ORCID Profile
0000-0002-2823-0575
Current Organisation
CSIRO
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
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.
Quaternary Environments | Geology | Geochronology
Expanding Knowledge in the Earth Sciences | Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Ecosystem Assessment and Management of Marine Environments |
Publisher: Public Library of Science (PLoS)
Date: 06-12-2022
DOI: 10.1371/JOURNAL.PBIO.3001907
Abstract: Quantifying patterns of dispersal and settlement in marine benthic invertebrates is challenging, largely due the complexity of life history traits, small sizes of larvae ( mm), and potential for large-scale dispersal ( km) in the marine environment. Here, we develop a novel method that allows for immediate differentiation and visual tracking of large numbers of coral larvae (10 6 to 10 9 ) from dispersal to settlement. Neutral red and Nile blue stains were extremely effective in coloring larvae, with minimal impacts on survival and settlement following optimization of incubation times and stain concentrations. Field validation to wild-captured larvae from the Great Barrier Reef demonstrates the efficacy of staining across erse taxa. The method provides a simple, rapid ( minutes), low-cost (approximately USD$1 per 10 5 larva) tool to color coral larvae that facilitates a wide range of de novo laboratory and field studies of larval behavior and ecology with potential applications for conservation planning and understanding patterns of connectivity.
Publisher: Public Library of Science (PLoS)
Date: 22-04-2009
Publisher: The Royal Society
Date: 07-2015
DOI: 10.1098/RSOS.150181
Abstract: Since the Mid-Holocene, some 5000 years ago, coral reefs in the Pacific Ocean have been vertically constrained by sea level. Contemporary sea-level rise is releasing these constraints, providing accommodation space for vertical reef expansion. Here, we show that Porites microatolls, from reef-flat environments in Palau (western Pacific Ocean), are ‘keeping up’ with contemporary sea-level rise. Measurements of 570 reef-flat Porites microatolls at 10 locations around Palau revealed recent vertical skeletal extension (78±13 mm) over the last 6–8 years, which is consistent with the timing of the recent increase in sea level. We modelled whether microatoll growth rates will potentially ‘keep up’ with predicted sea-level rise in the near future, based upon average growth, and assuming a decline in growth for every 1°C increase in temperature. We then compared these estimated extension rates with rates of sea-level rise under four Representative Concentration Pathways (RCPs). Our model suggests that under low–mid RCP scenarios, reef-coral growth will keep up with sea-level rise, but if greenhouse gas concentrations exceed 670 ppm atmospheric CO 2 levels and with +2.2°C sea-surface temperature by 2100 (RCP 6.0 W m −2 ), our predictions indicate that Porites microatolls will be unable to keep up with projected rates of sea-level rise in the twenty-first century.
Publisher: Springer Science and Business Media LLC
Date: 08-10-2012
DOI: 10.1007/S00248-011-9946-0
Abstract: Interactions between corals and associated bacteria and amongst these bacterial groups are likely to play a key role in coral health. However, the complexity of these interactions is poorly understood. We investigated the functional role of specific coral-associated bacteria in maintaining microbial communities on the coral Acropora millepora (Ehrenberg 1834) and the ability of coral mucus to support or inhibit bacterial growth. Culture-independent techniques were used to assess bacterial community structures whilst bacterial culture was employed to assess intra- and inter-specific antimicrobial activities of bacteria. Members of Pseudoalteromonas and ribotypes closely related to Vibrio coralliilyticus displayed potent antimicrobial activity against a range of other cultured isolates and grew readily on detached coral mucus. Although such bacterial ribotypes would be expected to have a competitive advantage, they were rare or absent on intact and healthy coral colonies growing in situ (analysed using denaturing gradient gel electrophoresis and 16S rRNA gene sequencing). The most abundant bacterial ribotypes found on healthy corals were Gammaproteobacteria, previously defined as type A coral associates. Our results indicate that this group of bacteria and specific members of the Alphaproteobacteria described here as 'type B associates' may be important functional groups for coral health. We suggest that bacterial communities on coral are kept in check by a combination of host-derived and microbial interactions and that the type A associates in particular may play a key role in maintaining stability of microbial communities on healthy coral colonies.
Publisher: Wiley
Date: 28-04-2021
DOI: 10.1111/COBI.13738
Abstract: By 2004, Belize was exhibiting classic fishing down of the food web. Groupers (Serranidae) and snappers (Lutjanidae) were scarce and fisheries turned to parrotfishes (Scarinae), leading to a 41% decline in their biomass. Several policies were enacted in 2009–2010, including a moratorium on fishing parrotfish and a new marine park with no‐take areas. Using a 20‐year time series on reef fish and benthos, we evaluated the impact of these policies approximately 10 years after their implementation. Establishment of the Southwater Caye Marine Reserve led to a recovery of snapper at 2 out of 3 sites, but there was no evidence of recovery outside the reserve. Snapper populations in an older reserve continued to increase, implying that at least 9 years is required for their recovery. Despite concerns over the feasibility of banning parrotfish harvest once it has become a dominant fin fishery, parrotfishes returned and exceeded biomass levels prior to the fishery. The majority of these changes involved an increase in parrotfish density species composition and adult body size generally exhibited little change. Recovery occurred equally well in reserves and areas open to other forms of fishing, implying strong compliance. Temporal trends in parrotfish grazing intensity were strongly negatively associated with the cover of macroalgae, which by 2018 had fallen to the lowest levels observed since measurements began in 1998. Coral populations remained resilient and continued to exhibit periods of net recovery after disturbance. We found that a moratorium on parrotfish harvesting is feasible and appears to help constrain macroalgae, which can otherwise impede coral resilience.
Publisher: Wiley
Date: 07-11-2018
DOI: 10.1002/ECM.1336
Publisher: Springer Science and Business Media LLC
Date: 25-12-2007
Publisher: Elsevier BV
Date: 06-2012
Publisher: Proceedings of the National Academy of Sciences
Date: 11-09-2017
Abstract: Branching Acropora corals are highly sensitive to environmental change and warrant close monitoring to avoid irreversible changes in ecosystem health. For the Great Barrier Reef, limited baseline information of ecological dynamics prior to ∼1980 makes it difficult to understand recent ecosystem trends. We demonstrate the use of high-resolution uranium–thorium dating, modern and palaeoecological techniques to improve our understanding of mortality and recovery dynamics over much broader scales. We found a loss of resilience in ecologically important branching Acropora corals at a regional scale. This work will prove valuable to reef managers by providing a reliable baseline for ongoing monitoring and identifying reefs at risk for deterioration, especially for those where modern observations are lacking.
Publisher: Springer Science and Business Media LLC
Date: 20-02-2016
Publisher: Wiley
Date: 02-04-2015
DOI: 10.1111/JBI.12509
Publisher: Copernicus GmbH
Date: 15-05-2020
Publisher: Wiley
Date: 02-2017
DOI: 10.1002/ECY.1663
Abstract: Community succession following disturbance depends on positive and negative interactions, the strength of which change along environmental gradients. To investigate how early succession affects coral reef recovery, we conducted an 18-month experiment in Palau, using recruitment tiles and herbivore exclusion cages. One set of reefs has higher wave exposure and had previously undergone a phase shift to macroalgae following a major typhoon, whereas the other set of reefs have lower wave exposure and did not undergo a macroalgal phase shift. Similar successional trajectories were observed at all sites when herbivores were excluded: turf algae dominated early succession, followed by shifts to foliose macroalgae and heterotrophic invertebrates. However, trajectories differed in the presence of herbivores. At low wave exposure reefs, herbivores promoted coralline algae and limited turf and encrusting fleshy algae in crevice microhabitats, facilitating optimal coral recruitment. Under medium wave exposure, relatively higher but still low coverage of turf and encrusting fleshy algae (15-25%) found in crevice microhabitats inhibited coral recruitment, persisting throughout multiple recruitment events. Our results indicate that altered interaction strength in different wave environments following disturbance can drive subtle changes in early succession that cascade to alter secondary succession to coral recruitment and system recovery.
Publisher: Springer Science and Business Media LLC
Date: 02-11-2016
DOI: 10.1038/SREP36271
Abstract: As climate change progresses, understanding the long-term response of corals and their endosymbionts ( Symbiodinium ) to prolonged environmental change is of immediate importance. Here, a total of 1152 fragments from 72 colonies of three common coral species ( Stylophora pistillata , Pocillopora damicornis , Seriatopora hystrix ) underwent a 32-month reciprocal depth transplantation. Genetic analysis showed that while S. hystrix maintained its generalist symbiont, some S. pistillata and P. damicornis underwent temporary changes in resident symbionts immediately after stress (transplantation natural bleaching). These temporary changes were phylogenetically constrained to ‘host-compatible’ symbionts only and reversion to original symbionts occurred within 7 to 12 months, indicating long-term fidelity and stability of adult symbioses. Measurements of symbiont photo-physiology (dark adapted yield, pressure over photosystem II) and coral health (host protein, bleaching status, mortality) indicated a broad acclimatory capacity. However, this came at an apparent energetic expense as disproportionate mortality amongst symbioses that persisted outside their distribution range was observed following a natural bleaching event. As environmental changes due to climate change become more continuous in nature, sub-lethal effects linked to the existence near tolerance range limits coupled with the inability of adult coral colonies to change resident symbionts makes corals particularly susceptible to additional environmental fluctuations or stress events and reduces the resilience of coral populations.
Publisher: No publisher found
Date: 2017
DOI: 10.5061/DRYAD.FS47H
Publisher: Copernicus GmbH
Date: 15-05-2020
Publisher: Public Library of Science (PLoS)
Date: 2018
Publisher: Public Library of Science (PLoS)
Date: 2015
Publisher: Elsevier BV
Date: 10-2014
Publisher: Wiley
Date: 02-08-2022
DOI: 10.1111/GCB.16323
Abstract: Increases in the magnitude, frequency, and duration of warm seawater temperatures are causing mass coral mortality events across the globe. Although, even during the most extensive bleaching events, some reefs escape exposure to severe stress, constituting potential refugia. Here, we identify present-day climate refugia on the Great Barrier Reef (GBR) and project their persistence into the future. To do this, we apply semi-dynamic downscaling to an ensemble of climate projections released for the IPCC's recent sixth Assessment Report. We find that GBR locations experiencing the least thermal stress over the past 20 years have done so because of their oceanographic circumstance, which implies that longer-term persistence of climate refugia is feasible. Specifically, tidal and wind mixing of warm water away from the sea surface appears to provide relief from warming. However, on average this relative advantage only persists until global warming exceeds ~3°C.
Publisher: The Royal Society
Date: 16-12-2020
Abstract: Sedimentation and overfishing are important local stressors on coral reefs that can independently result in declines in coral recruitment and shifts to algal-dominated states. However, the role of herbivory in driving recovery across environmental gradients is often unclear. Here we investigate early successional benthic communities and coral recruitment across a sediment gradient in Palau, Micronesia over a 12-month period. Total sedimentation rates measured by ‘TurfPods’ varied from 0.03 ± 0.1 SE mg cm −2 d −1 at offshore sites to 1.32 ± 0.2 mg cm −2 d −1 at inshore sites. To assess benthic succession, three-dimensional settlement tiles were deployed at sites with experimental cages used to exclude tile access to larger herbivorous fish. Benthic assemblages exhibited rapid transitions across the sediment gradient within three months of deployment. At low levels of sedimentation (less than 0.6 mg cm −2 d −1 ), herbivory resulted in communities dominated by coral recruitment inducers (short turf algae and crustose coralline algae), whereas exclusion of herbivores resulted in the overgrowth of coral inhibitors (encrusting and upright foliose macroalgae). An ‘inducer threshold’ was found under increasing levels of sedimentation (greater than 0.6 mg cm −2 d −1 ), with coral inducers having limited to no presence in communities, and herbivore access to tiles resulted in sediment-laden turf algal assemblages, while exclusion of herbivores resulted in invertebrates (sponges, ascidians) and terrestrial sediment accumulation. A ‘coral recruitment threshold’ was found at 0.8 mg cm −2 d −1 , below which net coral recruitment was reduced by 50% in the absence of herbivores, while recruitment was minimal above the threshold. Our results highlight nonlinear trajectories of benthic succession across sediment gradients and identify strong interactions between sediment and herbivory that have cascading effects on coral recruitment. Local management strategies that aim to reduce sedimentation and turbidity and manage herbivore fisheries can have measurable effects on benthic community succession and coral recruitment, enhancing reef resilience and driving coral recovery.
Publisher: Springer Science and Business Media LLC
Date: 13-12-2018
DOI: 10.1038/S42003-018-0233-1
Abstract: Overexploitation of large apex marine predators is widespread in the world’s oceans, yet the timing and extent of declines are poorly understood. Here we reconstruct a unique fisheries-independent dataset from a shark control programme spanning 1760 km of the Australian coastline over the past 55 years. We report substantial declines (74–92%) of catch per unit effort of hammerhead (Sphyrnidae), whaler (Carcharhinidae), tiger shark ( Galeocerdo cuvier ) and white sharks ( Carcharodon carcharias ). Following onset of the program in the 1960s, catch rates in new installations in subsequent decades occurred at a substantially lower rate, indicating regional depletion of shark populations over the past half a century. Concurrent declines in body size and the probability of encountering mature in iduals suggests that apex shark populations are more vulnerable to exploitation than previously thought. Ongoing declines and lack of recovery of vulnerable and protected shark species are a cause for concern.
Publisher: Springer Science and Business Media LLC
Date: 12-08-2006
Publisher: Wiley
Date: 25-11-2022
DOI: 10.1111/GCB.15994
Abstract: Tropical coral reefs are among the most sensitive ecosystems to climate change and will benefit from the more ambitious aims of the United Nations Framework Convention on Climate Change's Paris Agreement, which proposed to limit global warming to 1.5° rather than 2°C above pre-industrial levels. Only in the latest Intergovernmental Panel on Climate Change focussed assessment, the Coupled Model Intercomparison Project phase 6 (CMIP6), have climate models been used to investigate the 1.5° warming scenario directly. Here, we combine the most recent model updates from CMIP6 with a semi-dynamic downscaling to evaluate the difference between the 1.5 and 2°C global warming targets on coral thermal stress metrics for the Great Barrier Reef (GBR). By ~2080, severe bleaching events are expected to occur annually under intensifying emissions (shared socioeconomic pathway SSP5-8.5). Adherence to 2° warming (SSP1-2.6) halves this frequency but the main benefit of confining warming to 1.5° (SSP1-1.9) is that bleaching events are reduced further to 3 events per decade. Attaining low emissions of 1.5° is also paramount to prevent the mean magnitude of thermal stress from stabilizing close to a critical thermal threshold (8 Degree Heating Weeks). Thermal stress under the more pessimistic pathways SSP3-7.0 and SSP5-8.5 is three to fourfold higher than the present day, with grave implications for future reef ecosystem health. As global warming continues, our projections also indicate more regional warming in the central and southern GBR than the far north and northern GBR.
Publisher: Springer Science and Business Media LLC
Date: 15-05-2015
Publisher: Elsevier BV
Date: 07-2016
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.
Publisher: Copernicus GmbH
Date: 12-2020
Abstract: Abstract. In recent decades, extensive mortality of reef-building corals throughout the Caribbean region has led to the erosion of reef frameworks and declines in bio ersity. Using field observations, structural models, and high-precision U–Th dating methods, we quantify changes in structural complexity in the major framework-building coral Orbicella annularis over a 20-year period at Long Caye (Belize). Despite extensive mortality following the mass coral bleaching event of 1998, the structural complexity of frameworks remained largely unchanged between 1998 (rugosity index, R, of 2.35±0.1) and 2018 (R of 2.29±0.1). Colony-scale structural complexity was maintained, as the rapid growth of surviving ramets (0.69±0.1 cm yr−1) offset the slower bioerosion of dead ramets (-0.11±0.16 cm yr−1). Despite the apparent stability of the structural complexity at colony scales, bioerosion of in idual dead ramets over 2 decades led to declines in microhabitat complexity, with an overall reduction in the depth of microhabitats within frameworks. Altered microhabitat complexity appears to have negative effects on cryptic fauna, with the grazing urchin Echinometra viridis declining from 1.5±0.4 in iduals m−2 in 1998 to 0.02± in iduals m−2 in 2018. Changes in microhabitat complexity have the potential to alter ecological interactions that can impact recovery dynamics on coral reefs in ways that are undetectable using traditional rugosity metrics of structural complexity.
Publisher: Wiley
Date: 13-10-2014
DOI: 10.1111/GCB.12725
Abstract: Under projections of global climate change and other stressors, significant changes in the ecology, structure and function of coral reefs are predicted. Current management strategies tend to look to the past to set goals, focusing on halting declines and restoring baseline conditions. Here, we explore a complementary approach to decision making that is based on the anticipation of future changes in ecosystem state, function and services. Reviewing the existing literature and utilizing a scenario planning approach, we explore how the structure of coral reef communities might change in the future in response to global climate change and overfishing. We incorporate uncertainties in our predictions by considering heterogeneity in reef types in relation to structural complexity and primary productivity. We examine 14 ecosystem services provided by reefs, and rate their sensitivity to a range of future scenarios and management options. Our predictions suggest that the efficacy of management is highly dependent on biophysical characteristics and reef state. Reserves are currently widely used and are predicted to remain effective for reefs with high structural complexity. However, when complexity is lost, maximizing service provision requires a broader portfolio of management approaches, including the provision of artificial complexity, coral restoration, fish aggregation devices and herbivore management. Increased use of such management tools will require capacity building and technique refinement and we therefore conclude that ersification of our management toolbox should be considered urgently to prepare for the challenges of managing reefs into the 21st century.
Publisher: Springer Science and Business Media LLC
Date: 23-11-2007
Publisher: Public Library of Science (PLoS)
Date: 2013
Publisher: Springer Science and Business Media LLC
Date: 13-02-2009
Publisher: Elsevier BV
Date: 08-2014
Publisher: Public Library of Science (PLoS)
Date: 2013
Publisher: Springer Science and Business Media LLC
Date: 13-03-2015
DOI: 10.1007/S00442-015-3282-X
Abstract: While positive interactions have been observed to influence patterns of recruitment and succession in marine and terrestrial plant communities, the role of facilitation in macroalgal phase shifts is relatively unknown. In December 2012, typhoon Bopha caused catastrophic losses of corals on the eastern reefs of Palau. Within weeks of the typhoon, an ephemeral bloom of monospecific macroalgae (Liagora sp.) was observed, reaching a peak of 38.6% cover in February 2013. At this peak, we observed a proliferation of a second macroalgal species, Lobophora variegata. Lobophora was distributed non-randomly, with higher abundances occurring within the shelter of Liagora canopies than on exposed substrates. Bite rates of two common herbivorous fish (Chlorurus sordidus and Ctenochaetus striatus) were significantly higher outside canopies (2.5- and sixfold, respectively), and cage exclusion resulted in a significant increase in Lobophora cover. Experimental removal of Liagora canopies resulted in a 53.1% decline in the surface area of Lobophora after 12 days, compared to a 51.7% increase within canopies. Collectively, these results indicate that Liagora canopies act as ecological facilitators, providing a 'nursery' exclusion zone from the impact of herbivorous fish, allowing for the establishment of understory Lobophora. While the ephemeral Liagora bloom had disappeared entirely 9 months post-typhoon, the facilitated shift to Lobophora has persisted for over 18 months, dominating ~40% of the reef substrate. While acute disturbance events such as typhoons have been suggested as a mechanism to reverse algal phase shifts, our results suggest that typhoons may also trigger, rather than just reverse, phase shifts.
Publisher: Wiley
Date: 20-06-2013
DOI: 10.1111/MAEC.12040
Publisher: Springer Science and Business Media LLC
Date: 03-04-2014
Publisher: Springer Science and Business Media LLC
Date: 13-04-2014
Publisher: Copernicus GmbH
Date: 26-09-2019
Publisher: Wiley
Date: 11-09-2022
Abstract: Bio ersity of terrestrial and marine ecosystems, including coral reefs, is dominated by small, often cryptic, invertebrate taxa that play important roles in ecosystem structure and functioning. While cryptofauna community structure is determined by strong small‐scale microhabitat associations, the extent to which ecological and environmental factors shape these communities are largely unknown, as is the relative importance of particular microhabitats in supporting reef trophodynamics from the bottom up. The goal of this study was to address these knowledge gaps, provided coral reefs are increasingly exposed to multiple disturbances and environmental gradients that influence habitat complexity, condition and ecosystem functioning. We compared the density, biomass, size range, phylogenetic ersity and functional roles of motile cryptofauna in Palau, Western Micronesia, among four coral‐derived microhabitats representing various states of degradation (live coral [ Acropora and Pocillopora ], dead coral and coral rubble) from reefs along a gradient of effluent exposure. In total, 122 families across ten phyla were identified, dominated by the Arthropoda (Crustacea) and Mollusca. Cryptofauna biomass was greatest in live Pocillopora , while coral rubble contained the greatest density and ersity. Size ranges were broader in live corals than both dead coral and rubble. From a bottom‐up perspective, effluent exposure had mixed effects on cryptic communities including a decline in total biomass in rubble. From a top‐down perspective, cryptofauna were generally unaffected by predator biomass. Our data show that, as coral reef ecosystems continue to decline in response to more frequent and severe disturbances, habitats other than live coral may become increasingly important in supporting coral reef bio ersity and food webs.
Publisher: No publisher found
Date: 2015
DOI: 10.5061/DRYAD.RJ653
Publisher: Springer Science and Business Media LLC
Date: 30-11-2013
Publisher: Wiley
Date: 23-02-2017
Publisher: Wiley
Date: 04-2008
DOI: 10.1111/J.1529-8817.2008.00480.X
Abstract: Morphological diagnosis and descriptions of seven disease-like syndromes affecting scleractinian corals were characterized from the southern Great Barrier Reef (GBR). Chl a fluorescence of PSII was measured using an Imaging-PAM (pulse litude modulated) fluorometer, enabling visualization of the two-dimensional variability in the photophysiology of endosymbiotic dinoflagellates (zooxanthellae) by measuring rapid light curves. Three of four syndromes associated with active tissue loss (type a) were spatially homogenous (white syndrome, brown band, and skeletal eroding band), with no impact on the photochemical function of zooxanthellae populations at or behind the lesion borders. However, a decline in maximum quantum yield (Fv /Fm ) and elevated levels of maximum nonphotochemical quenching (NPQmax ) occurred in visually healthy tissue of black band disease adjacent to the lesion borders, possibly due to hypoxic conditions caused by the black band cyanobacterial mat. Two out of three syndromes associated with pathological change of intact tissue with no active tissue loss (type b) showed variable photophysiological responses (neoplasia and pigmentation response). Only the bleached foci associated with white patch syndrome appeared to impact primarily on the symbiotic dinoflagellates, as evidenced by declines in minimum fluorescence (F0 ) and maximum quantum yield (Fv /Fm ), with no indication of degeneration in the host tissues. Our results suggest that for the majority of coral syndromes from the GBR, pathogenesis occurs in the host tissue, while the impact on the zooxanthellae populations residing in affected corals is minimal.
Publisher: Wiley
Date: 10-2015
DOI: 10.1111/GCB.13006
Abstract: As the frequency and intensity of coral mortality events increase under climate change, understanding how declines in coral cover may affect the bioerosion of reef frameworks is of increasing importance. Here, we explore decadal-scale rates of bioerosion of the framework building coral Orbicella annularis by grazing parrotfish following the 1997/1998 El Niño-related mass mortality event at Long Cay, Belize. Using high-precision U-Th dating and CT scan analysis, we quantified in situ rates of external bioerosion over a 13-year period (1998-2011). Based upon the error-weighted average U-Th age of dead O. annularis skeletons, we estimate the average external bioerosion between 1998 and 2011 as 0.92 ± 0.55 cm depth. Empirical observations of herbivore foraging, and a nonlinear numerical response of parrotfish to an increase in food availability, were used to create a model of external bioerosion at Long Cay. Model estimates of external bioerosion were in close agreement with U-Th estimates (0.85 ± 0.09 cm). The model was then used to quantify how rates of external bioerosion changed across a gradient of coral mortality (i.e., from few corals experiencing mortality following coral bleaching to complete mortality). Our results indicate that external bioerosion is remarkably robust to declines in coral cover, with no significant relationship predicted between the rate of external bioerosion and the proportion of O. annularis that died in the 1998 bleaching event. The outcome was robust because the reduction in grazing intensity that follows coral mortality was compensated for by a positive numerical response of parrotfish to an increase in food availability. Our model estimates further indicate that for an O. annularis-dominated reef to maintain a positive state of reef accretion, a necessity for sustained ecosystem function, live cover of O. annularis must not drop below a ~5-10% threshold of cover.
Publisher: Copernicus GmbH
Date: 26-09-2019
DOI: 10.5194/BG-2019-329
Abstract: Abstract. In recent decades, extensive mortality of reef-building corals throughout the Caribbean region has led to erosion of reef frameworks and declines in bio ersity. Using field observations, structural models and high-precision U-th dating methods, we quantify changes in structural complexity in the major framework building coral Orbicella annularis over a 20-year period at Long Cay (Belize). Despite extensive mortality following the mass coral bleaching event of 1998, structural complexity of frameworks remained largely unchanged between 1998 (rugosity index = 2.35 ± 0.1) and 2018 (2.29 ± 0.1). Reef-scale structural complexity was maintained through rapid growth of surviving ramets (0.69 ± 0.1 cm yr−1) offsetting slower bioerosion of dead ramets (−0.11 ± 0.16 cm yr−1). Despite apparent stability of structural complexity at reef-scales, bioerosion of in idual dead ramets over two decades led to declines in microhabitat complexity, with an overall reduction of the depth of microhabitats within frameworks. Altered microhabitat complexity appears to have negative effects for cryptic fauna, with the grazing urchin Echinometra viridis declining from 1.5 ± 0.4 per m2 in 1998 to 0.02 ± 0.02 per m2 in 2018. Changes in microhabitat complexity have the potential to alter ecological interactions that can impact recovery dynamics on coral reefs in ways that are undetectable using reef-scale metrics of structural complexity.
Publisher: Public Library of Science (PLoS)
Date: 2009
Publisher: Public Library of Science (PLoS)
Date: 2009
Publisher: Wiley
Date: 11-02-2022
DOI: 10.1002/ECY.3621
Publisher: Springer Science and Business Media LLC
Date: 10-2008
Publisher: Springer Science and Business Media LLC
Date: 13-09-2008
Publisher: Wiley
Date: 13-03-2021
DOI: 10.1002/ECY.3303
Abstract: Global overfishing of higher‐level predators has caused cascading effects to lower trophic levels in many marine ecosystems. On coral reefs, which support highly erse food webs, the degree to which top‐down trophic cascades can occur remains equivocal. Using extensive survey data from coral reefs across the relatively unfished northern Great Barrier Reef (nGBR), we quantified the role of reef sharks in structuring coral reef fish assemblages. Using a structural equation modeling (SEM) approach, we explored the interactions between shark abundance and teleost mesopredator and prey functional group density and biomass, while explicitly accounting for the potentially confounding influence of environmental variation across sites. Although a fourfold difference in reef shark density was observed across our survey sites, this had no impact on either the density or biomass of teleost mesopredators or prey, providing evidence for a lack of trophic cascading across nGBR systems. Instead, many functional groups, including sharks, responded positively to environmental drivers. We found reef sharks to be positively associated with habitat complexity. In turn, physical processes such as wave exposure and current velocity were both correlated well with multiple functional groups, reflecting how changes to energetic conditions and food availability, or modification of habitat affect fish distribution. The ersity of species within coral reef food webs and their associations with bottom‐up drivers likely buffers against trophic cascading across GBR functional guilds when reef shark assemblages are depleted, as has been demonstrated in other complex ecosystems.
Publisher: Public Library of Science (PLoS)
Date: 13-09-2013
Publisher: Geological Society of America
Date: 04-2015
DOI: 10.1130/G36478.1
Publisher: Springer Science and Business Media LLC
Date: 30-03-2017
Publisher: Elsevier BV
Date: 07-2012
DOI: 10.1016/J.TREE.2012.04.007
Abstract: The great sensitivity of coral reefs to climate change has raised concern over their resilience. An emerging body of resilience theory stems largely from research carried out in a single biogeographic region the Caribbean. Such geographic bias raises the question of transferability of concepts among regions. In this article, we identify factors that might predispose the Caribbean to its low resilience, including faster rates of macroalgal growth, higher rates of algal recruitment, basin-wide iron-enrichment of algal growth from aeolian dust, a lack of acroporid corals, lower herbivore biomass and missing groups of herbivores. Although mechanisms of resilience are likely to be ubiquitous, our analysis suggests that Indo-Pacific reefs would have to be heavily degraded to exhibit bistability or undergo coral-macroalgal phase shifts.
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.MARPOLBUL.2014.07.038
Abstract: Measurements of coral structural strength are coupled with a fluid dynamics-structural analysis to investigate the resilience of coral to wave loading under sea level rise and a typical Great Barrier Reef lagoon wave climate. The measured structural properties were used to determine the wave conditions and flow velocities that lead to structural failure. Hydrodynamic modelling was subsequently used to investigate the type of the bathymetry where coral is most vulnerable to breakage under cyclonic wave conditions, and how sea level rise (SLR) changes this vulnerability. Massive corals are determined not to be vulnerable to wave induced structural damage, whereas branching corals are susceptible at wave induced orbital velocities exceeding 0.5m/s. Model results from a large suite of idealised bathymetry suggest that SLR of 1m or a loss of skeleton strength of order 25% significantly increases the area of reef flat where branching corals are exposed to damaging wave induced flows.
Publisher: Public Library of Science (PLoS)
Date: 07-12-2011
Publisher: Elsevier BV
Date: 05-2016
DOI: 10.1016/J.TREE.2016.02.014
Abstract: Sharks are considered the apex predator of coral reefs, but the consequences of their global depletion are uncertain. Here we explore the ecological roles of sharks on coral reefs and, conversely, the importance of reefs for sharks. We find that most reef-associated shark species do not act as apex predators but instead function as mesopredators along with a erse group of reef fish. While sharks perform important direct and indirect ecological roles, the evidence to support hypothesised shark-driven trophic cascades that benefit corals is weak and equivocal. Coral reefs provide some functional benefits to sharks, but sharks do not appear to favour healthier reef environments. Restoring populations of sharks is important and can yet deliver ecological surprise.
Publisher: Springer Science and Business Media LLC
Date: 18-03-2006
Publisher: The Royal Society
Date: 07-01-2013
Abstract: The inshore reefs of the Great Barrier Reef (GBR) have undergone significant declines in water quality following European settlement (approx. 1870 AD). However, direct evidence of impacts on coral assemblages is limited by a lack of historical baselines prior to the onset of modern monitoring programmes in the early 1980s. Through palaeoecological reconstructions, we report a previously undocumented historical collapse of Acropora assemblages at Pelorus Island (central GBR). High-precision U-series dating of dead Acropora fragments indicates that this collapse occurred between 1920 and 1955, with few dates obtained after 1980. Prior to this event, our results indicate remarkable long-term stability in coral community structure over centennial scales. We suggest that chronic increases in sediment flux and nutrient loading following European settlement acted as the ultimate cause for the lack of recovery of Acropora assemblages following a series of acute disturbance events (SST anomalies, cyclones and flood events). Evidence for major degradation in reef condition owing to human impacts prior to modern ecological surveys indicates that current monitoring of inshore reefs on the GBR may be predicated on a significantly shifted baseline.
Publisher: Springer Science and Business Media LLC
Date: 06-12-2008
Abstract: Coral bleaching occurs when the endosymbiosis between corals and their symbionts disintegrates during stress. Mass coral bleaching events have increased over the past 20 years and are directly correlated with periods of warm sea temperatures. However, some hypotheses have suggested that reef-building corals bleach due to infection by bacterial pathogens. The 'Bacterial Bleaching' hypothesis is based on laboratory studies of the Mediterranean invading coral, Oculina patagonica, and has further generated conclusions such as the coral probiotic hypothesis and coral hologenome theory of evolution. We aimed to investigate the natural microbial ecology of O. patagonica during the annual bleaching using fluorescence in situ hybridization to map bacterial populations within the coral tissue layers, and found that the coral bleaches on the temperate rocky reefs of the Israeli coastline without the presence of Vibrio shiloi or bacterial penetration of its tissue layers. Bacterial communities were found associated with the endolithic layer of bleached coral regions, and a community dominance shift from an apparent cyanobacterial-dominated endolithic layer to an algal-dominated layer was found in bleached coral s les. While bacterial communities certainly play important roles in coral stasis and health, we suggest environmental stressors, such as those documented with reef-building corals, are the primary triggers leading to bleaching of O. patagonica and suggest that bacterial involvement in patterns of bleaching is that of opportunistic colonization.
Publisher: Elsevier BV
Date: 03-2016
Publisher: Public Library of Science (PLoS)
Date: 27-12-2011
Publisher: Public Library of Science (PLoS)
Date: 26-05-2015
Publisher: Springer Science and Business Media LLC
Date: 23-11-2020
Location: Australia
Start Date: 2018
End Date: 2021
Funder: Australian Research Council
View Funded ActivityStart Date: 02-2018
End Date: 03-2023
Amount: $416,584.00
Funder: Australian Research Council
View Funded Activity