ORCID Profile
0000-0003-4148-2555
Current Organisation
The University of Newcastle
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Ecology | Ecological Applications | Global Change Biology | Ecological Impacts of Climate Change | Conservation And Biodiversity | Ecological Physiology | Evolutionary biology | Environmental Science and Management | Global Change Biology | Environment And Resource Economics | Oceanography | Biological Oceanography | Environmental Management And Rehabilitation | Physical Oceanography | Animal Physiology - Cell | Phycology (incl. Marine Grasses) | Microbial Ecology | Gene Expression (incl. Microarray and other genome-wide approaches) | Other Biological Sciences | Population And Ecological Genetics | Environmental Chemistry (incl. Atmospheric Chemistry) | Marine And Estuarine Ecology (Incl. Marine Ichthyology) | Ecological impacts of climate change and ecological adaptation | Marine and estuarine ecology (incl. marine ichthyology) | Biological adaptation |
ANZSRC Socio-Economic Objective (SEO)
Ecosystem Assessment and Management of Marine Environments | Global climate change adaptation measures | Ecosystem Adaptation to Climate Change | Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Integrated (ecosystem) assessment and management | Climate change | Living resources (flora and fauna) | Physical and Chemical Conditions of Water in Marine Environments | Integrated (ecosystem) assessment and management | Marine Flora, Fauna and Biodiversity | Regional planning
Related Links
Publications
The effect of thermal history on the susceptibility of reef-building corals to thermal stress
Publisher: The Company of Biologists
Date: 04-2008
DOI: 10.1242/JEB.013284
Abstract: The mutualistic relationship between corals and their unicellular dinoflagellate symbionts (Symbiodinium sp.) is a fundamental component within the ecology of coral reefs. Thermal stress causes the breakdown of the relationship between corals and their symbionts (bleaching). As with other organisms, this symbiosis may acclimate to changes in the environment, thereby potentially modifying the environmental threshold at which they bleach. While a few studies have examined the acclimation capacity of reef-building corals, our understanding of the underlying mechanism is still in its infancy. The present study focused on the role of recent thermal history in influencing the response of both corals and symbionts to thermal stress, using the reef-building coral Acropora aspera. The symbionts of corals that were exposed to 31°C for 48 h (pre-stress treatment) 1 or 2 weeks prior to a 6-day simulated bleaching event (when corals were exposed to 34°C) were found to have more effective photoprotective mechanisms. These mechanisms included changes in non-photochemical quenching and xanthophyll cycling. These differences in photoprotection were correlated with decreased loss of symbionts, with those corals that were not prestressed performing significantly worse, losing over 40% of their symbionts and having a greater reduction in photosynthetic efficiency. These results are important in that they show that thermal history, in addition to light history, can influence the response of reef-building corals to thermal stress and therefore have implications for the modeling of bleaching events. However, whether acclimation is capable of modifying the thermal threshold of corals sufficiently to cope as sea temperatures increase in response to global warming has not been fully explored. Clearly increases in sea temperatures that extend beyond 1–2°C will exhaust the extent to which acclimation can modify the thermal threshold of corals.
Resolving coral photoacclimation dynamics through coupled photophysiological and metabolomic profiling
Publisher: The Company of Biologists
Date: 2019
DOI: 10.1242/JEB.195982
Abstract: Corals continuously adjust to short term variation in light availability on shallow reefs. Long-term light alterations can also occur due to natural and anthropogenic stressors, as well as management interventions such as coral transplantation. Although short term photophysiological responses are relatively well-understood in corals, little information is available regarding photoacclimation dynamics over weeks of altered light availability. We coupled photophysiology and metabolomic profiling to explore changes that accompany longer-term photoacclimation in a key Great Barrier Reef coral species (Acropora muricata). High (HL) and low light (LL) acclimated corals were collected from the reef and reciprocally exposed to high and low light ex situ. Rapid light curves using Pulse Amplitude Modulation (PAM) fluorometry revealed photophysiological acclimation of LL to HL and HL to LL shifted corals within 21 days. A subset of colonies s led at 7 and 21 days for untargeted LC-MS and GC-MS metabolomic profiling revealed metabolic reorganization before acclimation was detected using PAM fluorometry. Metabolomic shifts were more pronounced for LL to HL treated corals than their HL to LL counterparts. Compounds driving metabolomic separation between HL-exposed and LL control colonies included amino acids, organic acids, fatty acids and sterols. Reduced glycerol and c esterol suggest decreased translocation of photosynthetic products from symbiont to host in LL to HL shifted corals, with concurrent increases in fatty acid abundance indicating reliance on stored lipids for energy. We discuss how these data provide novel insight into environmental regulation of metabolism and implications for management strategies that drive rapid changes in light availability.
Microalgal blooms in the skeletons of bleached corals during the 2020 bleaching event on Heron Island, Australia
Publisher: CSIRO Publishing
Date: 12-07-2021
DOI: 10.1071/MF21050
Abstract: Climate change is increasing the frequency of marine heatwaves around the world, causing widespread degradation of coral reefs. Endolithic microalgae inhabiting the coral skeleton have been highlighted as potentially important mediators of the consequences of heatwaves on coral reefs. These microalgae often bloom during heat stress due to greater light availability, theoretically delaying coral starvation by providing photoassimilates. However, these microalgae also dissolve coral skeletons at an accelerated rate during marine heatwaves, affecting the structural complexity of the reef. Despite their ecological role, no studies have examined endolithic algal blooms during a natural bleaching event. We quantified blooms of endolithic microalgae in the skeletons of lagoon corals bleaching on Heron Island in the austral summer of 2020. At the peak of heat stress, 20–30% of bleached corals across 9 genera at 3 sites had blooms. They were predominantly seen in branching Acropora spp. (37.8, 65.7 and 66.7% at three sites), which are primary reef builders at Heron Island. At the end of the bleaching event, the overall prevalence varied between 5 and 42%, and nearly all blooms were observed in acroporids. The relative high frequency of these blooms highlights the ongoing need to understand the role of these microbes during coral bleaching events.
Revealing changes in the microbiome of Symbiodiniaceae under thermal stress
Publisher: Wiley
Date: 04-2020
Abstract: Symbiodiniaceae are a erse family of marine dinoflagellates, well known as coral endosymbionts. Isolation and in vitro culture of Symbiodiniaceae strains for physiological studies is a widely adopted tool, especially in the context of understanding how environmental stress perturbs Symbiodiniaceae cell functioning. While the bacterial microbiomes of corals often correlate with coral health, the bacterial communities co-cultured with Symbiodiniaceae isolates have been largely overlooked, despite the potential of bacteria to significantly influence the emergent physiological properties of Symbiodiniaceae cultures. We examined the physiological response to heat stress by Symbiodiniaceae isolates (spanning three genera) with well-described thermal tolerances, and combined these observations with matched changes in bacterial composition and abundance through 16S rRNA metabarcoding. Under thermal stress, there were Symbiodiniaceae strain-specific changes in maximum quantum yield of photosystem II (proxy for health) and growth rates that were accompanied by changes in the relative abundance of multiple Symbiodiniaceae-specific bacteria. However, there were no Symbiodiniaceae-independent signatures of bacterial community reorganisation under heat stress. Notably, the thermally tolerant Durusdinium trenchii (ITS2 major profile D1a) had the most stable bacterial community under heat stress. Ultimately, this study highlights the complexity of Symbiodiniaceae-bacteria interactions and provides a first step towards uncoupling their relative contributions towards Symbiodiniaceae physiological functioning.
Fidelity and flexibility in coral symbioses
Publisher: Inter-Research Science Center
Date: 11-10-2007
DOI: 10.3354/MEPS07220
Near-future reductions in pH will have no consistent ecological effects on the early life-history stages of reef corals
Publisher: Inter-Research Science Center
Date: 12-07-2013
DOI: 10.3354/MEPS10318
Rapid Coral Decay Is Associated with Marine Heatwave Mortality Events on Reefs
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.CUB.2019.06.077
Abstract: Severe marine heatwaves have recently become a common feature of global ocean conditions due to a rapidly changing climate [1, 2]. These increasingly severe thermal conditions are causing an unprecedented increase in the frequency and severity of mortality events in marine ecosystems, including on coral reefs [3]. The degradation of coral reefs will result in the collapse of ecosystem services that sustain over half a billion people globally [4, 5]. Here, we show that marine heatwave events on coral reefs are biologically distinct to how coral bleaching has been understood to date, in that heatwave conditions result in an immediate heat-induced mortality of the coral colony, rapid coral skeletal dissolution, and the loss of the three-dimensional reef structure. During heatwave-induced mortality, the coral skeletons exposed by tissue loss are, within days, encased by a complex biofilm of phototrophic microbes, whose metabolic activity accelerates calcium carbonate dissolution to rates exceeding accretion by healthy corals and far greater than has been documented on reefs under normal seawater conditions. This dissolution reduces the skeletal density and hardness and increases porosity. These results demonstrate that severe-heatwave-induced mortality events should be considered as a distinct biological phenomenon from bleaching events on coral reefs. We also suggest that such heatwave mortality events, and rapid reef decay, will become more frequent as the intensity of marine heatwaves increases and provides further compelling evidence for the need to mitigate climate change and instigate actions to reduce marine heatwaves.
Early cellular changes are indicators of pre-bleaching thermal stress in the coral host
Publisher: Elsevier BV
Date: 10-2008
Light Capture, Skeletal Morphology, and the Biomass of Corals’ Boring Endoliths
Publisher: American Society for Microbiology
Date: 24-02-2021
Abstract: Microbial communities living inside the skeletons of living corals play a variety of important roles within the coral meta-organism, both symbiotic and parasitic. Properly contextualizing the contribution of these enigmatic microbes to the life history of coral reefs requires knowledge of how these endolithic biofilms vary between coral species.
Understanding decay in marine calcifiers: Micro-CT analysis of skeletal structures provides insight into the impacts of a changing climate in marine ecosystems
Publisher: Wiley
Date: 18-07-2020
Defining the tipping point. A complex cellular life/death balance in corals in response to stress
Publisher: Springer Science and Business Media LLC
Date: 17-11-2011
DOI: 10.1038/SREP00160
Multiple techniques point to oxygenic phototrophs dominating the Isopora palifera skeletal microbiome
Publisher: Springer Science and Business Media LLC
Date: 15-02-2021
Temperature affects the early life history stages of corals more than near future ocean acidification
Publisher: Inter-Research Science Center
Date: 14-02-2013
DOI: 10.3354/MEPS10077
Antioxidant plasticity and thermal sensitivity in four types of S ymbiodinium sp.
Publisher: Wiley
Date: 15-10-2014
DOI: 10.1111/JPY.12232
Abstract: Warmer than average summer sea surface temperature is one of the main drivers for coral bleaching, which describes the loss of endosymbiotic dinoflagellates (genus: Symbiodinium) in reef-building corals. Past research has established that oxidative stress in the symbiont plays an important part in the bleaching cascade. Corals hosting different genotypes of Symbiodinium may have varying thermal bleaching thresholds, but changes in the symbiont's antioxidant system that may accompany these differences have received less attention. This study shows that constitutive activity and up-regulation of different parts of the antioxidant network under thermal stress differs between four Symbiodinium types in culture and that thermal susceptibility can be linked to glutathione redox homeostasis. In Symbiodinium B1, C1 and E, declining maximum quantum yield of PSII (Fv /Fm ) and death at 33°C were generally associated with elevated superoxide dismutase (SOD) activity and a more oxidized glutathione pool. Symbiodinium F1 exhibited no decline in Fv /Fm or growth, but showed proportionally larger increases in ascorbate peroxidase (APX) activity and glutathione content (GSx), while maintaining GSx in a reduced state. Depressed growth in Symbiodinium B1 at a sublethal temperature of 29°C was associated with transiently increased APX activity and glutathione pool size, and an overall increase in glutathione reductase (GR) activity. The collapse of GR activity at 33°C, together with increased SOD, APX and glutathione S-transferase activity, contributed to a strong oxidation of the glutathione pool with subsequent death. Integrating responses of multiple components of the antioxidant network highlights the importance of antioxidant plasticity in explaining type-specific temperature responses in Symbiodinium.
Transcriptomic Analysis of Thermally Stressed Symbiodinium Reveals Differential Expression of Stress and Metabolism Genes
Publisher: Frontiers Media SA
Date: 28-02-2017
Unlocking the black‐box of inorganic carbon‐uptake and utilization strategies among coral endosymbionts (Symbiodiniaceae)
Publisher: Wiley
Date: 20-02-2020
DOI: 10.1002/LNO.11416
An ancient and variable mannose-binding lectin from the coral Acropora millepora binds both pathogens and symbionts
Publisher: Elsevier BV
Date: 2008
DOI: 10.1016/J.DCI.2008.05.010
Abstract: Corals form the framework of the world's coral reefs and are under threat from increases in disease and bleaching (symbiotic dysfunction), yet the mechanisms of pathogen and symbiont recognition remain largely unknown. Here we describe the isolation and characterisation of an ancient mannose-binding lectin in the coral Acropora millepora, which is likely to be involved in both processes. The lectin ('Millectin') was isolated by affinity chromatography and was shown to bind to bacterial pathogens as well as coral symbionts, dinoflagellates of the genus Symbiodinium. cDNA analysis of Millectin indicate extensive sequence variation in the binding region, reflecting its ability to recognise various mannose-like carbohydrate structures on non-self cells, including symbionts and pathogens. This is the first mannose-binding lectin to show extensive sequence variability as observed for pattern recognition proteins in other invertebrate immune systems and, given that invertebrates rely on non-adaptive immunity, is a potential keystone component of coral defence mechanisms.
A novel carbonic anhydrase from the giant clam Tridacna gigas contains two carbonic anhydrase domains
Publisher: Wiley
Date: 24-06-2005
DOI: 10.1111/J.1742-4658.2005.04742.X
Abstract: This report describes the presence of a unique dual domain carbonic anhydrase (CA) in the giant clam, Tridacna gigas. CA plays an important role in the movement of inorganic carbon (Ci) from the surrounding seawater to the symbiotic algae that are found within the clam's tissue. One of these isoforms is a glycoprotein which is significantly larger (70 kDa) than any previously reported from animals (generally between 28 and 52 kDa). This alpha-family CA contains two complete carbonic anhydrase domains within the one protein, accounting for its large size dual domain CAs have previously only been reported from two algal species. The protein contains a leader sequence, an N-terminal CA domain and a C-terminal CA domain. The two CA domains have relatively little identity at the amino acid level (29%). The genomic sequence spans in excess of 17 kb and contains at least 12 introns and 13 exons. A number of these introns are in positions that are only found in the membrane attached/secreted CAs. This fact, along with phylogenetic analysis, suggests that this protein represents the second ex le of a membrane attached invertebrate CA and it contains a dual domain structure unique amongst all animal CAs characterized to date.
Symbiosis and microbiome flexibility in calcifying benthic foraminifera of the great Barrier Reef
Publisher: Springer Science and Business Media LLC
Date: 23-03-2017
Differential Responses of the Coral Host and Their Algal Symbiont to Thermal Stress
Publisher: Public Library of Science (PLoS)
Date: 24-10-2011
Photoreactivation is the main repair pathway for UV-induced DNA damage in coral planulae
Publisher: The Company of Biologists
Date: 09-2009
DOI: 10.1242/JEB.031286
Abstract: The larvae of most coral species spend some time in the plankton, floating just below the surface and hence exposed to high levels of ultraviolet radiation (UVR). The high levels of UVR are potentially stressful and damaging to DNA and other cellular components, such as proteins, reducing survivorship. Consequently, mechanisms to either shade (prevent) or repair damage potentially play an important role. In this study, the role of photoreactivation in the survival of coral planulae was examined. Photoreactivation is a light-stimulated response to UV-damaged DNA in which photolyase proteins repair damaged DNA. Photoreactivation rates, as well as the localization of photolyase, were explored in planulae under conditions where photoreactivation was or was not inhibited. The results indicate that photoreactivation is the main DNA repair pathway in coral planulae, repairing UV-induced DNA damage swiftly (K=1.75 h–1 and a half-life of repair of 23 min), with no evidence of any light-independent DNA repair mechanisms, such as nucleotide excision repair (NER), at work. Photolyase mRNA was localized to both the ectoderm and endoderm of the larvae. The amount of cell death in the coral planulae increased significantly when photoreactivation was inhibited, by blocking photoreactivating light. We found that photoreactivation, along with additional UV shielding in the form of five mycosporine-like amino acids, are sufficient for survival in surface tropical waters and that planulae do not accumulate DNA damage despite being exposed to high UVR.
Increased prevalence of ubiquitous ascomycetes in an acropoid coral (Acropora formosa) exhibiting symptoms of brown band syndrome and skeletal eroding band disease
Publisher: American Society for Microbiology
Date: 15-04-2007
DOI: 10.1128/AEM.02738-06
Abstract: The prevalence of coral-associated fungi was four times higher in diseased Acropora formosa colonies than in healthy colonies. Since taxonomically related fungal species were isolated from diseased and healthy colonies, we suggest that their association with coral may be constitutive but that their abundance is dependent on coral health.
Complementary sampling methods for coral histology, metabolomics and microbiome
Publisher: Wiley
Date: 28-06-2020
Aerial exposure influences bleaching patterns
Publisher: Springer Science and Business Media LLC
Date: 13-06-2006
In situ hybridisation detects pro-apoptotic gene expression of a Bcl-2 family member in white syndrome-affected coral
Publisher: Inter-Research Science Center
Date: 09-12-2015
DOI: 10.3354/DAO02882
Abstract: White syndrome has been described as one of the most prolific diseases on the Great Barrier Reef. Previously, apoptotic cell death has been described as the mechanism driving the characteristic rapid tissue loss associated with this disease, but the molecular mechanisms controlling apoptotic cell death in coral disease have yet to be investigated. In situ methods were used to study the expression patterns of 2 distinct regulators of apoptosis in Acropora hyacinthus tissues undergoing white syndrome and apoptotic cell death. Apoptotic genes within the Bcl-2 family were not localized in apparently healthy coral tissues. However, a Bcl-2 family member (bax-like) was found to localize to cells and tissues affected by white syndrome and those with morphological evidence for apoptosis. A potential up-regulation of pro-apoptotic or bax-like gene expression in tissues with apoptotic cell death adjacent to disease lesions is consistent with apoptosis being the primary cause of rapid tissue loss in coral affected by white syndrome. Pro-apoptotic (bax-like) expression in desmocytes and the basal tissue layer, the calicodermis, distant from the disease lesion suggests that apoptosis may also underlie the sloughing of healthy tissues associated with the characteristic, rapid spread of tissue loss, evident of this disease. This study also shows that in situ hybridisation is an effective tool for studying gene expression in adult corals, and wider application of these methods should allow a better understanding of many aspects of coral biology and disease pathology.
Transcriptomic characterization of the enzymatic antioxidants FeSOD, MnSOD, APX and KatG in the dinoflagellate genus Symbiodinium
Publisher: Springer Science and Business Media LLC
Date: 18-03-2015
The ReFuGe 2020 Consortium—using “omics” approaches to explore the adaptability and resilience of coral holobionts to environmental change
Publisher: Frontiers Media SA
Date: 2015
Marine Heatwave Hotspots in Coral Reef Environments: Physical Drivers, Ecophysiological Outcomes, and Impact Upon Structural Complexity
Publisher: Frontiers Media SA
Date: 16-08-2019
The combined effects of temperature and CO2 lead to altered gene expression in Acropora aspera
Publisher: Springer Science and Business Media LLC
Date: 14-06-2013
Extraction Protocol for Nontargeted NMR and LC-MS Metabolomics-Based Analysis of Hard Coral and Their Algal Symbionts
Publisher: Humana Press
Date: 2013
DOI: 10.1007/978-1-62703-577-4_10
Abstract: Metabolomics and in particular, nontargeted metabolomics, has become a popular technique for the study of biological s les as it provides considerable amounts of information on extractable metabolites and is ideal for studying the metabolic response of an organism to stressors in its environment. One such organism, the symbiotic hard coral, presents its own complexity when considering a metabolomics approach in that it forms intricate associations with an array of symbiotic macro- and microbiota. While not discounting the importance of these many associations to the function of the coral holobiont, the coral-Symbiodinium relationship has been the most studied to date and as such, is the primary focus of this extraction protocol. This protocol provides details for the s le collection, extraction, and measurement of hard coral holobiont metabolites using both (1)H nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography coupled with mass spectrometry (LC-MS). Using this nontargeted metabolomics approach, the holobiont metabolism can be investigated for perturbations resulting from either (1) natural or anthropogenic environmental challenges, (2) the controlled application of stressors, and (3) differences between phenotypes or species. Consequently, this protocol will benefit both environmental and natural products based research of hard coral and their algal symbionts. Every effort has been made to provide the reader with all the details required to perform this protocol, including many of the costly and time consuming "pitfalls" or "traps" that were discovered during its development. As a result, this protocol can be confidently accomplished by those with less experience in the extraction and analysis of symbiotic hard coral, requiring minimal user input whilst ensuring reproducible and reliable results using readily available lab ware and reagents.
Imaging the fluorescence of marine invertebrates and their associated flora
Publisher: Wiley
Date: 31-10-2008
DOI: 10.1111/J.1365-2818.2008.02089.X
Abstract: The cells and tissues of many marine invertebrates and their associated flora contain fluorescent pigments and proteins, many of which have been utilized commercially and provide marker molecules in other systems for fluorescence imaging technology. However, in the study of marine invertebrates and their symbioses these naturally occurring molecules have been seen to limit or confound fluorescence microscopy analyses. Here we demonstrate the endogenous fluorescence associated with two marine invertebrates (coral and foraminifera) and describe how these qualities can be utilized in fluorescence microanalyses. Understanding and imaging the ersity of fluorescent molecules provide insight into how fluorescence microscopy techniques can now be applied to these complex systems.
Meeting the photosynthetic demand for inorganic carbon in an alga–invertebrate association: preferential use of CO 2 by symbionts in the giant clam Tr
Publisher: The Royal Society
Date: 07-03-2000
The microbiome of the endosymbiotic Symbiodiniaceae in corals exposed to thermal stress
Publisher: Springer Science and Business Media LLC
Date: 18-04-2023
DOI: 10.1007/S10750-023-05221-7
Abstract: The coral reef crisis has influenced research for over two decades, during which time the capacity of corals to withstand and respond to environmental stress has been documented from the cellular to ecosystem level. Over the past decade, research is increasingly working towards uncovering the extent of coral–bacterial interactions, finding that erse and stable microbial interactions can be indicative of the health of the coral host. However, we have yet to determine at which level of organismal organisation these interactions occur, in particular those with the coral’s photosynthetic dinoflagellate symbionts. This information is critical if we are to understand the impact of stress on meta-organism functioning. Using 16S gene licon sequencing, we investigated the bacterial microbiome of endosymbiotic Symbiodiniaceae from thermally stressed Acropora aspera , under 3 ecologically relevant temperature trajectories (defined as protective, repetitive and single) that are expected under a changing climate. We show that endosymbiotic Symbiodiniaceae host a distinct and erse bacterial assemblage when compared with the A. aspera host. Alphaproteobacteria (mainly Rhodobacteraceae and Bradyrhizobiaceae), from the Rhizobiales order dominated the Symbiodiniaceae microbiome, while Gammaproteobacteria (mainly Endozoicomonadaceae) dominated the coral microbiome. The Symbiodiniaceae core microbiome also reflected the distinct microbiomes of the two partners, specifically, Rhizobiales were not present in the A. aspera core, while Endozoicomonadaceae were not present in the Symbiodiniaceae core. We show the Symbiodiniaceae-associated microbiome was highly responsive to increases in temperature, and the microbial consortium was significantly altered in the Symbiodiniaceae retained in the host exposed to different temperature. Most notably, Myxococcolaes were up to 25-fold higher relative abundance in dinoflagellate partner microbiomes under the single temperature trajectory, compared with the repetitive and control treatments. The distinct composition of bacteria associated with Symbiodiniaceae suggests a previously unrecognised, yet important functional role of these associations to overall coral health, which is increasingly important as reefs decline worldwide. Our study provides the first characterisation of Symbiodiniaceae-associated microbes from a coral host under a range of temperature trajectories occurring on the Great Barrier Reef.
High flow conditions mediate damaging impacts of sub-lethal thermal stress on corals’ endosymbiotic algae
Publisher: Oxford University Press (OUP)
Date: 2021
Abstract: The effects of thermal anomalies on tropical coral endosymbiosis can be mediated by a range of environmental factors, which in turn ultimately influence coral health and survival. One such factor is the water flow conditions over coral reefs and corals. Although the physiological benefits of living under high water flow are well known, there remains a lack of conclusive experimental evidence characterizing how flow mitigates thermal stress responses in corals. Here we use in situ measurements of flow in a variety of reef habitats to constrain the importance of flow speeds on the endosymbiosis of an important reef building species under different thermal regimes. Under high flow speeds (0.15 m s−1) and thermal stress, coral endosymbionts retained photosynthetic function and recovery capacity for longer compared to low flow conditions (0.03 m s−1). We hypothesize that this may be due to increased rates of mass transfer of key metabolites under higher flow, putatively allowing corals to maintain photosynthetic efficiency for longer. We also identified a positive interactive effect between high flow and a pre-stress, sub-lethal pulse in temperature. While higher flow may delay the onset of photosynthetic stress, it does not appear to confer long-term protection sustained exposure to thermal stress (eDHW accumulation equivalent to 4.9°C weeks) eventually overwhelmed the coral meta-organism as evidenced by eventual declines in photo-physiological function and endosymbiont densities. Investigating flow patterns at the scale of metres within the context of these physiological impacts can reveal interesting avenues for coral reef management. This study increases our understanding of the effects of water flow on coral reef health in an era of climate change and highlights the potential to learn from existing beneficial bio-physical interactions for the effective preservation of coral reefs into the future.
The effect of temperature on the size and population density of dinoflagellates in larvae of the reef coral Porites astreoides
Publisher: Wiley
Date: 09-2005
Light-Responsive Cryptochromes from a Simple Multicellular Animal, the Coral Acropora millepora
Publisher: American Association for the Advancement of Science (AAAS)
Date: 19-10-2007
Abstract: Hundreds of species of reef-building corals spawn synchronously over a few nights each year, and moonlight regulates this spawning event. However, the molecular elements underpinning the detection of moonlight remain unknown. Here we report the presence of an ancient family of blue-light–sensing photoreceptors, cryptochromes, in the reef-building coral Acropora millepora . In addition to being cryptochrome genes from one of the earliest- erging eumetazoan phyla, cry1 and cry2 were expressed preferentially in light. Consistent with potential roles in the synchronization of fundamentally important behaviors such as mass spawning, cry2 expression increased on full moon nights versus new moon nights. Our results demonstrate phylogenetically broad roles of these ancient circadian clock–related molecules in the animal kingdom.
The coral core microbiome identifies rare bacterial taxa as ubiquitous endosymbionts
Publisher: Springer Science and Business Media LLC
Date: 17-04-2015
The impact of bleaching on the metabolic contribution of dinoflagellate symbionts to their giant clam host
Publisher: Wiley
Date: 17-11-2003
Recent progress in Symbiodinium transcriptomics
Publisher: Elsevier BV
Date: 11-2011
Integral Light-Harvesting Complex Expression In Symbiodinium Within The Coral Acropora aspera Under Thermal Stress
Publisher: Springer Science and Business Media LLC
Date: 27-04-2016
DOI: 10.1038/SREP25081
Abstract: Coral reef success is largely dependent on the symbiosis between coral hosts and dinoflagellate symbionts belonging to the genus Symbiodinium . Elevated temperatures can result in the expulsion of Symbiodinium or loss of their photosynthetic pigments and is known as coral bleaching. It has been postulated that the expression of light-harvesting protein complexes (LHCs), which bind chlorophylls (chl) and carotenoids, are important in photobleaching. This study explored the effect a sixteen-day thermal stress (increasing daily from 25–34 °C) on integral LHC (chlorophyll a -chlorophyll c 2 -peridinin protein complex ( acpPC )) gene expression in Symbiodinium within the coral Acropora aspera. Thermal stress leads to a decrease in Symbiodinium photosynthetic efficiency by day eight, while symbiont density was significantly lower on day sixteen. Over this time period, the gene expression of five Symbiodinium acpPC genes was quantified. Three acpPC genes exhibited up-regulated expression when corals were exposed to temperatures above 31.5 °C ( acpPCSym_1:1 , day sixteen acpPCSym_15 , day twelve and acpPCSym_18 , day ten and day sixteen). In contrast, the expression of acpPCSym_5:1 and acpPCSym_10:1 was unchanged throughout the experiment. Interestingly, the three acpPC genes with increased expression cluster together in a phylogenetic analysis of light-harvesting complexes.
Exposure to elevated sea-surface temperatures below the bleaching threshold impairs coral recovery and regeneration following injury
Publisher: PeerJ
Date: 18-08-2017
DOI: 10.7717/PEERJ.3719
Abstract: Elevated sea surface temperatures (SSTs) are linked to an increase in the frequency and severity of bleaching events due to temperatures exceeding corals’ upper thermal limits. The temperatures at which a breakdown of the coral- Symbiodinium endosymbiosis (coral bleaching) occurs are referred to as the upper thermal limits for the coral species. This breakdown of the endosymbiosis results in a reduction of corals’ nutritional uptake, growth, and tissue integrity. Periods of elevated sea surface temperature, thermal stress and coral bleaching are also linked to increased disease susceptibility and an increased frequency of storms which cause injury and physical damage to corals. Herein we aimed to determine the capacity of corals to regenerate and recover from injuries (removal of apical tips) sustained during periods of elevated sea surface temperatures which result in coral stress responses, but which do not result in coral bleaching (i.e., sub-bleaching thermal stress events). In this study, exposure of the species Acropora aspera to an elevated SST of 32 °C (2 °C below the bleaching threshold, 34 °C) was found to result in reduced fluorescence of green fluorescent protein (GFP), reduced skeletal calcification and a lack of branch regrowth at the site of injury, compared to corals maintained under ambient SST conditions (26 °C). Corals maintained under normal, ambient, sea surface temperatures expressed high GFP fluorescence at the injury site, underwent a rapid regeneration of the coral branch apical tip within 12 days of sustaining injury, and showed extensive regrowth of the coral skeleton. Taken together, our results have demonstrated that periods of sustained increased sea surface temperatures, below the corals’ bleaching threshold but above long-term summertime averages, impair coral recovery from damage, regardless of the onset or occurrence of coral bleaching.
Experiment Degree Heating Week (eDHW) as a novel metric to reconcile and validate past and future global coral bleaching studies
Publisher: Elsevier BV
Date: 2022
DOI: 10.1016/J.JENVMAN.2021.113919
Abstract: Coral bleaching has increasingly impacted reefs worldwide over the past four decades. Despite almost 40 years of research into the mechanistic, physiological, ecological, biophysical and climatic drivers of coral bleaching, metrics to allow comparison between ecological observations and experimental simulations still do not exist. Here we describe a novel metric - experimental Degree Heating Week (eDHW) - with which to standardise the persistently variable thermal conditions employed across experimental studies of coral bleaching by modify the widely used Degree Heating Week (DHW) metric used in ecological studies to standardise cumulative heat loading.
Diverse symbiont bleaching responses are evident from 2-degree heating week bleaching conditions as thermal stress intensifies in coral
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/MF19220
Abstract: Coral bleaching is the dysfunction of the coral–algal endosymbiosis and is characterised as a loss of Symbiodiniaceae cells from host tissues or the loss of photosynthetic pigments. This breakdown of symbiosis occurs as a result of elevated temperature beyond the organism’s thermal threshold. The thermal tipping points within the symbiosis have not yet been well resolved, and the mechanisms underlying the various cellular processes of the corals bleaching response remain unknown. This study characterised the cellular responses of the symbiont Cladocopium sp. (syn. clade C3) within the host coral Acropora aspera during exposure to thermal stress. Exposure to temperatures between 2 and 3°C below the bleaching threshold, equating to 2-degree heating weeks (DHWs), results in changes to the symbiont cell morphology and cell ision rates. Once corals were exposed to 4 DHWs, over 90% of the symbiont cells showed signs of degradation. Although sub-bleaching thermal stress is not sufficient to trigger bleaching alerts at an ecological scale, this stressor substantially affects the coral symbiosis. It is therefore vital that we begin to quantify how sub-bleaching thermal stress affects the fitness of Symbiodiniacea populations, their coral hosts and subsequently reefs worldwide.
Hyperdiversity of Genes Encoding Integral Light-Harvesting Proteins in the Dinoflagellate Symbiodinium sp
Publisher: Public Library of Science (PLoS)
Date: 24-10-2012
The hologenome theory disregards the coral holobiont
Publisher: Springer Science and Business Media LLC
Date: 10-2007
New‐old hemoglobin‐like proteins of symbiotic dinoflagellates
Publisher: Wiley
Date: 26-02-2013
DOI: 10.1002/ECE3.498
Analysis of an EST library from the dinoflagellate (Symbiodinium sp.) symbiont of reef‐building corals1
Publisher: Wiley
Date: 15-09-2007
Photoacclimatory and photoprotective responses to cold versus heat stress in high latitude reef corals
Publisher: Wiley
Date: 24-01-2017
DOI: 10.1111/JPY.12492
Abstract: Corals at the world's southernmost coral reef of Lord Howe Island (LHI) experience large temperature and light fluctuations and need to deal with periods of cold temperature (<18°C), but few studies have investigated how corals are able to cope with these conditions. Our study characterized the response of key photophysiological parameters, as well as photoacclimatory and photoprotective pigments (chlorophylls, xanthophylls, and β-carotene), to short-term (5-d) cold stress (~15°C 7°C below control) in three LHI coral species hosting distinct Symbiodinium ITS2 types, and compared the coral-symbiont response to that under elevated temperature (~29°C 7°C above control). Under cold stress, Stylophora sp. hosting Symbiodinium C118 showed the strongest effects with regard to losses of photochemical performance and symbionts. Pocillopora damicornis hosting Symbiodinium C100/C118 showed less severe bleaching responses to reduced temperature than to elevated temperature, while Porites heronensis hosting Symbiodinium C111* withstood both reduced and elevated temperature. Under cold stress, photoprotection in the form of xanthophyll de-epoxidation increased in unbleached P. heronensis (by 178%) and bleached Stylophora sp. (by 225%), while under heat stress this parameter increased in unbleached P. heronensis (by 182%) and in bleached P. damicornis (by 286%). The xanthophyll pool size was stable in all species at all temperatures. Our comparative study demonstrates high variability in the bleaching vulnerability of these coral species to low and high thermal extremes and shows that this variability is not solely determined by the ability to activate xanthophyll de-epoxidation.
Rebuilding relationships on coral reefs: Coral bleaching knowledge‐sharing to aid adaptation planning for reef users
Publisher: Wiley
Date: 05-08-2021
Abstract: Coral bleaching has impacted reefs worldwide and the predictions of near‐annual bleaching from over two decades ago have now been realized. While technology currently provides the means to predict large‐scale bleaching, predicting reef‐scale and within‐reef patterns in real‐time for all reef users is limited. In 2020, heat stress across the Great Barrier Reef underpinned the region's third bleaching event in 5 years. Here we review the heterogeneous emergence of bleaching across Heron Island reef habitats and discuss the oceanographic drivers that underpinned variable bleaching emergence. We do so as a case study to highlight how reef end‐user groups who engage with coral reefs in different ways require targeted guidance for how, and when, to alter their use of coral reefs in response to bleaching events. Our case study of coral bleaching emergence demonstrates how within‐reef scale nowcasting of coral bleaching could aid the development of accessible and equitable bleaching response strategies on coral reefs. Also see the video abstract here: youtu.be/N9Tgb8N-vN0
A Comparative Analysis of Microbial DNA Preparation Methods for Use With Massive and Branching Coral Growth Forms
Publisher: Frontiers Media SA
Date: 07-09-2018
Differential coral bleaching—Contrasting the activity and response of enzymatic antioxidants in symbiotic partners under thermal stress
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.CBPA.2015.08.012
Abstract: Mass coral bleaching due to thermal stress represents a major threat to the integrity and functioning of coral reefs. Thermal thresholds vary, however, between corals, partly as a result of the specific type of endosymbiotic dinoflagellate (Symbiodinium sp.) they harbour. The production of reactive oxygen species (ROS) in corals under thermal and light stress has been recognised as one mechanism that can lead to cellular damage and the loss of their symbiont population (Oxidative Theory of Coral Bleaching). Here, we compared the response of symbiont and host enzymatic antioxidants in the coral species Acropora millepora and Montipora digitata at 28°C and 33°C. A. millepora at 33°C showed a decrease in photochemical efficiency of photosystem II (PSII) and increase in maximum midday excitation pressure on PSII, with subsequent bleaching (declining photosynthetic pigment and symbiont density). M. digitata exhibited no bleaching response and photochemical changes in its symbionts were minor. The symbiont antioxidant enzymes superoxide dismutase, ascorbate peroxidase, and catalase peroxidase showed no significant upregulation to elevated temperatures in either coral, while only catalase was significantly elevated in both coral hosts at 33°C. Increased host catalase activity in the susceptible coral after 5days at 33°C was independent of antioxidant responses in the symbiont and preceded significant declines in PSII photochemical efficiencies. This finding suggests a potential decoupling of host redox mechanisms from symbiont photophysiology and raises questions about the importance of symbiont-derived ROS in initiating coral bleaching.
Molecular processes of transgenerational acclimation to a warming ocean
Publisher: Springer Science and Business Media LLC
Date: 20-07-2015
DOI: 10.1038/NCLIMATE2724
Bleaching, mortality and lengthy recovery on the coral reefs of Lord Howe Island. The 2019 marine heatwave suggests an uncertain future for high-latitude ecosystems
Publisher: Public Library of Science (PLoS)
Date: 12-04-2023
DOI: 10.1371/JOURNAL.PCLM.0000080
Abstract: Oceanic thermal anomalies are increasing in both frequency and strength, causing detrimental impacts to coral reef communities. Water temperatures beyond the corals optimum threshold causeing coral bleaching and mass mortality, impacting our global coral reef ecosystems, including marginal high-latitude reefs. Coral bleaching and mortality were observed at the southernmost coral reef, Lord Howe Island Marine Park, during the summer of 2019, coinciding with anomalously high sea surface temperatures across the reef system from January-April. Here we document the extent of coral impacts within the Lord Howe Island lagoonal reef and the recovery from bleaching eight-months later. Significant differences in bleaching prevalence were observed across the lagoonal coral reef, ranging from 16 to 83% across offshore and inshore reef regions and with variable onset timing. Coral mortality of up to 40% was recorded in the reef’s most severely impacted near-shore area. The four most dominant species, Stylophora pistillata , Pocillopora damicornis , Porites spp . and Seriatopora hystrix , were the most susceptible to bleaching, with all coral colonies found either bleached or dead at the most affected inshore site during and following peak heat stress. Interestingly, during the eight-months following bleaching, there was no evidence of bleaching recovery (i.e., re-establishment of symbiosis) at the offshore lagoonal site. However, there was a significant increase in the abundance of healthy coral colonies at the inshore site, suggesting the recovery of the surviving bleached corals at this site. Importantly, we found no evidence for bleaching or mortality in the Acropora spp . and minimal bleaching and no mortality in Isopora cuneata during the study period, typically highly susceptible species. Given the isolation of high-latitude reefs such as Lord Howe Island, our results highlight the importance of understanding the impacts of bleaching, mortality and bleaching recovery on coral population structure and resilience of high-latitude coral reefs.
Symbiodinium—Invertebrate Symbioses and the Role of Metabolomics
Publisher: MDPI AG
Date: 30-09-2010
DOI: 10.3390/MD8102546
The coral immune response facilitates protection against microbes during tissue regeneration
Publisher: Wiley
Date: 19-06-2015
DOI: 10.1111/MEC.13257
Abstract: Increasing physical damage on coral reefs from predation, storms and anthropogenic disturbances highlights the need to understand the impact of injury on the coral immune system. In this study, we examined the regulation of the coral immune response over 10 days following physical trauma artificially inflicted on in situ colonies of the coral Acropora aspera, simultaneously with bacterial colonization of the lesions. Corals responded to injury by increasing the expression of immune system-related genes involved in the Toll-like and NOD-like receptor signalling pathways and the lectin-complement system in three phases (<2, 4 and 10 days post-injury). Phenoloxidase activity was also significantly upregulated in two phases (<3 and 10 days post-injury), as were levels of non-fluorescent chromoprotein. In addition, green fluorescent protein expression was upregulated in response to injury from 4 days post-injury, while cyan fluorescent protein expression was reduced. No shifts in the composition of coral-associated bacterial communities were evident following injury based on 16S rRNA gene licon pyrosequencing. Bacteria-specific fluorescence in situ hybridization also showed no evidence of bacterial colonization of the wound or regenerating tissues. Coral tissues showed near-complete regeneration of lesions within 10 days. This study demonstrates that corals exhibit immune responses that support rapid recovery following physical injury, maintain coral microbial homeostasis and prevent bacterial infestation that may compromise coral fitness.
Analysis of evolutionarily conserved innate immune components in coral links immunity and symbiosis
Publisher: Elsevier BV
Date: 11-2010
DOI: 10.1016/J.DCI.2010.06.016
Abstract: Reef-building corals are representatives of one of the earliest erging metazoan lineages and are experiencing increases in bleaching events (breakdown of the coral-Symbiodinium symbiosis) and disease outbreaks. The present study investigates the roles of two pattern recognition proteins, the mannose binding lectin Millectin and a complement factor C3-like protein (C3-Am), in the coral Acropora millepora. The results indicate that the innate immune functions of these molecules are conserved and arose early in evolution. C3-Am is expressed in response to injury, and may function as an opsonin. In contrast, Millectin expression is up-regulated in response to lipopolysaccharide and peptidoglycan. These observations, coupled with localization of Millectin in nematocysts in epidermal tissue, and reported binding of pathogens, are consistent with a key role for the lectin in innate immunity. Furthermore, Millectin was consistently detected binding to the symbiont Symbiodinium in vivo, indicating that the Millectin function of recognition and binding of non-self-entities may have been co-opted from an ancient innate immune system into a role in symbiosis.
Proteome metabolome and transcriptome data for three Symbiodiniaceae under ambient and heat stress conditions
Publisher: Springer Science and Business Media LLC
Date: 05-04-2022
DOI: 10.1038/S41597-022-01258-W
Abstract: The Symbiodiniaceae are a taxonomically and functionally erse family of marine dinoflagellates. Their symbiotic relationship with invertebrates such as scleractinian corals has made them the focus of decades of research to resolve the underlying biology regulating their sensitivity to stressors, particularly thermal stress. Research to-date suggests that Symbiodiniaceae stress sensitivity is governed by a complex interplay between phylogenetic dependent and independent traits ( ersity of characteristics of a species). Consequently, there is a need for datasets that simultaneously broadly resolve molecular and physiological processes under stressed and non-stressed conditions. Therefore, we provide a dataset simultaneously generating transcriptome, metabolome, and proteome data for three ecologically important Symbiodiniaceae isolates under nutrient replete growth conditions and two temperature treatments (ca. 26 °C and 32 °C). Elevated sea surface temperature is primarily responsible for coral bleaching events that occur when the coral-Symbiodiniaceae relationship has been disrupted. Symbiodiniaceae can strongly influence their host’s response to thermal stress and consequently it is necessary to resolve drivers of Symbiodiniaceae heat stress tolerance. We anticipate these datasets to expand our understanding on the key genotypic and functional properties that influence the sensitivities of Symbiodiniaceae to thermal stress.
A place for taxonomic profiling in the study of the coral prokaryotic microbiome
Publisher: Oxford University Press (OUP)
Date: 03-2019
Abstract: The enormous variability in richness, abundance and ersity of unknown bacterial organisms inhabiting the coral microbiome have challenged our understanding of their functional contribution to coral health. Identifying the attributes of the healthy meta-organism is paramount for contemporary approaches aiming to manipulate dysbiotic stages of the coral microbiome. This review evaluates the current knowledge on the structure and mechanisms driving bacterial communities in the coral microbiome and discusses two topics requiring further research to define the healthy coral microbiome. (i) We examine the necessity to establish microbial baselines to understand the spatial and temporal dynamics of the healthy coral microbiome and summarise conceptual and logistic challenges to consider in the design of these baselines. (ii) We propose potential mechanical, physical and chemical mechanisms driving bacterial distribution within coral compartments and suggest experiments to test them. Finally, we highlight aspects of the use of 16S licon sequencing requiring standardization and discuss its contribution to other multi-omics approaches.
Coral Disease Causes, Consequences, and Risk within Coral Restoration
Publisher: Elsevier BV
Date: 10-2020
Rethinking the Coral Microbiome: Simplicity Exists within a Diverse Microbial Biosphere
Publisher: American Society for Microbiology
Date: 07-11-2018
Abstract: We propose that the coral holobiont should be conceptualized as a erse transient microbial community that is responsive to the surrounding environment and encompasses a simple, redundant, resident microbiome and a small conserved core microbiome. Most importantly, we show that the coral microbiome is comparable to the microbiomes of other organisms studied thus far. Accurately characterizing the coral-microbe interactions provides an important baseline from which the functional roles and the functional niches within which microbes reside can be deciphered.
Ammonium, but not nitrate, stimulates an increase in glutamine concentration in the haemolymph of Tridacna gigas
Publisher: Springer Science and Business Media LLC
Date: 28-01-1999
Elevated seawater temperatures have a limited impact on the coral immune response following physical damage
Publisher: Springer Science and Business Media LLC
Date: 17-03-2015
The Microbial Signature Provides Insight into the Mechanistic Basis of Coral Success across Reef Habitats
Publisher: American Society for Microbiology
Date: 07-09-2016
Abstract: For ecosystems vulnerable to environmental change, understanding the spatiotemporal stability of functionally crucial symbioses is fundamental to determining the mechanisms by which these ecosystems may persist. The coral Pachyseris speciosa is a successful environmental generalist that succeeds in erse reef habitats. The generalist nature of this coral suggests it may have the capacity to form functionally significant microbial partnerships to facilitate access to a range of nutritional sources within different habitats. Here, we propose that coral is a metaorganism hosting three functionally distinct microbial interactions: a ubiquitous core microbiome of very few symbiotic host-selected bacteria, a microbiome of spatially and/or regionally explicit core microbes filling functional niches ( phylotypes), and a highly variable bacterial community that is responsive to biotic and abiotic processes across spatial and temporal scales ( ,000 phylotypes). We find that this coral hosts upwards of 170,000 distinct phylotypes and provide evidence for the persistence of a select group of bacteria in corals across environmental habitats of the Great Barrier Reef and Coral Sea. We further show that a higher number of bacteria are consistently associated with corals on mesophotic reefs than on shallow reefs. An increase in microbial ersity with depth suggests reliance by this coral on bacteria for nutrient acquisition on reefs exposed to nutrient upwelling. Understanding the complex microbial communities of host organisms across broad biotic and abiotic environments as functionally distinct microbiomes can provide insight into those interactions that are ubiquitous niche symbioses and those that provide competitive advantage within the hosts’ environment. IMPORTANCE Corals have been proposed as the most erse microbial biosphere. The high variability of microbial communities has h ered the identification of bacteria playing key functional roles that contribute to coral survival. Exploring the bacterial community in a coral with a broad environmental distribution, we found a group of bacteria present across all environments and a higher number of bacteria consistently associated with mesophotic corals (60 to 80 m). These results provide evidence of consistent and ubiquitous coral-bacterial partnerships and support the consideration of corals as metaorganisms hosting three functionally distinct microbiomes: a ubiquitous core microbiome, a microbiome filling functional niches, and a highly variable bacterial community.
Evolutionary analysis of orthologous cDNA sequences from cultured and symbiotic dinoflagellate symbionts of reef-building corals (Dinophyceae: Symbiodinium)
Publisher: Elsevier BV
Date: 06-2009
DOI: 10.1016/J.CBD.2008.11.001
Abstract: Dinoflagellates are ubiquitous marine and freshwater protists. The endosymbiotic relationship between dinoflagellates of the genus Symbiodinium (also known as zooxanthellae) and corals forms the basis of coral reefs. We constructed and analyzed a cDNA library from a cultured Symbiodinium species clade A (CassKB8). The majority of annotated ESTs from the Symbiodinium sp. CassKB8 library cover metabolic genes. Most of those belong to either carbohydrate or energy metabolism. In addition, components of extracellular signal transduction pathways and genes that play a role in cell-cell communication were identified. In a subsequent analysis, we determined all orthologous cDNA sequences between this library (1,484 unique sequences) and a library from a Symbiodinium species clade C (C3) (3,336 unique sequences) that was isolated directly from its symbiotic host. A set of 115 orthologs were identified between Symbiodinium sp. CassKB8 and Symbiodinium sp. C3. These orthologs were sub ided into three groups that show different characteristics and functions: conserved across eukaryotes (CE), dinoflagellate-specific (DS) and Symbiodinium-specific (SS). Orthologs conserved across eukaryotes are mainly comprised of housekeeping genes, photosynthesis-related transcripts and metabolic proteins, whereas the function for most of the dinoflagellate-specific orthologs remains unknown. A dN/dS analysis identified the highest ratio in a Symbiodinium-specific ortholog and evidence for positive selection in a dinoflagellate-specific gene. Evolution of genes and pathways in different dinoflagellates seems to be affected by different lifestyles, and a symbiotic lifestyle may affect population structure and strength of selection. This study is the first evolutionary comparative analysis of orthologs from two coral dinoflagellate symbionts.
Symbiotic Dinoflagellate Functional Diversity Mediates Coral Survival under Ecological Crisis
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.TREE.2017.07.013
Abstract: Coral reefs have entered an era of 'ecological crisis' as climate change drives catastrophic reef loss worldwide. Coral growth and stress susceptibility are regulated by their endosymbiotic dinoflagellates (genus Symbiodinium). The phylogenetic ersity of Symbiodinium frequently corresponds to patterns of coral health and survival, but knowledge of functional ersity is ultimately necessary to reconcile broader ecological success over space and time. We explore here functional traits underpinning the complex biology of Symbiodinium that spans free-living algae to coral endosymbionts. In doing so we propose a mechanistic framework integrating the primary traits of resource acquisition and utilisation as a means to explain Symbiodinium functional ersity and to resolve the role of Symbiodinium in driving the stability of coral reefs under an uncertain future.
Seeking Resistance in Coral Reef Ecosystems: The Interplay of Biophysical Factors and Bleaching Resistance under a Changing Climate
Publisher: Wiley
Date: 19-06-2019
Abstract: If we are to ensure the persistence of species in an increasingly warm world, of interest is the identification of drivers that affect the ability of an organism to resist thermal stress. Underpinning any organism's capacity for resistance is a complex interplay between biological and physical factors occurring over multiple scales. Tropical coral reefs are a unique system, in that their function is dependent upon the maintenance of a coral-algal symbiosis that is directly disrupted by increases in water temperature. A number of physical factors have been identified as affecting the biological responses of the coral organism under broadscale thermal anomalies. One such factor is water flow, which is capable of modulating both organismal metabolic functioning and thermal environments. Understanding the physiological and hydrodynamic drivers of organism response to thermal stress improves predictive capabilities and informs targeted management responses, thereby increasing the resilience of reefs into the future.
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