1
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Strand EL, Wong KH, Farraj A, Gray S, McMenamin A, Putnam HM. Coral species-specific loss and physiological legacy effects are elicited by an extended marine heatwave. J Exp Biol 2024; 227:jeb246812. [PMID: 38774956 DOI: 10.1242/jeb.246812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 05/03/2024] [Indexed: 06/18/2024]
Abstract
Marine heatwaves are increasing in frequency and intensity, with potentially catastrophic consequences for marine ecosystems such as coral reefs. An extended heatwave and recovery time-series that incorporates multiple stressors and is environmentally realistic can provide enhanced predictive capacity for performance under climate change conditions. We exposed common reef-building corals in Hawai'i, Montipora capitata and Pocillopora acuta, to a 2-month period of high temperature and high PCO2 conditions or ambient conditions in a factorial design, followed by 2 months of ambient conditions. High temperature, rather than high PCO2, drove multivariate physiology shifts through time in both species, including decreases in respiration rates and endosymbiont densities. Pocillopora acuta exhibited more significantly negatively altered physiology, and substantially higher bleaching and mortality than M. capitata. The sensitivity of P. acuta appears to be driven by higher baseline rates of photosynthesis paired with lower host antioxidant capacity, creating an increased sensitivity to oxidative stress. Thermal tolerance of M. capitata may be partly due to harboring a mixture of Cladocopium and Durusdinium spp., whereas P. acuta was dominated by other distinct Cladocopium spp. Only M. capitata survived the experiment, but physiological state in heatwave-exposed M. capitata remained significantly diverged at the end of recovery relative to individuals that experienced ambient conditions. In future climate scenarios, particularly marine heatwaves, our results indicate a species-specific loss of corals that is driven by baseline host and symbiont physiological differences as well as Symbiodiniaceae community compositions, with the surviving species experiencing physiological legacies that are likely to influence future stress responses.
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Affiliation(s)
- Emma L Strand
- Department of Biology, University of Rhode Island, Kingston, RI 02881, USA
- Gloucester Marine Genomics Institute, Gloucester, MA 01930, USA
| | - Kevin H Wong
- Department of Biology, University of Rhode Island, Kingston, RI 02881, USA
- Department of Marine Biology and Ecology, University of Miami Rosenstiel School of Marine and Atmospheric Science, Miami, FL 33149, USA
| | - Alexa Farraj
- Department of Biology, University of Rhode Island, Kingston, RI 02881, USA
| | - Sierra Gray
- Department of Biology, University of Rhode Island, Kingston, RI 02881, USA
- Department of Biology, University of Victoria, Victoria, BC, Canada, V8P 5C2
| | - Ana McMenamin
- Department of Biology, University of Rhode Island, Kingston, RI 02881, USA
| | - Hollie M Putnam
- Department of Biology, University of Rhode Island, Kingston, RI 02881, USA
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2
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Helgoe J, Davy SK, Weis VM, Rodriguez-Lanetty M. Triggers, cascades, and endpoints: connecting the dots of coral bleaching mechanisms. Biol Rev Camb Philos Soc 2024; 99:715-752. [PMID: 38217089 DOI: 10.1111/brv.13042] [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: 03/02/2023] [Revised: 12/08/2023] [Accepted: 12/12/2023] [Indexed: 01/15/2024]
Abstract
The intracellular coral-dinoflagellate symbiosis is the engine that underpins the success of coral reefs, one of the most diverse ecosystems on the planet. However, the breakdown of the symbiosis and the loss of the microalgal symbiont (i.e. coral bleaching) due to environmental changes are resulting in the rapid degradation of coral reefs globally. There is an urgent need to understand the cellular physiology of coral bleaching at the mechanistic level to help develop solutions to mitigate the coral reef crisis. Here, at an unprecedented scope, we present novel models that integrate putative mechanisms of coral bleaching within a common framework according to the triggers (initiators of bleaching, e.g. heat, cold, light stress, hypoxia, hyposalinity), cascades (cellular pathways, e.g. photoinhibition, unfolded protein response, nitric oxide), and endpoints (mechanisms of symbiont loss, e.g. apoptosis, necrosis, exocytosis/vomocytosis). The models are supported by direct evidence from cnidarian systems, and indirectly through comparative evolutionary analyses from non-cnidarian systems. With this approach, new putative mechanisms have been established within and between cascades initiated by different bleaching triggers. In particular, the models provide new insights into the poorly understood connections between bleaching cascades and endpoints and highlight the role of a new mechanism of symbiont loss, i.e. 'symbiolysosomal digestion', which is different from symbiophagy. This review also increases the approachability of bleaching physiology for specialists and non-specialists by mapping the vast landscape of bleaching mechanisms in an atlas of comprehensible and detailed mechanistic models. We then discuss major knowledge gaps and how future research may improve the understanding of the connections between the diverse cascade of cellular pathways and the mechanisms of symbiont loss (endpoints).
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Affiliation(s)
- Joshua Helgoe
- Department of Biological Sciences, Institute of Environment, Florida International University, 11200 SW 8th Street, OE 167, Miami, FL, USA
| | - Simon K Davy
- School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand
| | - Virginia M Weis
- Department of Integrative Biology, Oregon State University, 2701 SW Campus Way, 2403 Cordley Hall, Corvallis, OR, USA
| | - Mauricio Rodriguez-Lanetty
- Department of Biological Sciences, Institute of Environment, Florida International University, 11200 SW 8th Street, OE 167, Miami, FL, USA
- Department of Biological Sciences, Biomolecular Sciences Institute, Florida International University, 11200 SW 8th Street, Miami, FL, USA
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3
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Cardoso PM, Hill LJ, Villela HDM, Vilela CLS, Assis JM, Rosado PM, Rosado JG, Chacon MA, Majzoub ME, Duarte GAS, Thomas T, Peixoto RS. Localization and symbiotic status of probiotics in the coral holobiont. mSystems 2024; 9:e0026124. [PMID: 38606974 PMCID: PMC11097643 DOI: 10.1128/msystems.00261-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 03/20/2024] [Indexed: 04/13/2024] Open
Abstract
Corals establish symbiotic relationships with microorganisms, especially endosymbiotic photosynthetic algae. Although other microbes have been commonly detected in coral tissues, their identity and beneficial functions for their host are unclear. Here, we confirm the beneficial outcomes of the inoculation of bacteria selected as probiotics and use fluorescence in situ hybridization (FISH) to define their localization in the coral Pocillopora damicornis. Our results show the first evidence of the inherent presence of Halomonas sp. and Cobetia sp. in native coral tissues, even before their inoculation. Furthermore, the relative enrichment of these coral tissue-associated bacteria through their inoculation in corals correlates with health improvements, such as increases in photosynthetic potential, and productivity. Our study suggests the symbiotic status of Halomonas sp. and Cobetia sp. in corals by indicating their localization within coral gastrodermis and epidermis and correlating their increased relative abundance through active inoculation with beneficial outcomes for the holobiont. This knowledge is crucial to facilitate the screening and application of probiotics that may not be transient members of the coral microbiome. IMPORTANCE Despite the promising results indicating the beneficial outcomes associated with the application of probiotics in corals and some scarce knowledge regarding the identity of bacterial cells found within the coral tissue, the correlation between these two aspects is still missing. This gap limits our understanding of the actual diversity of coral-associated bacteria and whether these symbionts are beneficial. Some researchers, for example, have been suggesting that probiotic screening should only focus on the very few known tissue-associated bacteria, such as Endozoicomonas sp., assuming that the currently tested probiotics are not tissue-associated. Here, we provide specific FISH probes for Halomonas sp. and Cobetia sp., expand our knowledge of the identity of coral-associated bacteria and confirm the probiotic status of the tested probiotics. The presence of these beneficial microorganisms for corals (BMCs) inside host tissues and gastric cavities also supports the notion that direct interactions with the host may underpin their probiotic role. This is a new breakthrough; these results argue against the possibility that the positive effects of BMCs are due to factors that are not related to a direct symbiotic interaction, for example, that the host simply feeds on inoculated bacteria or that the bacteria change the water quality.
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Affiliation(s)
- P. M. Cardoso
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - L. J. Hill
- Laboratory of Molecular Microbial Ecology, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - H. D. M. Villela
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - C. L. S. Vilela
- Laboratory of Molecular Microbial Ecology, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - J. M. Assis
- Laboratory of Molecular Microbial Ecology, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - P. M. Rosado
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - J. G. Rosado
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - M. A. Chacon
- Laboratory of Molecular Microbial Ecology, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - M. E. Majzoub
- Center for Marine Science and Innovation; School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, New South Wales, Australia
| | - G. A. S. Duarte
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Laboratory of Molecular Microbial Ecology, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - T. Thomas
- Center for Marine Science and Innovation; School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, New South Wales, Australia
| | - R. S. Peixoto
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Computational Biology Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- Marine Science and Bioscience Programs, Biological, Environmental and Engineering Sciences Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
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4
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Crehan O, Davy SK, Grover R, Ferrier-Pagès C. Nutrient depletion and heat stress impair the assimilation of nitrogen compounds in a scleractinian coral. J Exp Biol 2024; 227:jeb246466. [PMID: 38563292 DOI: 10.1242/jeb.246466] [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: 07/24/2023] [Accepted: 03/21/2024] [Indexed: 04/04/2024]
Abstract
Concentrations of dissolved nitrogen in seawater can affect the resilience of the cnidarian-dinoflagellate symbiosis to climate change-induced bleaching. However, it is not yet known how the assimilation and translocation of the various nitrogen forms change during heat stress, nor how the symbiosis responds to nutrient depletion, which may occur due to increasing water stratification. Here, the tropical scleractinian coral Stylophora pistillata, in symbiosis with dinoflagellates of the genus Symbiodinium, was grown at different temperatures (26°C, 30°C and 34°C), before being placed in nutrient-replete or -depleted seawater for 24 h. The corals were then incubated with 13C-labelled sodium bicarbonate and different 15N-labelled nitrogen forms (ammonium, urea and dissolved free amino acids) to determine their assimilation rates. We found that nutrient depletion inhibited the assimilation of all nitrogen sources studied and that heat stress reduced the assimilation of ammonium and dissolved free amino acids. However, the host assimilated over 3-fold more urea at 30°C relative to 26°C. Overall, both moderate heat stress (30°C) and nutrient depletion individually decreased the total nitrogen assimilated by the symbiont by 66%, and combined, they decreased assimilation by 79%. This led to the symbiotic algae becoming nitrogen starved, with the C:N ratio increasing by over 3-fold at 34°C, potentially exacerbating the impacts of coral bleaching.
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Affiliation(s)
- Oscar Crehan
- School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
| | - Simon K Davy
- School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
| | - Renaud Grover
- Marine Department, Centre Scientifique de Monaco, MC 98000 Monaco, Principality of Monaco
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5
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Quigley KM. Breeding and Selecting Corals Resilient to Global Warming. Annu Rev Anim Biosci 2024; 12:209-332. [PMID: 37931139 DOI: 10.1146/annurev-animal-021122-093315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
Selective breeding of resilient organisms is an emerging topic in marine conservation. It can help us predict how species will adapt in the future and how we can help restore struggling populations effectively in the present. Scleractinian corals represent a potential tractable model system given their widescale phenotypic plasticity across fitness-related traits and a reproductive life history based on mass synchronized spawning. Here, I explore the justification for breeding in corals, identify underutilized pathways of acclimation, and highlight avenues for quantitative targeted breeding from the coral host and symbiont perspective. Specifically, the facilitation of enhanced heat tolerance by targeted breeding of plasticity mechanisms is underutilized. Evidence from theoretical genetics identifies potential pitfalls, including inattention to physical and genetic characteristics of the receiving environment. Three criteria for breeding emerge from this synthesis: selection from warm, variable reefs that have survived disturbance. This information will be essential to protect what we have and restore what we can.
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Affiliation(s)
- K M Quigley
- The Minderoo Foundation, Perth, Western Australia, Australia;
- James Cook University, Townsville, Queensland, Australia
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6
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Allen-Waller LR, Jones KG, Martynek MP, Brown KT, Barott KL. Comparative physiology reveals heat stress disrupts acid-base homeostasis independent of symbiotic state in the model cnidarian Exaiptasia diaphana. J Exp Biol 2024; 227:jeb246222. [PMID: 38269486 PMCID: PMC10911193 DOI: 10.1242/jeb.246222] [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: 05/31/2023] [Accepted: 01/17/2024] [Indexed: 01/26/2024]
Abstract
Climate change threatens the survival of symbiotic cnidarians by causing photosymbiosis breakdown in a process known as bleaching. Direct effects of temperature on cnidarian host physiology remain difficult to describe because heatwaves depress symbiont performance, leading to host stress and starvation. The symbiotic sea anemone Exaiptasia diaphana provides an opportune system to disentangle direct versus indirect heat effects on the host, as it can survive indefinitely without symbionts. We tested the hypothesis that heat directly impairs cnidarian physiology by comparing symbiotic and aposymbiotic individuals of two laboratory subpopulations of a commonly used clonal strain of E. diaphana, CC7. We exposed anemones to a range of temperatures (ambient, +2°C, +4°C and +6°C) for 15-18 days, then measured their symbiont population densities, autotrophic carbon assimilation and translocation, photosynthesis, respiration and host intracellular pH (pHi). Symbiotic anemones from the two subpopulations differed in size and symbiont density and exhibited distinct heat stress responses, highlighting the importance of acclimation to different laboratory conditions. Specifically, the cohort with higher initial symbiont densities experienced dose-dependent symbiont loss with increasing temperature and a corresponding decline in host photosynthate accumulation. In contrast, the cohort with lower initial symbiont densities did not lose symbionts or assimilate less photosynthate when heated, similar to the response of aposymbiotic anemones. However, anemone pHi decreased at higher temperatures regardless of cohort, symbiont presence or photosynthate translocation, indicating that heat consistently disrupts cnidarian acid-base homeostasis independent of symbiotic status or mutualism breakdown. Thus, pH regulation may be a critical vulnerability for cnidarians in a changing climate.
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Affiliation(s)
| | - Katelyn G. Jones
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Kristen T. Brown
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Katie L. Barott
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
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7
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Jacobovitz MR, Hambleton EA, Guse A. Unlocking the Complex Cell Biology of Coral-Dinoflagellate Symbiosis: A Model Systems Approach. Annu Rev Genet 2023; 57:411-434. [PMID: 37722685 DOI: 10.1146/annurev-genet-072320-125436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Abstract
Symbiotic interactions occur in all domains of life, providing organisms with resources to adapt to new habitats. A prime example is the endosymbiosis between corals and photosynthetic dinoflagellates. Eukaryotic dinoflagellate symbionts reside inside coral cells and transfer essential nutrients to their hosts, driving the productivity of the most biodiverse marine ecosystem. Recent advances in molecular and genomic characterization have revealed symbiosis-specific genes and mechanisms shared among symbiotic cnidarians. In this review, we focus on the cellular and molecular processes that underpin the interaction between symbiont and host. We discuss symbiont acquisition via phagocytosis, modulation of host innate immunity, symbiont integration into host cell metabolism, and nutrient exchange as a fundamental aspect of stable symbiotic associations. We emphasize the importance of using model systems to dissect the cellular complexity of endosymbiosis, which ultimately serves as the basis for understanding its ecology and capacity to adapt in the face of climate change.
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Affiliation(s)
- Marie R Jacobovitz
- Cell Biology and Biophysics, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Elizabeth A Hambleton
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria;
| | - Annika Guse
- Faculty of Biology, Ludwig-Maximilians-Universität Munich, Munich, Germany;
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8
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Matthews JL, Hoch L, Raina JB, Pablo M, Hughes DJ, Camp EF, Seymour JR, Ralph PJ, Suggett DJ, Herdean A. Symbiodiniaceae photophysiology and stress resilience is enhanced by microbial associations. Sci Rep 2023; 13:20724. [PMID: 38007500 PMCID: PMC10676399 DOI: 10.1038/s41598-023-48020-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 11/21/2023] [Indexed: 11/27/2023] Open
Abstract
Symbiodiniaceae form associations with extra- and intracellular bacterial symbionts, both in culture and in symbiosis with corals. Bacterial associates can regulate Symbiodiniaceae fitness in terms of growth, calcification and photophysiology. However, the influence of these bacteria on interactive stressors, such as temperature and light, which are known to influence Symbiodiniaceae physiology, remains unclear. Here, we examined the photophysiological response of two Symbiodiniaceae species (Symbiodinium microadriaticum and Breviolum minutum) cultured under acute temperature and light stress with specific bacterial partners from their microbiome (Labrenzia (Roseibium) alexandrii, Marinobacter adhaerens or Muricauda aquimarina). Overall, bacterial presence positively impacted Symbiodiniaceae core photosynthetic health (photosystem II [PSII] quantum yield) and photoprotective capacity (non-photochemical quenching; NPQ) compared to cultures with all extracellular bacteria removed, although specific benefits were variable across Symbiodiniaceae genera and growth phase. Symbiodiniaceae co-cultured with M. aquimarina displayed an inverse NPQ response under high temperatures and light, and those with L. alexandrii demonstrated a lowered threshold for induction of NPQ, potentially through the provision of antioxidant compounds such as zeaxanthin (produced by Muricauda spp.) and dimethylsulfoniopropionate (DMSP; produced by this strain of L. alexandrii). Our co-culture approach empirically demonstrates the benefits bacteria can deliver to Symbiodiniaceae photochemical performance, providing evidence that bacterial associates can play important functional roles for Symbiodiniaceae.
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Affiliation(s)
- Jennifer L Matthews
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia.
| | - Lilian Hoch
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Jean-Baptiste Raina
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Marine Pablo
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
- Sorbonne University, Paris, France
| | - David J Hughes
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
- Australian Institute of Marine Sciences, Townsville, QLD, Australia
| | - Emma F Camp
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Justin R Seymour
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - Peter J Ralph
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
| | - David J Suggett
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
- KAUST Reefscape Restoration Initiative (KRRI) and Red Sea Reseach Centre (RSRC), King Abdullah University of Science & Technology, 23955, Thuwal, Saudi Arabia
| | - Andrei Herdean
- Climate Change Cluster, University of Technology Sydney, Ultimo, NSW, Australia
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9
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Rädecker N, Escrig S, Spangenberg JE, Voolstra CR, Meibom A. Coupled carbon and nitrogen cycling regulates the cnidarian-algal symbiosis. Nat Commun 2023; 14:6948. [PMID: 37914705 PMCID: PMC10620199 DOI: 10.1038/s41467-023-42579-7] [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: 12/15/2022] [Accepted: 10/16/2023] [Indexed: 11/03/2023] Open
Abstract
Efficient nutrient recycling underpins the ecological success of cnidarian-algal symbioses in oligotrophic waters. In these symbioses, nitrogen limitation restricts the growth of algal endosymbionts in hospite and stimulates their release of photosynthates to the cnidarian host. However, the mechanisms controlling nitrogen availability and their role in symbiosis regulation remain poorly understood. Here, we studied the metabolic regulation of symbiotic nitrogen cycling in the sea anemone Aiptasia by experimentally altering labile carbon availability in a series of experiments. Combining 13C and 15N stable isotope labeling experiments with physiological analyses and NanoSIMS imaging, we show that the competition for environmental ammonium between the host and its algal symbionts is regulated by labile carbon availability. Light regimes optimal for algal photosynthesis increase carbon availability in the holobiont and stimulate nitrogen assimilation in the host metabolism. Consequently, algal symbiont densities are lowest under optimal environmental conditions and increase toward the lower and upper light tolerance limits of the symbiosis. This metabolic regulation promotes efficient carbon recycling in a stable symbiosis across a wide range of environmental conditions. Yet, the dependence on resource competition may favor parasitic interactions, explaining the instability of the cnidarian-algal symbiosis as environmental conditions in the Anthropocene shift towards its tolerance limits.
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Affiliation(s)
- Nils Rädecker
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | - Stéphane Escrig
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Jorge E Spangenberg
- Institute of Earth Surface Dynamics, University of Lausanne, Lausanne, Switzerland
| | | | - Anders Meibom
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Center for Advanced Surface Analysis, Institute of Earth Sciences, University of Lausanne, Lausanne, Switzerland
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10
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Speelman PE, Parger M, Schoepf V. Divergent recovery trajectories of intertidal and subtidal coral communities highlight habitat-specific recovery dynamics following bleaching in an extreme macrotidal reef environment. PeerJ 2023; 11:e15987. [PMID: 37727686 PMCID: PMC10506583 DOI: 10.7717/peerj.15987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 08/08/2023] [Indexed: 09/21/2023] Open
Abstract
Coral reefs face an uncertain future punctuated by recurring climate-induced disturbances. Understanding how reefs can recover from and reassemble after mass bleaching events is therefore important to predict their responses and persistence in a rapidly changing ocean. On naturally extreme reefs characterized by strong daily temperature variability, coral heat tolerance can vary significantly over small spatial gradients but it remains poorly understood how this impacts bleaching resilience and recovery dynamics, despite their importance as resilience hotspots and potential refugia. In the macrotidal Kimberley region in NW Australia, the 2016 global mass bleaching event had a strong habitat-specific impact on intertidal and subtidal coral communities at our study site: corals in the thermally variable intertidal bleached less severely and recovered within six months, while 68% of corals in the moderately variable subtidal died. We therefore conducted benthic surveys 3.5 years after the bleaching event to determine potential changes in benthic cover and coral community composition. In the subtidal, we documented substantial increases in algal cover and live coral cover had not fully recovered to pre-bleaching levels. Furthermore, the subtidal coral community shifted from being dominated by branching Acropora corals with a competitive life history strategy to opportunistic, weedy Pocillopora corals which likely has implications for the functioning and stress resilience of this novel coral community. In contrast, no shifts in algal and live coral cover or coral community composition occurred in the intertidal. These findings demonstrate that differences in coral heat tolerance across small spatial scales can have large consequences for bleaching resilience and that spatial patchiness in recovery trajectories and community reassembly after bleaching might be a common feature on thermally variable reefs. Our findings further confirm that reefs adapted to high daily temperature variability play a key role as resilience hotspots under current climate conditions, but their ability to do so may be limited under intensifying ocean warming.
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Affiliation(s)
- P. Elias Speelman
- Institute for Biodiversity and Ecosystem Dynamics, Dept. of Freshwater and Marine Ecology, University of Amsterdam, Amsterdam, The Netherlands
| | - Michael Parger
- UWA Ocean Institute, The University of Western Australia, Perth, WA, Australia
| | - Verena Schoepf
- Institute for Biodiversity and Ecosystem Dynamics, Dept. of Freshwater and Marine Ecology, University of Amsterdam, Amsterdam, The Netherlands
- UWA Ocean Institute, The University of Western Australia, Perth, WA, Australia
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11
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Contardi M, Fadda M, Isa V, Louis YD, Madaschi A, Vencato S, Montalbetti E, Bertolacci L, Ceseracciu L, Seveso D, Lavorano S, Galli P, Athanassiou A, Montano S. Biodegradable Zein-Based Biocomposite Films for Underwater Delivery of Curcumin Reduce Thermal Stress Effects in Corals. ACS APPLIED MATERIALS & INTERFACES 2023. [PMID: 37376819 PMCID: PMC10360034 DOI: 10.1021/acsami.3c01166] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
Massive coral bleaching episodes induced by thermal stress are one of the first causes of coral death worldwide. Overproduction of reactive oxygen species (ROS) has been identified as one of the potential causes of symbiosis breakdown between polyps and algae in corals during extreme heat wave events. Here, we propose a new strategy for mitigating heat effects by delivering underwater an antioxidant to the corals. We fabricated zein/polyvinylpyrrolidone (PVP)-based biocomposite films laden with the strong and natural antioxidant curcumin as an advanced coral bleaching remediation tool. Biocomposites' mechanical, water contact angle (WCA), swelling, and release properties can be tuned thanks to different supramolecular rearrangements that occur by varying the zein/PVP weight ratio. Following immersion in seawater, the biocomposites became soft hydrogels that did not affect the coral's health in the short (24 h) and long periods (15 days). Laboratory bleaching experiments at 29 and 33 °C showed that coral colonies of Stylophora pistillata coated with the biocomposites had ameliorated conditions in terms of morphological aspects, chlorophyll content, and enzymatic activity compared to untreated colonies and did not bleach. Finally, biochemical oxygen demand (BOD) confirmed the full biodegradability of the biocomposites, showing a low potential environmental impact in the case of open-field application. These insights may pave the way for new frontiers in mitigating extreme coral bleaching events by combining natural antioxidants and biocomposites.
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Affiliation(s)
- Marco Contardi
- Department of Earth and Environmental Sciences (DISAT), University of Milan - Bicocca, Milan 20126, Italy
- MaRHE Center (Marine Research and High Education Center), Magoodhoo Island, Faafu Atoll 12030, Republic of Maldives
| | - Marta Fadda
- Smart Materials, Istituto Italiano di Tecnologia, Genova 16163, Italy
| | - Valerio Isa
- Department of Earth and Environmental Sciences (DISAT), University of Milan - Bicocca, Milan 20126, Italy
- MaRHE Center (Marine Research and High Education Center), Magoodhoo Island, Faafu Atoll 12030, Republic of Maldives
| | - Yohan D Louis
- Department of Earth and Environmental Sciences (DISAT), University of Milan - Bicocca, Milan 20126, Italy
- MaRHE Center (Marine Research and High Education Center), Magoodhoo Island, Faafu Atoll 12030, Republic of Maldives
| | - Andrea Madaschi
- Department of Earth and Environmental Sciences (DISAT), University of Milan - Bicocca, Milan 20126, Italy
- MaRHE Center (Marine Research and High Education Center), Magoodhoo Island, Faafu Atoll 12030, Republic of Maldives
| | - Sara Vencato
- Department of Earth and Environmental Sciences (DISAT), University of Milan - Bicocca, Milan 20126, Italy
- MaRHE Center (Marine Research and High Education Center), Magoodhoo Island, Faafu Atoll 12030, Republic of Maldives
| | - Enrico Montalbetti
- Department of Earth and Environmental Sciences (DISAT), University of Milan - Bicocca, Milan 20126, Italy
- MaRHE Center (Marine Research and High Education Center), Magoodhoo Island, Faafu Atoll 12030, Republic of Maldives
| | - Laura Bertolacci
- Smart Materials, Istituto Italiano di Tecnologia, Genova 16163, Italy
| | - Luca Ceseracciu
- Materials Characterization Facility, Istituto Italiano di Tecnologia, Genova 16163, Italy
| | - Davide Seveso
- Department of Earth and Environmental Sciences (DISAT), University of Milan - Bicocca, Milan 20126, Italy
- MaRHE Center (Marine Research and High Education Center), Magoodhoo Island, Faafu Atoll 12030, Republic of Maldives
| | - Silvia Lavorano
- Costa Edutainment SpA - Acquario di Genova, Genova 16128, Italy
| | - Paolo Galli
- Department of Earth and Environmental Sciences (DISAT), University of Milan - Bicocca, Milan 20126, Italy
- MaRHE Center (Marine Research and High Education Center), Magoodhoo Island, Faafu Atoll 12030, Republic of Maldives
- Dubai Business School, University of Dubai, Dubai 14143, United Arab Emirates
| | | | - Simone Montano
- Department of Earth and Environmental Sciences (DISAT), University of Milan - Bicocca, Milan 20126, Italy
- MaRHE Center (Marine Research and High Education Center), Magoodhoo Island, Faafu Atoll 12030, Republic of Maldives
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12
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McRae CJ, Keshavmurthy S, Chen HK, Ye ZM, Meng PJ, Rosset SL, Huang WB, Chen CA, Fan TY, Côté IM. Baseline dynamics of Symbiodiniaceae genera and photochemical efficiency in corals from reefs with different thermal histories. PeerJ 2023; 11:e15421. [PMID: 37283898 PMCID: PMC10239617 DOI: 10.7717/peerj.15421] [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: 12/02/2022] [Accepted: 04/25/2023] [Indexed: 06/08/2023] Open
Abstract
Ocean warming and marine heatwaves induced by climate change are impacting coral reefs globally, leading to coral bleaching and mortality. Yet, coral resistance and resilience to warming are not uniform across reef sites and corals can show inter- and intraspecific variability. To understand changes in coral health and to elucidate mechanisms of coral thermal tolerance, baseline data on the dynamics of coral holobiont performance under non-stressed conditions are needed. We monitored the seasonal dynamics of algal symbionts (family Symbiodiniaceae) hosted by corals from a chronically warmed and thermally variable reef compared to a thermally stable reef in southern Taiwan over 15 months. We assessed the genera and photochemical efficiency of Symbiodiniaceae in three coral species: Acropora nana, Pocillopora acuta, and Porites lutea. Both Durusdinium and Cladocopium were present in all coral species at both reef sites across all seasons, but general trends in their detection (based on qPCR cycle) varied between sites and among species. Photochemical efficiency (i.e., maximum quantum yield; Fv/Fm) was relatively similar between reef sites but differed consistently among species; no clear evidence of seasonal trends in Fv/Fm was found. Quantifying natural Symbiodiniaceae dynamics can help facilitate a more comprehensive interpretation of thermal tolerance response as well as plasticity potential of the coral holobiont.
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Affiliation(s)
- Crystal J McRae
- Department of Planning and Research, National Museum of Marine Biology & Aquarium, Checheng, Pingtung, Taiwan
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | | | - Hung-Kai Chen
- Department of Planning and Research, National Museum of Marine Biology & Aquarium, Checheng, Pingtung, Taiwan
| | - Zong-Min Ye
- Department of Planning and Research, National Museum of Marine Biology & Aquarium, Checheng, Pingtung, Taiwan
| | - Pei-Jie Meng
- Department of Planning and Research, National Museum of Marine Biology & Aquarium, Checheng, Pingtung, Taiwan
- Graduate Institute of Marine Biology, National Dong Hwa University, Checheng, Pingtung, Taiwan
| | - Sabrina L Rosset
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Wen-Bin Huang
- Department of Natural Resources and Environmental Studies, National Dong Hwa University, Shoufeng, Hualien, Taiwan
| | | | - Tung-Yung Fan
- Department of Planning and Research, National Museum of Marine Biology & Aquarium, Checheng, Pingtung, Taiwan
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Isabelle M Côté
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
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13
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Beavers KM, Van Buren EW, Rossin AM, Emery MA, Veglia AJ, Karrick CE, MacKnight NJ, Dimos BA, Meiling SS, Smith TB, Apprill A, Muller EM, Holstein DM, Correa AMS, Brandt ME, Mydlarz LD. Stony coral tissue loss disease induces transcriptional signatures of in situ degradation of dysfunctional Symbiodiniaceae. Nat Commun 2023; 14:2915. [PMID: 37217477 DOI: 10.1038/s41467-023-38612-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 05/10/2023] [Indexed: 05/24/2023] Open
Abstract
Stony coral tissue loss disease (SCTLD), one of the most pervasive and virulent coral diseases on record, affects over 22 species of reef-building coral and is decimating reefs throughout the Caribbean. To understand how different coral species and their algal symbionts (family Symbiodiniaceae) respond to this disease, we examine the gene expression profiles of colonies of five species of coral from a SCTLD transmission experiment. The included species vary in their purported susceptibilities to SCTLD, and we use this to inform gene expression analyses of both the coral animal and their Symbiodiniaceae. We identify orthologous coral genes exhibiting lineage-specific differences in expression that correlate to disease susceptibility, as well as genes that are differentially expressed in all coral species in response to SCTLD infection. We find that SCTLD infection induces increased expression of rab7, an established marker of in situ degradation of dysfunctional Symbiodiniaceae, in all coral species accompanied by genus-level shifts in Symbiodiniaceae photosystem and metabolism gene expression. Overall, our results indicate that SCTLD infection induces symbiophagy across coral species and that the severity of disease is influenced by Symbiodiniaceae identity.
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Affiliation(s)
- Kelsey M Beavers
- Biology Department, University of Texas at Arlington, Arlington, TX, USA
| | - Emily W Van Buren
- Biology Department, University of Texas at Arlington, Arlington, TX, USA
| | - Ashley M Rossin
- Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Madison A Emery
- Biology Department, University of Texas at Arlington, Arlington, TX, USA
| | - Alex J Veglia
- Department of BioSciences, Rice University, Houston, TX, USA
| | - Carly E Karrick
- Department of BioSciences, Rice University, Houston, TX, USA
| | | | - Bradford A Dimos
- Biology Department, University of Texas at Arlington, Arlington, TX, USA
| | - Sonora S Meiling
- Center for Marine and Environmental Studies, University of the Virgin Islands, St. Thomas, USVI, USA
| | - Tyler B Smith
- Center for Marine and Environmental Studies, University of the Virgin Islands, St. Thomas, USVI, USA
| | - Amy Apprill
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | | | - Daniel M Holstein
- Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA, USA
| | | | - Marilyn E Brandt
- Center for Marine and Environmental Studies, University of the Virgin Islands, St. Thomas, USVI, USA
| | - Laura D Mydlarz
- Biology Department, University of Texas at Arlington, Arlington, TX, USA.
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14
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Doering T, Maire J, van Oppen MJH, Blackall LL. Advancing coral microbiome manipulation to build long-term climate resilience. MICROBIOLOGY AUSTRALIA 2023. [DOI: 10.1071/ma23009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023] Open
Abstract
Coral reefs house one-third of all marine species and are of high cultural and socioeconomic importance. However, coral reefs are under dire threat from climate change and other anthropogenic stressors. Climate change is causing coral bleaching, the breakdown of the symbiosis between the coral host and its algal symbionts, often resulting in coral mortality and the deterioration of these valuable ecosystems. While it is essential to counteract the root causes of climate change, it remains urgent to develop coral restoration and conservation methods that will buy time for coral reefs. The manipulation of the bacterial microbiome that is associated with corals has been suggested as one intervention to improve coral climate resilience. Early coral microbiome-manipulation studies, which are aimed at enhancing bleaching tolerance, have shown promising results, but the inoculated bacteria did generally not persist within the coral microbiome. Here, we highlight the importance of long-term incorporation of bacterial inocula into the microbiome of target corals, as repeated inoculations will be too costly and not feasible on large reef systems like the Great Barrier Reef. Therefore, coral microbiome-manipulation studies need to prioritise approaches that can provide sustained coral climate resilience.
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15
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Hernández Elizárraga VH, Olguín-López N, Hernández-Matehuala R, Caballero-Pérez J, Ibarra-Alvarado C, Rojas-Molina A. Transcriptomic differences between bleached and unbleached hydrozoan Millepora complanata following the 2015-2016 ENSO in the Mexican Caribbean. PeerJ 2023; 11:e14626. [PMID: 36691486 PMCID: PMC9864129 DOI: 10.7717/peerj.14626] [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: 04/27/2022] [Accepted: 12/02/2022] [Indexed: 01/19/2023] Open
Abstract
The 2015-2016 El Niño-southern oscillation or "ENSO" caused many M. complanata colonies that live in the Mexican Caribbean to experience extensive bleaching. The purpose of this work was to analyze the effect of bleaching on the cellular response of M. complanata, employing a transcriptomic approach with RNA-seq. As expected, bleached specimens contained a significantly lower chlorophyll content than unbleached hydrocorals. The presence of algae of the genera Durusdinium and Cladocopium was only found in tissues of unbleached M. complanata, which could be associated to the greater resistance that these colonies exhibited during bleaching. We found that 299 genes were differentially expressed in M. complanata bleached colonies following the 2015-2016 ENSO in the Mexican Caribbean. The differential expression analysis of bleached M. complanata specimens evidenced enriched terms for functional categories, such as ribosome, RNA polymerase and basal transcription factors, chaperone, oxidoreductase, among others. Our results suggest that the heat-shock response mechanisms displayed by M. complanata include: an up-regulation of endogenous antioxidant defenses; a higher expression of heat stress response genes; up-regulation of transcription-related genes, higher expression of genes associated to transport processes, inter alia. This study constitutes the first differential gene expression analysis of the molecular response of a reef-forming hydrozoan during bleaching.
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Affiliation(s)
| | - Norma Olguín-López
- Posgrado en Ciencias Químico Biológicas, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, México
| | - Rosalina Hernández-Matehuala
- Posgrado en Ciencias Químico Biológicas, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, México
| | | | - César Ibarra-Alvarado
- Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, México
| | - Alejandra Rojas-Molina
- Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, México
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16
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Evaluation of fluorescence-based viability stains in cells dissociated from scleractinian coral Pocillopora damicornis. Sci Rep 2022; 12:15297. [PMID: 36097278 PMCID: PMC9468155 DOI: 10.1038/s41598-022-19586-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Accepted: 08/31/2022] [Indexed: 11/09/2022] Open
Abstract
The application of established cell viability assays such as the commonly used trypan blue staining method to coral cells is not straightforward due to different culture parameters and different cellular features specific to mammalian cells compared to marine invertebrates. Using Pocillopora damicornis as a model, we characterized the autofluorescence and tested different fluorescent dye pair combinations to identify alternative viability indicators. The cytotoxicity of different representative molecules, namely small organic molecules, proteins and nanoparticles (NP), was measured after 24 h of exposure using the fluorescent dye pair Hoechst 33342 and SYTOX orange. Our results show that this dye pair can be distinctly measured in the presence of fluorescent proteins plus chlorophyll. P. damicornis cells exposed for 24 h to Triton-X100, insulin or titanium dioxide (TiO2) NPs, respectively, at concentrations ranging from 0.5 to 100 µg/mL, revealed a LC50 of 0.46 µg/mL for Triton-X100, 6.21 µg/mL for TiO2 NPs and 33.9 µg/mL for insulin. This work presents the approach used to customize dye pairs for membrane integrity-based cell viability assays considering the species- and genotype-specific autofluorescence of scleractinian corals, namely: endogenous fluorescence characterization followed by the selection of dyes that do not overlap with endogenous signals.
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17
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Winston M, Oliver T, Couch C, Donovan MK, Asner GP, Conklin E, Fuller K, Grady BW, Huntington B, Kageyama K, Kindinger TL, Kozar K, Kramer L, Martinez T, McCutcheon A, McKenna S, Rodgers K, Shayler CK, Vargas-Angel B, Zgliczynski B. Coral taxonomy and local stressors drive bleaching prevalence across the Hawaiian Archipelago in 2019. PLoS One 2022; 17:e0269068. [PMID: 36048764 PMCID: PMC9436070 DOI: 10.1371/journal.pone.0269068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 05/13/2022] [Indexed: 11/18/2022] Open
Abstract
The Hawaiian Archipelago experienced a moderate bleaching event in 2019—the third major bleaching event over a 6-year period to impact the islands. In response, the Hawai‘i Coral Bleaching Collaborative (HCBC) conducted 2,177 coral bleaching surveys across the Hawaiian Archipelago. The HCBC was established to coordinate bleaching monitoring efforts across the state between academic institutions, non-governmental organizations, and governmental agencies to facilitate data sharing and provide management recommendations. In 2019, the goals of this unique partnership were to: 1) assess the spatial and temporal patterns of thermal stress; 2) examine taxa-level patterns in bleaching susceptibility; 3) quantify spatial variation in bleaching extent; 4) compare 2019 patterns to those of prior bleaching events; 5) identify predictors of bleaching in 2019; and 6) explore site-specific management strategies to mitigate future bleaching events. Both acute thermal stress and bleaching in 2019 were less severe overall compared to the last major marine heatwave events in 2014 and 2015. Bleaching observed was highly site- and taxon-specific, driven by the susceptibility of remaining coral assemblages whose structure was likely shaped by previous bleaching and subsequent mortality. A suite of environmental and anthropogenic predictors was significantly correlated with observed bleaching in 2019. Acute environmental stressors, such as temperature and surface light, were equally important as previous conditions (e.g. historical thermal stress and historical bleaching) in accounting for variation in bleaching during the 2019 event. We found little evidence for acclimation by reefs to thermal stress in the main Hawaiian Islands. Moreover, our findings illustrate how detrimental effects of local anthropogenic stressors, such as tourism and urban run-off, may be exacerbated under high thermal stress. In light of the forecasted increase in severity and frequency of bleaching events, future mitigation of both local and global stressors is a high priority for the future of corals in Hawai‘i.
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Affiliation(s)
- Morgan Winston
- Cooperative Institute for Marine and Atmospheric Research, University of Hawai‘i, Honolulu, Hawai‘i, United States of America
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, Honolulu, Hawai‘i, United States of America
- Center for Global Discovery and Conservation Science and School of Geographic Sciences and Urban Planning, Arizona State University, Hilo, Hawai‘i, United States of America
- * E-mail:
| | - Thomas Oliver
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, Honolulu, Hawai‘i, United States of America
| | - Courtney Couch
- Cooperative Institute for Marine and Atmospheric Research, University of Hawai‘i, Honolulu, Hawai‘i, United States of America
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, Honolulu, Hawai‘i, United States of America
| | - Mary K. Donovan
- Center for Global Discovery and Conservation Science and School of Geographic Sciences and Urban Planning, Arizona State University, Hilo, Hawai‘i, United States of America
| | - Gregory P. Asner
- Center for Global Discovery and Conservation Science and School of Geographic Sciences and Urban Planning, Arizona State University, Hilo, Hawai‘i, United States of America
| | - Eric Conklin
- The Nature Conservancy, Honolulu, Hawai‘i, United States of America
| | - Kimberly Fuller
- Division of Aquatic Resources (O‘ahu), Anuenue Fisheries Research Center, Honolulu, Hawai‘i, United States of America
| | - Bryant W. Grady
- Center for Global Discovery and Conservation Science and School of Geographic Sciences and Urban Planning, Arizona State University, Hilo, Hawai‘i, United States of America
| | - Brittany Huntington
- Cooperative Institute for Marine and Atmospheric Research, University of Hawai‘i, Honolulu, Hawai‘i, United States of America
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, Honolulu, Hawai‘i, United States of America
| | - Kazuki Kageyama
- Division of Aquatic Resources (O‘ahu), Anuenue Fisheries Research Center, Honolulu, Hawai‘i, United States of America
| | - Tye L. Kindinger
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, Honolulu, Hawai‘i, United States of America
| | - Kelly Kozar
- Pacific Island Network Inventory and Monitoring Program, Hawai‘i National Park, Hawai‘i, United States of America
| | - Lindsey Kramer
- Division of Aquatic Resources (Kona), Kailua-Kona, Hawai‘i, United States of America
| | - Tatiana Martinez
- Division of Aquatic Resources (Maui), Wailuku, Hawai‘i, United States of America
| | - Amanda McCutcheon
- Pacific Island Network Inventory and Monitoring Program, Hawai‘i National Park, Hawai‘i, United States of America
| | - Sheila McKenna
- Pacific Island Network Inventory and Monitoring Program, Hawai‘i National Park, Hawai‘i, United States of America
| | - Ku‘ulei Rodgers
- Hawai‘i Institute of Marine Biology, Kāne‘ohe, Hawai‘i, United States of America
| | | | - Bernardo Vargas-Angel
- Cooperative Institute for Marine and Atmospheric Research, University of Hawai‘i, Honolulu, Hawai‘i, United States of America
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, Honolulu, Hawai‘i, United States of America
| | - Brian Zgliczynski
- Scripps Institution of Oceanography, La Jolla, California, United States of America
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18
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Heat Stress of Algal Partner Hinders Colonization Success and Alters the Algal Cell Surface Glycome in a Cnidarian-Algal Symbiosis. Microbiol Spectr 2022; 10:e0156722. [PMID: 35639004 PMCID: PMC9241721 DOI: 10.1128/spectrum.01567-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Corals owe their ecological success to their symbiotic relationship with dinoflagellate algae (family Symbiodiniaceae). While the negative effects of heat stress on this symbiosis are well studied, how heat stress affects the onset of symbiosis and symbiont specificity is less explored. In this work, we used the model sea anemone, Exaiptasia diaphana (commonly referred to as Aiptasia), and its native symbiont, Breviolum minutum, to study the effects of heat stress on the colonization of Aiptasia by algae and the algal cell-surface glycome. Heat stress caused a decrease in the colonization of Aiptasia by algae that were not due to confounding variables such as algal motility or oxidative stress. With mass spectrometric analysis and lectin staining, a thermally induced enrichment of glycans previously found to be associated with free-living strains of algae (high-mannoside glycans) and a concomitant reduction in glycans putatively associated with symbiotic strains of algae (galactosylated glycans) were identified. Differential enrichment of specific sialic acid glycans was also identified, although their role in this symbiosis remains unclear. We also discuss the methods used to analyze the cell-surface glycome of algae, evaluate current limitations, and provide suggestions for future work in algal-coral glycobiology. Overall, this study provided insight into how stress may affect the symbiosis between cnidarians and their algal symbionts by altering the glycome of the symbiodinian partner. IMPORTANCE Coral reefs are under threat from global climate change. Their decline is mainly caused by the fragility of their symbiotic relationship with dinoflagellate algae which they rely upon for their ecological success. To better understand coral biology, researchers used the sea anemone, Aiptasia, a model system for the study of coral-algal symbiosis, and characterized how heat stress can alter the algae's ability to communicate to the coral host. This study found that heat stress caused a decline in algal colonization success and impacted the cell surface molecules of the algae such that it became more like that of nonsymbiotic species of algae. This work adds to our understanding of the molecular signals involved in coral-algal symbiosis and how it breaks down during heat stress.
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19
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Jury CP, Boeing BM, Trapido-Rosenthal H, Gates RD, Toonen RJ. Nitric oxide production rather than oxidative stress and cell death is associated with the onset of coral bleaching in Pocillopora acuta. PeerJ 2022; 10:e13321. [PMID: 35669951 PMCID: PMC9166681 DOI: 10.7717/peerj.13321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 04/01/2022] [Indexed: 01/13/2023] Open
Abstract
Elevated seawater temperatures associated with climate change lead to coral bleaching. While the ultimate causes of bleaching are well understood, the proximate physiological mechanisms underlying the bleaching response are not as well defined. Here we measured nitric oxide synthase activity, oxidative stress, and cell death in algal symbionts (Symbiodinaceae) freshly isolated from the reef-building coral Pocillopora acuta collected in the field under natural non-bleaching conditions and from corals experimentally exposed to elevated temperatures. Nitric oxide synthase activity in the algal symbionts was >3 orders of magnitude higher than that of the host and increased dramatically with increasing temperature and time of exposure (up to 72 h), consistent with the onset of bleaching for these corals. Oxidative stress and cell death among the algal symbionts were highest in coral holobionts exposed to intermediate as opposed to maximal temperatures, suggesting that these mechanisms are not proximal triggers for bleaching in this species. Our results point to nitric oxide production by the algal symbionts, rather than symbiont dysfunction, as a more important driver of coral bleaching under acute thermal stress in this coral.
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Affiliation(s)
| | - Brian M. Boeing
- Hawaiʻi Institute of Marine Biology, Kāneʻohe, HI, United States
| | | | - Ruth D. Gates
- Hawaiʻi Institute of Marine Biology, Kāneʻohe, HI, United States
| | - Robert J. Toonen
- Hawaiʻi Institute of Marine Biology, Kāneʻohe, HI, United States
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20
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Abstract
Recent human activity has profoundly transformed Earth biomes on a scale and at rates that are unprecedented. Given the central role of symbioses in ecosystem processes, functions, and services throughout the Earth biosphere, the impacts of human-driven change on symbioses are critical to understand. Symbioses are not merely collections of organisms, but co-evolved partners that arise from the synergistic combination and action of different genetic programs. They function with varying degrees of permanence and selection as emergent units with substantial potential for combinatorial and evolutionary innovation in both structure and function. Following an articulation of operational definitions of symbiosis and related concepts and characteristics of the Anthropocene, we outline a basic typology of anthropogenic change (AC) and a conceptual framework for how AC might mechanistically impact symbioses with select case examples to highlight our perspective. We discuss surprising connections between symbiosis and the Anthropocene, suggesting ways in which new symbioses could arise due to AC, how symbioses could be agents of ecosystem change, and how symbioses, broadly defined, of humans and “farmed” organisms may have launched the Anthropocene. We conclude with reflections on the robustness of symbioses to AC and our perspective on the importance of symbioses as ecosystem keystones and the need to tackle anthropogenic challenges as wise and humble stewards embedded within the system.
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Affiliation(s)
- Erik F Y Hom
- Department of Biology and Center for Biodiversity and Conservation Research, University of Mississippi, University, MS 38677 USA
| | - Alexandra S Penn
- Department of Sociology and Centre for Evaluation of Complexity Across the Nexus, University of Surrey, Guildford, Surrey, GU2 7XH UK
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21
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Ishibashi H, Takaichi D, Takeuchi I. Effects of the herbicide Irgarol 1051 on the transcriptome of hermatypic coral Acropora tenuis and its symbiotic dinoflagellates. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 780:146542. [PMID: 34030298 DOI: 10.1016/j.scitotenv.2021.146542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/09/2021] [Accepted: 03/13/2021] [Indexed: 06/12/2023]
Abstract
Coral reefs face multiple threats, including climate change, agricultural runoff, shipping activities, coastal development, and chemical pollutants. Irgarol 1051, a PSII herbicide, has been used as an antifouling booster since the previously used antibiofouling agent tributyltin (TBT) was banned worldwide. Although the mechanisms through which elevated temperatures cause coral bleaching have been reported, it remains unclear how PSII herbicides cause bleaching. Thus, in this study, we investigated the transcriptomes of Acropora tenuis and its symbiotic dinoflagellates by RNA-sequencing (RNA-Seq) to elucidate the molecular mechanisms underlying Irgarol-induced bleaching. Coral exposure to 10 μg/L Irgarol for 7 d affected coral body colour, specifically by an increase in their red, green, and blue (RGB) values; however, no such effect was observed in corals exposed to 1 μg/L Irgarol. RNA-Seq revealed the differentially expressed genes (DEGs) in corals and symbiotic dinoflagellates following Irgarol exposure. Coral DEGs encoded green fluorescent protein, blue-light-sensing photoreceptor (cryptochrome), chromoprotein, caspase 8, and nuclear receptors; DEGs in symbiotic dinoflagellates encoded light-harvesting proteins, photosystem II proteins, and heat shock proteins (i.e. HSP70 and HSP90), and ubiquitin. Bioinformatic analyses revealed that both Irgarol treatments disrupted various gene ontology terms, pathways, and protein interaction networks; these are different in corals (e.g. oxidative phosphorylation, metabolic pathway, transforming growth factor-β signalling pathway, adherens junction, and apoptosis) and symbiotic dinoflagellates (e.g. protein processing in endoplasmic reticulum, carbon fixation in photosynthetic organisms, metabolic pathway, and photosynthesis). Our data suggest that Irgarol disrupts the expression of various coral genes, thereby affecting various gene ontology terms, pathways, and protein interaction networks. Our study provides new insights into the potential molecular mechanisms underlying the bleaching effect of PSII herbicides, such as Irgarol, on corals and symbiotic dinoflagellates.
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Affiliation(s)
- Hiroshi Ishibashi
- The United Graduate School of Agricultural Sciences, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan; Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan; Center of Advanced Technology for the Environment (CATE), Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan
| | - Daisuke Takaichi
- The United Graduate School of Agricultural Sciences, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan
| | - Ichiro Takeuchi
- The United Graduate School of Agricultural Sciences, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan; Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan; Center of Advanced Technology for the Environment (CATE), Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan.
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22
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Majerova E, Carey FC, Drury C, Gates RD. Preconditioning improves bleaching tolerance in the reef-building coral Pocillopora acuta through modulations in the programmed cell death pathways. Mol Ecol 2021; 30:3560-3574. [PMID: 34008873 DOI: 10.1111/mec.15988] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/07/2021] [Accepted: 05/10/2021] [Indexed: 12/25/2022]
Abstract
Reef-building corals rely on intracellular algal symbionts to meet energetic demands. Increasing extreme weather driven by climate change often leads to disruption of this symbiosis and to coral death. Corals can better withstand stress after previous exposure to sublethal conditions, but the mechanisms for this resilience remain unclear. Here, we show that a three-day thermal preconditioning increases tolerance of acute heat stress through modulations in cell death pathways in the stony coral Pocillopora acuta. In preconditioned corals, the ratio of pro-survival (pa-Bcl-2 and pa-BI-1) to pro-death (pa-BAK and pa-BAX) gene expression increased and the corals underwent significantly less bleaching. When treated with Bcl-2 inhibitor, corals lost the improved thermal tolerance, suggesting an important role of programmed cell death in coral bleaching and acclimatization. During heat stress, the activity of acid phosphatase increased but caspase-3 did not, suggesting the involvement of autophagy/symbiophagy rather than apoptosis in this process. A similar shift in gene expression also occurs in thermally stressed corals that have been exposed to naturally higher temperatures during summer thermal maxima in Kāne'ohe Bay, Hawai'i, suggesting that corals can increase their resilience to realistic warming events during high-risk periods through alterations in cell signalling. These data suggest that programmed cell death pathways underly coral acclimatization and resilience and may be important for coral reef conservation and management.
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Affiliation(s)
- Eva Majerova
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA
| | - Fiona C Carey
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA
| | - Crawford Drury
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA
| | - Ruth D Gates
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA
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23
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Innis T, Allen-Waller L, Brown KT, Sparagon W, Carlson C, Kruse E, Huffmyer AS, Nelson CE, Putnam HM, Barott KL. Marine heatwaves depress metabolic activity and impair cellular acid-base homeostasis in reef-building corals regardless of bleaching susceptibility. GLOBAL CHANGE BIOLOGY 2021; 27:2728-2743. [PMID: 33784420 DOI: 10.1111/gcb.15622] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/18/2021] [Accepted: 03/21/2021] [Indexed: 06/12/2023]
Abstract
Ocean warming is causing global coral bleaching events to increase in frequency, resulting in widespread coral mortality and disrupting the function of coral reef ecosystems. However, even during mass bleaching events, many corals resist bleaching despite exposure to abnormally high temperatures. While the physiological effects of bleaching have been well documented, the consequences of heat stress for bleaching-resistant individuals are not well understood. In addition, much remains to be learned about how heat stress affects cellular-level processes that may be overlooked at the organismal level, yet are crucial for coral performance in the short term and ecological success over the long term. Here we compared the physiological and cellular responses of bleaching-resistant and bleaching-susceptible corals throughout the 2019 marine heatwave in Hawai'i, a repeat bleaching event that occurred 4 years after the previous regional event. Relative bleaching susceptibility within species was consistent between the two bleaching events, yet corals of both resistant and susceptible phenotypes exhibited pronounced metabolic depression during the heatwave. At the cellular level, bleaching-susceptible corals had lower intracellular pH than bleaching-resistant corals at the peak of bleaching for both symbiont-hosting and symbiont-free cells, indicating greater disruption of acid-base homeostasis in bleaching-susceptible individuals. Notably, cells from both phenotypes were unable to compensate for experimentally induced cellular acidosis, indicating that acid-base regulation was significantly impaired at the cellular level even in bleaching-resistant corals and in cells containing symbionts. Thermal disturbances may thus have substantial ecological consequences, as even small reallocations in energy budgets to maintain homeostasis during stress can negatively affect fitness. These results suggest concern is warranted for corals coping with ocean acidification alongside ocean warming, as the feedback between temperature stress and acid-base regulation may further exacerbate the physiological effects of climate change.
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Affiliation(s)
- Teegan Innis
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Kristen T Brown
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
- ARC Centre of Excellence for Coral Reef Studies and School of Biological Sciences, University of Queensland, St. Lucia, Qld, Australia
| | - Wesley Sparagon
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, Department of Oceanography and Sea Grant College Program, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | | | - Elisa Kruse
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ariana S Huffmyer
- Department of Biological Sciences, University of Rhode Island, Kingston, RI, USA
| | - Craig E Nelson
- Daniel K. Inouye Center for Microbial Oceanography: Research and Education, Department of Oceanography and Sea Grant College Program, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Hollie M Putnam
- Department of Biological Sciences, University of Rhode Island, Kingston, RI, USA
| | - Katie L Barott
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
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24
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Coral bleaching response is unaltered following acclimatization to reefs with distinct environmental conditions. Proc Natl Acad Sci U S A 2021; 118:2025435118. [PMID: 34050025 PMCID: PMC8179235 DOI: 10.1073/pnas.2025435118] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Ocean warming has caused catastrophic losses of corals on reefs worldwide and is intensifying faster than the adaptive rate of most coral populations that remain. Human interventions, such as propagation of heat-resistant corals, may help maintain reef function and delay further devastation of these valuable ecosystems as society confronts the climate crisis. However, exposing adult corals to a complex suite of new environmental conditions could lead to tradeoffs that alter their heat stress responses, and empirical data are needed to test the utility of this approach. Here, we show that corals transplanted to novel reef conditions did not exhibit changes in their heat stress response or negative fitness tradeoffs, supporting the inclusion of this approach in our management arsenal. Urgent action is needed to prevent the demise of coral reefs as the climate crisis leads to an increasingly warmer and more acidic ocean. Propagating climate change–resistant corals to restore degraded reefs is one promising strategy; however, empirical evidence is needed to determine whether stress resistance is affected by transplantation beyond a coral’s native reef. Here, we assessed the performance of bleaching-resistant individuals of two coral species following reciprocal transplantation between reefs with distinct pH, salinity, dissolved oxygen, sedimentation, and flow dynamics to determine whether heat stress response is altered following coral exposure to novel physicochemical conditions in situ. Critically, transplantation had no influence on coral heat stress responses, indicating that this trait was relatively fixed. In contrast, growth was highly plastic, and native performance was not predictive of performance in the novel environment. Coral metabolic rates and overall fitness were higher at the reef with higher flow, salinity, sedimentation, and diel fluctuations of pH and dissolved oxygen, and did not differ between native and cross-transplanted corals, indicating acclimatization via plasticity within just 3 mo. Conversely, cross-transplants at the second reef had higher fitness than native corals, thus increasing the fitness potential of the recipient population. This experiment was conducted during a nonbleaching year, so the potential benefits to recipient population fitness are likely enhanced during bleaching years. In summary, this study demonstrates that outplanting bleaching-resistant corals is a promising tool for elevating the resistance of coral populations to ocean warming.
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25
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Putnam HM. Avenues of reef-building coral acclimatization in response to rapid environmental change. J Exp Biol 2021; 224:224/Suppl_1/jeb239319. [DOI: 10.1242/jeb.239319] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
ABSTRACT
The swiftly changing climate presents a challenge to organismal fitness by creating a mismatch between the current environment and phenotypes adapted to historic conditions. Acclimatory mechanisms may be especially crucial for sessile benthic marine taxa, such as reef-building corals, where climate change factors including ocean acidification and increasing temperature elicit strong negative physiological responses such as bleaching, disease and mortality. Here, within the context of multiple stressors threatening marine organisms, I describe the wealth of metaorganism response mechanisms to rapid ocean change and the ontogenetic shifts in organism interactions with the environment that can generate plasticity. I then highlight the need to consider the interactions of rapid and evolutionary responses in an adaptive (epi)genetic continuum. Building on the definitions of these mechanisms and continuum, I also present how the interplay of the microbiome, epigenetics and parental effects creates additional avenues for rapid acclimatization. To consider under what conditions epigenetic inheritance has a more substantial role, I propose investigation into the offset of timing of gametogenesis leading to different environmental integration times between eggs and sperm and the consequences of this for gamete epigenetic compatibility. Collectively, non-genetic, yet heritable phenotypic plasticity will have significant ecological and evolutionary implications for sessile marine organism persistence under rapid climate change. As such, reef-building corals present ideal and time-sensitive models for further development of our understanding of adaptive feedback loops in a multi-player (epi)genetic continuum.
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Affiliation(s)
- Hollie M. Putnam
- Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA
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26
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Peixoto RS, Sweet M, Villela HDM, Cardoso P, Thomas T, Voolstra CR, Høj L, Bourne DG. Coral Probiotics: Premise, Promise, Prospects. Annu Rev Anim Biosci 2020; 9:265-288. [PMID: 33321044 DOI: 10.1146/annurev-animal-090120-115444] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The use of Beneficial Microorganisms for Corals (BMCs) has been proposed recently as a tool for the improvement of coral health, with knowledge in this research topic advancing rapidly. BMCs are defined as consortia of microorganisms that contribute to coral health through mechanisms that include (a) promoting coral nutrition and growth, (b) mitigating stress and impacts of toxic compounds, (c) deterring pathogens, and (d) benefiting early life-stage development. Here, we review the current proposed BMC approach and outline the studies that have proven its potential to increase coral resilience to stress. We revisit and expand the list of putative beneficial microorganisms associated with corals and their proposed mechanismsthat facilitate improved host performance. Further, we discuss the caveats and bottlenecks affecting the efficacy of BMCs and close by focusing on the next steps to facilitate application at larger scales that can improve outcomes for corals and reefs globally.
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Affiliation(s)
- Raquel S Peixoto
- Laboratory of Molecular Microbial Ecology, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro 21941-901, Brazil; .,IMAM-AquaRio, Rio de Janeiro Aquarium Research Center, Rio de Janeiro, 20220-360, Brazil.,Current affiliation: Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Michael Sweet
- Aquatic Research Facility, Environmental Sustainability Research Centre, University of Derby, Derby DE22 1GB, United Kingdom
| | - Helena D M Villela
- Laboratory of Molecular Microbial Ecology, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro 21941-901, Brazil;
| | - Pedro Cardoso
- Laboratory of Molecular Microbial Ecology, Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro 21941-901, Brazil;
| | - Torsten Thomas
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Christian R Voolstra
- Department of Biology, University of Konstanz, Konstanz 78457, Germany.,Division of Biological and Environmental Science and Engineering, Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - Lone Høj
- Australian Institute of Marine Science, Townsville, Queensland 4810, Australia
| | - David G Bourne
- Australian Institute of Marine Science, Townsville, Queensland 4810, Australia.,College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
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27
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A breakthrough in understanding the molecular basis of coral heat tolerance. Proc Natl Acad Sci U S A 2020; 117:28546-28548. [PMID: 33168724 DOI: 10.1073/pnas.2020201117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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28
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Herrera M, Klein SG, Schmidt‐Roach S, Campana S, Cziesielski MJ, Chen JE, Duarte CM, Aranda M. Unfamiliar partnerships limit cnidarian holobiont acclimation to warming. GLOBAL CHANGE BIOLOGY 2020; 26:5539-5553. [PMID: 32627905 PMCID: PMC7539969 DOI: 10.1111/gcb.15263] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 06/23/2020] [Indexed: 05/08/2023]
Abstract
Enhancing the resilience of corals to rising temperatures is now a matter of urgency, leading to growing efforts to explore the use of heat tolerant symbiont species to improve their thermal resilience. The notion that adaptive traits can be retained by transferring the symbionts alone, however, challenges the holobiont concept, a fundamental paradigm in coral research. Holobiont traits are products of a specific community (holobiont) and all its co-evolutionary and local adaptations, which might limit the retention or transference of holobiont traits by exchanging only one partner. Here we evaluate how interchanging partners affect the short- and long-term performance of holobionts under heat stress using clonal lineages of the cnidarian model system Aiptasia (host and Symbiodiniaceae strains) originating from distinct thermal environments. Our results show that holobionts from more thermally variable environments have higher plasticity to heat stress, but this resilience could not be transferred to other host genotypes through the exchange of symbionts. Importantly, our findings highlight the role of the host in determining holobiont productivity in response to thermal stress and indicate that local adaptations of holobionts will likely limit the efficacy of interchanging unfamiliar compartments to enhance thermal tolerance.
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Affiliation(s)
- Marcela Herrera
- Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
| | - Shannon G. Klein
- Red Sea Research Center (RSRC) and Computational Bioscience Research Center (CBRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
| | - Sebastian Schmidt‐Roach
- Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
| | - Sara Campana
- Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
- Present address:
Faculty of ScienceInstitute for Biodiversity and Ecosystem DynamicsUniversity of Amsterdam1090 GEAmsterdamThe Netherlands
| | - Maha J. Cziesielski
- Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
| | - Jit Ern Chen
- Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
- Present address:
School of Science and TechnologyDepartment of Biological SciencesSunway UniversitySubang JayaSelangorMalaysia
| | - Carlos M. Duarte
- Red Sea Research Center (RSRC) and Computational Bioscience Research Center (CBRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
| | - Manuel Aranda
- Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE)King Abdullah University of Science and Technology (KAUST)ThuwalSaudi Arabia
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29
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Kenkel CD, Mocellin VJL, Bay LK. Global gene expression patterns in Porites white patch syndrome: Disentangling symbiont loss from the thermal stress response in reef-building coral. Mol Ecol 2020; 29:3907-3920. [PMID: 32858771 DOI: 10.1111/mec.15608] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 12/14/2022]
Abstract
The mechanisms resulting in the breakdown of the coral symbiosis once the process of bleaching has been initiated remain unclear. Distinguishing the process of symbiont loss from the thermal stress response may shed light on the cellular and molecular pathways involved in each process. This study examined physiological changes and global gene expression patterns associated with white patch syndrome (WPS) in Porites lobata, which manifests in localized bleaching independent of thermal stress. In addition, a meta-analysis of global gene expression studies in other corals and anemones was used to contrast differential regulation as a result of disease and thermal stress from patterns correlated with symbiotic state. Symbiont density, chlorophyll a content, holobiont productivity, instant calcification rate, and total host protein content were uniformly reduced in WPS relative to healthy tissue. While expression patterns associated with WPS were secondary to fixed effects of source colony, specific functional enrichments combined with a lack of immune regulation suggest that the viral infection putatively giving rise to this condition affects symbiont rather than host cells. Expression in response to WPS also clustered independently of patterns in white syndrome impacted A. hyacinthus, further supporting a distinct aetiology of this syndrome. Expression patterns in WPS-affected tissues were significantly correlated with prior studies that examined short-term thermal stress responses independent of symbiotic state, suggesting that the majority of expression changes reflect a nonspecific stress response. Across studies, the magnitude and direction of expression change among particular functional enrichments suggests unique responses to stressor duration and highlights distinct responses to bleaching in an anemone model.
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Affiliation(s)
- Carly D Kenkel
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | | | - Line K Bay
- Australian Institute of Marine Science, Townsville, Qld, Australia
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30
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Venn AA, Bernardet C, Chabenat A, Tambutté E, Tambutté S. Paracellular transport to the coral calcifying medium: effects of environmental parameters. J Exp Biol 2020; 223:jeb227074. [PMID: 32675232 DOI: 10.1242/jeb.227074] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/13/2020] [Indexed: 12/11/2022]
Abstract
Coral calcification relies on the transport of ions and molecules to the extracellular calcifying medium (ECM). Little is known about paracellular transport (via intercellular junctions) in corals and other marine calcifiers. Here, we investigated whether the permeability of the paracellular pathway varied in different environmental conditions in the coral Stylophora pistillata Using the fluorescent dye calcein, we characterised the dynamics of calcein influx from seawater to the ECM and showed that increases in paracellular permeability (leakiness) induced by hyperosmotic treatment could be detected by changes in calcein influx rates. We then used the calcein-imaging approach to investigate the effects of two environmental stressors on paracellular permeability: seawater acidification and temperature change. Under conditions of seawater acidification (pH 7.2) known to depress pH in the ECM and the calcifying cells of S. pistillata, we observed a decrease in half-times of calcein influx, indicating increased paracellular permeability. By contrast, high temperature (31°C) had no effect, whereas low temperature (20°C) caused decreases in paracellular permeability. Overall, our study establishes an approach to conduct further in vivo investigation of paracellular transport and suggests that changes in paracellular permeability could form an uncharacterised aspect of the physiological response of S. pistillata to seawater acidification.
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Affiliation(s)
- Alexander A Venn
- Marine Biology Department, Centre Scientifique de Monaco, 8 Quai Antoine 1er, 98000 Monaco
| | - Coralie Bernardet
- Marine Biology Department, Centre Scientifique de Monaco, 8 Quai Antoine 1er, 98000 Monaco
| | - Apolline Chabenat
- Marine Biology Department, Centre Scientifique de Monaco, 8 Quai Antoine 1er, 98000 Monaco
| | - Eric Tambutté
- Marine Biology Department, Centre Scientifique de Monaco, 8 Quai Antoine 1er, 98000 Monaco
| | - Sylvie Tambutté
- Marine Biology Department, Centre Scientifique de Monaco, 8 Quai Antoine 1er, 98000 Monaco
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31
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Sun F, Yang H, Wang G, Shi Q. Combination Analysis of Metatranscriptome and Metagenome Reveal the Composition and Functional Response of Coral Symbionts to Bleaching During an El Niño Event. Front Microbiol 2020; 11:448. [PMID: 32265879 PMCID: PMC7104784 DOI: 10.3389/fmicb.2020.00448] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 03/02/2020] [Indexed: 01/12/2023] Open
Abstract
With the abnormal rise in ocean temperatures globally in recent years, coral bleaching is becoming common and serious. However, the response mechanisms and processes of coral symbionts to bleaching are not well understood. In this study, metagenomics and metatranscriptomics were used to explore the composition of coral symbionts and their functions in response to coral bleaching. All four bleaching coral species displayed a significant reduction of the abundance and function of Dinophyceae-like eukaryotes at the DNA and RNA levels. However, different species of bleaching coral have their own characteristic symbiotic components. Bleaching Acropora tenuis and Goniastrea minuta corals exhibited a very high abundance of prokaryotes and associated gene functions, especially for opportunistic bacteria. In contrast, algae and fungi were identified as the main microbial associate components and had relatively high RNA abundance in bleaching Pocillopora verrucosa and Pocillopora meandrina. Different coral species, whether unbleached or bleaching, have the same symbiotic taxa that perform the same biological functions in vivo. Different stages of bleaching, or transitional states, were identified by different genome content and functional gene abundance among bleaching corals. These stages should be considered in future coral bleaching studies to accurately determine symbiont structure and function. An implicit hypothesis is that there is a causal relationship between the stability of eukaryotic communities and coral bleaching.
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Affiliation(s)
- Fulin Sun
- South China Sea Institute of Oceanology, Institute of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China.,State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,Daya Bay Marine Biology Research Station, Chinese Academy of Sciences, Shenzhen, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Hongqiang Yang
- South China Sea Institute of Oceanology, Institute of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China.,Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,Nansha Marine Ecological and Environmental Research Station, Chinese Academy of Sciences, Sansha, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Guan Wang
- South China Sea Institute of Oceanology, Institute of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China.,Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Qi Shi
- South China Sea Institute of Oceanology, Institute of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China.,Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
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32
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Howells EJ, Bauman AG, Vaughan GO, Hume BCC, Voolstra CR, Burt JA. Corals in the hottest reefs in the world exhibit symbiont fidelity not flexibility. Mol Ecol 2020; 29:899-911. [DOI: 10.1111/mec.15372] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/17/2020] [Accepted: 01/29/2020] [Indexed: 12/25/2022]
Affiliation(s)
- Emily J. Howells
- Center for Genomics and Systems Biology New York University Abu Dhabi Abu Dhabi United Arab Emirates
- Centre for Sustainable Ecosystem Solutions and School of Earth, Atmospheric and Life Sciences University of Wollongong Wollongong NSW Australia
| | - Andrew G. Bauman
- Experimental Marine Ecology Laboratory Department of Biological Sciences National University of Singapore Singapore City Singapore
| | - Grace O. Vaughan
- Center for Genomics and Systems Biology New York University Abu Dhabi Abu Dhabi United Arab Emirates
| | - Benjamin C. C. Hume
- Red Sea Research Center Division of Biological and Environmental Sciences and Engineering King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
| | - Christian R. Voolstra
- Red Sea Research Center Division of Biological and Environmental Sciences and Engineering King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
- Department of Biology University of Konstanz Konstanz Germany
| | - John A. Burt
- Center for Genomics and Systems Biology New York University Abu Dhabi Abu Dhabi United Arab Emirates
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33
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Bernardet C, Tambutté E, Techer N, Tambutté S, Venn AA. Ion transporter gene expression is linked to the thermal sensitivity of calcification in the reef coral Stylophora pistillata. Sci Rep 2019; 9:18676. [PMID: 31822787 PMCID: PMC6904480 DOI: 10.1038/s41598-019-54814-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 10/21/2019] [Indexed: 12/22/2022] Open
Abstract
Coral calcification underpins biodiverse reef ecosystems, but the physiology underlying the thermal sensitivity of corals to changing seawater temperatures remains unclear. Furthermore, light is also a key factor in modulating calcification rates, but a mechanistic understanding of how light interacts with temperature to affect coral calcification is lacking. Here, we characterized the thermal performance curve (TPC) of calcification of the wide-spread, model coral species Stylophora pistillata, and used gene expression analysis to investigate the role of ion transport mechanisms in thermally-driven declines in day and nighttime calcification. Focusing on genes linked to transport of dissolved inorganic carbon (DIC), calcium and H+, our study reveals a high degree of coherence between physiological responses (e.g. calcification and respiration) with distinct gene expression patterns to the different temperatures in day and night conditions. At low temperatures, calcification and gene expression linked to DIC transport processes were downregulated, but showed little response to light. By contrast, at elevated temperature, light had a positive effect on calcification and stimulated a more functionally diverse gene expression response of ion transporters. Overall, our findings highlight the role of mechanisms linked to DIC, calcium and H+ transport in the thermal sensitivity of coral calcification and how this sensitivity is influenced by light.
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Affiliation(s)
- C Bernardet
- Centre Scientifique de Monaco, Marine Biology Department, 8 Quai Antoine 1er, Monaco, 98000, Monaco
- Sorbonne Université, Collège Doctoral, F-75005, Paris, France
| | - E Tambutté
- Centre Scientifique de Monaco, Marine Biology Department, 8 Quai Antoine 1er, Monaco, 98000, Monaco
| | | | - S Tambutté
- Centre Scientifique de Monaco, Marine Biology Department, 8 Quai Antoine 1er, Monaco, 98000, Monaco
| | - A A Venn
- Centre Scientifique de Monaco, Marine Biology Department, 8 Quai Antoine 1er, Monaco, 98000, Monaco.
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34
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Weis VM. Cell Biology of Coral Symbiosis: Foundational Study Can Inform Solutions to the Coral Reef Crisis. Integr Comp Biol 2019; 59:845-855. [DOI: 10.1093/icb/icz067] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Abstract
Coral reefs are faced with almost complete destruction by the end of the century due to global warming unless humanity can cap global temperature rise. There is now a race to develop a diverse set of solutions to save coral reefs. In this perspective, a case is made for understanding the cell biology of coral–dinoflagellate symbiosis to help inform development of solutions for saving reefs. Laboratory model systems for the study of coral symbiosis, including the sea anemone Exaiptasia pallida, are featured as valuable tools in the fight to save corals. The roles of host innate immunity and inter-partner nutrient dynamics in the onset, ongoing maintenance, and dysregulation of symbiosis are reviewed and discussed. Key innate immune genes and pathways, such as glycan–lectin interactions, the sphingosine rheostat, and the cytokine transforming growth factor beta are shown to modulate a host immune response in the symbiotic state. An upset in the homeostatic inorganic nutrient balance during heat stress and high exogenous nutrient availability is credited with driving the partnership toward dysregulation and coral bleaching. Specific examples are given where knowledge of the cell biology of symbiosis is informing the development of solutions, including studies showing clear limitations in the value of partner switching and acclimatization protocols. Finally, emphasis is placed on rapid advancement of knowledge to try to meet the urgent need for solutions. This includes real-time open communication with colleagues on successes and failures, sharing of resources and information, and working together in the spirit of a collective mission to save coral reefs.
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Affiliation(s)
- Virginia M Weis
- Department of Integrative Biology, Oregon State University, Corvallis, OR 97331, USA
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