ulrich Struck
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany.,Department of Earth Sciences, Freie Universität Berlin, Berlin, Germany
| | - Christian Wild
- Faculty of Biology and Chemistry, Marine Ecology Department, University of Bremen, Bremen, Germany
| | - Mathieu Pernice
- Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia
| | - Jean-Baptiste Raina
- Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia
| | - Anders Meibom
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Center for Advanced Surface Analysis, Institute of Earth Sciences, Université de Lausanne, Lausanne, Switzerland
| | - Christian R Voolstra
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Department of Biology, University of Konstanz, Konstanz, Germany
| |
Collapse
|
11
|
Contrasting microbiome dynamics of putative denitrifying bacteria in two octocoral species exposed to dissolved organic carbon (DOC) and warming. Appl Environ Microbiol 2021; 88:e0188621. [PMID: 34788073 PMCID: PMC8788706 DOI: 10.1128/aem.01886-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Mutualistic nutrient cycling in the coral-algae symbiosis depends on limited nitrogen (N) availability for algal symbionts. Denitrifying prokaryotes capable of reducing nitrate or nitrite to dinitrogen could thus support coral holobiont functioning by limiting N availability. Octocorals show some of the highest denitrification rates among reef organisms; however, little is known about the community structures of associated denitrifiers and their response to environmental fluctuations. Combining 16S rRNA gene amplicon sequencing with nirS in-silico PCR and quantitative PCR, we found differences in bacterial community dynamics between two octocorals exposed to excess dissolved organic carbon (DOC) and concomitant warming. Although bacterial communities of the gorgonian Pinnigorgia flava remained largely unaffected by DOC and warming, the soft coral Xenia umbellata exhibited a pronounced shift toward Alphaproteobacteria dominance under excess DOC. Likewise, the relative abundance of denitrifiers was not altered in P. flava but decreased by 1 order of magnitude in X. umbellata under excess DOC, likely due to decreased proportions of Ruegeria spp. Given that holobiont C:N ratios remained stable in P. flava but showed a pronounced increase with excess DOC in X. umbellata, our results suggest that microbial community dynamics may reflect the nutritional status of the holobiont. Hence, denitrifier abundance may be directly linked to N availability. This suggests a passive regulation of N cycling microbes based on N availability, which could help stabilize nutrient limitation in the coral-algal symbiosis and thereby support holobiont functioning in a changing environment. IMPORTANCE Octocorals are important members of reef-associated benthic communities that can rapidly replace scleractinian corals as the dominant ecosystem engineers on degraded reefs. Considering the substantial change in the (a)biotic environment that is commonly driving reef degradation, maintaining a dynamic and metabolically diverse microbial community might contribute to octocoral acclimatization. Nitrogen (N) cycling microbes, in particular denitrifying prokaryotes, may support holobiont functioning by limiting internal N availability, but little is known about the identity and (a)biotic drivers of octocoral-associated denitrifiers. Here, we show contrasting dynamics of bacterial communities associated with two common octocoral species, the soft coral Xenia umbellata and the gorgonian Pinnigorgia flava after a 6-week exposure to excess dissolved organic carbon under concomitant warming conditions. The specific responses of denitrifier communities of the two octocoral species aligned with the nutritional status of holobiont members. This suggests a passive regulation based on N availability in the coral holobiont.
Collapse
|
12
|
Kulbir, Das S, Devi T, Goswami M, Yenuganti M, Bhardwaj P, Ghosh S, Chandra Sahoo S, Kumar P. Oxygen atom transfer promoted nitrate to nitric oxide transformation: a step-wise reduction of nitrate → nitrite → nitric oxide. Chem Sci 2021; 12:10605-10612. [PMID: 35003574 PMCID: PMC8666158 DOI: 10.1039/d1sc00803j] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 07/01/2021] [Indexed: 12/22/2022] Open
Abstract
Nitrate reductases (NRs) are molybdoenzymes that reduce nitrate (NO3−) to nitrite (NO2−) in both mammals and plants. In mammals, the salival microbes take part in the generation of the NO2− from NO3−, which further produces nitric oxide (NO) either in acid-induced NO2− reduction or in the presence of nitrite reductases (NiRs). Here, we report a new approach of VCl3 (V3+ ion source) induced step-wise reduction of NO3− in a CoII-nitrato complex, [(12-TMC)CoII(NO3−)]+ (2,{CoII–NO3−}), to a CoIII–nitrosyl complex, [(12-TMC)CoIII(NO)]2+ (4,{CoNO}8), bearing an N-tetramethylated cyclam (TMC) ligand. The VCl3 inspired reduction of NO3− to NO is believed to occur in two consecutive oxygen atom transfer (OAT) reactions, i.e., OAT-1 = NO3− → NO2− (r1) and OAT-2 = NO2− → NO (r2). In these OAT reactions, VCl3 functions as an O-atom abstracting species, and the reaction of 2 with VCl3 produces a CoIII-nitrosyl ({CoNO}8) with VV-Oxo ({VV
Created by potrace 1.16, written by Peter Selinger 2001-2019
]]>
O}3+) species, via a proposed CoII-nitrito (3, {CoII–NO2−}) intermediate species. Further, in a separate experiment, we explored the reaction of isolated complex 3 with VCl3, which showed the generation of 4 with VV-Oxo, validating our proposed reaction sequences of OAT reactions. We ensured and characterized 3 using VCl3 as a limiting reagent, as the second-order rate constant of OAT-2 (k2/) is found to be ∼1420 times faster than that of the OAT-1 (k2) reaction. Binding constant (Kb) calculations also support our proposition of NO3− to NO transformation in two successive OAT reactions, as Kb(CoII–NO2−) is higher than Kb(CoII–NO3−), hence the reaction moves in the forward direction (OAT-1). However, Kb(CoII–NO2−) is comparable to Kb{CoNO}8, and therefore sequenced the second OAT reaction (OAT-2). Mechanistic investigations of these reactions using 15N-labeled-15NO3− and 15NO2− revealed that the N-atom in the {CoNO}8 is derived from NO3− ligand. This work highlights the first-ever report of VCl3 induced step-wise NO3− reduction (NRs activity) followed by the OAT induced NO2− reduction and then the generation of Co-nitrosyl species {CoNO}8. Single metal-induced reduction of NO3− → {NO2−} → NO via oxygen atom transfer reaction.![]()
Collapse
Affiliation(s)
- Kulbir
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati 517507 India
| | - Sandip Das
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati 517507 India
| | - Tarali Devi
- Humboldt-Universität zu Berlin, Institut für Chemie Brook-Taylor-Straße 2 D-12489 Berlin Germany
| | - Mrigaraj Goswami
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati 517507 India
| | - Mahesh Yenuganti
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati 517507 India
| | - Prabhakar Bhardwaj
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati 517507 India
| | - Somnath Ghosh
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati 517507 India
| | | | - Pankaj Kumar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati 517507 India
| |
Collapse
|
13
|
El-Khaled YC, Nafeh R, Roth F, Rädecker N, Karcher DB, Jones BH, Voolstra CR, Wild C. High plasticity of nitrogen fixation and denitrification of common coral reef substrates in response to nitrate availability. MARINE POLLUTION BULLETIN 2021; 168:112430. [PMID: 34000709 DOI: 10.1016/j.marpolbul.2021.112430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 06/12/2023]
Abstract
Nitrogen cycling in coral reefs may be affected by nutrient availability, but knowledge about concentration-dependent thresholds that modulate dinitrogen fixation and denitrification is missing. We determined the effects of different nitrate concentrations (ambient, 1, 5, 10 μM nitrate addition) on both processes under two light scenarios (i.e., light and dark) using a combined acetylene assay for two common benthic reef substrates, i.e., turf algae and coral rubble. For both substrates, dinitrogen fixation rates peaked at 5 μM nitrate addition in light, whereas denitrification was highest at 10 μM nitrate addition in the dark. At 10 μm nitrate addition in the dark, a near-complete collapse of dinitrogen fixation concurrent with a 76-fold increase in denitrification observed for coral rubble, suggesting potential threshold responses linked to the nutritional state of the community. We conclude that dynamic nitrogen cycling activity may help stabilise nitrogen availability in microbial communities associated with coral reef substrates.
Collapse
Affiliation(s)
- Yusuf C El-Khaled
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, 28359 Bremen, Germany.
| | - Rassil Nafeh
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, 28359 Bremen, Germany
| | - Florian Roth
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), 23995 Thuwal, Saudi Arabia; Baltic Sea Centre, Stockholm University, 10691 Stockholm, Sweden; Faculty of Biological and Environmental Sciences, Tvärminne Zoological Station, University of Helsinki, 00014 Helsinki, Finland
| | - Nils Rädecker
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), 23995 Thuwal, Saudi Arabia; Department of Biology, University of Konstanz, 78457 Konstanz, Germany; Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Denis B Karcher
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, 28359 Bremen, Germany; Australian National Centre for the Public Awareness of Science, Australian National University, ACT 2601 Canberra, Australia
| | - Burton H Jones
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), 23995 Thuwal, Saudi Arabia
| | - Christian R Voolstra
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), 23995 Thuwal, Saudi Arabia; Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Christian Wild
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, 28359 Bremen, Germany
| |
Collapse
|
14
|
Pupier CA, Grover R, Fine M, Rottier C, van de Water JAJM, Ferrier-Pagès C. Dissolved Nitrogen Acquisition in the Symbioses of Soft and Hard Corals With Symbiodiniaceae: A Key to Understanding Their Different Nutritional Strategies? Front Microbiol 2021; 12:657759. [PMID: 34149646 PMCID: PMC8211778 DOI: 10.3389/fmicb.2021.657759] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 04/23/2021] [Indexed: 11/13/2022] Open
Abstract
Nitrogen is one of the limiting nutrients for coral growth and primary productivity. Therefore, the capacity of different associations between corals and their algal symbionts (Symbiodiniaceae) to efficiently exploit the available nitrogen sources will influence their distribution and abundance. Recent studies have advanced our understanding of nitrogen assimilation in reef-building scleractinian (hard) coral-Symbiodiniaceae symbioses. However, the nutrient metabolism of other coral taxa, such as Alcyoniina (soft corals), remains underexplored. Using stable isotope labeling, we investigated the assimilation of dissolved nitrogen (i.e., ammonium, nitrate, and free amino acids) by multiple species of soft and hard corals sampled in the Gulf of Aqaba in shallow (8-10 m) and mesophotic (40-50 m) reefs. Our results show that dissolved nitrogen assimilation rates per tissue biomass were up to 10-fold higher in hard than in soft coral symbioses for all sources of nitrogen. Although such differences in assimilation rates could be linked to the Symbiodiniaceae density, Symbiodiniaceae species, or the C:N ratio of the host and algal symbiont fractions, none of these parameters were different between the two coral taxa. Instead, the lower assimilation rates in soft coral symbioses might be explained by their different nutritional strategy: whereas soft corals may obtain most of their nitrogen via the capture of planktonic prey by the coral host (heterotrophic feeding), hard corals may rely more on dissolved nitrogen assimilation by their algal symbionts to fulfill their needs. This study highlights different nutritional strategies in soft and hard coral symbioses. A higher reliance on heterotrophy may help soft corals to grow in reefs with higher turbidity, which have a high concentration of particles in suspension in seawater. Further, soft corals may benefit from lower dissolved nitrogen assimilation rates in areas with low water quality.
Collapse
Affiliation(s)
- Chloé A. Pupier
- Marine Department, Centre Scientifique de Monaco, Monaco, Monaco
- Collège Doctoral, Sorbonne Université, Paris, France
| | - Renaud Grover
- Marine Department, Centre Scientifique de Monaco, Monaco, Monaco
| | - Maoz Fine
- The Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
- The Interuniversity Institute for Marine Science in Eilat, Eilat, Israel
| | - Cécile Rottier
- Marine Department, Centre Scientifique de Monaco, Monaco, Monaco
| | | | | |
Collapse
|
15
|
El-Khaled YC, Roth F, Rädecker N, Tilstra A, Karcher DB, Kürten B, Jones BH, Voolstra CR, Wild C. Nitrogen fixation and denitrification activity differ between coral- and algae-dominated Red Sea reefs. Sci Rep 2021; 11:11820. [PMID: 34083565 PMCID: PMC8175748 DOI: 10.1038/s41598-021-90204-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 05/07/2021] [Indexed: 11/18/2022] Open
Abstract
Coral reefs experience phase shifts from coral- to algae-dominated benthic communities, which could affect the interplay between processes introducing and removing bioavailable nitrogen. However, the magnitude of such processes, i.e., dinitrogen (N2) fixation and denitrification levels, and their responses to phase shifts remain unknown in coral reefs. We assessed both processes for the dominant species of six benthic categories (hard corals, soft corals, turf algae, coral rubble, biogenic rock, and reef sands) accounting for > 98% of the benthic cover of a central Red Sea coral reef. Rates were extrapolated to the relative benthic cover of the studied organisms in co-occurring coral- and algae-dominated areas of the same reef. In general, benthic categories with high N2 fixation exhibited low denitrification activity. Extrapolated to the respective reef area, turf algae and coral rubble accounted for > 90% of overall N2 fixation, whereas corals contributed to more than half of reef denitrification. Total N2 fixation was twice as high in algae- compared to coral-dominated areas, whereas denitrification levels were similar. We conclude that algae-dominated reefs promote new nitrogen input through enhanced N2 fixation and comparatively low denitrification. The subsequent increased nitrogen availability could support net productivity, resulting in a positive feedback loop that increases the competitive advantage of algae over corals in reefs that experienced a phase shift.
Collapse
Affiliation(s)
- Yusuf C El-Khaled
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, 28359, Bremen, Germany.
| | - Florian Roth
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23995, Saudi Arabia
- Baltic Sea Centre, Stockholm University, 10691, Stockholm, Sweden
- Faculty of Biological and Environmental Sciences, Tvärminne Zoological Station, University of Helsinki, 00014, Helsinki, Finland
| | - Nils Rädecker
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23995, Saudi Arabia
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Arjen Tilstra
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, 28359, Bremen, Germany
| | - Denis B Karcher
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, 28359, Bremen, Germany
- Australian National Centre for the Public Awareness of Science, Australian National University, ACT, Canberra, 2601, Australia
| | - Benjamin Kürten
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23995, Saudi Arabia
- Project Management Jülich, Jülich Research Centre GmbH, 18069, Rostock, Germany
| | - Burton H Jones
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23995, Saudi Arabia
| | - Christian R Voolstra
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23995, Saudi Arabia
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Christian Wild
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, 28359, Bremen, Germany
| |
Collapse
|
16
|
Röthig T, Puntin G, Wong JCY, Burian A, McLeod W, Baker DM. Holobiont nitrogen control and its potential for eutrophication resistance in an obligate photosymbiotic jellyfish. MICROBIOME 2021; 9:127. [PMID: 34078452 PMCID: PMC8173792 DOI: 10.1186/s40168-021-01075-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 04/07/2021] [Indexed: 05/08/2023]
Abstract
BACKGROUND Marine holobionts depend on microbial members for health and nutrient cycling. This is particularly evident in cnidarian-algae symbioses that facilitate energy and nutrient acquisition. However, this partnership is highly sensitive to environmental change-including eutrophication-that causes dysbiosis and contributes to global coral reef decline. Yet, some holobionts exhibit resistance to dysbiosis in eutrophic environments, including the obligate photosymbiotic scyphomedusa Cassiopea xamachana. METHODS Our aim was to assess the mechanisms in C. xamachana that stabilize symbiotic relationships. We combined labelled bicarbonate (13C) and nitrate (15N) with metabarcoding approaches to evaluate nutrient cycling and microbial community composition in symbiotic and aposymbiotic medusae. RESULTS C-fixation and cycling by algal Symbiodiniaceae was essential for C. xamachana as even at high heterotrophic feeding rates aposymbiotic medusae continuously lost weight. Heterotrophically acquired C and N were readily shared among host and algae. This was in sharp contrast to nitrate assimilation by Symbiodiniaceae, which appeared to be strongly restricted. Instead, the bacterial microbiome seemed to play a major role in the holobiont's DIN assimilation as uptake rates showed a significant positive relationship with phylogenetic diversity of medusa-associated bacteria. This is corroborated by inferred functional capacity that links the dominant bacterial taxa (~90 %) to nitrogen cycling. Observed bacterial community structure differed between apo- and symbiotic C. xamachana putatively highlighting enrichment of ammonium oxidizers and nitrite reducers and depletion of nitrogen-fixers in symbiotic medusae. CONCLUSION Host, algal symbionts, and bacterial associates contribute to regulated nutrient assimilation and cycling in C. xamachana. We found that the bacterial microbiome of symbiotic medusae was seemingly structured to increase DIN removal and enforce algal N-limitation-a mechanism that would help to stabilize the host-algae relationship even under eutrophic conditions. Video abstract.
Collapse
Affiliation(s)
- Till Röthig
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong, SAR of China
- Department of Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Giulia Puntin
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong, SAR of China
- Department of Animal Ecology & Systematics, Justus Liebig University, Giessen, Germany
| | - Jane C. Y. Wong
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong, SAR of China
| | - Alfred Burian
- Marine Ecology Department, Lurio University, Nampula, Mozambique
- Department of Computational Landscape Ecology, UFZ– Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - Wendy McLeod
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong, SAR of China
| | - David M. Baker
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong, SAR of China
| |
Collapse
|
17
|
Tilstra A, Roth F, El-Khaled YC, Pogoreutz C, Rädecker N, Voolstra CR, Wild C. Relative abundance of nitrogen cycling microbes in coral holobionts reflects environmental nitrate availability. ROYAL SOCIETY OPEN SCIENCE 2021; 8:201835. [PMID: 34109033 PMCID: PMC8170195 DOI: 10.1098/rsos.201835] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 05/14/2021] [Indexed: 06/12/2023]
Abstract
Recent research suggests that nitrogen (N) cycling microbes are important for coral holobiont functioning. In particular, coral holobionts may acquire bioavailable N via prokaryotic dinitrogen (N2) fixation or remove excess N via denitrification activity. However, our understanding of environmental drivers on these processes in hospite remains limited. Employing the strong seasonality of the central Red Sea, this study assessed the effects of environmental parameters on the proportional abundances of N cycling microbes associated with the hard corals Acropora hemprichii and Stylophora pistillata. Specifically, we quantified changes in the relative ratio between nirS and nifH gene copy numbers, as a proxy for seasonal shifts in denitrification and N2 fixation potential in corals, respectively. In addition, we assessed coral tissue-associated Symbiodiniaceae cell densities and monitored environmental parameters to provide a holobiont and environmental context, respectively. While ratios of nirS to nifH gene copy numbers varied between seasons, they revealed similar seasonal patterns in both coral species, with ratios closely following patterns in environmental nitrate availability. Symbiodiniaceae cell densities aligned with environmental nitrate availability, suggesting that the seasonal shifts in nirS to nifH gene abundance ratios were probably driven by nitrate availability in the coral holobiont. Thereby, our results suggest that N cycling in coral holobionts probably adjusts to environmental conditions by increasing and/or decreasing denitrification and N2 fixation potential according to environmental nitrate availability. Microbial N cycling may, thus, extenuate the effects of changes in environmental nitrate availability on coral holobionts to support the maintenance of the coral-Symbiodiniaceae symbiosis.
Collapse
Affiliation(s)
- Arjen Tilstra
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Florian Roth
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
- Baltic Sea Centre, Stockholm University, Stockholm, Sweden
- Tvärminne Zoological Station, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Yusuf C. El-Khaled
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Claudia Pogoreutz
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Nils Rädecker
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
- Department of Biology, University of Konstanz, Konstanz, Germany
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Christian R. Voolstra
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Christian Wild
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
| |
Collapse
|
18
|
Discovery and quantification of anaerobic nitrogen metabolisms among oxygenated tropical Cuban stony corals. THE ISME JOURNAL 2021; 15:1222-1235. [PMID: 33342999 PMCID: PMC8115149 DOI: 10.1038/s41396-020-00845-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 10/23/2020] [Accepted: 11/13/2020] [Indexed: 01/29/2023]
Abstract
Coral reef health depends on an intricate relationship among the coral animal, photosynthetic algae, and a complex microbial community. The holobiont can impact the nutrient balance of their hosts amid an otherwise oligotrophic environment, including by cycling physiologically important nitrogen compounds. Here we use 15N-tracer experiments to produce the first simultaneous measurements of ammonium oxidation, nitrate reduction, and nitrous oxide (N2O) production among five iconic species of reef-building corals (Acropora palmata, Diploria labyrinthiformis, Orbicella faveolata, Porites astreoides, and Porites porites) in the highly protected Jardines de la Reina reefs of Cuba. Nitrate reduction is present in most species, but ammonium oxidation is low potentially due to photoinhibition and assimilatory competition. Coral-associated rates of N2O production indicate a widespread potential for denitrification, especially among D. labyrinthiformis, at rates of ~1 nmol cm-2 d-1. In contrast, A. palmata displays minimal active nitrogen metabolism. Enhanced rates of nitrate reduction and N2O production are observed coincident with dark net respiration periods. Genomes of bacterial cultures isolated from multiple coral species confirm that microorganisms with the ability to respire nitrate anaerobically to either dinitrogen gas or ammonium exist within the holobiont. This confirmation of anaerobic nitrogen metabolisms by coral-associated microorganisms sheds new light on coral and reef productivity.
Collapse
|
19
|
Fiore CL, Jarett JK, Steinert G, Lesser MP. Trait-Based Comparison of Coral and Sponge Microbiomes. Sci Rep 2020; 10:2340. [PMID: 32047192 PMCID: PMC7012828 DOI: 10.1038/s41598-020-59320-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 01/27/2020] [Indexed: 12/27/2022] Open
Abstract
Corals and sponges harbor diverse microbial communities that are integral to the functioning of the host. While the taxonomic diversity of their microbiomes has been well-established for corals and sponges, their functional roles are less well-understood. It is unclear if the similarities of symbiosis in an invertebrate host would result in functionally similar microbiomes, or if differences in host phylogeny and environmentally driven microhabitats within each host would shape functionally distinct communities. Here we addressed this question, using metatranscriptomic and 16S rRNA gene profiling techniques to compare the microbiomes of two host organisms from different phyla. Our results indicate functional similarity in carbon, nitrogen, and sulfur assimilation, and aerobic nitrogen cycling. Additionally, there were few statistical differences in pathway coverage or abundance between the two hosts. For example, we observed higher coverage of phosphonate and siderophore metabolic pathways in the star coral, Montastraea cavernosa, while there was higher coverage of chloroalkane metabolism in the giant barrel sponge, Xestospongia muta. Higher abundance of genes associated with carbon fixation pathways was also observed in M. cavernosa, while in X. muta there was higher abundance of fatty acid metabolic pathways. Metagenomic predictions based on 16S rRNA gene profiling analysis were similar, and there was high correlation between the metatranscriptome and metagenome predictions for both hosts. Our results highlight several metabolic pathways that exhibit functional similarity in these coral and sponge microbiomes despite the taxonomic differences between the two microbiomes, as well as potential specialization of some microbially based metabolism within each host.
Collapse
Affiliation(s)
- Cara L Fiore
- University of New Hampshire, Department of Molecular, Cellular and Biomedical Sciences, School of Marine Science and Ocean Engineering, Durham, NH, USA.
- Appalachian State University, Biology Department, Boone, NC, USA.
| | - Jessica K Jarett
- University of New Hampshire, Department of Molecular, Cellular and Biomedical Sciences, School of Marine Science and Ocean Engineering, Durham, NH, USA
- AnimalBiome, Oakland, CA, USA
| | - Georg Steinert
- Institute for Chemistry and Biology of the Marine Environment, Carl-von-Ossietzky University Oldenburg, Wilhelmshaven, Germany
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Marine Symbioses, Kiel, Germany
| | - Michael P Lesser
- University of New Hampshire, Department of Molecular, Cellular and Biomedical Sciences, School of Marine Science and Ocean Engineering, Durham, NH, USA
| |
Collapse
|