scholarly journals Climate change and tropical sponges: The effect of elevated pCO₂ and temperature on the sponge holobiont

2021 ◽  
Author(s):  
◽  
Holly Bennett
Keyword(s):  
Climate Change ◽  
Thermal Stress ◽  
Coral Reef ◽  
Cell Membrane ◽  
Coral Reefs ◽  
Climate Change Scenarios ◽  
Holistic View ◽  
Biochemical Constituents ◽  
Functional Components

<p>As atmospheric CO₂ concentrations rise, associated ocean warming (OW) and ocean acidification (OA) are predicted to cause declines in reef-building corals globally, shifting reefs from coral-dominated systems to those dominated by less sensitive species. Sponges are important structural and functional components of coral reef ecosystems, but despite increasing field-based evidence that sponges may be ‘winners’ in response to environmental degradation, our understanding of how they respond to the combined effects of OW and OA is limited. This PhD thesis explores the response of four abundant Great Barrier Reef species – the phototrophic Carteriospongia foliascens and Cymbastela coralliophila and the heterotrophic Stylissa flabelliformis and Rhopaloeides odorabile to OW and OA levels predicted for 2100, under two CO₂ Representative Concentration Pathways (RCPs). The overall aim of this research is to bridge gaps in our understanding of how these important coral reef organisms will respond to projected climate change, to begin to explore whether a sponge dominated state is a possible future trajectory for coral reefs.  To determine the tolerance of adult sponges to climate change, these four species were exposed to OW and OA in the Australian Institute of Marine Science’s (AIMS) National Sea Simulator (SeaSim) in a 3-month experimental study. The first data chapter explores the physiological responses of these sponges to OW and OA to gain a broad understanding of sponge holobiont survival and functioning under these conditions. In this chapter I also address the hypothesis that phototrophic and heterotrophic sponges will exhibit differential responses to climate change. In the second and third data chapters I explore the cellular lipid and fatty acid composition of sponges, and how these biochemical constituents vary with OW and OA. Lipids and fatty acids are not only vital energy stores, they form the major components of cell membranes, and the structure and composition of these biochemical constituents ultimately determines the integrity and physiological competency of a cell. Therefore through these analyses I aimed to determine how OW and OA affects the metabolic balance of sponges, and to understand mechanisms underpinning observed systemic sponge responses. Finally, to provide greater insight into the population level impacts of climate change on tropical sponges, in the last data chapter I explore the response of the phototrophic species Carteriospongia foliascens to OW/OA throughout its developmental stages.   I found that while sponges can generally tolerate climate change scenarios predicted under the RCP6.0 conditions for 2100 (30ºC/ pH 7.8), environmental projections for the end of this century under the RCP8.5 (31.5ºC/ pH 7.6) will have significant implications for their survival. Temperature effects were much stronger than OA effects for all species; however, phototrophic and heterotrophic species responded differently to OA. Elevated pCO₂ exacerbated temperature stress in heterotrophic sponges but somewhat ameliorated thermal stress in phototrophic species. Furthermore, sponges with siliceous spiculated skeletons resisted the RCP 8.5 conditions for longer than the aspiculate species. Biochemical analysis revealed that spiculated species also have greater cell membrane support features, which is likely to contribute to the observed stress tolerance. I also found that the additional energy available to phototrophic sponges under OA conditions may be used for investment into cell membrane support, providing protection against thermal stress. Finally, larval survival and settlement success of C. foliascens was unaffected by OW and OA treatments, and juvenile sponges exhibited greater tolerance than their adult counterparts, again with evidence that OA reduces OW stress for some of these life stages.   Based on the species studied here, this thesis confirms that sponges are better able to deal with OW and OA levels predicted for 2100 under RCP6.0, compared to many corals for which survival in a high CO₂ world requires OW to remain below 1.5°C. This suggests sponges may be future ‘winners’ on coral reefs under global climate change. However, if CO₂ atm concentrations reach levels predicted under RCP8.5, the prognosis for sponge survival by the end of this century changes as inter-species sponge tolerances to OW and OA differ. Under this projection it is likely we will also start to see a shift in sponge populations to those dominated by phototrophic sponges with siliceous spiculated skeletons. Overall, this thesis gives a holistic view of OW and OA impacts on tropical sponges and provides the basis from which to explore the potential for a sponge-coral regime shift in a high CO₂ world.</p>

scholarly journals Climate change and tropical sponges: The effect of elevated pCO₂ and temperature on the sponge holobiont

2021 ◽  
Author(s):  
◽  
Holly Bennett
Keyword(s):  
Climate Change ◽  
Thermal Stress ◽  
Coral Reef ◽  
Cell Membrane ◽  
Coral Reefs ◽  
Climate Change Scenarios ◽  
Holistic View ◽  
Biochemical Constituents ◽  
Functional Components

<p>As atmospheric CO₂ concentrations rise, associated ocean warming (OW) and ocean acidification (OA) are predicted to cause declines in reef-building corals globally, shifting reefs from coral-dominated systems to those dominated by less sensitive species. Sponges are important structural and functional components of coral reef ecosystems, but despite increasing field-based evidence that sponges may be ‘winners’ in response to environmental degradation, our understanding of how they respond to the combined effects of OW and OA is limited. This PhD thesis explores the response of four abundant Great Barrier Reef species – the phototrophic Carteriospongia foliascens and Cymbastela coralliophila and the heterotrophic Stylissa flabelliformis and Rhopaloeides odorabile to OW and OA levels predicted for 2100, under two CO₂ Representative Concentration Pathways (RCPs). The overall aim of this research is to bridge gaps in our understanding of how these important coral reef organisms will respond to projected climate change, to begin to explore whether a sponge dominated state is a possible future trajectory for coral reefs.  To determine the tolerance of adult sponges to climate change, these four species were exposed to OW and OA in the Australian Institute of Marine Science’s (AIMS) National Sea Simulator (SeaSim) in a 3-month experimental study. The first data chapter explores the physiological responses of these sponges to OW and OA to gain a broad understanding of sponge holobiont survival and functioning under these conditions. In this chapter I also address the hypothesis that phototrophic and heterotrophic sponges will exhibit differential responses to climate change. In the second and third data chapters I explore the cellular lipid and fatty acid composition of sponges, and how these biochemical constituents vary with OW and OA. Lipids and fatty acids are not only vital energy stores, they form the major components of cell membranes, and the structure and composition of these biochemical constituents ultimately determines the integrity and physiological competency of a cell. Therefore through these analyses I aimed to determine how OW and OA affects the metabolic balance of sponges, and to understand mechanisms underpinning observed systemic sponge responses. Finally, to provide greater insight into the population level impacts of climate change on tropical sponges, in the last data chapter I explore the response of the phototrophic species Carteriospongia foliascens to OW/OA throughout its developmental stages.   I found that while sponges can generally tolerate climate change scenarios predicted under the RCP6.0 conditions for 2100 (30ºC/ pH 7.8), environmental projections for the end of this century under the RCP8.5 (31.5ºC/ pH 7.6) will have significant implications for their survival. Temperature effects were much stronger than OA effects for all species; however, phototrophic and heterotrophic species responded differently to OA. Elevated pCO₂ exacerbated temperature stress in heterotrophic sponges but somewhat ameliorated thermal stress in phototrophic species. Furthermore, sponges with siliceous spiculated skeletons resisted the RCP 8.5 conditions for longer than the aspiculate species. Biochemical analysis revealed that spiculated species also have greater cell membrane support features, which is likely to contribute to the observed stress tolerance. I also found that the additional energy available to phototrophic sponges under OA conditions may be used for investment into cell membrane support, providing protection against thermal stress. Finally, larval survival and settlement success of C. foliascens was unaffected by OW and OA treatments, and juvenile sponges exhibited greater tolerance than their adult counterparts, again with evidence that OA reduces OW stress for some of these life stages.   Based on the species studied here, this thesis confirms that sponges are better able to deal with OW and OA levels predicted for 2100 under RCP6.0, compared to many corals for which survival in a high CO₂ world requires OW to remain below 1.5°C. This suggests sponges may be future ‘winners’ on coral reefs under global climate change. However, if CO₂ atm concentrations reach levels predicted under RCP8.5, the prognosis for sponge survival by the end of this century changes as inter-species sponge tolerances to OW and OA differ. Under this projection it is likely we will also start to see a shift in sponge populations to those dominated by phototrophic sponges with siliceous spiculated skeletons. Overall, this thesis gives a holistic view of OW and OA impacts on tropical sponges and provides the basis from which to explore the potential for a sponge-coral regime shift in a high CO₂ world.</p>

Dimethylated sulfur compounds in coral-reef ecosystems

2016 ◽  
Vol 13 (2) ◽  
pp. 239 ◽  
Author(s):  
Elisabeth Deschaseaux ◽  
Graham Jones ◽  
Hilton Swan
Keyword(s):  
Climate Change ◽  
Coral Reef ◽  
Coral Reefs ◽  
Sulfur Compounds ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Reef Communities ◽  
Coral Reef Ecosystems ◽  
Coral Reef Communities

Environmental contextDimethylated sulfur compounds can exert multiple biological and environmental effects including climate regulation. Climate change and other anthropogenic factors are predicted to affect coral-reef ecosystems where these sulfur compounds are particularly abundant. We review the processes that regulate the production of dimethylated sulfur compounds in coral reefs and the potential consequences of environmental changes on their biogenic cycle in such fragile ecosystems under future climate change scenarios. AbstractDimethylsulfoniopropionate (DMSP) and its main breakdown products dimethylsulfide (DMS) and dimethylsulfoxide (DMSO) are biogenic species in the marine environment. In coral reefs, these dimethylated sulfur compounds (DSCs) have been reported at greater concentrations than in other marine ecosystems, which is most likely attributable to the extraordinary large biodiversity of coral reef communities (e.g. corals, macroalgae, coralline algae, invertebrates) and to the unique ability of zooxanthellate corals to synthesise DMSP from both the animal host and algal symbionts. Besides the various biological functions that have been attributed to DSCs, including thermoregulation, osmoregulation, chemoattraction and antioxidant response, DMS is suspected to take part in a climate feedback loop that could help counteract global warming. Nowadays, anthropogenic effects such as pollution, overfishing, increased sedimentation and global climate change are imminently threatening the health of coral reef communities around the world, with possible consequences on the natural cycle of DSCs within these ecosystems. This review provides insight into the biogeochemistry of DSCs in coral reefs and discusses the implications of projected changes in DSC production in these increasingly stressed ecosystems under future climate change scenarios. It shows that DSC dynamics will incontestably be affected in the near future, with possible feedback consequences on local climate.

scholarly journals Turbid Coral Reefs: Past, Present and Future—A Review

Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 251
Author(s):  
Adi Zweifler (Zvifler) ◽  
Michael O’Leary ◽  
Kyle Morgan ◽  
Nicola K. Browne
Keyword(s):  
Climate Change ◽  
Coral Reef ◽  
Coral Reefs ◽  
Environmental Change ◽  
Scientific Literature ◽  
Conservation Status ◽  
Climate Change Impacts ◽  
Geographic Range ◽  
Reef Complex ◽  
Sediment Input

Increasing evidence suggests that coral reefs exposed to elevated turbidity may be more resilient to climate change impacts and serve as an important conservation hotspot. However, logistical difficulties in studying turbid environments have led to poor representation of these reef types within the scientific literature, with studies using different methods and definitions to characterize turbid reefs. Here we review the geological origins and growth histories of turbid reefs from the Holocene (past), their current ecological and environmental states (present), and their potential responses and resilience to increasing local and global pressures (future). We classify turbid reefs using new descriptors based on their turbidity regime (persistent, fluctuating, transitional) and sources of sediment input (natural versus anthropogenic). Further, by comparing the composition, function and resilience of two of the most studied turbid reefs, Paluma Shoals Reef Complex, Australia (natural turbidity) and Singapore reefs (anthropogenic turbidity), we found them to be two distinct types of turbid reefs with different conservation status. As the geographic range of turbid reefs is expected to increase due to local and global stressors, improving our understanding of their responses to environmental change will be central to global coral reef conservation efforts.

scholarly journals Biobricks and Crocheted Coral: Dispatches from the Life Sciences in the Age of Fabrication

2013 ◽  
Vol 26 (1) ◽  
pp. 153-171 ◽  
Author(s):  
Sophia Roosth
Keyword(s):  
Climate Change ◽  
Coral Reef ◽  
Synthetic Biology ◽  
Coral Reefs ◽  
Experimental Research ◽  
Life Sciences ◽  
Research Initiative ◽  
Folk Theories

ArgumentWhat does “life” become at a moment when biological inquiry proceeds by manufacturing biological artifacts and systems? In this article, I juxtapose two radically different communities, synthetic biologists and Hyperbolic Crochet Coral Reef crafters (HCCR). Synthetic biology is a decade-old research initiative that seeks to merge biology with engineering and experimental research with manufacture. The HCCR is a distributed venture of three thousand craftspeople who cooperatively fabricate a series of yarn and plastic coral reefs to draw attention to the menace climate change poses to the Great Barrier and other reefs. Interpreting these two groups alongside one another, I suggest that for both, manufacturing biological artifacts advances their understandings of biology: in a rhetorical loop, they build new biological things in order to understand the things they are making. The resulting fabrications condense scientific and folk theories about “life” and also undo “life” as a coherent analytic object.

scholarly journals Climate Change Induced Thermal Stress Caused Recurrent Coral Bleaching over Gulf of Kachchh and Malvan Marine Sanctuary, West Coast of India

2021 ◽  
Author(s):  
Mohit Arora ◽  
Kalyan De ◽  
Nandini Ray Chaudhury ◽  
Mandar Nanajkar ◽  
Prakash Chauhan ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Coral Reef ◽  
Coral Reefs ◽  
Coral Bleaching ◽  
Large Scale ◽  
Heat Waves ◽  
Southern Oscillation ◽  
Coral Cover ◽  
Imminent Threat ◽  
Marginal Reefs

Coral reefs are one of the most sensitive, productive, and invaluable biological resources on the earth. However, coral reefs are facing unprecedented stress due to ongoing climate changes and intensified anthropogenic disturbances globally. Elevated Sea Surface Temperature (SST) has emerged as the most imminent threat to the thermos-sensitive reef-building corals. The 2010–2014-2016 El Niño Southern Oscillation (ENSO) caused prolonged marine heat waves (MHWs) that led to the most widespread coral bleaching and mortality in the tropical Indi-Pacific regions. Coral bleaching prediction is vital for the management of the reef biodiversity, ecosystem functioning, and services. Recent decades, satellite remote sensing has emerged as a convenient tool for large-scale coral reef monitoring programs. As thermal stress is a critical physical attribute for coral bleaching hence, the present study examines the effectiveness of the elevated SSTs as a proxy to predict coral bleaching in shallow water marginal reefs. Advanced Very High-Resolution Radiometer (AVHRR) satellite data from the NOAA Coral Reef Watch’s (CRW) platform has been used for this study. Coral bleaching indices like Bleaching Threshold (BT), Positive SST Anomaly (PA), and Degree Heating Weeks (DHW) are computed to analyze the thermal stress on the coral reefs. The computed thermal stress from satellite-derived SST data over regions concurrence with the mass coral bleaching (MCB) events. This study concludes that in the last decades (2010 to 2019) the coral cover around these regions has dramatically declined due to higher SST, which indicates that the thermal stress induced recurrent bleaching events attributed to the coral loss.

scholarly journals Coral Reef Resilience through Biodiversity

2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Caroline S. Rogers
Keyword(s):  
Climate Change ◽  
Coral Reef ◽  
Coral Reefs ◽  
Environmental Changes ◽  
Marine Protected Area ◽  
Future Research ◽  
Ecological Processes ◽  
Coral Reef Resilience ◽  
Global Action ◽  
Coral Reef Degradation

Irrefutable evidence of coral reef degradation worldwide and increasing pressure from rising seawater temperatures and ocean acidification associated with climate change have led to a focus on reef resilience and a call to “manage” coral reefs for resilience. Ideally, global action to reduce emission of carbon dioxide and other greenhouse gases will be accompanied by local action. Effective management requires reduction of local stressors, identification of the characteristics of resilient reefs, and design of marine protected area networks that include potentially resilient reefs. Future research is needed on how stressors interact, on how climate change will affect corals, fish, and other reef organisms as well as overall biodiversity, and on basic ecological processes such as connectivity. Not all reef species and reefs will respond similarly to local and global stressors. Because reef-building corals and other organisms have some potential to adapt to environmental changes, coral reefs will likely persist in spite of the unprecedented combination of stressors currently affecting them. The biodiversity of coral reefs is the basis for their remarkable beauty and for the benefits they provide to society. The extraordinary complexity of these ecosystems makes it both more difficult to predict their future and more likely they will have a future.

scholarly journals Climate Change Leads to a Reduction in Symbiotic Derived Cnidarian Biodiversity on Coral Reefs

2021 ◽  
Vol 9 ◽  
Author(s):  
Tamar L. Goulet ◽  
Denis Goulet
Keyword(s):  
Climate Change ◽  
Coral Reef ◽  
Coral Reefs ◽  
Environmental Conditions ◽  
Sea Anemones ◽  
Coral Reef Ecosystem ◽  
Symbiotic Relationships ◽  
Cascade Effect ◽  
Symbiotic Partner ◽  
Reef Ecosystem

Symbiotic relationships enable partners to thrive and survive in habitats where they would either not be as successful, or potentially not exist, without the symbiosis. The coral reef ecosystem, and its immense biodiversity, relies on the symbioses between cnidarians (e.g., scleractinian corals, octocorals, sea anemones, jellyfish) and multiple organisms including dinoflagellate algae (family Symbiodiniaceae), bivalves, crabs, shrimps, and fishes. In this review, we discuss the ramifications of whether coral reef cnidarian symbioses are obligatory, whereby at least one of the partners must be in the symbiosis in order to survive or are facultative. Furthermore, we cover the consequences of cnidarian symbioses exhibiting partner flexibility or fidelity. Fidelity, where a symbiotic partner can only engage in symbiosis with a subset of partners, may be absolute or context dependent. Current literature demonstrates that many cnidarian symbioses are highly obligative and appear to exhibit absolute fidelity. Consequently, for many coral reef cnidarian symbioses, surviving changing environmental conditions will depend on the robustness and potential plasticity of the existing host-symbiont(s) combination. If environmental conditions detrimentally affect even one component of this symbiotic consortium, it may lead to a cascade effect and the collapse of the entire symbiosis. Symbiosis is at the heart of the coral reef ecosystem, its existence, and its high biodiversity. Climate change may cause the demise of some of the cnidarian symbioses, leading to subsequent reduction in biodiversity on coral reefs.

scholarly journals WAVE TRANSFORMATION WITHIN A CORAL REEF LAGOON SYSTEM, ERAKOR LAGOON, VANUATU

2020 ◽  
pp. 38
Author(s):  
Gaelle Faivre ◽  
Oriane Lagrabe ◽  
Krishna Kotra ◽  
Rodger Tomlinson ◽  
Brendan Mackey ◽  
...  
Keyword(s):  
Climate Change ◽  
Coral Reef ◽  
Coral Reefs ◽  
Wave Energy ◽  
Coastal Communities ◽  
Coastal Hazards ◽  
Wave Transformation ◽  
Reef Lagoon ◽  
Waves And Currents ◽  
Coral Reef Lagoon

Coral reefs encircle most of the islands in Vanuatu and provide natural breakwaters for coastal communities by reducing wave energy arriving at the shoreline acting to control both inundation and erosion. Climate Change is projected to both exacerbate coastal hazards and endanger corals. The aim of this paper is to better understand the parameters that govern hydrodynamics on fringing reef systems. The interaction between the depth, waves and currents are studied from measurements conducted in Erakor lagoon, Vanuatu.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/mPrG6NWL4dM

scholarly journals Exploring the Lack of Funding for Coral Reef Research and it’s Effects on Coral Reef Management and Conservation

2021 ◽  
Vol 10 (4) ◽  
Author(s):  
Jenna Bushnell ◽  
Soo Park
Keyword(s):  
Climate Change ◽  
Coral Reef ◽  
Coral Reefs ◽  
Marine Biology ◽  
Government Officials ◽  
Reef Management ◽  
Research Programs ◽  
College Professor ◽  
Initial Assumption ◽  
Coral Reef Ecosystems

Climate change is greatly harming coral reefs (Gibbs and West, 2019). It is important to research how to help these coral reefs build resilience against climate change but research programs are severely underfunded (Johnston et al. 2020). This paper explored how lack of funding prevents scientists from saving coral reefs and how scientists themselves can be affected. The goal of this paper was to bring to light the struggles faced in the midst of underfunding to feasibly gain support from politicians and government officials to promote funding for these programs. Through three virtual interviews with two scientists and one college professor, I gathered personal experiences from these participants on how coral reefs are being affected today, why research is necessary, and how lack of funding prevents the restoration of these reefs. With the use of a thematic analysis, I was able to recognize common themes between the interviews in order to conclude how lack of program funding prevents scientists from managing and restoring these coral reef ecosystems. The initial assumption for this paper was that coral reef research is underfunded because coral reefs are considered less important, however, the analysis of the data for this paper concluded that all research programs are underfunded. In essence, marine biology, in general, is underfunded as opposed to mainly research on coral reefs. As a result, scientists can be very limited in their abilities to conduct research.

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