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Tilstra A, Braxator L, Thobor B, Mezger SD, Hill CEL, El-Khaled YC, Caporale G, Kim S, Wild C. Short-term ocean acidification decreases pulsation and growth of the widespread soft coral Xenia umbellata. PLoS One 2023; 18:e0294470. [PMID: 37967066 PMCID: PMC10651030 DOI: 10.1371/journal.pone.0294470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 10/31/2023] [Indexed: 11/17/2023] Open
Abstract
Coral reefs may experience lower pH values as a result of ocean acidification (OA), which has negative consequences, particularly for calcifying organisms. Thus far, the effects of this global factor have been mainly investigated on hard corals, while the effects on soft corals remain relatively understudied. We therefore carried out a manipulative aquarium experiment for 21 days to study the response of the widespread pulsating soft coral Xenia umbellata to simulated OA conditions. We gradually decreased the pH from ambient (~8.3) to three consecutive 7-day long pH treatments of 8.0, 7.8, and 7.6, using a CO2 dosing system. Monitored response variables included pulsation rate, specific growth rate, visual coloration, survival, Symbiodiniaceae cell densities and chlorophyll a content, photosynthesis and respiration, and finally stable isotopes of carbon (C) and nitrogen (N) as well as CN content. Pulsation decreased compared to controls with each consecutive lowering of the pH, i.e., 17% at pH 8.0, 26% at pH 7.8 and 32% at pH 7.6, accompanied by an initial decrease in growth rates of ~60% at pH 8.0, not decreasing further at lower pH. An 8.3 ‰ decrease of δ13C confirmed that OA exposed colonies had a higher uptake and availability of atmospheric CO2. Coral productivity, i.e., photosynthesis, was not affected by higher dissolved inorganic C availability and none of the remaining response variables showed any significant differences. Our findings suggest that pulsation is a phenotypically plastic mechanism for X. umbellata to adjust to different pH values, resulting in reduced growth rates only, while maintaining high productivity. Consequently, pulsation may allow X. umbellata to inhabit a broad pH range with minimal effects on its overall health. This resilience may contribute to the competitive advantage that soft corals, particularly X. umbellata, have over hard corals.
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Affiliation(s)
- Arjen Tilstra
- Department of Marine Ecology, University of Bremen, Bremen, Germany
| | - Lorena Braxator
- Department of Marine Ecology, University of Bremen, Bremen, Germany
| | - Bianca Thobor
- Department of Marine Ecology, University of Bremen, Bremen, Germany
| | - Selma D. Mezger
- Department of Marine Ecology, University of Bremen, Bremen, Germany
| | | | | | - Giulia Caporale
- Department of Marine Ecology, University of Bremen, Bremen, Germany
| | - Sohyoung Kim
- Department of Marine Ecology, University of Bremen, Bremen, Germany
| | - Christian Wild
- Department of Marine Ecology, University of Bremen, Bremen, Germany
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Xiang N, Meyer A, Pogoreutz C, Rädecker N, Voolstra CR, Wild C, Gärdes A. Excess labile carbon promotes diazotroph abundance in heat-stressed octocorals. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221268. [PMID: 36938541 PMCID: PMC10014249 DOI: 10.1098/rsos.221268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
Nitrogen limitation is the foundation of stable coral-algal symbioses. Diazotrophs, prokaryotes capable of fixing N2 into ammonia, support the productivity of corals in oligotrophic waters, but could contribute to the destabilization of holobiont functioning when overstimulated. Recent studies on reef-building corals have shown that labile dissolved organic carbon (DOC) enrichment or heat stress increases diazotroph abundance and activity, thereby increasing nitrogen availability and destabilizing the coral-algal symbiosis. However, the (a)biotic drivers of diazotrophs in octocorals are still poorly understood. We investigated diazotroph abundance (via relative quantification of nifH gene copy numbers) in two symbiotic octocorals, the more mixotrophic soft coral Xenia umbellata and the more autotrophic gorgonian Pinnigorgia flava, under (i) labile DOC enrichment for 21 days, followed by (ii) combined labile DOC enrichment and heat stress for 24 days. Without heat stress, relative diazotroph abundances in X. umbellata and P. flava were unaffected by DOC enrichment. During heat stress, DOC enrichment (20 and 40 mg glucose l-1) increased the relative abundances of diazotrophs by sixfold in X. umbellata and fourfold in P. flava, compared with their counterparts without excess DOC. Our data suggest that labile DOC enrichment and concomitant heat stress could disrupt the nitrogen limitation in octocorals by stimulating diazotroph proliferation. Ultimately, the disruption of nitrogen cycling may further compromise octocoral fitness by destabilizing symbiotic nutrient cycling. Therefore, improving local wastewater facilities to reduce labile DOC input into vulnerable coastal ecosystems may help octocorals cope with ocean warming.
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Affiliation(s)
- Nan Xiang
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen Bremen 28359, Germany
- Section of Polar Biological Oceanography, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven 27570, Germany
- Leibniz Center for Tropical Marine Research (ZMT), Bremen 28359, Germany
| | - Achim Meyer
- Leibniz Center for Tropical Marine Research (ZMT), Bremen 28359, Germany
| | - Claudia Pogoreutz
- Department of Biology, University of Konstanz, Konstanz 78457, Germany
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Nils Rädecker
- Department of Biology, University of Konstanz, Konstanz 78457, Germany
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | | | - Christian Wild
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen Bremen 28359, Germany
| | - Astrid Gärdes
- Section of Polar Biological Oceanography, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven 27570, Germany
- Leibniz Center for Tropical Marine Research (ZMT), Bremen 28359, Germany
- Hochschule Bremerhaven, Fachbereich 1, An der Karlstadt 8, Bremerhaven 27568, Germany
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Mezger SD, Klinke A, Tilstra A, El-Khaled YC, Thobor B, Wild C. The widely distributed soft coral Xenia umbellata exhibits high resistance against phosphate enrichment and temperature increase. Sci Rep 2022; 12:22135. [PMID: 36550166 PMCID: PMC9780247 DOI: 10.1038/s41598-022-26325-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
Both global and local factors affect coral reefs worldwide, sometimes simultaneously. An interplay of these factors can lead to phase shifts from hard coral dominance to algae or other invertebrates, particularly soft corals. However, most studies have targeted the effects of single factors, leaving pronounced knowledge gaps regarding the effects of combined factors on soft corals. Here, we investigated the single and combined effects of phosphate enrichment (1, 2, and 8 μM) and seawater temperature increase (26 to 32 °C) on the soft coral Xenia umbellata by quantifying oxygen fluxes, protein content, and stable isotope signatures in a 5-week laboratory experiment. Findings revealed no significant effects of temperature increase, phosphate enrichment, and the combination of both factors on oxygen fluxes. However, regardless of the phosphate treatment, total protein content and carbon stable isotope ratios decreased significantly by 62% and 7% under temperature increase, respectively, suggesting an increased assimilation of their energy reserves. Therefore, we hypothesize that heterotrophic feeding may be important for X. umbellata to sustain their energy reserves under temperature increase, highlighting the advantages of a mixotrophic strategy. Overall, X. umbellata shows a high tolerance towards changes in global and local factors, which may explain their competitive advantage observed at many Indo-Pacific reef locations.
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Affiliation(s)
- Selma D. Mezger
- grid.7704.40000 0001 2297 4381Department of Marine Ecology, Faculty of Biology and Chemistry, University of Bremen, Leobener Str. 6, 28359 Bremen, Germany
| | - Annabell Klinke
- grid.7704.40000 0001 2297 4381Department of Marine Ecology, Faculty of Biology and Chemistry, University of Bremen, Leobener Str. 6, 28359 Bremen, Germany ,grid.461729.f0000 0001 0215 3324Leibniz Centre for Tropical Marine Research, Fahrenheitstraße 6, 28359 Bremen, Germany
| | - Arjen Tilstra
- grid.7704.40000 0001 2297 4381Department of Marine Ecology, Faculty of Biology and Chemistry, University of Bremen, Leobener Str. 6, 28359 Bremen, Germany
| | - Yusuf C. El-Khaled
- grid.7704.40000 0001 2297 4381Department of Marine Ecology, Faculty of Biology and Chemistry, University of Bremen, Leobener Str. 6, 28359 Bremen, Germany
| | - Bianca Thobor
- grid.7704.40000 0001 2297 4381Department of Marine Ecology, Faculty of Biology and Chemistry, University of Bremen, Leobener Str. 6, 28359 Bremen, Germany
| | - Christian Wild
- grid.7704.40000 0001 2297 4381Department of Marine Ecology, Faculty of Biology and Chemistry, University of Bremen, Leobener Str. 6, 28359 Bremen, Germany
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Bouderlique T, Petersen J, Faure L, Abed-Navandi D, Bouchnita A, Mueller B, Nazarov M, Englmaier L, Tesarova M, Frade PR, Zikmund T, Koehne T, Kaiser J, Fried K, Wild C, Pantos O, Hellander A, Bythell J, Adameyko I. Surface flow for colonial integration in reef-building corals. Curr Biol 2022; 32:2596-2609.e7. [PMID: 35561678 DOI: 10.1016/j.cub.2022.04.054] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 03/04/2022] [Accepted: 04/20/2022] [Indexed: 11/29/2022]
Abstract
Reef-building corals are endangered animals with a complex colonial organization. Physiological mechanisms connecting multiple polyps and integrating them into a coral colony are still enigmatic. Using live imaging, particle tracking, and mathematical modeling, we reveal how corals connect individual polyps and form integrated polyp groups via species-specific, complex, and stable networks of currents at their surface. These currents involve surface mucus of different concentrations, which regulate joint feeding of the colony. Inside the coral, within the gastrovascular system, we expose the complexity of bidirectional branching streams that connect individual polyps. This system of canals extends the surface area by 4-fold and might improve communication, nutrient supply, and symbiont transfer. Thus, individual polyps integrate via complex liquid dynamics on the surface and inside the colony.
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Affiliation(s)
- Thibault Bouderlique
- Department of Neuroimmunology, Center for Brain Research, Medical University Vienna, 1090 Vienna, Austria
| | - Julian Petersen
- Department of Neuroimmunology, Center for Brain Research, Medical University Vienna, 1090 Vienna, Austria; Department of Orthodontics, University of Leipzig Medical Center, Leipzig, Germany
| | - Louis Faure
- Department of Neuroimmunology, Center for Brain Research, Medical University Vienna, 1090 Vienna, Austria
| | | | - Anass Bouchnita
- Department of Information Technology, University of Uppsala, 751 05 Uppsala, Sweden
| | - Benjamin Mueller
- Department of Freshwater and Marine Ecology, University of Amsterdam, 1090 GE Amsterdam, the Netherlands; CARMABI Foundation, Willemstad, Curaçao
| | - Murtazo Nazarov
- Department of Information Technology, University of Uppsala, 751 05 Uppsala, Sweden
| | - Lukas Englmaier
- Department of Neuroimmunology, Center for Brain Research, Medical University Vienna, 1090 Vienna, Austria
| | - Marketa Tesarova
- Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic
| | | | - Tomas Zikmund
- Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic
| | - Till Koehne
- Department of Orthodontics, University of Leipzig Medical Center, Leipzig, Germany
| | - Jozef Kaiser
- Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic
| | - Kaj Fried
- Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Christian Wild
- Department of Marine Ecology, Faculty of Biology & Chemistry of Bremen, 28359 Bremen, Germany
| | - Olga Pantos
- Institute of Environmental Science and Research, 27 Creyke Road, Ila, Christchurch 8041, New Zealand
| | - Andreas Hellander
- Department of Information Technology, University of Uppsala, 751 05 Uppsala, Sweden
| | - John Bythell
- School of Natural and Environmental Sciences, Newcastle University, NE1 7RU Newcastle Upon Tyne, UK
| | - Igor Adameyko
- Department of Neuroimmunology, Center for Brain Research, Medical University Vienna, 1090 Vienna, Austria; Department of Physiology and Pharmacology, Karolinska Institutet, 17177 Stockholm, Sweden.
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Kim S, Wild C, Tilstra A. Effective asexual reproduction of a widespread soft coral: comparative assessment of four different fragmentation methods. PeerJ 2022; 10:e12589. [PMID: 35111389 PMCID: PMC8783554 DOI: 10.7717/peerj.12589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 11/12/2021] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Many coral reefs worldwide are experiencing declines in hard corals, resulting in other benthic organisms, e.g., soft corals, becoming more dominant. As such, more studies on the ecophysiology of soft corals are needed. Despite many methods for asexual reproduction of hard corals, effective methods for soft corals, i.e., without a hard skeleton, are scarce. This study, thus, assessed four fragmentation methods, the glue, rubber band, tunnel mesh, and plug mesh method for the pulsating soft coral Xenia umbellata that is widely distributed in the tropical Indo-Pacific. METHODS Methods were comparatively assessed by determining the required time and labor for the fragmentation plus the health status of the fragmented corals by measuring their oxygen fluxes and pulsation rates, i.e., a special feature of this soft coral that can be used as a proxy for its health. RESULTS There were no significant health status differences between methods. This was indicated by similar gross photosynthesis (between 7.4 to 9.7 μg O2 polyp-1 h-1) and pulsating rates (between 35 and 44 pulses min-1) among methods. In terms of time/labor intensity and success rates, i.e., the percentage of fragments attached to the desired surface, the plug mesh method was the most efficient method with a significantly higher success rate (95 ± 5%), while the others had a success rate between 5 ± 5 and 45 ± 15%. The time needed for fragmentation, though not significant, was also the shortest (78 ± 11 s fragment-1), while other methods required between 84 ± 14 and 126 ± 8 s frag-1. The plug mesh method may thus be a valuable tool related to the reproduction of soft corals for use in subsequent experimental work.
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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.
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Samson JE, Ray DD, Porfiri M, Miller LA, Garnier S. Collective Pulsing in Xeniid Corals: Part I-Using Computer Vision and Information Theory to Search for Coordination. Bull Math Biol 2020; 82:90. [PMID: 32638174 DOI: 10.1007/s11538-020-00759-2] [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: 09/30/2019] [Accepted: 06/04/2020] [Indexed: 11/24/2022]
Abstract
Xeniid corals (Cnidaria: Alcyonacea), a family of soft corals, include species displaying a characteristic pulsing behavior. This behavior has been shown to increase oxygen diffusion away from the coral tissue, resulting in higher photosynthetic rates from mutualistic symbionts. Maintaining such a pulsing behavior comes at a high energetic cost, and it has been proposed that coordinating the pulse of individual polyps within a colony might enhance the efficiency of fluid transport. In this paper, we test whether patterns of collective pulsing emerge in coral colonies and investigate possible interactions between polyps within a colony. We video recorded different colonies of Heteroxenia sp. in a laboratory environment. Our methodology is based on the systematic integration of a computer vision algorithm (ISOMAP) and an information-theoretic approach (transfer entropy), offering a vantage point to assess coordination in collective pulsing. Perhaps surprisingly, we did not detect any form of collective pulsing behavior in the colonies. Using artificial data sets, however, we do demonstrate that our methodology is capable of detecting even weak information transfer. The lack of a coordination is consistent with previous work on many cnidarians where coordination between actively pulsing polyps and medusa has not been observed. In our companion paper, we show that there is no fluid dynamic benefit of coordinated pulsing, supporting this result. The lack of coordination coupled with no obvious fluid dynamic benefit to grouping suggests that there may be non-fluid mechanical advantages to forming colonies, such as predator avoidance and defense.
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Affiliation(s)
- Julia E Samson
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Collective Behaviour, Max Planck Institute of Animal Behavior, Constance, Germany.,Chair of Biodiversity and Collective Behaviour, Department of Biology, University of Konstanz, Constance, Germany.,Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Constance, Germany
| | - Dylan D Ray
- Department of Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Maurizio Porfiri
- Department of Mechanical and Aerospace Engineering and Department of Biomedical Engineering, New York University, Tandon School of Engineering, Brooklyn, NY, USA
| | - Laura A Miller
- Biology Department, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Simon Garnier
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ, USA.
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Vollstedt S, Xiang N, Simancas-Giraldo SM, Wild C. Organic eutrophication increases resistance of the pulsating soft coral Xenia umbellata to warming. PeerJ 2020; 8:e9182. [PMID: 32607278 PMCID: PMC7316076 DOI: 10.7717/peerj.9182] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 04/22/2020] [Indexed: 11/21/2022] Open
Abstract
Recent research indicates that hard corals in a process that is termed phase shift are often replaced by soft corals in reefs. The simultaneous occurrence of local (i.e. organic eutrophication as highly under-investigated parameter) and global (i.e. ocean warming) factors may facilitate these phase shifts as hard corals are negatively affected by both ocean warming and organic eutrophication. Knowledge about soft coral responses to environmental change remains incomplete, although these organisms are becoming important players in reefs. The present study thus investigated the individual and combined effects of organic eutrophication (as glucose addition) and warming on the ecological data of the pulsating soft coral Xenia umbellata. We assessed health status, growth and pulsation rates of soft corals in a 45 day aquarium experiment, with first manipulation of organic eutrophication (no, low, medium and high glucose addition) over 21 days followed by step-wise increases in water temperature from 26 to 32 °C over 24 days. Findings revealed that glucose addition did not affect health status, growth and pulsation rates of the investigated soft corals. Under simulated ocean warming, soft corals that had experienced organic eutrophication before, maintained significantly higher pulsation rates (averaging 22 beats per minute—bpm) and no mortality compared to the controls that showed a decrease of 56% (averaging 15 bpm) in pulsation rates and mortality of 30% at water temperatures of 32 °C compared to 26 °C. This apparently positive effect of organic eutrophication on the ecological data of soft corals under an ocean warming scenario decreased with increasing water temperature. This study thus indicates that (a) organic eutrophication as additional energy source up to a certain threshold may increase the resistance of soft corals to ocean warming and (b) pulsation rates of soft corals may be used as inexpensive, easily detectable, and non-invasive early warning indicator for ocean warming effects on benthic reef communities. When comparing findings of this study for soft corals with previous results for hard corals, it can be assumed that soft corals under the predicted increases of organic eutrophication and warming gain more and more competitive advantages. This may further facilitate phase shifts from hard to soft corals in warming reefs.
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Affiliation(s)
- Svea Vollstedt
- Faculty of Biology and Chemistry, Universität Bremen, Bremen, Germany
| | - Nan Xiang
- Faculty of Biology and Chemistry, Universität Bremen, Bremen, Germany.,WG Tropical Marine Microbiology, Leibniz Centre for Tropical Marine Research, Bremen, Germany
| | | | - Christian Wild
- Faculty of Biology and Chemistry, Universität Bremen, Bremen, Germany
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Ochsenkühn MA, Schmitt-Kopplin P, Harir M, Amin SA. Coral metabolite gradients affect microbial community structures and act as a disease cue. Commun Biol 2018; 1:184. [PMID: 30417121 PMCID: PMC6218554 DOI: 10.1038/s42003-018-0189-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 10/09/2018] [Indexed: 11/09/2022] Open
Abstract
Corals are threatened worldwide due to prevalence of disease and bleaching. Recent studies suggest the ability of corals to resist disease is dependent on maintaining healthy microbiomes that span coral tissues and surfaces, the holobiont. Although our understanding of the role endosymbiotic microbes play in coral health has advanced, the role surface-associated microbes and their chemical signatures play in coral health is limited. Using minimally invasive water sampling, we show that the corals Acropora and Platygyra harbor unique bacteria and metabolites at their surface, distinctly different from surrounding seawater. The surface metabolites released by the holobiont create concentration gradients at 0–5 cm away from the coral surface. These molecules are identified as chemo-attractants, antibacterials, and infochemicals, suggesting they may structure coral surface-associated microbes. Further, we detect surface-associated metabolites characteristic of healthy or white syndrome disease infected corals, a finding which may aid in describing effects of diseases. Michael Ochsenkühn et al. look at the microbial and metabolic composition of coral surfaces and the surrounding seawater. They find that the metabolites found on the surface of the coral create a concentration gradient that influences the surrounding microbiome.
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Affiliation(s)
- Michael A Ochsenkühn
- Biology Division, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, 129188, United Arab Emirates
| | - Philippe Schmitt-Kopplin
- Research Unit Analytical BioGeoChemistry, Helmholtz Centre Munich, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.,Lehrstuhl für Analytische Lebensmittelchemie, Technische Universität München, Alte Akademie 10, 85354, Freising, Germany
| | - Mourad Harir
- Research Unit Analytical BioGeoChemistry, Helmholtz Centre Munich, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Shady A Amin
- Biology Division, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, 129188, United Arab Emirates. .,Chemistry Division, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, 129188, United Arab Emirates.
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10
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Garcia-Herrera N, Ferse SCA, Kunzmann A, Genin A. Mutualistic damselfish induce higher photosynthetic rates in their host coral. ACTA ACUST UNITED AC 2018; 220:1803-1811. [PMID: 28515171 DOI: 10.1242/jeb.152462] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Accepted: 02/28/2017] [Indexed: 01/25/2023]
Abstract
Coral reefs are amongst the most diverse ecosystems on Earth where complex inter-specific interactions are ubiquitous. An example of such interactions is the mutualistic relationship between damselfishes and branching corals in the Northern Red Sea, where the fish use corals as shelter and provide them with nutrients, enhance the flow between their branches, and protect them from predators. By enhancing the flow between the coral branches, the fish ventilate the coral's inner zone, mitigating hypoxic conditions that otherwise develop within that zone during the night. Here, we tested, for the first time, the effects of the damselfish Dascyllus marginatus on photosynthesis and respiration in its host coral Stylophora pistillata Laboratory experiments using an intermittent-flow respirometer showed that the presence of fish between the coral branches under light conditions augmented the coral's photosynthetic rate. No effect on the coral's respiration was found under dark conditions. When a fish was allowed to enter the inner zone of a dead coral skeleton, its respiration was higher than when it was in a live coral. Field observations indicated that damselfish were present between coral branches 18-34% of the time during daylight hours and at all times during the night. Considering the changes induced by the fish together with the proportion of time they were found between coral branches in the field, the effect of the fish amounted to an augmentation of 3-6% of the coral's daily photosynthesis. Our findings reveal a previously unknown positive contribution of coral-dwelling fish to their host's photosynthesis.
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Affiliation(s)
- Nur Garcia-Herrera
- Leibniz Center for Tropical Marine Ecology (ZMT) Bremen GmbH, Fahrenheitstraße 6, Bremen 28359, Germany .,Faculty of Biology & Chemistry (FB2), University of Bremen, PO Box 33 04 40, Bremen 28334, Germany
| | - Sebastian C A Ferse
- Leibniz Center for Tropical Marine Ecology (ZMT) Bremen GmbH, Fahrenheitstraße 6, Bremen 28359, Germany
| | - Andreas Kunzmann
- Leibniz Center for Tropical Marine Ecology (ZMT) Bremen GmbH, Fahrenheitstraße 6, Bremen 28359, Germany
| | - Amatzia Genin
- The Interuniversity Institute for Marine Sciences of Eilat, PO Box 469, Eilat 88103, Israel.,Department of Ecology, Evolution, and Behavior, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel
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Benayahu Y, van Ofwegen LP, McFadden CS. Evaluating the genus Cespitularia MilneEdwards & Haime, 1850 with descriptions of new genera of the family Xeniidae (Octocorallia, Alcyonacea). Zookeys 2018:63-101. [PMID: 29755257 PMCID: PMC5943446 DOI: 10.3897/zookeys.754.23368] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 02/22/2018] [Indexed: 11/12/2022] Open
Abstract
Several species of the family Xeniidae, previously assigned to the genus Cespitularia Milne Edwards & Haime, 1850 are revised. Based on the problematical identity and status of the type of this genus, it became apparent that the literature has introduced misperceptions concerning its diagnosis. A consequent examination of the type colonies of Cespitularia coerulea May, 1898 has led to the establishment of the new genus Conglomeratuscleragen. n. and similarly to the assignment of Cespitularia simplex Thomson & Dean, 1931 to the new genus, Caementabundagen. n. Both new genera are described and depicted and both feature unique sclerite morphology, further highlighting the importance of sclerite microstructure for generic position among Xeniidae. Freshly collected material was subjected to molecular phylogenetic analysis, whose results substantiated the taxonomic assignment of the new genera, as well as the synonymies of several others.
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Affiliation(s)
- Yehuda Benayahu
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, 69978, Israel
| | - Leen P van Ofwegen
- Naturalis Biodiversity Center, P.O. Box 9517, 2300 RA Leiden, The Netherlands
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Gedan KB, Altieri AH, Feller I, Burrell R, Breitburg D. Community composition in mangrove ponds with pulsed hypoxic and acidified conditions. Ecosphere 2017. [DOI: 10.1002/ecs2.2053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Keryn B. Gedan
- Biological Sciences; George Washington University; 800 22nd Street NW Washington D.C. 20052 USA
| | - Andrew H. Altieri
- Smithsonian Tropical Research Institute; Apartado 0843-03092 Balboa Ancon Panama
| | - Ilka Feller
- Smithsonian Environmental Research Center; 647 Contees Wharf Road Edgewater Maryland 21037 USA
| | - Rebecca Burrell
- Maryland Department of Natural Resources; 580 Taylor Avenue Annapolis Maryland 21401 USA
| | - Denise Breitburg
- Smithsonian Environmental Research Center; 647 Contees Wharf Road Edgewater Maryland 21037 USA
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13
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Limited phosphorus availability is the Achilles heel of tropical reef corals in a warming ocean. Sci Rep 2016; 6:31768. [PMID: 27531136 PMCID: PMC4987665 DOI: 10.1038/srep31768] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 07/27/2016] [Indexed: 12/04/2022] Open
Abstract
During the 20th century, seawater temperatures have significantly increased, leading to profound alterations in biogeochemical cycles and ecosystem processes. Elevated temperatures have also caused massive bleaching (symbiont/pigment loss) of autotrophic symbioses, such as in coral-dinoflagellate association. As symbionts provide most nutrients to the host, their expulsion during bleaching induces host starvation. However, with the exception of carbon, the nutritional impact of bleaching on corals is still unknown, due to the poorly understood requirements in inorganic nutrients during stress. We therefore assessed the uptake rates of nitrogen and phosphate by five coral species maintained under normal and thermal stress conditions. Our results showed that nitrogen acquisition rates were significantly reduced during thermal stress, while phosphorus uptake rates were significantly increased in most species, suggesting a key role of this nutrient. Additional experiments showed that during thermal stress, phosphorus was required to maintain symbiont density and photosynthetic rates, as well as to enhance the translocation and retention of carbon within the host tissue. These findings shed new light on the interactions existing between corals and inorganic nutrients during thermal stress, and highlight the importance of phosphorus for symbiont health.
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Naumann MS, Bednarz VN, Ferse SCA, Niggl W, Wild C. Monitoring of coastal coral reefs near Dahab (Gulf of Aqaba, Red Sea) indicates local eutrophication as potential cause for change in benthic communities. ENVIRONMENTAL MONITORING AND ASSESSMENT 2015; 187:44. [PMID: 25637388 DOI: 10.1007/s10661-014-4257-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 12/29/2014] [Indexed: 06/04/2023]
Abstract
Coral reef ecosystems fringing the coastline of Dahab (South Sinai, Egypt) have experienced increasing anthropogenic disturbance as an emergent international tourism destination. Previous reports covering tourism-related impacts on coastal environments, particularly mechanical damage and destructive fishing, have highlighted the vital necessity for regular ecosystem monitoring of coral reefs near Dahab. However, a continuous scientific monitoring programme of permanent survey sites has not been established to date. Thus, this study conducted in situ monitoring surveys to investigate spatio-temporal variability of benthic reef communities and selected reef-associated herbivores along with reef health indicator organisms by revisiting three of the locally most frequented dive sites during expeditions in March 2010, September 2011 and February 2013. In addition, inorganic nutrient concentrations in reef-surrounding waters were determined to evaluate bottom-up effects of key environmental parameters on benthic reef community shifts in relation to grazer-induced top-down control. Findings revealed that from 2010 to 2013, live hard coral cover declined significantly by 12 % at the current-sheltered site Three Pools (TP), while showing negative trends for the Blue Hole (BH) and Lighthouse (LH) sites. Hard coral cover decline was significantly and highly correlated to a substantial increase in turf algae cover (up to 57 % at TP) at all sites, replacing hard corals as dominant benthic space occupiers in 2013. These changes were correlated to ambient phosphate and ammonium concentrations that exhibited highest values (0.64 ± 0.07 μmol PO4 (3-) l(-1), 1.05 ± 0.07 μmol NH4 (+) l(-1)) at the degraded site TP. While macroalgae appeared to respond to both bottom-up and top-down factors, change in turf algae was consistent with expected indications for bottom-up control. Temporal variability measured in herbivorous reef fish stocks reflected seasonal impacts by local fisheries, with concomitant changes in macroalgal cover. These findings represent the first record of rapid, localised change in benthic reef communities near Dahab, consistent with indications for bottom-up controlled early-stage phase shifts, underlining the necessity for efficient regional wastewater management for coastal facilities.
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Affiliation(s)
- Malik S Naumann
- Coral Reef Ecology Group (CORE), Leibniz Center for Tropical Marine Ecology (ZMT), Fahrenheitstrasse 6, 28359, Bremen, Germany,
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Naumann MS, Jantzen C, Haas AF, Iglesias-Prieto R, Wild C. Benthic primary production budget of a Caribbean reef lagoon (Puerto Morelos, Mexico). PLoS One 2013; 8:e82923. [PMID: 24367570 PMCID: PMC3867400 DOI: 10.1371/journal.pone.0082923] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 10/29/2013] [Indexed: 11/18/2022] Open
Abstract
High photosynthetic benthic primary production (P) represents a key ecosystem service provided by tropical coral reef systems. However, benthic P budgets of specific ecosystem compartments such as macrophyte-dominated reef lagoons are still scarce. To address this, we quantified individual and lagoon-wide net (Pn) and gross (Pg) primary production by all dominant functional groups of benthic primary producers in a typical macrophyte-dominated Caribbean reef lagoon near Puerto Morelos (Mexico) via measurement of O2 fluxes in incubation experiments. The photosynthetically active 3D lagoon surface area was quantified using conversion factors to allow extrapolation to lagoon-wide P budgets. Findings revealed that lagoon 2D benthic cover was primarily composed of sand-associated microphytobenthos (40%), seagrasses (29%) and macroalgae (27%), while seagrasses dominated the lagoon 3D surface area (84%). Individual Pg was highest for macroalgae and scleractinian corals (87 and 86 mmol O2 m−2 specimen area d−1, respectively), however seagrasses contributed highest (59%) to the lagoon-wide Pg. Macroalgae exhibited highest individual Pn rates, but seagrasses generated the largest fraction (51%) of lagoon-wide Pn. Individual R was highest for scleractinian corals and macroalgae, whereas seagrasses again provided the major lagoon-wide share (68%). These findings characterise the investigated lagoon as a net autotrophic coral reef ecosystem compartment revealing similar P compared to other macrophyte-dominated coastal environments such as seagrass meadows and macroalgae beds. Further, high lagoon-wide P (Pg: 488 and Pn: 181 mmol O2 m−2 lagoon area d−1) and overall Pg:R (1.6) indicate substantial benthic excess production within the Puerto Morelos reef lagoon and suggest the export of newly synthesised organic matter to surrounding ecosystems.
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Affiliation(s)
- Malik S. Naumann
- Coral Reef Ecology Group (CORE), Leibniz Center for Tropical Marine Ecology (ZMT), Bremen, Germany
- * E-mail:
| | - Carin Jantzen
- Coral Reef Ecology Group (CORE), Leibniz Center for Tropical Marine Ecology (ZMT), Bremen, Germany
| | - Andreas F. Haas
- Coral Reef Ecology Group (CORE), Leibniz Center for Tropical Marine Ecology (ZMT), Bremen, Germany
| | - Roberto Iglesias-Prieto
- Unidad Academica Puerto Morelos, Instituto de Ciencias del Mar y Limnologıa, Universidad Nacional Autonoma de Mexico (UNAM), Cancun, Quintana Roo, Mexico
| | - Christian Wild
- Coral Reef Ecology Group (CORE), Leibniz Center for Tropical Marine Ecology (ZMT), Bremen, Germany
- Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
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