1
|
Martinez S, Grover R, Ferrier-Pagès C. Unveiling the importance of heterotrophy for coral symbiosis under heat stress. mBio 2024:e0196624. [PMID: 39207106 DOI: 10.1128/mbio.01966-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2024] [Accepted: 08/09/2024] [Indexed: 09/04/2024] Open
Abstract
Global warming endangers reef-building corals as they lose their photosynthetic symbionts, which limits their ability to feed autotrophically. Consequently, heterotrophy, the capture of zooplankton, can become crucial for the energy budget of heat-stressed corals. However, it is difficult to assess the extent of the heterotrophic contribution in corals, as well as the dynamics of nutrient exchange between the host and its symbionts. In this pioneering study, we employed a suite of isotopic markers, including 13C- and 15N bulk tissue isotope measurements, compound-specific isotope analysis of amino acids (CSIA-AAs), and 13C- and 15N-labeled food incubations, to investigate nutrient acquisition and allocation in the coral Stylophora pistillata under controlled and heat-induced bleaching conditions. Bulk isotope values and inorganic carbon assimilation remained unchanged in the bleached corals compared to the control corals, overall indicating undisturbed autotrophic activity of the symbionts under heat stress. However, CSIA-AAs showed an increased dependence on heterotrophy for amino acid synthesis in both the host and the symbionts despite reduced assimilation of 15N-labeled food. Overall, these results suggest that although S. pistillata reduces its assimilation of heterotrophic food under heat stress, the acquisition of amino acids by the coral host and symbionts still relies on heterotrophy. This study emphasizes the importance of using multiple indicators to gain a comprehensive understanding of coral nutrition. It shows that coral dependence on heterotrophy is not only associated with a decline in autotrophic availability. Rather, it demonstrates the ability of S. pistillata to adapt its utilization of food sources to the prevailing environmental conditions.IMPORTANCEThis work highlights that every isotopic marker displays a piece of different information concerning the diet of the model coral S. pistillata. By combining all markers, we observed that although S. pistillata exhibited reduced heterotrophic assimilation under heat stress, amino acid acquisition and synthesis remained dependent on heterotrophy. The findings emphasize the adaptability of corals in utilizing different food sources, which is vital for their resilience and recovery in changing environmental conditions. This research underscores the complexity of coral symbiosis and highlights the need for multiple indicators to understand dietary dynamics comprehensively.
Collapse
Affiliation(s)
- Stephane Martinez
- Centre Scientifique de Monaco, Coral Ecophysiology Team, Monte Carlo, Monaco
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA
| | - Renaud Grover
- Centre Scientifique de Monaco, Coral Ecophysiology Team, Monte Carlo, Monaco
| | | |
Collapse
|
2
|
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
|
3
|
Zou Y, Ip JCH, Xie JY, Yeung YH, Wei L, Guo Z, Zhang Y, Qiu JW. Dynamic changes in bacterial communities in three species of corals during the 2017 bleaching event in subtropical Hong Kong waters. MARINE POLLUTION BULLETIN 2024; 199:116002. [PMID: 38181470 DOI: 10.1016/j.marpolbul.2023.116002] [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: 07/23/2023] [Revised: 11/28/2023] [Accepted: 12/26/2023] [Indexed: 01/07/2024]
Abstract
Bacteria play important roles in coral health, yet little is known about the dynamics of coral-associated bacterial communities during coral bleaching. Here, we reported the dynamic changes of bacterial communities in three scleractinian corals (Montipora peltiformis, Pavona decussata and Platygyra carnosa) during and after bleaching through amplicon sequencing. Our results revealed that the bacterial composition and dominant bacteria varied among the three coral species. The higher susceptibility of M. peltiformis to bleaching corresponded to a lower bacterial community diversity, and the dominant Synechococcus shifted in abundance during the bleaching and coral recovery phases. The resilient P. decussata and P. carnosa had higher bacterial diversity and a more similar bacterial composition between the healthy and bleached conditions. Overall, our study reveals the dynamic changes in coral-associated microbial diversity under different conditions, contributing to explaining the differential susceptibility of corals to extreme climate conditions.
Collapse
Affiliation(s)
- Ying Zou
- School of Life and Health Sciences, Hainan University, Haikou, China
| | | | - James Y Xie
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Yip Hung Yeung
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Lu Wei
- School of Life and Health Sciences, Hainan University, Haikou, China
| | - Zhiqiang Guo
- School of Life and Health Sciences, Hainan University, Haikou, China
| | - Yanjie Zhang
- School of Life and Health Sciences, Hainan University, Haikou, China.
| | - Jian-Wen Qiu
- Department of Biology, Hong Kong Baptist University, Hong Kong, China.
| |
Collapse
|
4
|
Greene A, Moriarty T, Leggatt W, Ainsworth TD, Donahue MJ, Raymundo L. Spatial extent of dysbiosis in the branching coral Pocillopora damicornis during an acute disease outbreak. Sci Rep 2023; 13:16522. [PMID: 37783737 PMCID: PMC10545779 DOI: 10.1038/s41598-023-43490-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 09/25/2023] [Indexed: 10/04/2023] Open
Abstract
Globally, coral reefs face increasing disease prevalence and large-scale outbreak events. These outbreaks offer insights into microbial and functional patterns of coral disease, including early indicators of disease that may be present in visually-healthy tissues. Outbreak events also allow investigation of how reef-building corals, typically colonial organisms, respond to disease. We studied Pocillopora damicornis during an acute tissue loss disease outbreak on Guam to determine whether dysbiosis was present in visually-healthy tissues ahead of advancing disease lesions. These data reveal that coral fragments with visual evidence of disease are expectedly dysbiotic with high microbial and metabolomic variability. However, visually-healthy tissues from the same colonies lacked dysbiosis, suggesting disease containment near the affected area. These results challenge the idea of using broad dysbiosis as a pre-visual disease indicator and prompt reevaluation of disease assessment in colonial organisms such as reef-building corals.
Collapse
Affiliation(s)
- Austin Greene
- University of Hawai'i at Mānoa, Honolulu, USA.
- Hawai'i Institute of Marine Biology, Kāne'Ohe, HI, USA.
- Woods Hole Oceanographic Institution, Woods Hole, USA.
| | | | | | | | - Megan J Donahue
- University of Hawai'i at Mānoa, Honolulu, USA
- Hawai'i Institute of Marine Biology, Kāne'Ohe, HI, USA
| | | |
Collapse
|
5
|
Llamas A, Leon-Miranda E, Tejada-Jimenez M. Microalgal and Nitrogen-Fixing Bacterial Consortia: From Interaction to Biotechnological Potential. PLANTS (BASEL, SWITZERLAND) 2023; 12:2476. [PMID: 37447037 DOI: 10.3390/plants12132476] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/15/2023] [Accepted: 06/26/2023] [Indexed: 07/15/2023]
Abstract
Microalgae are used in various biotechnological processes, such as biofuel production due to their high biomass yields, agriculture as biofertilizers, production of high-value-added products, decontamination of wastewater, or as biological models for carbon sequestration. The number of these biotechnological applications is increasing, and as such, any advances that contribute to reducing costs and increasing economic profitability can have a significant impact. Nitrogen fixing organisms, often called diazotroph, also have great biotechnological potential, mainly in agriculture as an alternative to chemical fertilizers. Microbial consortia typically perform more complex tasks than monocultures and can execute functions that are challenging or even impossible for individual strains or species. Interestingly, microalgae and diazotrophic organisms are capable to embrace different types of symbiotic associations. Certain corals and lichens exhibit this symbiotic relationship in nature, which enhances their fitness. However, this relationship can also be artificially created in laboratory conditions with the objective of enhancing some of the biotechnological processes that each organism carries out independently. As a result, the utilization of microalgae and diazotrophic organisms in consortia is garnering significant interest as a potential alternative for reducing production costs and increasing yields of microalgae biomass, as well as for producing derived products and serving biotechnological purposes. This review makes an effort to examine the associations of microalgae and diazotrophic organisms, with the aim of highlighting the potential of these associations in improving various biotechnological processes.
Collapse
Affiliation(s)
- Angel Llamas
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
| | - Esperanza Leon-Miranda
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
| | - Manuel Tejada-Jimenez
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
| |
Collapse
|
6
|
Al-Hammady MA, Silva TF, Hussein HN, Saxena G, Modolo LV, Belasy MB, Westphal H, Farag MA. How do algae endosymbionts mediate for their coral host fitness under heat stress? A comprehensive mechanistic overview. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
7
|
Li J, Zou Y, Yang J, Li Q, Bourne DG, Sweet M, Liu C, Guo A, Zhang S. Cultured Bacteria Provide Insight into the Functional Potential of the Coral-Associated Microbiome. mSystems 2022; 7:e0032722. [PMID: 35695425 PMCID: PMC9426491 DOI: 10.1128/msystems.00327-22] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 05/20/2022] [Indexed: 01/07/2023] Open
Abstract
Improving the availability of representative isolates from the coral microbiome is essential for investigating symbiotic mechanisms and applying beneficial microorganisms to improve coral health. However, few studies have explored the diversity of bacteria which can be isolated from a single species. Here, we isolated a total of 395 bacterial strains affiliated with 49 families across nine classes from the coral Pocillopora damicornis. Identification results showed that most of the strains represent potential novel bacterial species or genera. We also sequenced and assembled the genomes of 118 of these isolates, and then the putative functions of these isolates were identified based on genetic signatures derived from the genomes and this information was combined with isolate-specific phenotypic data. Genomic information derived from the isolates identified putative functions including nitrification and denitrification, dimethylsulfoniopropionate transformation, and supply of fixed carbon, amino acids, and B vitamins which may support their eukaryotic partners. Furthermore, the isolates contained genes associated with chemotaxis, biofilm formation, quorum sensing, membrane transport, signal transduction, and eukaryote-like repeat-containing and cell-cell attachment proteins, all of which potentially help the bacterium establish association with the coral host. Our work expands on the existing culture collection of coral-associated bacteria and provides important information on the metabolic potential of these isolates which can be used to refine understanding of the role of bacteria in coral health and are now available to be applied to novel strategies aimed at improving coral resilience through microbiome manipulation. IMPORTANCE Microbes underpin the health of corals which are the building blocks of diverse and productive reef ecosystems. Studying the culturable fraction of coral-associated bacteria has received less attention in recent times than using culture-independent molecular methods. However, the genomic and phenotypic characterization of isolated strains allows assessment of their functional role in underpinning coral health and identification of beneficial microbes for microbiome manipulation. Here, we isolated 395 bacterial strains from tissues of Pocillopora damicornis with many representing potentially novel taxa and therefore providing a significant contribution to coral microbiology through greatly enlarging the existing cultured coral-associated bacterial bank. Through analysis of the genomes obtained in this study for the coral-associated bacteria and coral host, we elucidate putative metabolic linkages and symbiotic establishment. The results of this study will help to elucidate the role of specific isolates in coral health and provide beneficial microbes for efforts aimed at improving coral health.
Collapse
Affiliation(s)
- Jie Li
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
- Key Laboratory of Tropical Marine Biotechnology of Hainan Province, Sanya Institute of Oceanology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
- Sanya National Marine Ecosystem Research Station, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Yiyang Zou
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Jian Yang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
- Key Laboratory of Tropical Marine Biotechnology of Hainan Province, Sanya Institute of Oceanology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
- Sanya National Marine Ecosystem Research Station, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Qiqi Li
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - David G. Bourne
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
- Australian Institute of Marine Science, Townsville, Queensland, Australia
| | - Michael Sweet
- Aquatic Research Facility, Environmental Sustainability Research Centre, University of Derby, Derby, United Kingdom
| | - Cong Liu
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Anjie Guo
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| | - Si Zhang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
- Key Laboratory of Tropical Marine Biotechnology of Hainan Province, Sanya Institute of Oceanology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
- Sanya National Marine Ecosystem Research Station, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China
| |
Collapse
|
8
|
Long-Term Heat Selection of the Coral Endosymbiont Cladocopium C1 acro (Symbiodiniaceae) Stabilizes Associated Bacterial Communities. Int J Mol Sci 2022; 23:ijms23094913. [PMID: 35563303 PMCID: PMC9101544 DOI: 10.3390/ijms23094913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 02/04/2023] Open
Abstract
Heat-tolerant strains of the coral endosymbiont, Cladocopium C1acro (Symbiodiniaceae), have previously been developed via experimental evolution. Here, we examine physiological responses and bacterial community composition (using 16S rRNA gene metabarcoding) in cultures of 10 heat-evolved (SS) and 9 wild-type (WT) strains, which had been exposed for 6 years to 31 °C and 27 °C, respectively. We also examine whether the associated bacterial communities were affected by a three-week reciprocal transplantation to both temperatures. The SS strains had bacterial communities with lower diversities that showed more stability and lower variability when exposed to elevated temperatures compared with the WT strains. Amplicon sequence variants (ASVs) of the bacterial genera Labrenzia, Algiphilus, Hyphobacterium and Roseitalea were significantly more associated with the SS strains compared with the WT strains. WT strains showed higher abundance of ASVs assigned to the genera Fabibacter and Tropicimonas. We hypothesize that these compositional differences in associated bacterial communities between SS and WT strains also contribute to the thermal tolerance of the microalgae. Future research should explore functional potential between bacterial communities using metagenomics to unravel specific genomic adaptations.
Collapse
|
9
|
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
|
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
|
Lesser MP. Eutrophication on Coral Reefs: What Is the Evidence for Phase Shifts, Nutrient Limitation and Coral Bleaching. Bioscience 2021. [DOI: 10.1093/biosci/biab101] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Coral reefs continue to experience extreme environmental pressure from climate change stressors, but many coral reefs are also exposed to eutrophication. It has been proposed that changes in the stoichiometry of ambient nutrients increase the mortality of corals, whereas eutrophication may facilitate phase shifts to macroalgae-dominated coral reefs when herbivory is low or absent. But are corals ever nutrient limited, and can eutrophication destabilize the coral symbiosis making it more sensitive to environmental stress because of climate change? The effects of eutrophication are confounded not just by the effects of climate change but by the presence of chemical pollutants in industrial, urban, and agricultural wastes. Because of these confounding effects, the increases in nutrients or changes in their stoichiometry in coastal environments, although they are important at the organismal and community level, cannot currently be disentangled from each other or from the more significant effects of climate change stressors on coral reefs.
Collapse
Affiliation(s)
- Michael P Lesser
- University of New Hampshire, Durham, New Hampshire, United States
| |
Collapse
|
13
|
Martinez S, Bellworthy J, Ferrier-Pagès C, Mass T. Selection of mesophotic habitats by Oculina patagonica in the Eastern Mediterranean Sea following global warming. Sci Rep 2021; 11:18134. [PMID: 34518595 PMCID: PMC8438053 DOI: 10.1038/s41598-021-97447-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/24/2021] [Indexed: 02/08/2023] Open
Abstract
Globally, species are migrating in an attempt to track optimal isotherms as climate change increasingly warms existing habitats. Stony corals are severely threatened by anthropogenic warming, which has resulted in repeated mass bleaching and mortality events. Since corals are sessile as adults and with a relatively old age of sexual maturity, they are slow to latitudinally migrate, but corals may also migrate vertically to deeper, cooler reefs. Herein we describe vertical migration of the Mediterranean coral Oculina patagonica from less than 10 m depth to > 30 m. We suggest that this range shift is a response to rapidly warming sea surface temperatures on the Israeli Mediterranean coastline. In contrast to the vast latitudinal distance required to track temperature change, this species has migrated deeper where summer water temperatures are up to 2 °C cooler. Comparisons of physiology, morphology, trophic position, symbiont type, and photochemistry between deep and shallow conspecifics revealed only a few depth-specific differences. At this study site, shallow colonies typically inhabit low light environments (caves, crevices) and have a facultative relationship with photosymbionts. We suggest that this existing phenotype aided colonization of the mesophotic zone. This observation highlights the potential for other marine species to vertically migrate.
Collapse
Affiliation(s)
- Stephane Martinez
- grid.18098.380000 0004 1937 0562Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel ,grid.18098.380000 0004 1937 0562Morris Kahn Marine Research Station, The Leon H. Charney School of Marine Sciences, University of Haifa, Sdot Yam, Israel ,grid.452353.60000 0004 0550 8241Coral Ecophysiology Team, Centre Scientifique de Monaco, 8 Quai Antoine 1er, Monaco City, 98000 Monaco
| | - Jessica Bellworthy
- grid.18098.380000 0004 1937 0562Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel ,grid.440849.50000 0004 0496 208XThe Interuniversity Institute of Marine Sciences, Eilat, Israel
| | - Christine Ferrier-Pagès
- grid.452353.60000 0004 0550 8241Coral Ecophysiology Team, Centre Scientifique de Monaco, 8 Quai Antoine 1er, Monaco City, 98000 Monaco
| | - Tali Mass
- grid.18098.380000 0004 1937 0562Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel ,grid.18098.380000 0004 1937 0562Morris Kahn Marine Research Station, The Leon H. Charney School of Marine Sciences, University of Haifa, Sdot Yam, Israel
| |
Collapse
|
14
|
Meunier V, Geissler L, Bonnet S, Rädecker N, Perna G, Grosso O, Lambert C, Rodolfo-Metalpa R, Voolstra CR, Houlbrèque F. Microbes support enhanced nitrogen requirements of coral holobionts in a high CO 2 environment. Mol Ecol 2021; 30:5888-5899. [PMID: 34473860 DOI: 10.1111/mec.16163] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 08/24/2021] [Accepted: 08/27/2021] [Indexed: 12/24/2022]
Abstract
Ocean acidification is posing a threat to calcifying organisms due to the increased energy requirements of calcification under high CO2 conditions. The ability of scleractinian corals to cope with future ocean conditions will thus depend on their ability to fulfil their carbon requirement. However, the primary productivity of coral holobionts is limited by low nitrogen (N) availability in coral reef waters. Here, we employed CO2 seeps of Tutum Bay (Papua New Guinea) as a natural laboratory to understand how coral holobionts offset their increased energy requirements under high CO2 conditions. Our results demonstrate for the first time that under high pCO2 conditions, N assimilation pathways of Pocillopora damicornis are jointly modified. We found that diazotroph-derived N assimilation rates in the Symbiodiniaceae were significantly higher in comparison to an ambient CO2 control site, concomitant with a restructured diazotroph community and the specific prevalence of an alpha-proteobacterium. Further, corals at the high CO2 site also had increased feeding rates on picoplankton and in particular exhibited selective feeding on Synechococcus sp., known to be rich in N. Given the high abundance of picoplankton in oligotrophic waters at large, our results suggest that corals exhibiting flexible diazotrophic communities and capable of exploiting N-rich picoplankton sources to offset their increased N requirements may be able to cope better in a high pCO2 world.
Collapse
Affiliation(s)
- Valentine Meunier
- Centre IRD Nouméa, UMR ENTROPIE (IRD, Université de La Réunion, CNRS, Université de La Nouvelle-Calédonie, Ifremer), Nouméa, New Caledonia
| | - Laura Geissler
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Sophie Bonnet
- Aix-Marseille Université, Université de Toulon, CNRS, IRD, Marseille, France
| | - Nils Rädecker
- 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
| | - Gabriela Perna
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Olivier Grosso
- Aix-Marseille Université, Université de Toulon, CNRS, IRD, Marseille, France
| | | | - Riccardo Rodolfo-Metalpa
- Centre IRD Nouméa, UMR ENTROPIE (IRD, Université de La Réunion, CNRS, Université de La Nouvelle-Calédonie, Ifremer), Nouméa, New Caledonia
| | | | - Fanny Houlbrèque
- Centre IRD Nouméa, UMR ENTROPIE (IRD, Université de La Réunion, CNRS, Université de La Nouvelle-Calédonie, Ifremer), Nouméa, New Caledonia
| |
Collapse
|
15
|
Bednarz VN, van de Water JAJM, Grover R, Maguer JF, Fine M, Ferrier-Pagès C. Unravelling the Importance of Diazotrophy in Corals - Combined Assessment of Nitrogen Assimilation, Diazotrophic Community and Natural Stable Isotope Signatures. Front Microbiol 2021; 12:631244. [PMID: 34248863 PMCID: PMC8264265 DOI: 10.3389/fmicb.2021.631244] [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: 11/19/2020] [Accepted: 05/28/2021] [Indexed: 11/22/2022] Open
Abstract
There is an increasing interest in understanding the structure and function of the microbiota associated with marine and terrestrial organisms, because it can play a major role in host nutrition and resistance to environmental stress. Reef-building corals live in association with diazotrophs, which are microbes able to fix dinitrogen. Corals are known to assimilate diazotrophically-derived nitrogen (DDN), but it is still not clear whether this nitrogen source is derived from coral-associated diazotrophs and whether it substantially contributes to the coral’s nitrogen budget. In this study, we aimed to provide a better understanding of the importance of DDN for corals using a holistic approach by simultaneously assessing DDN assimilation rates (using 15N2 tracer technique), the diazotrophic bacterial community (using nifH gene amplicon sequencing) and the natural δ15N signature in Stylophora pistillata corals from the Northern Red Sea along a depth gradient in winter and summer. Overall, our results show a discrepancy between the three parameters. DDN was assimilated by the coral holobiont during winter only, with an increased assimilation with depth. Assimilation rates were, however, not linked to the presence of coral-associated diazotrophs, suggesting that the presence of nifH genes does not necessarily imply functionality. It also suggests that DDN assimilation was independent from coral-associated diazotrophs and may instead result from nitrogen derived from planktonic diazotrophs. In addition, the δ15N signature presented negative values in almost all coral samples in both seasons, suggesting that nitrogen sources other than DDN contribute to the nitrogen budget of corals from this region. This study yields novel insight into the origin and importance of diazotrophy for scleractinian corals from the Northern Red Sea using multiple proxies.
Collapse
Affiliation(s)
- Vanessa N Bednarz
- Marine Department, Centre Scientifique de Monaco, Monaco City, Monaco
| | | | - Renaud Grover
- Marine Department, Centre Scientifique de Monaco, Monaco City, Monaco
| | - Jean-François Maguer
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539 UBO/CNRS/IRD/IFREMER, Institut Universitaire Européen de la Mer, Plouzané, France
| | - Maoz Fine
- Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel.,The Interuniversity Institute for Marine Sciences, Eilat, Israel
| | | |
Collapse
|
16
|
Mutalipassi M, Riccio G, Mazzella V, Galasso C, Somma E, Chiarore A, de Pascale D, Zupo V. Symbioses of Cyanobacteria in Marine Environments: Ecological Insights and Biotechnological Perspectives. Mar Drugs 2021; 19:227. [PMID: 33923826 PMCID: PMC8074062 DOI: 10.3390/md19040227] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/14/2021] [Accepted: 04/15/2021] [Indexed: 01/07/2023] Open
Abstract
Cyanobacteria are a diversified phylum of nitrogen-fixing, photo-oxygenic bacteria able to colonize a wide array of environments. In addition to their fundamental role as diazotrophs, they produce a plethora of bioactive molecules, often as secondary metabolites, exhibiting various biological and ecological functions to be further investigated. Among all the identified species, cyanobacteria are capable to embrace symbiotic relationships in marine environments with organisms such as protozoans, macroalgae, seagrasses, and sponges, up to ascidians and other invertebrates. These symbioses have been demonstrated to dramatically change the cyanobacteria physiology, inducing the production of usually unexpressed bioactive molecules. Indeed, metabolic changes in cyanobacteria engaged in a symbiotic relationship are triggered by an exchange of infochemicals and activate silenced pathways. Drug discovery studies demonstrated that those molecules have interesting biotechnological perspectives. In this review, we explore the cyanobacterial symbioses in marine environments, considering them not only as diazotrophs but taking into consideration exchanges of infochemicals as well and emphasizing both the chemical ecology of relationship and the candidate biotechnological value for pharmaceutical and nutraceutical applications.
Collapse
Affiliation(s)
- Mirko Mutalipassi
- Department of Marine Biotechnology, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (G.R.); (C.G.); (D.d.P.)
| | - Gennaro Riccio
- Department of Marine Biotechnology, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (G.R.); (C.G.); (D.d.P.)
| | - Valerio Mazzella
- Department of Integrated Marine Ecology, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy;
| | - Christian Galasso
- Department of Marine Biotechnology, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (G.R.); (C.G.); (D.d.P.)
| | - Emanuele Somma
- Department of Life Sciences, University of Trieste, Via Licio Giorgieri, 34127 Trieste, Italy;
- Department of Marine Biotechnology, Ischia Marine Centre, Stazione Zoologica Anton Dohrn, Punta San Pietro, 80077 Naples, Italy;
| | - Antonia Chiarore
- Department of Biology, University of Naples Federico II, Via Cinthia, 80126 Naples, Italy;
| | - Donatella de Pascale
- Department of Marine Biotechnology, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (G.R.); (C.G.); (D.d.P.)
| | - Valerio Zupo
- Department of Marine Biotechnology, Ischia Marine Centre, Stazione Zoologica Anton Dohrn, Punta San Pietro, 80077 Naples, Italy;
| |
Collapse
|
17
|
Selective Uptake of Pelagic Microbial Community Members by Caribbean Reef Corals. Appl Environ Microbiol 2021; 87:AEM.03175-20. [PMID: 33674432 PMCID: PMC8091028 DOI: 10.1128/aem.03175-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Accepted: 02/21/2021] [Indexed: 11/30/2022] Open
Abstract
We identify interactions between coral grazing behavior and the growth rates and cell abundances of pelagic microbial groups found surrounding a Caribbean reef. During incubation experiments with three reef corals, reductions in microbial cell abundance differed according to coral species and suggest specific coral or microbial mechanisms are at play. Coral reefs are possible sinks for microbes; however, the removal mechanisms at play are not well understood. Here, we characterize pelagic microbial groups at the CARMABI reef (Curaçao) and examine microbial consumption by three coral species: Madracis mirabilis, Porites astreoides, and Stephanocoenia intersepta. Flow cytometry analyses of water samples collected from a depth of 10 m identified 6 microbial groups: Prochlorococcus, three groups of Synechococcus, photosynthetic eukaryotes, and heterotrophic bacteria. Minimum growth rates (μ) for Prochlorococcus, all Synechococcus groups, and photosynthetic eukaryotes were 0.55, 0.29, and 0.45 μ day−1, respectively, and suggest relatively high rates of productivity despite low nutrient conditions on the reef. During a series of 5-h incubations with reef corals performed just after sunset or prior to sunrise, reductions in the abundance of photosynthetic picoeukaryotes, Prochlorococcus and Synechococcus cells, were observed. Of the three Synechococcus groups, one decreased significantly during incubations with each coral and the other two only with M. mirabilis. Removal of carbon from the water column is based on coral consumption rates of phytoplankton and averaged between 138 ng h−1 and 387 ng h−1, depending on the coral species. A lack of coral-dependent reduction in heterotrophic bacteria, differences in Synechococcus reductions, and diurnal variation in reductions of Synechococcus and Prochlorococcus, coinciding with peak cell division, point to selective feeding by corals. Our study indicates that bentho-pelagic coupling via selective grazing of microbial groups influences carbon flow and supports heterogeneity of microbial communities overlying coral reefs. IMPORTANCE We identify interactions between coral grazing behavior and the growth rates and cell abundances of pelagic microbial groups found surrounding a Caribbean reef. During incubation experiments with three reef corals, reductions in microbial cell abundance differed according to coral species and suggest specific coral or microbial mechanisms are at play. Peaks in removal rates of Prochlorococcus and Synechococcus cyanobacteria appear highest during postsunset incubations and coincide with microbial cell division. Grazing rates and effort vary across coral species and picoplankton groups, possibly influencing overall microbial composition and abundance over coral reefs. For reef corals, use of such a numerically abundant source of nutrition may be advantageous, especially under environmentally stressful conditions when symbioses with dinoflagellate algae break down.
Collapse
|
18
|
Keller-Costa T, Lago-Lestón A, Saraiva JP, Toscan R, Silva SG, Gonçalves J, Cox CJ, Kyrpides N, Nunes da Rocha U, Costa R. Metagenomic insights into the taxonomy, function, and dysbiosis of prokaryotic communities in octocorals. MICROBIOME 2021; 9:72. [PMID: 33766108 PMCID: PMC7993494 DOI: 10.1186/s40168-021-01031-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 02/08/2021] [Indexed: 05/06/2023]
Abstract
BACKGROUND In octocorals (Cnidaria Octocorallia), the functional relationship between host health and its symbiotic consortium has yet to be determined. Here, we employed comparative metagenomics to uncover the distinct functional and phylogenetic features of the microbiomes of healthy Eunicella gazella, Eunicella verrucosa, and Leptogorgia sarmentosa tissues, in contrast with the microbiomes found in seawater and sediments. We further explored how the octocoral microbiome shifts to a pathobiome state in E. gazella. RESULTS Multivariate analyses based on 16S rRNA genes, Clusters of Orthologous Groups of proteins (COGs), Protein families (Pfams), and secondary metabolite-biosynthetic gene clusters annotated from 20 Illumina-sequenced metagenomes each revealed separate clustering of the prokaryotic communities of healthy tissue samples of the three octocoral species from those of necrotic E. gazella tissue and surrounding environments. While the healthy octocoral microbiome was distinguished by so-far uncultivated Endozoicomonadaceae, Oceanospirillales, and Alteromonadales phylotypes in all host species, a pronounced increase of Flavobacteriaceae and Alphaproteobacteria, originating from seawater, was observed in necrotic E. gazella tissue. Increased abundances of eukaryotic-like proteins, exonucleases, restriction endonucleases, CRISPR/Cas proteins, and genes encoding for heat-shock proteins, inorganic ion transport, and iron storage distinguished the prokaryotic communities of healthy octocoral tissue regardless of the host species. An increase of arginase and nitric oxide reductase genes, observed in necrotic E. gazella tissues, suggests the existence of a mechanism for suppression of nitrite oxide production by which octocoral pathogens may overcome the host's immune system. CONCLUSIONS This is the first study to employ primer-less, shotgun metagenome sequencing to unveil the taxonomic, functional, and secondary metabolism features of prokaryotic communities in octocorals. Our analyses reveal that the octocoral microbiome is distinct from those of the environmental surroundings, is host genus (but not species) specific, and undergoes large, complex structural changes in the transition to the dysbiotic state. Host-symbiont recognition, abiotic-stress response, micronutrient acquisition, and an antiviral defense arsenal comprising multiple restriction endonucleases, CRISPR/Cas systems, and phage lysogenization regulators are signatures of prokaryotic communities in octocorals. We argue that these features collectively contribute to the stabilization of symbiosis in the octocoral holobiont and constitute beneficial traits that can guide future studies on coral reef conservation and microbiome therapy. Video Abstract.
Collapse
Affiliation(s)
- T. Keller-Costa
- Instituto de Bioengenharia e Biociências (iBB), Instituto Superior Técnico (IST), Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal
| | - A. Lago-Lestón
- División de Biología Experimental y Aplicada (DBEA), Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Carr. Ensenada-Tijuana 3918, Zona Playitas, C.P 22860 Ensenada, Baja California Mexico
| | - J. P. Saraiva
- Helmholtz Centre for Environmental Research (UFZ), Leipzig, 04318 Germany
| | - R. Toscan
- Helmholtz Centre for Environmental Research (UFZ), Leipzig, 04318 Germany
| | - S. G. Silva
- Instituto de Bioengenharia e Biociências (iBB), Instituto Superior Técnico (IST), Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal
| | - J. Gonçalves
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, 8005-139 Faro, Portugal
| | - C. J. Cox
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, 8005-139 Faro, Portugal
| | - N. Kyrpides
- Department of Energy, Joint Genome Institute, Berkeley, CA 94720 USA
| | - U. Nunes da Rocha
- Helmholtz Centre for Environmental Research (UFZ), Leipzig, 04318 Germany
| | - R. Costa
- Instituto de Bioengenharia e Biociências (iBB), Instituto Superior Técnico (IST), Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, 8005-139 Faro, Portugal
- Department of Energy, Joint Genome Institute, Berkeley, CA 94720 USA
| |
Collapse
|
19
|
Matthews JL, Raina J, Kahlke T, Seymour JR, Oppen MJH, Suggett DJ. Symbiodiniaceae‐bacteria interactions: rethinking metabolite exchange in reef‐building corals as multi‐partner metabolic networks. Environ Microbiol 2020; 22:1675-1687. [DOI: 10.1111/1462-2920.14918] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Jennifer L. Matthews
- Climate Change Cluster University of Technology Sydney 2007 New South Wales Australia
| | - Jean‐Baptiste Raina
- Climate Change Cluster University of Technology Sydney 2007 New South Wales Australia
| | - Tim Kahlke
- Climate Change Cluster University of Technology Sydney 2007 New South Wales Australia
| | - Justin R. Seymour
- Climate Change Cluster University of Technology Sydney 2007 New South Wales Australia
| | - Madeleine J. H. Oppen
- The University of Melbourne Parkville 3010 Victoria Australia
- Australian Institute of Marine Science PMB No 3 Townsville MC 4810 QLD Australia
| | - David J. Suggett
- Climate Change Cluster University of Technology Sydney 2007 New South Wales Australia
| |
Collapse
|
20
|
Meunier V, Bonnet S, Pernice M, Benavides M, Lorrain A, Grosso O, Lambert C, Houlbrèque F. Bleaching forces coral's heterotrophy on diazotrophs and Synechococcus. THE ISME JOURNAL 2019; 13:2882-2886. [PMID: 31249389 PMCID: PMC6794269 DOI: 10.1038/s41396-019-0456-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 05/20/2019] [Accepted: 06/02/2019] [Indexed: 11/08/2022]
Abstract
Coral reefs are threatened by global warming, which disrupts the symbiosis between corals and their photosynthetic symbionts (Symbiodiniaceae), leading to mass coral bleaching. Planktonic diazotrophs or dinitrogen (N2)-fixing prokaryotes are abundant in coral lagoon waters and could be an alternative nutrient source for corals. Here we incubated untreated and bleached coral colonies of Stylophora pistillata with a 15N2-pre-labelled natural plankton assemblage containing diazotrophs. 15N2 assimilation rates in Symbiodiniaceae cells and tissues of bleached corals were 5- and 30-fold higher, respectively, than those measured in untreated corals, demonstrating that corals incorporate more nitrogen derived from planktonic diazotrophs under bleaching conditions. Bleached corals also preferentially fed on Synechococcus, nitrogen-rich picophytoplanktonic cells, instead of Prochlorococcus and picoeukaryotes, which have a lower cellular nitrogen content. By providing an alternative source of bioavailable nitrogen, both the incorporation of nitrogen derived from planktonic diazotrophs and the ingestion of Synechococcus may have profound consequences for coral bleaching recovery, especially for the many coral reef ecosystems characterized by high abundance and activity of planktonic diazotrophs.
Collapse
Affiliation(s)
- Valentine Meunier
- Laboratoire d'Excellence CORAIL, ENTROPIE (UMR9220), IRD, 98848, Nouméa cedex, New Caledonia.
| | - Sophie Bonnet
- Aix Marseille University, Université́ de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Mathieu Pernice
- Faculty of Science, Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, 2007, Australia
| | - Mar Benavides
- Aix Marseille University, Université́ de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | - Anne Lorrain
- Univ Brest, CNRS, IRD, Ifremer, LEMAR, F-29280, Plouzané, France
| | - Olivier Grosso
- Aix Marseille University, Université́ de Toulon, CNRS, IRD, MIO UM 110, 13288, Marseille, France
| | | | - Fanny Houlbrèque
- Laboratoire d'Excellence CORAIL, ENTROPIE (UMR9220), IRD, 98848, Nouméa cedex, New Caledonia
| |
Collapse
|
21
|
Wall CB, Ritson‐Williams R, Popp BN, Gates RD. Spatial variation in the biochemical and isotopic composition of corals during bleaching and recovery. LIMNOLOGY AND OCEANOGRAPHY 2019; 64:2011-2028. [PMID: 31598010 PMCID: PMC6774332 DOI: 10.1002/lno.11166] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 12/24/2018] [Accepted: 03/01/2019] [Indexed: 06/01/2023]
Abstract
Ocean warming and the increased prevalence of coral bleaching events threaten coral reefs. However, the biology of corals during and following bleaching events under field conditions is poorly understood. We examined bleaching and postbleaching recovery in Montipora capitata and Porites compressa corals that either bleached or did not bleach during a 2014 bleaching event at three reef locations in Kāne'ohe Bay, O'ahu, Hawai'i. We measured changes in chlorophylls, tissue biomass, and nutritional plasticity using stable isotopes (δ 13C, δ 15N). Coral traits showed significant variation among periods, sites, bleaching conditions, and their interactions. Bleached colonies of both species had lower chlorophyll and total biomass, and while M. capitata chlorophyll and biomass recovered 3 months later, P. compressa chlorophyll recovery was location dependent and total biomass of previously bleached colonies remained low. Biomass energy reserves were not affected by bleaching, instead M. capitata proteins and P. compressa biomass energy and lipids declined over time and P. compressa lipids were site specific during bleaching recovery. Stable isotope analyses did not indicate increased heterotrophic nutrition in bleached colonies of either species, during or after thermal stress. Instead, mass balance calculations revealed that variations in δ 13C values reflect biomass compositional change (i.e., protein : lipid : carbohydrate ratios). Observed δ 15N values reflected spatiotemporal variability in nitrogen sources in both species and bleaching effects on symbiont nitrogen demand in P. compressa. These results highlight the dynamic responses of corals to natural bleaching and recovery and identify the need to consider the influence of biomass composition in the interpretation of isotopic values in corals.
Collapse
Affiliation(s)
- Christopher B. Wall
- Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai‘i at MānoaKāne‘oheHawai‘i
| | - Raphael Ritson‐Williams
- Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai‘i at MānoaKāne‘oheHawai‘i
- Invertebrate Zoology DepartmentCalifornia Academy of SciencesSan FranciscoCalifornia
| | - Brian N. Popp
- Department of Earth SciencesUniversity of Hawai‘i at MānoaHonoluluHawai‘i
| | - Ruth D. Gates
- Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai‘i at MānoaKāne‘oheHawai‘i
| |
Collapse
|
22
|
Pupier CA, Bednarz VN, Grover R, Fine M, Maguer JF, Ferrier-Pagès C. Divergent Capacity of Scleractinian and Soft Corals to Assimilate and Transfer Diazotrophically Derived Nitrogen to the Reef Environment. Front Microbiol 2019; 10:1860. [PMID: 31474958 PMCID: PMC6702326 DOI: 10.3389/fmicb.2019.01860] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 07/29/2019] [Indexed: 12/04/2022] Open
Abstract
Corals are associated with dinitrogen (N2)-fixing bacteria that potentially represent an additional nitrogen (N) source for the coral holobiont in oligotrophic reef environments. Nevertheless, the few studies investigating the assimilation of diazotrophically derived nitrogen (DDN) by tropical corals are limited to a single scleractinian species (i.e., Stylophora pistillata). The present study quantified DDN assimilation rates in four scleractinian and three soft coral species from the shallow waters of the oligotrophic Northern Red Sea using the 15N2 tracer technique. All scleractinian species significantly stimulated N2 fixation in the coral-surrounding seawater (and mucus) and assimilated DDN into their tissue. Interestingly, N2 fixation was not detected in the tissue and surrounding seawater of soft corals, despite the fact that soft corals were able to take up DDN from a culture of free-living diazotrophs. Soft coral mucus likely represents an unfavorable habitat for the colonization and activity of diazotrophs as it contains a low amount of particulate organic matter, with a relatively high N content, compared to the mucus of scleractinian corals. In addition, it is known to present antimicrobial properties. Overall, this study suggests that DDN assimilation into coral tissues depends on the presence of active diazotrophs in the coral’s mucus layer and/or surrounding seawater. Since N is often a limiting nutrient for primary productivity in oligotrophic reef waters, the divergent capacity of scleractinian and soft corals to promote N2 fixation may have implications for N availability and reef biogeochemistry in scleractinian versus soft coral-dominated reefs.
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 Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel.,The Interuniversity Institute for Marine Science in Eilat, Eilat, Israel
| | - Jean-François Maguer
- Laboratoire de l'Environnement Marin (LEMAR), UMR 6539, UBO/CNRS/IRD/IFREMER, Institut Universitaire Européen de la Mer, Plouzané, France
| | | |
Collapse
|
23
|
Morris LA, Voolstra CR, Quigley KM, Bourne DG, Bay LK. Nutrient Availability and Metabolism Affect the Stability of Coral-Symbiodiniaceae Symbioses. Trends Microbiol 2019; 27:678-689. [PMID: 30987816 DOI: 10.1016/j.tim.2019.03.004] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/28/2019] [Accepted: 03/13/2019] [Indexed: 01/19/2023]
Abstract
Coral reefs rely upon the highly optimized coral-Symbiodiniaceae symbiosis, making them sensitive to environmental change and susceptible to anthropogenic stress. Coral bleaching is predominantly attributed to photo-oxidative stress, yet nutrient availability and metabolism underpin the stability of symbioses. Recent studies link symbiont proliferation under nutrient enrichment to bleaching; however, the interactions between nutrients and symbiotic stability are nuanced. Here, we demonstrate how bleaching is regulated by the forms and ratios of available nutrients and their impacts on autotrophic carbon metabolism, rather than algal symbiont growth. By extension, historical nutrient conditions mediate host-symbiont compatibility and bleaching tolerance over proximate and evolutionary timescales. Renewed investigations into the coral nutrient metabolism will be required to truly elucidate the cellular mechanisms leading to coral bleaching.
Collapse
Affiliation(s)
- Luke A Morris
- AIMS@JCU, Australian Institute of Marine Science, College of Science and Engineering, James Cook University, Townsville, Australia; Australian Institute of Marine Science, Townsville, Australia; College of Science and Engineering, James Cook University, Townsville, Australia. https://twitter.com/ReefLuke
| | - Christian R Voolstra
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia. https://twitter.com/reefgenomics
| | - Kate M Quigley
- AIMS@JCU, Australian Institute of Marine Science, College of Science and Engineering, James Cook University, Townsville, Australia; Australian Institute of Marine Science, Townsville, Australia. https://twitter.com/la__cientifica
| | - David G Bourne
- AIMS@JCU, Australian Institute of Marine Science, College of Science and Engineering, James Cook University, Townsville, Australia; Australian Institute of Marine Science, Townsville, Australia; College of Science and Engineering, James Cook University, Townsville, Australia
| | - Line K Bay
- AIMS@JCU, Australian Institute of Marine Science, College of Science and Engineering, James Cook University, Townsville, Australia; Australian Institute of Marine Science, Townsville, Australia.
| |
Collapse
|
24
|
Bernasconi R, Stat M, Koenders A, Huggett MJ. Global Networks of Symbiodinium-Bacteria Within the Coral Holobiont. MICROBIAL ECOLOGY 2019; 77:794-807. [PMID: 30218130 DOI: 10.1007/s00248-018-1255-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 08/29/2018] [Indexed: 05/12/2023]
Abstract
Scleractinian corals form the framework of coral reefs and host abundant and diverse microbial communities that are fundamental to their success. A very limited number of studies have examined the co-occurrence of multiple partners within the coral 'holobiont' and their pattern of specificity over different geographical scales. In this study, we explored two molecular sequence datasets representing associations between corals and dinoflagellates in the genus Symbiodinium and between corals and bacteria, across the globe. Through a network theory approach, we characterised patterns of co-occurrences between bacteria and Symbiodinium with 13 coral genera across six water basins. The majority of the bacteria-Symbiodinium co-occurrences were specific to either a coral genus or water basin, emphasising both coral host and environment as important factors driving the diversity of coral assemblages. Yet, results also identified bacteria and Symbiodinium that were shared by multiple coral genera across several water basins. The analyses indicate that shared co-occurrences are independent of the phylogenetic and biogeographic relationship of coral hosts.
Collapse
Affiliation(s)
- Rachele Bernasconi
- Centre for Marine Ecosystems Research, School of Science, Edith Cowan University, 270 Joondalup Dr, Joondalup, Western Australia, 6027, Australia.
| | - Michael Stat
- Trace and Environmental DNA Laboratory, Department of Environment and Agriculture Curtin University, Bentley, 6102, Western Australia
- Department of Biological Sciences, Macquarie University, Sydney, 2109, Australia
| | - Annette Koenders
- Centre for Ecosystem Management, School of Science, Edith Cowan University, 270 Joondalup Dr, Joondalup, Western Australia, 6027, Australia
| | - Megan J Huggett
- Centre for Marine Ecosystems Research, School of Science, Edith Cowan University, 270 Joondalup Dr, Joondalup, Western Australia, 6027, Australia
- Centre for Ecosystem Management, School of Science, Edith Cowan University, 270 Joondalup Dr, Joondalup, Western Australia, 6027, Australia
- School of Environmental and Life Sciences, Faculty of Science, The University of Newcastle, PO Box 127, Ourimbah, New South Wales, 2258, Australia
| |
Collapse
|
25
|
Ezzat L, Maguer J, Grover R, Rottier C, Tremblay P, Ferrier‐Pagès C. Nutrient starvation impairs the trophic plasticity of reef‐building corals under ocean warming. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13285] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Leïla Ezzat
- Marine Department Centre Scientifique de Monaco Monaco Principality of Monaco
| | - Jean‐François Maguer
- Laboratoire de l'Environnement Marin (LEMAR), UMR 6539, UBO/CNRS/IRD/IFREMER Institut Universitaire Européen de la Mer Plouzané France
| | - Renaud Grover
- Marine Department Centre Scientifique de Monaco Monaco Principality of Monaco
| | - Cécile Rottier
- Marine Department Centre Scientifique de Monaco Monaco Principality of Monaco
| | - Pascale Tremblay
- Département de biologie, chimie et géographie Université du Québec à Rimouski Rimouski Quebec Canada
| | | |
Collapse
|
26
|
Ferrier‐Pagès C, Leal MC. Stable isotopes as tracers of trophic interactions in marine mutualistic symbioses. Ecol Evol 2019; 9:723-740. [PMID: 30680151 PMCID: PMC6342181 DOI: 10.1002/ece3.4712] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 09/17/2018] [Accepted: 10/26/2018] [Indexed: 12/31/2022] Open
Abstract
Mutualistic nutritional symbioses are widespread in marine ecosystems. They involve the association of a host organism (algae, protists, or marine invertebrates) with symbiotic microorganisms, such as bacteria, cyanobacteria, or dinoflagellates. Nutritional interactions between the partners are difficult to identify in symbioses because they only occur in intact associations. Stable isotope analysis (SIA) has proven to be a useful tool to highlight original nutrient sources and to trace nutrients acquired by and exchanged between the different partners of the association. However, although SIA has been extensively applied to study different marine symbiotic associations, there is no review taking into account of the different types of symbiotic associations, how they have been studied via SIA, methodological issues common among symbiotic associations, and solutions that can be transferred from one type of association with another. The present review aims to fill such gaps in the scientific literature by summarizing the current knowledge of how isotopes have been applied to key marine symbioses to unravel nutrient exchanges between partners, and by describing the difficulties in interpreting the isotopic signal. This review also focuses on the use of compound-specific stable isotope analysis and on statistical advances to analyze stable isotope data. It also highlights the knowledge gaps that would benefit from future research.
Collapse
Affiliation(s)
| | - Miguel Costa Leal
- MARE – Marine and Environmental Sciences CentreFaculdade de Ciências da Universidade de LisboaLisbonPortugal
| |
Collapse
|
27
|
Kahng SE, Akkaynak D, Shlesinger T, Hochberg EJ, Wiedenmann J, Tamir R, Tchernov D. Light, Temperature, Photosynthesis, Heterotrophy, and the Lower Depth Limits of Mesophotic Coral Ecosystems. CORAL REEFS OF THE WORLD 2019. [DOI: 10.1007/978-3-319-92735-0_42] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
28
|
Bednarz VN, van de Water JAJM, Rabouille S, Maguer JF, Grover R, Ferrier-Pagès C. Diazotrophic community and associated dinitrogen fixation within the temperate coral Oculina patagonica. Environ Microbiol 2018; 21:480-495. [PMID: 30452101 DOI: 10.1111/1462-2920.14480] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 10/25/2018] [Indexed: 01/08/2023]
Abstract
Dinitrogen (N2 ) fixing bacteria (diazotrophs) are an important source of new nitrogen in oligotrophic environments and represent stable members of the microbiome in tropical corals, while information on corals from temperate oligotrophic regions is lacking. Therefore, this study provides new insights into the diversity and activity of diazotrophs associated with the temperate coral Oculina patagonica from the Mediterranean Sea by combining metabarcoding sequencing of amplicons of both the 16S rRNA and nifH genes and 15 N2 stable isotope tracer analysis to assess diazotroph-derived nitrogen (DDN) assimilation by the coral. Results show that the diazotrophic community of O. patagonica is dominated by autotrophic bacteria (i.e. Cyanobacteria and Chlorobia). The majority of DDN was assimilated into the tissue and skeletal matrix, and DDN assimilation significantly increased in bleached corals. Thus, diazotrophs may constitute an additional nitrogen source for the coral host, when nutrient exchange with Symbiodinium is disrupted (e.g. bleaching) and external food supply is limited (e.g. oligotrophic summer season). Furthermore, we hypothesize that DDN can facilitate the fast proliferation of endolithic algae, which provide an alternative carbon source for bleached O. patagonica. Overall, O. patagonica could serve as a good model for investigating the importance of diazotrophs in coral recovery from bleaching.
Collapse
Affiliation(s)
- Vanessa N Bednarz
- Marine Department, Centre Scientifique de Monaco, 8 Quai Antoine Ier, MC-98000, Monaco, Principality of Monaco
| | - Jeroen A J M van de Water
- Marine Department, Centre Scientifique de Monaco, 8 Quai Antoine Ier, MC-98000, Monaco, Principality of Monaco
| | - Sophie Rabouille
- Sorbonne Universités, UPMC Univ Paris 06, UMR 7093, LOV, Observatoire océanologique, F-06230, Villefranche/mer, France.,CNRS, UMR 7093, LOV, Observatoire océanologique, F-06230, Villefranche/mer, France
| | - Jean-François Maguer
- LEMAR - UMR 6539 UBO/CNRS/IRD, Institut Universitaire Européen de la Mer, Place Nicolas Copernic, Plouzané 29280, France
| | - Renaud Grover
- Marine Department, Centre Scientifique de Monaco, 8 Quai Antoine Ier, MC-98000, Monaco, Principality of Monaco
| | - Christine Ferrier-Pagès
- Marine Department, Centre Scientifique de Monaco, 8 Quai Antoine Ier, MC-98000, Monaco, Principality of Monaco
| |
Collapse
|
29
|
Lesser MP, Slattery M, Mobley CD. Biodiversity and Functional Ecology of Mesophotic Coral Reefs. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2018. [DOI: 10.1146/annurev-ecolsys-110617-062423] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mesophotic coral reefs, currently defined as deep reefs between 30 and 150 m, are linked physically and biologically to their shallow water counterparts, have the potential to be refuges for shallow coral reef taxa such as coral and sponges, and might be a source of larvae that could contribute to the resiliency of shallow water reefs. Mesophotic coral reefs are found worldwide, but most are undescribed and understudied. Here, we review our current knowledge of mesophotic coral reefs and their functional ecology as it relates to their geomorphology, changes in the abiotic environment along depth gradients, trophic ecology, their reproduction, and their connectivity to shallow depths. Understanding the ecology of mesophotic coral reefs, and the connectivity between them and their shallow water counterparts, is now a primary focus for many reef studies as the worldwide degradation of shallow coral reefs, and the ecosystem services they provide, continues unabated.
Collapse
Affiliation(s)
- Michael P. Lesser
- Department of Molecular, Cellular and Biomedical Sciences, and School of Marine Science and Ocean Engineering, University of New Hampshire, Durham, New Hampshire 03824, USA
| | - Marc Slattery
- Department of BioMolecular Science, University of Mississippi, Oxford, Mississippi 38677, USA
| | | |
Collapse
|
30
|
Marine Invertebrates: Underexplored Sources of Bacteria Producing Biologically Active Molecules. DIVERSITY-BASEL 2018. [DOI: 10.3390/d10030052] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
31
|
Bednarz VN, Naumann MS, Cardini U, van Hoytema N, Rix L, Al-Rshaidat MMD, Wild C. Contrasting seasonal responses in dinitrogen fixation between shallow and deep-water colonies of the model coral Stylophora pistillata in the northern Red Sea. PLoS One 2018; 13:e0199022. [PMID: 29902263 PMCID: PMC6002246 DOI: 10.1371/journal.pone.0199022] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 05/30/2018] [Indexed: 01/08/2023] Open
Abstract
Tropical corals are often associated with dinitrogen (N2)-fixing bacteria (diazotrophs), and seasonal changes in key environmental parameters, such as dissolved inorganic nitrogen (DIN) availability and seawater temperature, are known to affect N2 fixation in coral-microbial holobionts. Despite, then, such potential for seasonal and depth-related changes in N2 fixation in reef corals, such variation has not yet been investigated. Therefore, this study quantified seasonal (winter vs. summer) N2 fixation rates associated with the reef-building coral Stylophora pistillata collected from depths of 5, 10 and 20 m in the northern Gulf of Aqaba (Red Sea). Findings revealed that corals from all depths exhibited the highest N2 fixation rates during the oligotrophic summer season, when up to 11% of their photo-metabolic nitrogen demand (CPND) could be met by N2 fixation. While N2 fixation remained seasonally stable for deep corals (20 m), it significantly decreased for the shallow corals (5 and 10 m) during the DIN-enriched winter season, accounting for less than 2% of the corals’ CPND. This contrasting seasonal response in N2 fixation across corals of different depths could be driven by 1) release rates of coral-derived organic matter, 2) the community composition of the associated diazotrophs, and/or 3) nutrient acquisition by the Symbiodinium community.
Collapse
Affiliation(s)
- Vanessa N. Bednarz
- Coral Reef Ecology Group, Leibniz Centre for Tropical Marine Research (ZMT), Bremen, Germany
- Marine Department, Centre Scientifique de Monaco, Principality of Monaco
- * E-mail:
| | - Malik S. Naumann
- Coral Reef Ecology Group, Leibniz Centre for Tropical Marine Research (ZMT), Bremen, Germany
| | - Ulisse Cardini
- Coral Reef Ecology Group, Leibniz Centre for Tropical Marine Research (ZMT), Bremen, Germany
- Integrative Marine Ecology Department, Stazione Zoologica Anton Dohrn, Villa Comunale, Naples, Italy
| | - Nanne van Hoytema
- Coral Reef Ecology Group, Leibniz Centre for Tropical Marine Research (ZMT), Bremen, Germany
| | - Laura Rix
- Coral Reef Ecology Group, Leibniz Centre for Tropical Marine Research (ZMT), Bremen, Germany
- RD3 Marine Microbiology, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Mamoon M. D. Al-Rshaidat
- Laboratory for Molecular Microbial Ecology, Marine Science Station, Aqaba, Jordan
- Molecular and Microbial Ecology, Department of Biological Sciences, The University of Jordan, Amman, Jordan
| | - Christian Wild
- Coral Reef Ecology Group, Leibniz Centre for Tropical Marine Research (ZMT), Bremen, Germany
- Marine Ecology Group, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
| |
Collapse
|
32
|
van de Water JAJM, Allemand D, Ferrier-Pagès C. Host-microbe interactions in octocoral holobionts - recent advances and perspectives. MICROBIOME 2018; 6:64. [PMID: 29609655 PMCID: PMC5880021 DOI: 10.1186/s40168-018-0431-6] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 03/01/2018] [Indexed: 05/05/2023]
Abstract
Octocorals are one of the most ubiquitous benthic organisms in marine ecosystems from the shallow tropics to the Antarctic deep sea, providing habitat for numerous organisms as well as ecosystem services for humans. In contrast to the holobionts of reef-building scleractinian corals, the holobionts of octocorals have received relatively little attention, despite the devastating effects of disease outbreaks on many populations. Recent advances have shown that octocorals possess remarkably stable bacterial communities on geographical and temporal scales as well as under environmental stress. This may be the result of their high capacity to regulate their microbiome through the production of antimicrobial and quorum-sensing interfering compounds. Despite decades of research relating to octocoral-microbe interactions, a synthesis of this expanding field has not been conducted to date. We therefore provide an urgently needed review on our current knowledge about octocoral holobionts. Specifically, we briefly introduce the ecological role of octocorals and the concept of holobiont before providing detailed overviews of (I) the symbiosis between octocorals and the algal symbiont Symbiodinium; (II) the main fungal, viral, and bacterial taxa associated with octocorals; (III) the dominance of the microbial assemblages by a few microbial species, the stability of these associations, and their evolutionary history with the host organism; (IV) octocoral diseases; (V) how octocorals use their immune system to fight pathogens; (VI) microbiome regulation by the octocoral and its associated microbes; and (VII) the discovery of natural products with microbiome regulatory activities. Finally, we present our perspectives on how the field of octocoral research should move forward, and the recognition that these organisms may be suitable model organisms to study coral-microbe symbioses.
Collapse
Affiliation(s)
| | - Denis Allemand
- Centre Scientifique de Monaco, 8 Quai Antoine 1er, 98000, Monaco, Monaco
| | | |
Collapse
|
33
|
Abstract
Tropical scleractinian corals are dependent to varying degrees on their photosymbiotic partners. Under normal levels of temperature and irradiance, they can provide most, but not all, of the host's nutritional requirements. Heterotrophy is required to adequately supply critical nutrients, especially nitrogen and phosphorus. Scleractinian corals are known as mesozooplankton predators, and most employ tentacle capture. The ability to trap nano- and picoplankton has been demonstrated by several coral species and appears to fulfill a substantial proportion of their daily metabolic requirements. The mechanism of capture likely involves mucociliary activity or extracoelenteric digestion, but the relative contribution of these avenues have not been evaluated. Many corals employ mesenterial filaments to procure food in various forms, but the functional morphology and chemical activities of these structures have been poorly documented. Corals are capable of acquiring nutrition from particulate and dissolved organic matter, although the degree of reliance on these sources generally has not been established. Corals, including tropical, deep- and cold-water species, are known as a major source of carbon and other nutrients for benthic communities through the secretion of mucus, despite wide variation in chemical composition. Mucus is cycled through the planktonic microbial loop, the benthos, and the microbial community within the sediments. The consensus indicates that the dissolved organic fraction of mucus usually exceeds the insoluble portion, and both serve as sources for the growth of nano- and picoplankton. As many corals employ mucus to trap food, a portion is taken back during feeding. The net gain or loss has not been evaluated, although production is generally thought to exceed consumption. The same is true for the net uptake and loss of dissolved organic matter by mucus secretion. Octocorals are thought not to employ mucus capture or mesenterial filaments during feeding and generally rely on tentacular filtration of weakly swimming mesozooplankton, particulates, dissolved organic matter, and picoplankton. Nonsymbiotic species in the tropics favor phytoplankton and weakly swimming zooplankton. Azooxanthellate soft corals are opportunistic feeders and shift their diet according to the season from phyto- and nanoplankton in summer to primarily particulate organic matter (POM) in winter. Cold-water species favor POM, phytodetritus, microplankton, and larger zooplankton when available. Antipatharians apparently feed on mesozooplankton but also use mucus nets, possibly for capture of POM. Feeding modes in this group are poorly known.
Collapse
Affiliation(s)
- Walter M Goldberg
- Department of Biological Sciences, Florida International University, Miami, FL, USA.
| |
Collapse
|
34
|
van de Water JAJM, Voolstra CR, Rottier C, Cocito S, Peirano A, Allemand D, Ferrier-Pagès C. Seasonal Stability in the Microbiomes of Temperate Gorgonians and the Red Coral Corallium rubrum Across the Mediterranean Sea. MICROBIAL ECOLOGY 2018; 75:274-288. [PMID: 28681143 DOI: 10.1007/s00248-017-1006-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 06/02/2017] [Indexed: 06/07/2023]
Abstract
Populations of key benthic habitat-forming octocoral species have declined significantly in the Mediterranean Sea due to mass mortality events caused by microbial disease outbreaks linked to high summer seawater temperatures. Recently, we showed that the microbial communities of these octocorals are relatively structured; however, our knowledge on the seasonal dynamics of these microbiomes is still limited. To investigate their seasonal stability, we collected four soft gorgonian species (Eunicella singularis, Eunicella cavolini, Eunicella verrucosa and Leptogorgia sarmentosa) and the precious red coral (Corallium rubrum) from two coastal locations with different terrestrial impact levels in the Mediterranean Sea, and used next-generation amplicon sequencing of the 16S rRNA gene. The microbiomes of all soft gorgonian species were dominated by the same 'core microbiome' bacteria belonging to the Endozoicomonas and the Cellvibrionales clade BD1-7, whereas the red coral microbiome was primarily composed of 'core' Spirochaetes, Oceanospirillales ME2 and Parcubacteria. The associations with these bacterial taxa were relatively consistent over time at each location for each octocoral species. However, differences in microbiome composition and seasonal dynamics were observed between locations and could primarily be attributed to locally variant bacteria. Overall, our data provide further evidence of the intricate symbiotic relationships that exist between Mediterranean octocorals and their associated microbes, which are ancient and highly conserved over both space and time, and suggest regulation of the microbiome composition by the host, depending on local conditions.
Collapse
Affiliation(s)
| | - Christian R Voolstra
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Cecile Rottier
- Centre Scientifique de Monaco, 8 Quai Antoine 1er, 98000, Monaco, Monaco
| | - Silvia Cocito
- Marine Environment Research Centre, ENEA, La Spezia, Italy
| | - Andrea Peirano
- Marine Environment Research Centre, ENEA, La Spezia, Italy
| | - Denis Allemand
- Centre Scientifique de Monaco, 8 Quai Antoine 1er, 98000, Monaco, Monaco
| | | |
Collapse
|
35
|
Diazotroph diversity and nitrogen fixation in the coral Stylophora pistillata from the Great Barrier Reef. ISME JOURNAL 2017; 12:813-824. [PMID: 29222444 DOI: 10.1038/s41396-017-0008-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 10/15/2017] [Accepted: 10/20/2017] [Indexed: 12/30/2022]
Abstract
Diazotrophs, both Bacteria and Archaea, capable of fixing nitrogen (N2), are present in the tissues and mucous, of corals and can supplement the coral holobiont nitrogen budget with fixed nitrogen (N) in the form of ammonia (NH3). Stylophora pistillata from Heron Island on the Great Barrier Reef collected at 5 and 15 m, and experimentally manipulated in the laboratory, showed that the rates of net photosynthesis, steady state quantum yields of photosystem II (PSII) fluorescence (∆Fv/Fm') and calcification varied based on irradiance as expected. Rates of N2 fixation were, however, invariant across treatments while the amount of fixed N contributing to Symbiodinium spp. N demand is irradiance dependent. Additionally, both the Symbiodinium and diazotrophic communities are significantly different based on depth, and novel Cluster V nifH gene phylotypes, which are not known to fix nitrogen, were recovered. A functional analysis using PICRUSt also showed that shallow corals were enriched in genes involved in nitrogen metabolism, and N2 fixation specifically. Corals have evolved a number of strategies to derive nitrogen from organic (e.g., heterotrophic feeding) and inorganic sources (e.g., N2 fixation) to maintain critical pathways such as protein synthesis to succeed ecologically in nitrogen-limited habitats.
Collapse
|
36
|
Pogoreutz C, Rädecker N, Cárdenas A, Gärdes A, Voolstra CR, Wild C. Sugar enrichment provides evidence for a role of nitrogen fixation in coral bleaching. GLOBAL CHANGE BIOLOGY 2017; 23:3838-3848. [PMID: 28429531 DOI: 10.1111/gcb.13695] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 03/06/2017] [Accepted: 03/06/2017] [Indexed: 06/07/2023]
Abstract
The disruption of the coral-algae symbiosis (coral bleaching) due to rising sea surface temperatures has become an unprecedented global threat to coral reefs. Despite decades of research, our ability to manage mass bleaching events remains hampered by an incomplete mechanistic understanding of the processes involved. In this study, we induced a coral bleaching phenotype in the absence of heat and light stress by adding sugars. The sugar addition resulted in coral symbiotic breakdown accompanied by a fourfold increase of coral-associated microbial nitrogen fixation. Concomitantly, increased N:P ratios by the coral host and algal symbionts suggest excess availability of nitrogen and a disruption of the nitrogen limitation within the coral holobiont. As nitrogen fixation is similarly stimulated in ocean warming scenarios, here we propose a refined coral bleaching model integrating the cascading effects of stimulated microbial nitrogen fixation. This model highlights the putative role of nitrogen-fixing microbes in coral holobiont functioning and breakdown.
Collapse
Affiliation(s)
- Claudia Pogoreutz
- Coral Reef Ecology Group (CORE), Marine Ecology Department, Faculty of Biology and Chemistry (FB 2), University of Bremen, Bremen, Germany
- Department of Ecology, Leibniz Center for Tropical Marine Ecology, Bremen, Germany
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Nils Rädecker
- Coral Reef Ecology Group (CORE), Marine Ecology Department, Faculty of Biology and Chemistry (FB 2), University of Bremen, Bremen, Germany
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Anny Cárdenas
- Coral Reef Ecology Group (CORE), Marine Ecology Department, Faculty of Biology and Chemistry (FB 2), University of Bremen, Bremen, Germany
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- Department of Biogeochemistry, Leibniz Center for Tropical Marine Ecology, Bremen, Germany
| | - Astrid Gärdes
- Department of Biogeochemistry, Leibniz Center for Tropical Marine Ecology, Bremen, Germany
| | - Christian R Voolstra
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Christian Wild
- Coral Reef Ecology Group (CORE), Marine Ecology Department, Faculty of Biology and Chemistry (FB 2), University of Bremen, Bremen, Germany
- Department of Ecology, Leibniz Center for Tropical Marine Ecology, Bremen, Germany
| |
Collapse
|
37
|
Courtial L, Ferrier-Pagès C, Jacquet S, Rodolfo-Metalpa R, Reynaud S, Rottier C, Houlbrèque F. Effects of temperature and UVR on organic matter fluxes and the metabolic activity of Acropora muricata. Biol Open 2017; 6:1190-1199. [PMID: 28811302 PMCID: PMC5576085 DOI: 10.1242/bio.026757] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 07/03/2017] [Indexed: 11/20/2022] Open
Abstract
Coral bleaching events are predicted to occur more frequently in the coming decades with global warming. The susceptibility of corals to bleaching during thermal stress episodes depends on many factors, including the magnitude of thermal stress and irradiance. The interactions among these two factors, and in particular with ultra-violet radiation (UVR), the most harmful component of light, are more complex than assumed, and are not yet well understood. This paper explores the individual and combined effects of temperature and UVR on the metabolism of Acropora muricata, one of the most abundant coral species worldwide. Particulate and dissolved organic matter (POM/DOM) fluxes and organic matter (OM) degradation by the mucus-associated bacteria were also monitored in all conditions. The results show that UVR exposure exacerbated the temperature-induced bleaching, but did not affect OM fluxes, which were only altered by seawater warming. Temperature increase induced a shift from POM release and DOM uptake in healthy corals to POM uptake and DOM release in stressed ones. POM uptake was linked to a significant grazing of pico- and nanoplankton particles during the incubation, to fulfil the energetic requirements of A. muricata in the absence of autotrophy. Finally, OM degradation by mucus-associated bacterial activity was unaffected by UVR exposure, but significantly increased under high temperature. Altogether, our results demonstrate that seawater warming and UVR not only affect coral physiology, but also the way corals interact with the surrounding seawater, with potential consequences for coral reef biogeochemical cycles and food webs.
Collapse
Affiliation(s)
- Lucile Courtial
- Sorbone Universités, UPMC, 4 Place Jussieu, 75252 Paris Cedex 05, France
- Centre Scientifique de Monaco, Equipe Ecophysiologie, 8 Quai Antoine 1er, 98000, Monaco (Principality)
- UMR ENTROPIE (IRD, Université de La Réunion, CNRS), Laboratoire d'Excellence CORAIL, BP A5, 98848, Nouméa Cedex, New Caledonia
| | - Christine Ferrier-Pagès
- Centre Scientifique de Monaco, Equipe Ecophysiologie, 8 Quai Antoine 1er, 98000, Monaco (Principality)
| | - Stéphan Jacquet
- INRA, UMR CARRTEL, 75 avenue de Corzent, 74200 Thonon-les-Bains, France
| | - Riccardo Rodolfo-Metalpa
- UMR ENTROPIE (IRD, Université de La Réunion, CNRS), Laboratoire d'Excellence CORAIL, BP A5, 98848, Nouméa Cedex, New Caledonia
| | - Stéphanie Reynaud
- Centre Scientifique de Monaco, Equipe Ecophysiologie, 8 Quai Antoine 1er, 98000, Monaco (Principality)
| | - Cécile Rottier
- Centre Scientifique de Monaco, Equipe Ecophysiologie, 8 Quai Antoine 1er, 98000, Monaco (Principality)
| | - Fanny Houlbrèque
- UMR ENTROPIE (IRD, Université de La Réunion, CNRS), Laboratoire d'Excellence CORAIL, BP A5, 98848, Nouméa Cedex, New Caledonia
| |
Collapse
|
38
|
Rädecker N, Pogoreutz C, Ziegler M, Ashok A, Barreto MM, Chaidez V, Grupstra CGB, Ng YM, Perna G, Aranda M, Voolstra CR. Assessing the effects of iron enrichment across holobiont compartments reveals reduced microbial nitrogen fixation in the Red Sea coral Pocillopora verrucosa. Ecol Evol 2017; 7:6614-6621. [PMID: 28861262 PMCID: PMC5574852 DOI: 10.1002/ece3.3293] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/07/2017] [Accepted: 07/09/2017] [Indexed: 11/09/2022] Open
Abstract
The productivity of coral reefs in oligotrophic tropical waters is sustained by an efficient uptake and recycling of nutrients. In reef-building corals, the engineers of these ecosystems, this nutrient recycling is facilitated by a constant exchange of nutrients between the animal host and endosymbiotic photosynthetic dinoflagellates (zooxanthellae), bacteria, and other microbes. Due to the complex interactions in this so-called coral holobiont, it has proven difficult to understand the environmental limitations of productivity in corals. Among others, the micronutrient iron has been proposed to limit primary productivity due to its essential role in photosynthesis and bacterial processes. Here, we tested the effect of iron enrichment on the physiology of the coral Pocillopora verrucosa from the central Red Sea during a 12-day experiment. Contrary to previous reports, we did not see an increase in zooxanthellae population density or gross photosynthesis. Conversely, respiration rates were significantly increased, and microbial nitrogen fixation was significantly decreased. Taken together, our data suggest that iron is not a limiting factor of primary productivity in Red Sea corals. Rather, increased metabolic demands in response to iron enrichment, as evidenced by increased respiration rates, may reduce carbon (i.e., energy) availability in the coral holobiont, resulting in reduced microbial nitrogen fixation. This decrease in nitrogen supply in turn may exacerbate the limitation of other nutrients, creating a negative feedback loop. Thereby, our results highlight that the effects of iron enrichment appear to be strongly dependent on local environmental conditions and ultimately may depend on the availability of other nutrients.
Collapse
Affiliation(s)
- Nils Rädecker
- Red Sea Research Center Division of Biological and Environmental Science and Engineering (BESE) King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
| | - Claudia Pogoreutz
- Red Sea Research Center Division of Biological and Environmental Science and Engineering (BESE) King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
| | - Maren Ziegler
- Red Sea Research Center Division of Biological and Environmental Science and Engineering (BESE) King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
| | - Ananya Ashok
- Red Sea Research Center Division of Biological and Environmental Science and Engineering (BESE) King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
| | - Marcelle M Barreto
- Red Sea Research Center Division of Biological and Environmental Science and Engineering (BESE) King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
| | - Veronica Chaidez
- Red Sea Research Center Division of Biological and Environmental Science and Engineering (BESE) King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
| | - Carsten G B Grupstra
- Red Sea Research Center Division of Biological and Environmental Science and Engineering (BESE) King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
| | - Yi Mei Ng
- Red Sea Research Center Division of Biological and Environmental Science and Engineering (BESE) King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
| | - Gabriela Perna
- Red Sea Research Center Division of Biological and Environmental Science and Engineering (BESE) King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
| | - Manuel Aranda
- Red Sea Research Center Division of Biological and Environmental Science and Engineering (BESE) King Abdullah University of Science and Technology (KAUST) 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 (KAUST) Thuwal Saudi Arabia
| |
Collapse
|
39
|
Pogoreutz C, Rädecker N, Cárdenas A, Gärdes A, Wild C, Voolstra CR. Nitrogen Fixation Aligns with nifH Abundance and Expression in Two Coral Trophic Functional Groups. Front Microbiol 2017; 8:1187. [PMID: 28702013 PMCID: PMC5487474 DOI: 10.3389/fmicb.2017.01187] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 06/12/2017] [Indexed: 01/15/2023] Open
Abstract
Microbial nitrogen fixation (diazotrophy) is a functional trait widely associated with tropical reef-building (scleractinian) corals. While the integral role of nitrogen fixation in coral nutrient dynamics is recognized, its ecological significance across different coral functional groups remains yet to be evaluated. Here we set out to compare molecular and physiological patterns of diazotrophy (i.e., nifH gene abundance and expression as well as nitrogen fixation rates) in two coral families with contrasting trophic strategies: highly heterotrophic, free-living members of the family Fungiidae (Pleuractis granulosa, Ctenactis echinata), and mostly autotrophic coral holobionts with low heterotrophic capacity (Pocilloporidae: Pocillopora verrucosa, Stylophora pistillata). The Fungiidae exhibited low diazotroph abundance (based on nifH gene copy numbers) and activity (based on nifH gene expression and the absence of detectable nitrogen fixation rates). In contrast, the mostly autotrophic Pocilloporidae exhibited nifH gene copy numbers and gene expression two orders of magnitude higher than in the Fungiidae, which coincided with detectable nitrogen fixation activity. Based on these data, we suggest that nitrogen fixation compensates for the low heterotrophic nitrogen uptake in autotrophic corals. Consequently, the ecological importance of diazotrophy in coral holobionts may be determined by the trophic functional group of the host.
Collapse
Affiliation(s)
- Claudia Pogoreutz
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST),Thuwal, Saudi Arabia.,Marine Ecology and Coral Reef Ecology Group, Faculty of Biology and Chemistry, University of BremenBremen, Germany.,Department of Ecology, Leibniz Center for Tropical Marine ResearchBremen, Germany
| | - Nils Rädecker
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST),Thuwal, Saudi Arabia.,Marine Ecology and Coral Reef Ecology Group, Faculty of Biology and Chemistry, University of BremenBremen, Germany
| | - Anny Cárdenas
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST),Thuwal, Saudi Arabia.,Tropical Marine Microbiology Group, Department of Biogeochemistry and Geology, Leibniz Center for Tropical Marine ResearchBremen, Germany
| | - Astrid Gärdes
- Tropical Marine Microbiology Group, Department of Biogeochemistry and Geology, Leibniz Center for Tropical Marine ResearchBremen, Germany
| | - Christian Wild
- Marine Ecology and Coral Reef Ecology Group, Faculty of Biology and Chemistry, University of BremenBremen, Germany
| | - Christian R Voolstra
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST),Thuwal, Saudi Arabia
| |
Collapse
|