ORCID Profile
0000-0002-3476-6595
Current Organisation
Australian Institute of Marine Science
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Marine and Estuarine Ecology (incl. Marine Ichthyology) | Population, Ecological and Evolutionary Genetics | Invasive Species Ecology | Genetics
Control of Pests, Diseases and Exotic Species in Marine Environments | Tourism not elsewhere classified | Marine Flora, Fauna and Biodiversity |
Publisher: BENTHAM SCIENCE PUBLISHERS
Date: 27-08-2012
DOI: 10.2174/978160805121211101010187
Abstract: In this chapter we review the effects of anthropogenically derived chemical pollutants on tropical coral reef ecosystems. A wide range of compounds, including pesticides, trace metals and petroleum hydrocarbons enter reef systems through various pathways and affect different reef species and/or life history stages. Tools for evaluation of chemical stress on coral reefs consist of molecular, biochemical, physiological and ecological bioindicators, providing information at organismal or community levels. This chapter collates and assesses available information on different chemical stressors in the marine environment and the effects on reef-building corals. Ecological effects from chemical stressors are strongly dependent on exposure characteristics. Three probable pollution scenarios are discussed and their in idual properties evaluated. Short-term, pulse-like pollution events including oil spills or antifoulant deposition through ship groundings often have a direct and severe impact upon multiple trophic levels of the system. However, these events are typically localised and possibly irrelevant on an ecosystem-wide scale. In contrast, recurring pollution events such as input from river floods or chronic pollution from land runoff (e.g. sewage treatment effluent or herbicides), may exert subtle effects on lower trophic levels of the system, affecting species fitness and driving adaptation. Effects from recurring or chronic pollution are more likely to combine and interact with other environmental factors, but remain poorly understood. Over time, chronic sub-lethal stress may decrease resilience of reef organisms to other forms of environmental stress like elevated sea surface temperatures and ocean acidification.
Publisher: Research Square Platform LLC
Date: 03-2021
Publisher: Elsevier BV
Date: 11-2001
Publisher: Springer Science and Business Media LLC
Date: 12-12-2000
Publisher: Springer Science and Business Media LLC
Date: 24-07-1999
Publisher: Wiley
Date: 19-09-2023
DOI: 10.1111/MEC.17124
Publisher: Springer Science and Business Media LLC
Date: 19-04-2014
Publisher: Springer Science and Business Media LLC
Date: 03-12-2010
Publisher: Wiley
Date: 02-2009
DOI: 10.1890/07-2136.1
Publisher: Frontiers Media SA
Date: 23-08-2017
Publisher: Inter-Research Science Center
Date: 2002
DOI: 10.3354/MEPS241221
Publisher: Springer Science and Business Media LLC
Date: 25-06-2013
Publisher: Springer Science and Business Media LLC
Date: 30-09-2019
DOI: 10.1007/S00227-019-3582-5
Abstract: Outbreaks of crown-of-thorns seastars (CoTS Acanthaster spp.) are a major contributor to degradation of Indo-Pacific coral reefs. Understanding the dispersal and fate of planktonic life stages is crucial to understand and manage outbreaks, but visual detection of CoTS larvae is challenging. We apply a quantitative PCR (qPCR) assay to enumerate CoTS larvae in a 3-year time series of plankton s les from two reefs (Agincourt and Moore Reefs) on the Great Barrier Reef. Plankton surveys were complemented with settlement assays, and benthic surveys of juvenile and adult densities over time. Only one out of 109 plankton s les from Agincourt Reef had detectable CoTS mtDNA compared to 41 out of 575 s les from Moore Reef. This may be explained by differences in adult densities, or differences in connectivity and larval retention. Detections of larval CoTS were restricted to summer (November–February), with first detections each year coinciding with water temperatures reaching 28 °C and peak detections late December. A disproportionate number of larval detections occurred in 7 days around full moon. Complementary s ling of settlement and post-settlement life stages confirmed that elevated densities of CoTS larvae at Moore Reef translated to high rates of settlement adding to infestations at this reef. Moreover, there were declines in the detection of larvae, as well densities of juvenile and adult CoTS at Moore Reef, in 2017 and 2018. This study demonstrates that qPCR for genetic identification and quantification of larvae can assist to elucidate life history parameters of nuisance species difficult to obtain with other tools.
Publisher: Inter-Research Science Center
Date: 17-02-2015
DOI: 10.3354/MEPS11088
Publisher: Elsevier BV
Date: 10-2008
Publisher: Elsevier BV
Date: 09-2010
DOI: 10.1016/J.YMPEV.2010.04.013
Abstract: The Stichopodidae comprise a erse assemblage of holothuroids most of which occur in the Indo-Pacific. Phylogenetic analyses of mitochondrial gene (COI, 16S rRNA) sequence for 111 in iduals (7 genera, 17 species) clarified taxonomic uncertainties, species relationships, biogeography and evolution of the family. A monophyly of the genus Stichopus was supported with the exception of Stichopus ellipes. Molecular analyses confirmed genus level taxonomy based on morphology. Most specimens harvested as S. horrens fell in the S. monotuberculatus clade, a morphologically variable assemblage with others from the S. naso clade. Taxonomic clarification of species fished as S. horrens will assist conservation measures. Evolutionary rates based on comparison of sequence from trans-ithmian Isostichopus species estimated that Stichopus and Isostichopus erged ca. 5.5-10.7Ma (Miocene). More recent splits were estimated to be younger than 1Ma.
Publisher: Wiley
Date: 28-10-2013
Abstract: Microorganisms form symbiotic partnerships with a erse range of marine organisms and can be critical to the health and survival of their hosts. Despite the importance of these relationships, the sensitivity of symbiotic microbes to ocean acidification (OA) is largely unknown and this needs to be redressed to adequately predict marine ecosystem resilience in a changing climate. We adopted a profiling approach to explore the sensitivity of microbes associated with coral reef biofilms and representatives of three ecologically important calcifying invertebrate phyla [corals, foraminifera and crustose coralline algae (CCA)] to OA. The experimental design for this study comprised four pHs consistent with current IPCC predictions for the next few centuries (pHNIST 8.1, 7.9, 7.7, 7.5) these pH CO₂ conditions were produced in flow-through aquaria using CO₂ bubbling. All reduced pH/increased pCO₂ treatments caused clear differences in the microbial communities associated with coral, foraminifera, CCA and reef biofilms over 6 weeks, while no visible signs of host stress were detected over this period. The microbial communities of coral, foraminifera, CCA and biofilms were significantly different between pH 8.1 (pCO₂ = 464 μatm) and pH 7.9 (pCO₂ = 822 μatm), a concentration likely to be exceeded by the end of the present century. This trend continued at lower pHs/higher pCO₂. 16S rRNA gene sequencing revealed variable and species-specific changes in the microbial communities with no microbial taxa consistently present or absent from specific pH treatments. The high sensitivity of coral, foraminifera, CCA and biofilm microbes to OA conditions projected to occur by 2100 is a concern for reef ecosystems and highlights the need for urgent research to assess the implications of microbial shifts for host health and coral reef processes.
Publisher: Springer Science and Business Media LLC
Date: 02-03-2007
Publisher: CRC Press
Date: 06-12-2016
Publisher: Elsevier BV
Date: 10-2020
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/MF00064
Abstract: To determine the effect of asexual reproduction by transverse fission on the population structure of holothurians, ensities and in idual weights of Holothuria atra (JÄÄger,1833)and Stichopus chloronotus (Brandt, 1835)were measured over a 26-month period on near-shore reefs of the Great Barrier Reef. Densities of H.atra (0.01—0.69 in iduals m –2 )and S. chloronotus (0.11—1.67) did not increase during periods of intense asexual reproduction, and the density on each reef remained relatively stable.The effect of fission was clearly visible in the weight —frequency distributions of both species. The average in idual wet weight in each population declined (H. atra from 105/134 g to 64/94 g in two respective populations S. chloronotus from 128/302 g to 82/190 g in two respective populations) with the onset of fission in early winter, and more in iduals in the weight range of fission products were found. The biomass followed the seasonal trend of the average weights for both species, with minimum values in winter. A conceptual model based on these and previous findings identified five possible factors (mortality, habitat stability, optimum in idual size, food availability, larval supply) involved in promoting or repressing transverse fission, and the model indicated the consequences for the population.
Publisher: MDPI AG
Date: 07-02-2017
DOI: 10.3390/D9010008
Publisher: Inter-Research Science Center
Date: 28-06-2018
DOI: 10.3354/MEPS12601
Publisher: Elsevier BV
Date: 05-2021
Publisher: CRC Press
Date: 16-11-2022
Publisher: Springer Science and Business Media LLC
Date: 13-02-2016
Publisher: Public Library of Science (PLoS)
Date: 09-03-2016
Publisher: Wiley
Date: 03-02-2011
Publisher: Springer Science and Business Media LLC
Date: 10-01-2013
Publisher: Springer Science and Business Media LLC
Date: 23-02-2016
DOI: 10.1038/SREP21936
Abstract: Large benthic foraminifera (LBF) are important for reef sediment formation, but sensitive to elevated temperature and nutrients. However, it is possible that conspecific foraminifera living in different reef sites present ergent response to environmental shifts. We investigated how populations of Amphistegina lobifera from reef sites located along a temperature and nutrient gradient of the northern Great Barrier Reef respond and acclimate to elevated temperature and nitrate under lab-controlled conditions. Generalized linear mixed models showed that interaction between reef sites and temperature or nitrate conditions had a significant effect on survivorship, bleaching frequency and growth rates of A. lobifera . Further physiological analyses of antioxidant capacity and Ca-ATPase activity showed that populations collected from the inner-shelf sites (highest nutrient levels, largest temperature variation) were consistently able to acclimate to both parameters after 30 days. In contrast, foraminifera collected from the reef sites located in the mid- and outer-shelfs were significantly more sensitive to elevated temperatures and nitrate. Our results highlight the importance of local habitat in shaping the tolerance of LBF to changing environmental conditions populations that live in stable environments are more sensitive to elevated temperature and nitrate, even within their fundamental tolerance range, than those that experience fluctuating conditions.
Publisher: Wiley
Date: 18-08-2019
DOI: 10.1002/ECE3.5563
Publisher: Springer Science and Business Media LLC
Date: 28-08-1998
Publisher: Cold Spring Harbor Laboratory
Date: 30-06-2023
DOI: 10.1101/2023.06.28.546961
Abstract: Lewontin’s paradox, the observation that levels of genetic ersity (π) among animals do not scale linearly with variation in census population sizes ( N c ), is an evolutionary conundrum, where the most extreme mismatches between π and N c are found for highly abundant marine invertebrates. Yet, whether new mutations influence π relative to extrinsic processes remains unknown for most taxa. Here, we provide the first direct germline mutation rate ( μ ) estimate for a marine invertebrate, using high-coverage (60x) whole-genome sequencing of wild-caught Acanthaster cf. solaris crown-of-thorns sea stars (Echinodermata). We also provide empirical estimates of adult N c in Australia’s Great Barrier Reef to jointly examine the determinants of π. Based on direct observations of 63 de novo mutations across 14 parent-offspring trios, the A. cf. solaris mean μ was 9.13 x 10 -09 mutations per-site per-generation (95% CI: 6.51 x 10 -09 to 1.18 x 10 -08 ). This value exceeds estimates for other invertebrates, showing greater concordance with reported vertebrate germline mutation rates. Lower-than-expected N e (∼70,000-180,000) and low N e / N c values (0.0047-0.048) indicated significant genetic drift and weak influences of contemporary population outbreaks on long-term π. Our findings of elevated μ and low N e in A. cf. solaris may help explain high mutational loads and extreme polymorphism levels observed in some marine invertebrate taxa and are consistent with μ evolving in response to N e (drift-barrier hypothesis). This study advances our understanding of the processes controlling levels of natural genetic variation and provides new data valuable for further testing hypotheses about mutation rate evolution across animal phyla.
Publisher: Springer Science and Business Media LLC
Date: 24-09-2006
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.CBPA.2015.02.018
Abstract: Around volcanic carbon dioxide (CO2) seeps in Papua New Guinea, partial pressures of CO2 (pCO2) approximate those as predicted for the end of this century, and coral communities have low ersity and low structural complexity. To assess the mechanisms for such community shifts in response to ocean acidification, we examined the physiological performance of two hard corals that occur with increased or unaltered abundance at a seep site (mean pHTotal=7.8, pCO2=862 μatm) compared to a control site (mean pHTotal=8.1, pCO2=323 μatm), namely massive Porites spp. and Pocillopora damicornis, and two species with reduced abundance, Acropora millepora and Seriatopora hystrix. Oxygen fluxes, calcification, and skeletal densities were analyzed in corals originating from the seep and control site. Net photosynthesis rates increased considerably in Porites spp. and A. millepora and slightly in P. damicornis at increased pCO2, but remained unaltered in S. hystrix. Dark respiration rates remained constant in all corals investigated from both sites. Rates of light calcification declined in S. hystrix at high pCO2, but were unaffected by pCO2 in the other three coral taxa. Dark and net calcification rates remained unchanged in massive Porites and P. damicornis, but were drastically reduced at high pCO2 in A. millepora and S. hystrix. However, skeletal densities were similar at both seep and control sites in all coral taxa investigated. Our data suggest that the pCO2-tolerant corals were characterized by an increased ability to acclimatize to ocean acidification, e.g. by maintaining net calcification. Thus, robust corals, such as Porites spp. and P. damicornis, are more likely to persist for longer in a future high pCO2 world than those unable to acclimatize.
Publisher: Inter-Research Science Center
Date: 02-06-2022
DOI: 10.3354/MEPS14055
Abstract: Climate change impacts and light attenuation from suspended sediments, due to runoff, natural resuspension or dredging, can both impede the replenishment of coral populations. Here we tested the independent and combined impacts of climate change (current temperature and dissolved CO 2 , and 2 future climate scenarios) and a 1 mo long light attenuation period at 5 different light levels (0.1 to 4 mol photons m -2 d -1 ) on early Acropora millepora recruits. Additionally, we evaluated whether the effects were age dependent by comparing responses of recruits that were 1 mo old (‘early attenuation’) vs. 2 mo old (‘late attenuation’). Recruit survival, size and Symbiodiniaceae densities increased slightly under moderate future climate conditions (current temperature +0.44°C, 692 ppm pCO 2 ), but decreased under a more severe climate scenario (+0.94°C, 985 ppm pCO 2 ). Light attenuation significantly decreased recruit survival, size and Symbiodiniaceae densities only for recruits exposed to the late attenuation, suggesting an increasing reliance on photosynthesis as recruits age. Under the more severe climate scenario tested, recruit survival was diminished by both climate change (≤18 ± 4% [SE] in the early attenuation) and light limitation (≤32 ± 6% in the late attenuation) compared with controls. However, there was no interaction between future climate scenarios and light attenuation, indicating that these effects were additive. This study demonstrates the potential effects of light limitation and future climate conditions on coral recruitment success and highlights the need to manage the timing of sediment-generating activities near reefs to optimise light availability for several months post settlement.
Publisher: Springer Science and Business Media LLC
Date: 13-01-2016
DOI: 10.1038/SREP19324
Abstract: Key calcifying reef taxa are currently threatened by thermal stress associated with elevated sea surface temperatures (SST) and reduced calcification linked to ocean acidification (OA). Here we undertook an 8 week experimental exposure to near-future climate change conditions and explored the microbiome response of the corals Acropora millepora and Seriatopora hystrix , the crustose coralline algae Hydrolithon onkodes , the foraminifera Marginopora vertebralis and Heterostegina depressa and the sea urchin Echinometra sp. Microbial communities of all taxa were tolerant of elevated p CO 2 /reduced pH, exhibiting stable microbial communities between pH 8.1 ( p CO 2 479–499 μatm) and pH 7.9 ( p CO 2 738–835 μatm). In contrast, microbial communities of the CCA and foraminifera were sensitive to elevated seawater temperature, with a significant microbial shift involving loss of specific taxa and appearance of novel microbial groups occurring between 28 and 31 °C. An interactive effect between stressors was also identified, with distinct communities developing under different p CO 2 conditions only evident at 31 °C. Microbiome analysis of key calcifying coral reef species under near-future climate conditions highlights the importance of assessing impacts from both increased SST and OA, as combinations of these global stressors can lify microbial shifts which may have concomitant impacts for coral reef structure and function.
Publisher: Elsevier BV
Date: 09-2007
Publisher: Elsevier BV
Date: 12-2022
DOI: 10.1016/J.SCITOTENV.2022.158143
Abstract: Outbreaks of the corallivorous Crown-of-Thorns Seastar (CoTS) Acanthaster cf. solaris contribute significantly to coral reef loss. Control of outbreaks is h ered because standard monitoring techniques do not detect outbreaks at early (low density) stages, thus preventing early intervention. We previously demonstrated that eDNA monitoring can detect CoTS at intermediate densities. Here, we test whether detection probability can be improved by (i) targeted site selection or collection at specific times and (ii) moving from an average eDNA copy number approach (based on the limit of quantification) to a presence/absence approach (based on the limit of detection). Using a dataset collected over three years and multiple reef sites, we demonstrated that adding water residence age, sea surface level and temperature into generalized linear models explained low amounts of variance of eDNA copy numbers. Site specific CoTS density, by contrast, was a significant predictor for eDNA copy numbers. Bayesian multi-scale occupancy modelling of the presence/absence data demonstrated that the probability of s le capture (θ) on most reefs with intermediate or high CoTS densities was >0.8. Thus, confirming CoTS presence on these reefs would only require 2-3 s les. S le capture decreased with decreasing CoTS density. Collecting ten filters was sufficient to reliably (based on the lower 95 % Credibility Interval) detect CoTS below nominal outbreak levels (3 Ind. ha
Publisher: Elsevier BV
Date: 07-2008
Publisher: Springer Science and Business Media LLC
Date: 04-01-2017
DOI: 10.1038/SREP39930
Abstract: When several models can describe a biological process, the equation that best fits the data is typically considered the best. However, models are most useful when they also possess biologically-meaningful parameters. In particular, model parameters should be stable, physically interpretable, and transferable to other contexts, e.g. for direct indication of system state, or usage in other model types. As an ex le of implementing these recommended requirements for model parameters, we evaluated twelve published empirical models for temperature-dependent tropical seagrass photosynthesis, based on two criteria: (1) goodness of fit, and (2) how easily biologically-meaningful parameters can be obtained. All models were formulated in terms of parameters characterising the thermal optimum ( T opt ) for maximum photosynthetic rate ( P max ). These parameters indicate the upper thermal limits of seagrass photosynthetic capacity, and hence can be used to assess the vulnerability of seagrass to temperature change. Our study exemplifies an approach to model selection which optimises the usefulness of empirical models for both modellers and ecologists alike.
Publisher: Copernicus GmbH
Date: 14-09-2015
Abstract: Abstract. There are concerns that Mg-calcite crustose coralline algae (CCA), which are key reef builders on coral reefs, will be most susceptible to increased rates of dissolution under higher pCO2 and ocean acidification. Due to the higher solubility of Mg-calcite, it has been hypothesised that magnesium concentrations in CCA Mg-calcite will decrease as the ocean acidifies, and that this decrease will make their skeletons more chemically stable. In addition to Mg-calcite, CCA Porolithon onkodes, the predominant encrusting species on tropical reefs, can have dolomite (Ca0.5Mg0.5CO3) infilling cell spaces which increases their stability. However, nothing is known about how bio-mineralised dolomite formation responds to higher pCO2. Using P. onkodes grown for 3 and 6 months in tank experiments, we aimed to determine (1) if mol % MgCO3 in new crust and new settlement was affected by increasing CO2 levels (365, 444, 676 and 904 μatm), (2) whether bio-mineralised dolomite formed within these time frames, and (3) if so, whether this was effected by CO2. Our results show that there was no significant effect of CO2 on mol % MgCO3 in any s le set, indicating an absence of a plastic response under a wide range of experimental conditions. Dolomite within the CCA cells formed within 3 months and dolomite abundance did not vary significantly with CO2 treatment. While evidence mounts that climate change will impact many sensitive coral and CCA species, the results from this study indicate that reef-building P. onkodes will continue to form stabilising dolomite infill under near-future acidification conditions, thereby retaining its higher resistance to dissolution.
Publisher: Springer Science and Business Media LLC
Date: 08-2017
Publisher: Wiley
Date: 2015
DOI: 10.1002/LNO.10021
Publisher: Oxford University Press (OUP)
Date: 24-06-2005
Publisher: Public Library of Science (PLoS)
Date: 03-03-2016
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CC00933A
Abstract: Polymorphic metal-organic framework (MOF) materials offer a platform for small-scale separation of complex mixtures of polycyclic aromatic hydrocarbons (PAHs) and polar compounds. Retention factors show dependence on both analyte dimensions and polarity, suggesting mixed-mode separation, allowing complete resolution of some analytes from multi-component mixtures.
Publisher: Informa UK Limited
Date: 2009
Publisher: The Royal Society
Date: 05-10-2013
Abstract: The stunting effect of ocean acidification on development of calcifying invertebrate larvae has emerged as a significant effect of global change. We assessed the arm growth response of sea urchin echinoplutei, here used as a proxy of larval calcification, to increased seawater acidity/ p CO 2 and decreased carbonate mineral saturation in a global synthesis of data from 15 species. Phylogenetic relatedness did not influence the observed patterns. Regardless of habitat or latitude, ocean acidification impedes larval growth with a negative relationship between arm length and increased acidity/ p CO 2 and decreased carbonate mineral saturation. In multiple linear regression models incorporating these highly correlated parameters, p CO 2 exerted the greatest influence on decreased arm growth in the global dataset and also in the data subsets for polar and subtidal species. Thus, reduced growth appears largely driven by organism hypercapnia. For tropical species, decreased carbonate mineral saturation was most important. No single parameter played a dominant role in arm size reduction in the temperate species. For intertidal species, the models were equivocal. Levels of acidification causing a significant (approx. 10–20+%) reduction in arm growth varied between species. In 13 species, reduction in length of arms and supporting skeletal rods was evident in larvae reared in near-future ( p CO 2 800+ µatm) conditions, whereas greater acidification ( p CO 2 1000+ µatm) reduced growth in all species. Although multi-stressor studies are few, when temperature is added to the stressor mix, near-future warming can reduce the negative effect of acidification on larval growth. Broadly speaking, responses of larvae from across world regions showed similar trends despite disparate phylogeny, environments and ecology. Larval success may be the bottleneck for species success with flow-on effects for sea urchin populations and marine ecosystems.
Publisher: Wiley
Date: 28-10-2020
Publisher: Springer Science and Business Media LLC
Date: 07-10-2005
Publisher: Canadian Science Publishing
Date: 04-2004
DOI: 10.1139/F04-013
Abstract: Population genetics analyses should be considered when releasing hatchery-produced juveniles of the sea cucumber Holothuria scabra when spawners from nonlocal populations are used. In New Caledonia, within-region genetic heterogeneity of H. scabra populations (examined through allozyme electrophoresis of 258 animals) indicated high gene flow between nine sites and F ST values did not deviate significantly from zero. However, exact tests indicated that populations at two sites with limited water exchange in the southern location were significantly different from populations at three other locations on the west coast. Inclusion of H. scabra s led in Bali (n = 90) and Knocker Bay, Australia (n = 47), and comparisons with existing data from the west Pacific (Torres Strait, Solomon Islands, Upstart Bay, Hervey Bay) showed that populations were significantly different (using exact tests) and s les partitioned distinctly using unweighted pair group method with arithmetic mean clustering. Rogers' genetic distance values between populations were significantly related to geographic distances, showing a pattern of isolation by distance. The rapid increase in genetic distance over the first few hundred kilometres supports the view that the spatial extent of any translocation needs to be carefully considered on the basis of knowledge of variation in allele frequencies within the target area.
Publisher: Springer Science and Business Media LLC
Date: 03-05-2013
DOI: 10.1038/SREP01769
Publisher: Springer Science and Business Media LLC
Date: 12-09-2018
DOI: 10.1007/S00338-018-1734-6
Abstract: Coral loss through consumption by corallivorous crown-of-thorns seastars (CoTS, Acanthaster spp. ) is a major contributor to the coral reef crisis in the Indo-Pacific region. The fourth wave of Acanthaster cf. solaris outbreaks since the 1960s started around 2010 on Australia’s Great Barrier Reef. Ecological monitoring failed to detect early outbreak stages, thus preventing timely intervention. Here, we develop a digital droplet PCR (ddPCR)-based method to detect environmental DNA (eDNA) of CoTS in 2-l water s les that can be compared with abundances of the species recorded by ers along 200-m 2 transects. Aquarium tests demonstrated that eDNA was readily detectable and increases proportional to the biomass of CoTS ( R 2 = 0.99, p 0.0001). Adaptation from a quantitative PCR technique developed for CoTS larvae (Doyle et al. in Marine Biology 164:176, 2017) to ddPCR improved the limit of quantification (LOQ) by a factor of 45. During field verification on 11 reefs, CoTS eDNA was detectable on all reefs suffering outbreaks. In contrast, CoTS eDNA was absent from ‘post-outbreak’ reefs after populations collapsed and from ‘pre-outbreak’ reefs. In linear models, CoTS densities explained a high amount of variance of eDNA concentrations, both for water s les taken at the depth of transects ( R 2 = 0.60, p 0.0001) and on the sea surface ( R 2 = 0.46, p = 0.0004). The proportion of s les above LOQ was also correlated with CoTS densities, with a similar amount of variance explained as for the concentration (underwater R 2 = 0.68, p 0.0001 surface R 2 = 0.49, p = 0.0004). We conclude that, after consideration of s ling locations and times, this method is promising for CoTS population monitoring and early detection of outbreaks and might supplement or replace traditional monitoring. Development of automated s lers and possibly on board PCR in the future will further improve early detection.
Publisher: Springer Science and Business Media LLC
Date: 27-09-2017
Publisher: Inter-Research Science Center
Date: 05-03-2020
DOI: 10.3354/MEPS13236
Abstract: Few studies have investigated the effects of ocean warming and acidification on marine benthic organisms over ecologically relevant time scales. We used an environmentally controlled coral reef mesocosm system to assess growth and physiological responses of the sea urchin species Echinometra sp. A over 2 generations. Each mesocosm was controlled for temperature and p CO 2 over 29 mo under 3 climate change scenarios (present day and predicted states in 2050 and 2100 under RCP 8.5). The system maintained treatment conditions including annual temperature cycles and a daily variation in p CO 2 . Over 20 mo, adult Echinometra exhibited no significant difference in size and weight among the treatments. Growth rates and respiration rates did not differ significantly among treatments. Urchins from the 2100 treatment had elevated ammonium excretion rates and reduced O 2 :N ratios, suggesting a change in catabolism. We detected no difference in spawning index scores or oocyte size after 20 mo in the treatments, suggesting that gonad development was not impaired by variations in p CO 2 and temperature reflecting anticipated climate change scenarios. Larvae produced from experimentally exposed adults were successfully settled from all treatments and raised for 5 mo inside the mesocosm. The final size of these juveniles exhibited no significant difference among treatments. Overall, we demonstrated that the mesocosm system provided a near natural environment for this urchin species. Climate change and ocean acidification did not affect the benthic life stages investigated here. Importantly, in previous short-term (weeks to months) experiments, this species exhibited reductions in growth and gonad development, highlighting the potential for short-term experiments with non-acclimated animals to yield contrasting, possibly erroneous results.
Publisher: Springer Science and Business Media LLC
Date: 20-04-2022
DOI: 10.1007/S00338-022-02255-6
Abstract: Prior to transitioning to a coral diet, juvenile Acanthaster cf. solaris , the Crown-of-Thorns Seastar (COTS), feed on crustose coralline algae. Although a detailed understanding of juvenile ecology is crucial to predict and prevent outbreaks, the exact timing of the transition is unresolved. Two experiments were conducted to measure time and size of COTS at the transition, and investigate potential modulating effects of different coral species. COTS began early transitions at similar sizes (7.5–8.5 mm), and these first transitions were observed around 136–145 d. Between 175 and 191 d, a 50% transition in the presence of Acropora tenuis was measured. After 175d, the percentage of COTS cohorts that had transitioned was significantly lower in A. millepora (38%) and Stylophora pistillata (7%) compared to A. tenuis (51%). These data fill important knowledge gaps in juvenile ecology, and the influence of coral species on transition suggests an undescribed feedback mechanism between prey and predator.
Publisher: Elsevier BV
Date: 04-2011
DOI: 10.1016/J.SYAPM.2011.01.003
Abstract: Microbial communities are potential indicators for water quality as they respond rapidly to environmental changes. In the Whitsunday Islands, Australia, microbial biofilm communities from two offshore islands were compared to those from two inshore islands subjected to poor water quality. Biofilm community composition was characterized using three culture-independent molecular techniques. The clone libraries indicated high genetic ersity, with somewhat higher scores in the offshore sites (57%) compared to the inshore sites (41%). The majority of microbes in the biofilms were related to Alphaproteobacteria (39.8%), Gammaproteobacteria (14.1%), Bacteroidetes (13.2%), diatoms (8.3%) and Cyanobacteria (3.9%). Redundancy analysis (RDA) for the CARD-FISH data showed distinct microbial assemblages between offshore and inshore communities. Additionally, 5 out of 13 water quality parameters (DIN, Chla, POP, TSS and POC) explained a significant amount of variation in the microbial communities and high values of these were associated with inshore communities. Analysis of variance (ANOVA) indicated that Cyanobacteria (p=0.01), Bacteroidetes (p=0.04) and to some extent Alphaproteobacteria (p=0.07), were significantly more abundant in the offshore biofilm communities. Principal Component Analysis (PCA) of DGGE data showed clear grouping of cyanobacterial communities into inshore and offshore communities. Reasons for community shifts in the bacterial lineages are currently not resolved. One possible causative factor may be that autotrophic primary producers are more dominant in offshore sites due to the higher light availability as well as the limitation by DIN. The trends found in this study are the bases for more detailed research on microbial indicator species for changes in water quality.
Publisher: Springer Science and Business Media LLC
Date: 28-10-2021
Publisher: Elsevier BV
Date: 08-2021
Publisher: Inter-Research Science Center
Date: 15-11-2011
DOI: 10.3354/MEPS09377
Publisher: Elsevier BV
Date: 08-2013
DOI: 10.1016/J.MARPOLBUL.2013.01.031
Abstract: While carbon capture and storage (CCS) is increasingly recognised as technologically possible, recent evidence from deep-sea CCS activities suggests that leakage from reservoirs may result in highly CO2 impacted biological communities. In contrast, shallow marine waters have higher primary productivity which may partially mitigate this leakage. We used natural CO2 seeps in shallow marine waters to assess if increased benthic primary productivity could capture and store CO2 leakage in areas targeted for CCS. We found that the productivity of seagrass communities (in situ, using natural CO2 seeps) and two in idual species (ex situ, Cymodocea serrulata and Halophila ovalis) increased with CO2 concentration, but only species with dense belowground biomass increased in abundance (e.g. C. serrulata). Importantly, the ratio of below:above ground biomass of seagrass communities increased fivefold, making seagrass good candidates to partially mitigate CO2 leakage from sub-seabed reservoirs, since they form carbon sinks that can be buried for millennia.
Publisher: Wiley
Date: 19-05-2016
DOI: 10.1111/TRAN.12125
Publisher: Springer Science and Business Media LLC
Date: 06-12-2008
Abstract: Environmental stressors such as increased sea surface temperatures are well-known for contributing to coral bleaching however, the effect of increased temperatures and subsequent bleaching on coral-associated microbial communities is poorly understood. Colonies of the hard coral Acropora millepora were tagged on a reef flat off Magnetic Island (Great Barrier Reef) and surveyed over 2.5 years, which included a severe bleaching event in January/February 2002. Daily average water temperatures exceeded the previous 10-year average by more than 1 degrees C for extended periods with field-based visual surveys recording all tagged colonies displaying signs of bleaching. During the bleaching period, direct counts of coral zooxanthellae densities decreased by approximately 64%, before recovery to pre-bleaching levels after the thermal stress event. A subset of three tagged coral colonies were s led through the bleaching event and changes in the microbial community elucidated. Denaturing gradient gel electrophoresis (DGGE) analysis demonstrated conserved bacterial banding profiles between the three coral colonies, confirming previous studies highlighting specific microbial associations. As coral colonies bleached, the microbial community shifted and redundancy analysis (RDA) of DGGE banding patterns revealed a correlation of increasing temperature with the appearance of Vibrio-affiliated sequences. Interestingly, this shift to a Vibrio-dominated community commenced prior to visual signs of bleaching. Clone libraries hybridized with Vibrio-specific oligonucleotide probes confirmed an increase in the fraction of Vibrio-affiliated clones during the bleaching period. Post bleaching, the coral microbial associations again shifted, returning to a profile similar to the fingerprints prior to bleaching. This provided further evidence for corals selecting and shaping their microbial partners. For non-bleached s les, a close association with Spongiobacter-related sequences were revealed by both clone libraries and DGGE profiling. Despite Vibrio species being previously implicated in bleaching of specific coral species, it is unsure if the relative increase in retrieved Vibrio sequences is due to bacterial infection or an opportunistic response to compromised health and changing environmental parameters of the coral host. This study provides the first molecular-based study demonstrating changes in coral-associated bacterial assemblages during a bleaching event on a natural reef system.
Publisher: Springer Science and Business Media LLC
Date: 15-03-2016
DOI: 10.1038/SREP23093
Abstract: Seagrasses are often considered “winners” of ocean acidification (OA) however, seagrass productivity responses to OA could be limited by nitrogen availability, since nitrogen-derived metabolites are required for carbon assimilation. We tested nitrogen uptake and assimilation, photosynthesis, growth, and carbon allocation responses of the tropical seagrasses Halodule uninervis and Thalassia hemprichii to OA scenarios (428, 734 and 1213 μatm p CO 2 ) under two nutrients levels (0.3 and 1.9 μM NO 3 − ). Net primary production (measured as oxygen production) and growth in H. uninervis increased with p CO 2 enrichment, but were not affected by nitrate enrichment. However, nitrate enrichment reduced whole plant respiration in H. uninervis . Net primary production and growth did not show significant changes with p CO 2 or nitrate by the end of the experiment (24 d) in T. hemprichii . However, nitrate incorporation in T. hemprichii was higher with nitrate enrichment. There was no evidence that nitrogen demand increased with p CO 2 enrichment in either species. Contrary to our initial hypothesis, nutrient increases to levels approximating present day flood plumes only had small effects on metabolism. This study highlights that the paradigm of increased productivity of seagrasses under ocean acidification may not be valid for all species under all environmental conditions.
Publisher: CRC Press
Date: 25-11-2016
Publisher: University of Chicago Press
Date: 06-2014
Publisher: Inter-Research Science Center
Date: 10-05-2016
DOI: 10.3354/MEPS11698
Publisher: Wiley
Date: 22-10-2011
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.MARPOLBUL.2011.08.008
Abstract: The effects of the photosystem II (PSII) herbicide diuron was assessed on thirteen tropical foraminifera hosting diatom, dinoflagellate, red or green algae endosymbionts. Inhibition of photosynthesis (reduced ΔF/F(m)(')) by diuron depended on both symbiont type and test ultrastructure, with greatest sensitivity observed for diatom- and chlorophyte-hosting species (24h IC(25) 2.5-4μg L(-1)). Inhibition kinetics was slow (24-48h until maximum inhibition) in comparison with corals, suggesting structural differences may influence herbicide uptake and transport. Although foraminifera were generally less sensitive to direct effects of diuron (inhibition ΔF/F(m)(')) than other marine phototrophs, damage to PSII (reduction F(v)/F(m)) occurred at concentrations lower than observed for other organisms (24h IC(25) 3-12μg L(-1)). Damage to PSII was highly light dependent and occurred at very low light intensities indicating limited photoprotective capacity. The high ersity, widespread occurrence and relative sensitivity make foraminifera good bioindicator organisms to evaluate phytotoxic stress on coral reefs.
Publisher: Oxford University Press (OUP)
Date: 2009
Publisher: Public Library of Science (PLoS)
Date: 12-08-2015
Publisher: Springer Science and Business Media LLC
Date: 11-05-2021
Publisher: Springer Science and Business Media LLC
Date: 15-09-2012
Publisher: Wiley
Date: 08-2023
DOI: 10.1002/ECE3.10307
Abstract: Rising ocean temperatures are threatening marine species and populations worldwide, and ectothermic taxa are particularly vulnerable. Echinoderms are an ecologically important phylum of marine ectotherms and shifts in their population dynamics can have profound impacts on the marine environment. The effects of warming on echinoderms are highly variable across controlled laboratory‐based studies. Accordingly, synthesis of these studies will facilitate the better understanding of broad patterns in responses of echinoderms to ocean warming. Herein, a meta‐analysis incorporating the results of 85 studies (710 in idual responses) is presented, exploring the effects of warming on various performance predictors. The mean responses of echinoderms to all magnitudes of warming were compared across multiple biological responses, ontogenetic life stages, taxonomic classes, and regions, facilitated by multivariate linear mixed effects models. Further models were conducted, which only incorporated responses to warming greater than the projected end‐of‐century mean annual temperatures at the collection sites. This meta‐analysis provides evidence that ocean warming will generally accelerate metabolic rate (+32%) and reduce survival (−35%) in echinoderms, and echinoderms from subtropical (−9%) and tropical (−8%) regions will be the most vulnerable. The relatively high vulnerability of echinoderm larvae to warming (−20%) indicates that this life stage may be a significant developmental bottleneck in the near‐future, likely reducing successful recruitment into populations. Furthermore, asteroids appear to be the class of echinoderms that are most negatively affected by elevated temperature (−30%). When considering only responses to magnitudes of warming representative of end‐of‐century climate change projections, the negative impacts on asteroids, tropical species and juveniles were exacerbated (−51%, −34% and −40% respectively). The results of these analyses enable better predictions of how keystone and invasive echinoderm species may perform in a warmer ocean, and the possible consequences for populations, communities and ecosystems.
Publisher: Wiley
Date: 15-09-2020
Publisher: University of Chicago Press
Date: 12-2021
DOI: 10.1086/717026
Abstract: AbstractCrown-of-thorns sea stars (
Publisher: Elsevier BV
Date: 10-2011
Publisher: Elsevier BV
Date: 04-2021
Publisher: The Royal Society
Date: 30-11-2016
Abstract: Laboratory experiments suggest that calcifying developmental stages of marine invertebrates may be the most ocean acidification (OA)-sensitive life-history stage and represent a life-history bottleneck. To better extrapolate laboratory findings to future OA conditions, developmental responses in sea urchin embryos/larvae were compared under ecologically relevant in situ exposures on vent-elevated p CO 2 and ambient p CO 2 coral reefs in Papua New Guinea. Echinometra embryos/larvae were reared in meshed chambers moored in arrays on either venting reefs or adjacent non-vent reefs. After 24 and 48 h, larval development and morphology were quantified. Compared with controls (mean pH (T) = 7.89–7.92), larvae developing in elevated p CO 2 vent conditions (pH (T) = 7.50–7.72) displayed a significant reduction in size and increased abnormality, with a significant correlation of seawater pH with both larval size and larval asymmetry across all experiments. Reciprocal transplants (embryos from vent adults transplanted to control conditions, and vice versa ) were also undertaken to identify if adult acclimatization can translate resilience to offspring (i.e. transgenerational processes). Embryos originating from vent adults were, however, no more tolerant to reduced pH. Sea temperature and chlorophyll- a concentrations (i.e. larval nutrition) did not contribute to difference in larval size, but abnormality was correlated with chlorophyll levels. This study is the first to examine the response of marine larvae to OA scenarios in the natural environment where, importantly, we found that stunted and abnormal development observed in situ are consistent with laboratory observations reported in sea urchins, in both the direction and magnitude of the response.
Publisher: Inter-Research Science Center
Date: 20-09-2006
DOI: 10.3354/MEPS322061
Publisher: Wiley
Date: 2012
DOI: 10.1890/11-0665.1
Abstract: Coral reefs are under pressure from a variety of human-induced disturbances, but demonstration of ecosystem changes and identification of stressors are often difficult. We tested whether global change or increased agricultural runoff after European settlement of Northeast Australia (ca. 1860) has affected inshore reefs of the Great Barrier Reef. Eleven sediment cores were retrieved from inner reefs, intermediate reefs, and outer-island reefs, and benthic foraminiferal assemblages were analyzed in dated (14C, 210Pb, 137Cs) core sections (N = 82 s les). Data were grouped into six age bands ( 1500 yr). Principal component analysis and two-factor (Zone and Age) permutational analysis of variance (PERMANOVA) suggested that assemblages from the three zones were significantly different from each other over several millennia, with symbiont-bearing (mixotrophic) species dominating the outer reefs. A significant interaction term indicated that within-zone patterns varied. Assemblages in outer reefs unaffected from increased land runoff were persistent until present times. In both other zones, assemblages were also persistent until 150 yr ago, suggesting that benthic foraminiferal assemblages are naturally highly persistent over long (> 2000 yr) timescales. Assemblages in core sections < 55 yr old from inner reefs were significantly (post hoc t test) different from those older than 150 yr. Similarly, assemblages < 55 yr old from intermediate reefs were significantly different compared to older assemblages. A multivariate regression tree (environmental variables: Zone and Age) explained 56.8% of the variance in foraminiferal assemblages and confirmed patterns identified by PERMANOVA. With some exceptions, changes on the inner and intermediate reefs were consistent with a model predicting that increased nutrients and higher turbidity enhance relative abundance of heterotrophic species. Given that assemblages did not change in outer-island reefs (not impacted by runoff) we argue that changes in assemblages due to global change can be rejected as an explanation. Thus, the findings are more consistent with the hypothesis that agricultural runoff since European settlement altered foraminiferal assemblages than with the hypothesis that global forcing caused changes.
Publisher: Wiley
Date: 25-02-2014
DOI: 10.1111/GCB.12530
Abstract: Outbreaks of crown-of-thorns starfish (COTS), Acanthaster planci, contribute to major declines of coral reef ecosystems throughout the Indo-Pacific. As the oceans warm and decrease in pH due to increased anthropogenic CO2 production, coral reefs are also susceptible to bleaching, disease and reduced calcification. The impacts of ocean acidification and warming may be exacerbated by COTS predation, but it is not known how this major predator will fare in a changing ocean. Because larval success is a key driver of population outbreaks, we investigated the sensitivities of larval A. planci to increased temperature (2-4 °C above ambient) and acidification (0.3-0.5 pH units below ambient) in flow-through cross-factorial experiments (3 temperature × 3 pH CO2 levels). There was no effect of increased temperature or acidification on fertilization or very early development. Larvae reared in the optimal temperature (28 °C) were the largest across all pH treatments. Development to advanced larva was negatively affected by the high temperature treatment (30 °C) and by both experimental pH levels (pH 7.6, 7.8). Thus, planktonic life stages of A. planci may be negatively impacted by near-future global change. Increased temperature and reduced pH had an additive negative effect on reducing larval size. The 30 °C treatment exceeded larval tolerance regardless of pH. As 30 °C sea surface temperatures may become the norm in low latitude tropical regions, poleward migration of A. planci may be expected as they follow optimal isotherms. In the absence of acclimation or adaptation, declines in low latitude populations may occur. Poleward migration will be facilitated by strong western boundary currents, with possible negative flow-on effects on high latitude coral reefs. The contrasting responses of the larvae of A. planci and those of its coral prey to ocean acidification and warming are considered in context with potential future change in tropical reef ecosystems.
Publisher: Wiley
Date: 02-05-2016
DOI: 10.1111/GCB.13223
Abstract: Rising atmospheric CO2 concentrations will significantly reduce ocean pH during the 21st century (ocean acidification, OA). This may h er calcification in marine organisms such as corals and echinoderms, as shown in many laboratory-based experiments. Sea urchins are considered highly vulnerable to OA. We studied an Echinometra species on natural volcanic CO2 vents in Papua New Guinea, where they are CO2 -acclimatized and also subjected to secondary ecological changes from elevated CO2 . Near the vent site, the urchins experienced large daily variations in pH (>1 unit) and pCO2 (>2000 ppm) and average pH values (pHT 7.73) much below those expected under the most pessimistic future emission scenarios. Growth was measured over a 17-month period using tetracycline tagging of the calcareous feeding lanterns. Average-sized urchins grew more than twice as fast at the vent compared with those at an adjacent control site and assumed larger sizes at the vent compared to the control site and two other sites at another reef near-by. A small reduction in gonad weight was detected at the vents, but no differences in mortality, respiration, or degree of test calcification were detected between urchins from vent and control populations. Thus, urchins did not only persist but actually 'thrived' under extreme CO2 conditions. We suggest an ecological basis for this response: Increased algal productivity under increased pCO2 provided more food at the vent, resulting in higher growth rates. The wider implication of our observation is that laboratory studies on non-acclimatized specimens, which typically do not consider ecological changes, can lead to erroneous conclusions on responses to global change.
Publisher: Frontiers Media SA
Date: 21-03-2017
Publisher: Springer Science and Business Media LLC
Date: 10-10-2023
Publisher: Springer Science and Business Media LLC
Date: 20-05-2014
Publisher: Springer Science and Business Media LLC
Date: 15-03-2015
Publisher: American Chemical Society (ACS)
Date: 17-12-2020
Abstract: Increased frequency of summer heatwaves and poor water quality are two of the most prevalent and severe pressures faced by coral reefs. While these pressures often co-occur, their potential risks to tropical marine species are usually considered independently. Here, we extended the application of multisubstance-Potentially Affected Fraction (ms-PAF) to a nonchemical stressor, elevated sea surface temperature. We then applied this method to calculate climate-adjusted water quality guideline values (GVs) for two reference toxicants, copper and the herbicide diuron, for tropical marine species. First, we developed a species sensitivity distribution (SSD) for thermal stress based on published experimental data for 41 tropical benthic marine species using methods adapted from water quality GV derivation. This enabled quantitative predictions of community effects as temperatures exceeded acclimation values. The resulting protective temperature values (PTx) were similar to temperatures known to initiate coral bleaching and are therefore relevant for application in multistressor risk assessments. The extended ms-PAF method enabled the adjustment of current water quality GVs to account for thermal stress events. This approach could be applied to other ecosystems and other non-contaminant stressors (e.g., sediment, low salinity, anoxia, and ocean acidification), offering an alternative approach for deriving environmental GVs, reporting and assessing the risk posed by multiple stressors.
Publisher: Wiley
Date: 12-09-2011
DOI: 10.1111/J.1462-2920.2011.02571.X
Abstract: Rising anthropogenic CO(2) emissions acidify the oceans, and cause changes to seawater carbon chemistry. Bacterial biofilm communities reflect environmental disturbances and may rapidly respond to ocean acidification. This study investigates community composition and activity responses to experimental ocean acidification in biofilms from the Australian Great Barrier Reef. Natural biofilms grown on glass slides were exposed for 11 d to four controlled pCO(2) concentrations representing the following scenarios: A) pre-industrial (∼300 ppm), B) present-day (∼400 ppm), C) mid century (∼560 ppm) and D) late century (∼1140 ppm). Terminal restriction fragment length polymorphism and clone library analyses of 16S rRNA genes revealed CO(2) -correlated bacterial community shifts between treatments A, B and D. Observed bacterial community shifts were driven by decreases in the relative abundance of Alphaproteobacteria and increases of Flavobacteriales (Bacteroidetes) at increased CO(2) concentrations, indicating pH sensitivity of specific bacterial groups. Elevated pCO(2) (C + D) shifted biofilm algal communities and significantly increased C and N contents, yet O(2) fluxes, measured using in light and dark incubations, remained unchanged. Our findings suggest that bacterial biofilm communities rapidly adapt and reorganize in response to high pCO(2) to maintain activity such as oxygen production.
Publisher: The Royal Society
Date: 22-03-2015
Abstract: Large benthic foraminifera are significant contributors to sediment formation on coral reefs, yet they are vulnerable to ocean acidification. Here, we assessed the biochemical and morphological impacts of acidification on the calcification of Amphistegina lessonii and Marginopora vertebralis exposed to different pH conditions. We measured growth rates (surface area and buoyant weight) and Ca-ATPase and Mg-ATPase activities and calculated shell density using micro-computer tomography images. In A. lessonii , we detected a significant decrease in buoyant weight, a reduction in the density of inner skeletal chambers, and an increase of Ca-ATPase and Mg-ATPase activities at pH 7.6 when compared with ambient conditions of pH 8.1. By contrast, M. vertebralis showed an inhibition in Mg-ATPase activity under lowered pH, with growth rate and skeletal density remaining constant. While M. vertebralis is considered to be more sensitive than A. lessonii owing to its high-Mg-calcite skeleton, it appears to be less affected by changes in pH, based on the parameters assessed in this study. We suggest difference in biochemical pathways of calcification as the main factor influencing response to changes in pH levels, and that A. lessonii and M. vertebralis have the ability to regulate biochemical functions to cope with short-term increases in acidity.
Publisher: Wiley
Date: 24-05-2012
DOI: 10.1111/J.1365-2486.2012.02715.X
Abstract: Changes in the seawater carbonate chemistry (ocean acidification) from increasing atmospheric carbon dioxide (CO2 ) concentrations negatively affect many marine calcifying organisms, but may benefit primary producers under dissolved inorganic carbon (DIC) limitation. To improve predictions of the ecological effects of ocean acidification, the net gains and losses between the processes of photosynthesis and calcification need to be studied jointly on physiological and population levels. We studied productivity, respiration, and abundances of the symbiont-bearing foraminifer species Marginopora vertebralis on natural CO2 seeps in Papua New Guinea and conducted additional studies on production and calcification on the Great Barrier Reef (GBR) using artificially enhanced pCO2 . Net oxygen production increased up to 90% with increasing pCO2 temperature, light, and pH together explaining 61% of the variance in production. Production increased with increasing light and increasing pCO2 and declined at higher temperatures. Respiration was also significantly elevated (~25%), whereas calcification was reduced (16-39%) at low pH/high pCO2 compared to present-day conditions. In the field, M. vertebralis was absent at three CO2 seep sites at pHTotal levels below ~7.9 (pCO2 ~700 μatm), but it was found in densities of over 1000 m(-2) at all three control sites. The study showed that endosymbiotic algae in foraminifera benefit from increased DIC availability and may be naturally carbon limited. The observed reduction in calcification may have been caused either by increased energy demands for proton pumping (measured as elevated rates of respiration) or by stronger competition for DIC from the more productive symbionts. The net outcome of these two competing processes is that M. vertebralis cannot maintain populations under pCO2 exceeding 700 μatm, thus are likely to be extinct in the next century.
Publisher: Springer Science and Business Media LLC
Date: 12-02-2015
DOI: 10.1038/SREP08402
Abstract: Coral reefs face a crisis due to local and global anthropogenic stressors. A large proportion of the ~50% coral loss on the Great Barrier Reef has been attributed to outbreaks of the crown-of-thorns-seastar (COTS). A widely assumed cause of primary COTS outbreaks is increased larval survivorship due to higher food availability, linked with anthropogenic runoff . Our experiment using a range of algal food concentrations at three temperatures representing present day average and predicted future increases, demonstrated a strong influence of food concentration on development is modulated by temperature. A 2°C increase in temperature led to a 4.2–4.9 times (at Day 10) or 1.2–1.8 times (Day 17) increase in late development larvae. A model indicated that food was the main driver, but that temperature was an important modulator of development. For instance, at 5000 cells ml −1 food, a 2°C increase may shorten developmental time by 30% and may increase the probability of survival by 240%. The main contribution of temperature is to ‘push’ well-fed larvae faster to settlement. We conclude that warmer sea temperature is an important co-factor promoting COTS outbreaks.
Publisher: University of Chicago Press
Date: 12-2021
DOI: 10.1086/717539
Abstract: AbstractPopulation irruptions of the western Pacific crown-of-thorns sea star (
Publisher: Springer Science and Business Media LLC
Date: 27-10-2013
Publisher: Springer Science and Business Media LLC
Date: 21-06-2018
DOI: 10.1038/S41598-018-27937-6
Abstract: A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
Publisher: Informa UK Limited
Date: 09-2002
Publisher: Wiley
Date: 21-09-2017
DOI: 10.1111/GCB.13452
Abstract: As the ocean warms, thermal tolerance of developmental stages may be a key driver of changes in the geographical distributions and abundance of marine invertebrates. Additional stressors such as ocean acidification may influence developmental thermal windows and are therefore important considerations for predicting distributions of species under climate change scenarios. The effects of reduced seawater pH on the thermal windows of fertilization, embryology and larval morphology were examined using five echinoderm species: two polar (Sterechinus neumayeri and Odontaster validus), two temperate (Fellaster zelandiae and Patiriella regularis) and one tropical (Arachnoides placenta). Responses were examined across 12-13 temperatures ranging from -1.1 °C to 5.7 °C (S. neumayeri), -0.5 °C to 10.7 °C (O. validus), 5.8 °C to 27 °C (F. zelandiae), 6.0 °C to 27.1 °C (P. regularis) and 13.9 °C to 34.8 °C (A. placenta) under present-day and near-future (2100+) ocean acidification conditions (-0.3 pH units) and for three important early developmental stages 1) fertilization, 2) embryo (prehatching) and 3) larval development. Thermal windows for fertilization were broad and were not influenced by a pH decrease. Embryological development was less thermotolerant. For O. validus, P. regularis and A. placenta, low pH reduced normal development, albeit with no effect on thermal windows. Larval development in all five species was affected by both temperature and pH however, thermal tolerance was not reduced by pH. Results of this study suggest that in terms of fertilization and development, temperature will remain as the most important factor influencing species' latitudinal distributions as the ocean continues to warm and decrease in pH, and that there is little evidence of a synergistic effect of temperature and ocean acidification on the thermal control of species ranges.
Publisher: Springer Science and Business Media LLC
Date: 19-03-2001
Publisher: MDPI AG
Date: 21-09-2017
DOI: 10.3390/D9040041
Publisher: Elsevier BV
Date: 03-2007
Publisher: Public Library of Science (PLoS)
Date: 15-11-2012
Publisher: Wiley
Date: 25-09-2013
DOI: 10.1111/GCB.12008
Publisher: Public Library of Science (PLoS)
Date: 08-10-2014
Publisher: Wiley
Date: 06-2018
DOI: 10.1111/NPH.15234
Abstract: Seagrasses are globally important coastal habitat-forming species, yet it is unknown how seagrasses respond to the combined pressures of ocean acidification and warming of sea surface temperature. We exposed three tropical species of seagrass (Cymodocea serrulata, Halodule uninervis, and Zostera muelleri) to increasing temperature (21, 25, 30, and 35°C) and pCO
Publisher: MDPI AG
Date: 22-08-2017
DOI: 10.20944/PREPRINTS201708.0076.V1
Abstract: Research on the coral-eating crown-of-thorns starfish (CoTS) has waxed and waned over the last few decades, mostly in accordance with the occurrence of population outbreaks at key locations, such as Australia& rsquo s Great Barrier Reef. This review considers advances in our understanding of the biology and ecology of CoTS based on the latest resurgence of research interest, which culminated in this current special issue on the Biology, Ecology and Management of Crown-of-Thorns Starfish. More specifically, this review considers progress against 41 specific research questions posed in the seminal review by P. Moran 30 years ago, as well as exploring new directions for CoTS research. Despite the plethora of research on CoTS (& ,200 research articles), there are persistent knowledge gaps that constrain effective management of outbreaks. Although directly addressing some of these questions will be extremely difficult, there have been considerable advances in understanding the biology of CoTS, if not the proximal and ultimate cause(s) of outbreaks. Moving forward, researchers need to embrace new technologies and opportunities to advance understanding of CoTS biology and behaviour, with focus given to key questions that will improve effectiveness of management to reduce the frequency and likelihood of future outbreaks, if not preventing them altogether.
Publisher: Inter-Research Science Center
Date: 02-10-2013
DOI: 10.3354/MEPS10465
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/MF04226
Abstract: Using mtDNA sequences we found that the Indo-Pacific teatfish fishery comprises at least three species, clarifying confusion on the taxonomic status of these commercially important holothurians. Traditional taxonomic characters, including the morphology of skeletal structures, could not be used to differentiate the species. Sequences of the COI gene (529 bp) distinguished three haplotype clusters, corresponding to distinct colour forms and, to some extent, previously described species. The white teatfish, Holothuria fuscogilva, comprises a range of colour morphs and has a wide distribution over the tropical Indo-Pacific region. The large sequence ergence indicates potential for the presence of several cryptic species in the white teatfish complex. In contrast to current taxonomy, we identified two species of black teatfish that appear to be allopatric: H. whitmaei is entirely black and has a Pacific distribution whereas H. nobilis has white ventro-lateral dots and only occurs in the Indian Ocean. There is evidence for allopatric speciation between the black teatfish species, possibly driven by separation of the oceans and altered current patterns during the Pliocene, resulting in relatively young species with low intraspecific sequence ergence. These results provide insight into speciation in these tropical holothurians and are crucial for their conservation management.
Publisher: Inter-Research Science Center
Date: 25-05-2012
DOI: 10.3354/AME01562
Publisher: Springer Science and Business Media LLC
Date: 30-09-1997
Publisher: Oxford University Press (OUP)
Date: 24-08-2011
DOI: 10.1111/J.1574-6968.2011.02374.X
Abstract: Natural and anthropogenic impacts such as terrestrial runoff, influence the water quality along the coast of the Great Barrier Reef (GBR) and may in turn affect coral reef communities. Associated bacterial biofilms respond rapidly to environmental conditions and are potential bioindicators for changes in water quality. As a prerequisite to study the effects of water quality on biofilm communities, appropriate biofilm substrates for deployment in the field must be developed and evaluated. This study investigates the effect of different settlement substrates (i.e. glass slides, ceramic tiles, coral skeletons and reef sediments) on bacterial biofilm communities grown in situ for 48 days at two locations in the Whitsunday Island Group (Central GBR) during two s ling times. Bacterial communities associated with the biofilms were analysed using terminal restriction fragment length polymorphism (T-RFLP) and clone library analyses of 16S rRNA genes. Findings revealed that substrate type had little influence on bacterial community composition. Of particular relevance, glass slides and coral skeletons exhibited very similar communities during both s ling times, suggesting the suitability of standardized glass slides for long-term biofilm indicator studies in tropical coral reef ecosystems.
Publisher: Elsevier BV
Date: 03-1999
Publisher: Springer Science and Business Media LLC
Date: 17-08-2013
Publisher: Public Library of Science (PLoS)
Date: 16-12-2013
Publisher: Wiley
Date: 02-11-2013
Publisher: Springer Science and Business Media LLC
Date: 08-2001
Publisher: Springer Science and Business Media LLC
Date: 17-10-2015
Publisher: Springer Science and Business Media LLC
Date: 19-11-2023
DOI: 10.1007/S00338-022-02314-Y
Abstract: Ocean warming and population irruptions of crown-of-thorns starfish (CoTS Acanthaster cf. solaris ) are two of the greatest threats to coral reefs. As such, there is significant interest in understanding how CoTS may be directly impacted by rising ocean temperatures. Settlement of planktonic larvae and subsequent metamorphosis is purported to be a major population bottleneck in marine invertebrates, yet it is unknown how ocean warming will impact these processes in CoTS. Herein, the effect of temperature (28 °C ambient, 30 °C, 32 °C, 34 °C) on the settlement success, metamorphic success, and post-settlement survival of this corallivore was explored. While larval settlement was robust to elevated temperature, with at least 94% of larvae settling after 48 h across all temperatures, it was observed that settlement success was lower on substrate that had been pre-treated ≥ 32 °C. Metamorphic success was also significantly constrained at temperatures ≥ 32 °C. At 32 °C and 34 °C metamorphic success was 16% and 63% lower than at ambient temperature, respectively. Significant adverse effects of warming on post-settlement survival were observed at even cooler temperatures, with 10% lower survival at 30 °C compared to at ambient temperature, and at 34 °C, survival was 34% lower. Substantial reductions in metamorphic success and early post-settlement survival at elevated temperatures, as well as negative impacts of warming on the settlement substrate and its capacity to induce settlement, may present a bottleneck for recruitment in a warmer ocean.
Publisher: Wiley
Date: 07-2010
Publisher: Inter-Research Science Center
Date: 1998
DOI: 10.3354/MEPS169001
Publisher: Springer Science and Business Media LLC
Date: 27-12-2013
Publisher: Proceedings of the National Academy of Sciences
Date: 29-10-2015
Publisher: Inter-Research Science Center
Date: 15-11-2018
DOI: 10.3354/MEPS12754
Publisher: Wiley
Date: 03-09-2021
DOI: 10.1002/EDN3.123
Publisher: The Royal Society
Date: 22-01-2013
Abstract: The ecological effects of ocean acidification (OA) from rising atmospheric carbon dioxide (CO 2 ) on benthic marine communities are largely unknown. We investigated in situ the consequences of long-term exposure to high CO 2 on coral-reef-associated macroinvertebrate communities around three shallow volcanic CO 2 seeps in Papua New Guinea. The densities of many groups and the number of taxa (classes and phyla) of macroinvertebrates were significantly reduced at elevated CO 2 (425–1100 µatm) compared with control sites. However, sensitivities of some groups, including decapod crustaceans, ascidians and several echinoderms, contrasted with predictions of their physiological CO 2 tolerances derived from laboratory experiments. High CO 2 reduced the availability of structurally complex corals that are essential refugia for many reef-associated macroinvertebrates. This loss of habitat complexity was also associated with losses in many macroinvertebrate groups, especially predation-prone mobile taxa, including crustaceans and crinoids. The transition from living to dead coral as substratum and habitat further altered macroinvertebrate communities, with far more taxa losing than gaining in numbers. Our study shows that indirect ecological effects of OA (reduced habitat complexity) will complement its direct physiological effects and together with the loss of coral cover through climate change will severely affect macroinvertebrate communities in coral reefs.
Publisher: Springer Science and Business Media LLC
Date: 29-05-2011
DOI: 10.1038/NCLIMATE1122
Publisher: Elsevier BV
Date: 03-2002
DOI: 10.1016/S0025-326X(01)00202-8
Abstract: The invasive green alga Caulerpa taxifolia has gained a high profile due to 'outbreaks' in the Mediterranean and California. During the year 2000 three new discrete locations colonised by abundant C. taxifolia were discovered in New South Wales (NSW), Australia. Sequencing of the internal transcribed spacer (ITS) region of the ribosomal DNA was used to explore the source(s) of these new records, which is an important prerequisite for subsequent environmental management responses. Our results indicate that the NSW C. taxifolia originated from several sources and, hence, through different invasion events. For two of the new records (Port Hacking, Careel Bay) it can be excluded that they are derived from the so-called "aquarium strain" of C. taxifolia, closely related to the invasive Mediterranean populations. Port Hacking is likely to have originated from tropical native populations. However, s les from Lake Conjola cannot be sufficiently distinguished with the applied technique from native C. taxifolia in Moreton Bay and the Mediterranean/"aquarium strain".
Publisher: Springer Science and Business Media LLC
Date: 06-01-2021
Publisher: Springer Science and Business Media LLC
Date: 13-01-2011
Publisher: Cambridge University Press (CUP)
Date: 09-07-2010
DOI: 10.1017/S0025315409990518
Abstract: Some sea cucumbers species are heavily exploited as bêche-de-mer for the Asian food industry and the global decline of certain highly sought after species has generated an interest in determining the ecological function of those animals within their ecosystem. This study investigated the ecological role of Holothuria scabra , a commercially valuable tropical species closely associated with seagrass beds. Seagrass productivity, seagrass and benthic microalgae (BMA) biomass and organic matter (OM) were measured during two exclusion experiments conducted using in situ cages deployed for two months both in 2003 and 2004. Density of H. scabra was manipulated in caged exclusions (near-zero density, ‘EX’), caged controls (natural densities, ‘CC’) and uncaged controls (natural density, ‘NC’). Seagrass growth was lower when holothurians were excluded (5% in 2003, 12% in 2004). Seagrass biomass decreased in all treatments, but reduction was greater in EX than in controls (18% in 2003, 21% in 2004). Both BMA biomass and OM increased in EX compared to NC/CC (in 2004). From a multivariate perspective, a principal component biplot separated EX from both types of controls in 2004, and multivariate tests based on four attributes supported this separation. These results indicate that seagrass systems may suffer in the absence of holothurians however, the effect size varied between the two experiments, possibly because experiments were conducted at different times of the year. Nevertheless, our results suggest that holothurian over-fishing could have a negative impact on the productivity of seagrass systems.
Publisher: Elsevier BV
Date: 09-2015
DOI: 10.1016/J.ENVPOL.2015.05.013
Abstract: Most reef building corals rely on symbiotic microalgae (genus Symbiodinium) to supply a substantial proportion of their energy requirements. Functional ersity of different Symbiodinium genotypes, endorsing the host with physiological advantages, has been widely reported. Yet, the influence of genotypic specificity on the symbiont's susceptibility to contaminants or cumulative stressors is unknown. Cultured Symbiodinium of presumed thermal-tolerant clade D tested especially vulnerable to the widespread herbicide diuron, suggesting important free-living populations may be at risk in areas subjected to terrestrial runoff. Co-exposure experiments where cultured Symbiodinium were exposed to diuron over a thermal stress gradient demonstrated how fast-growing clade C1 better maintained photosynthetic capability than clade D. The mixture toxicity model of Independent Action, considering combined thermal stress and herbicide contamination, revealed response additivity for inhibition of photosynthetic yield in both tested cultures, emphasizing the need to account for cumulative stressor impacts in ecological risk assessment and resource management.
Publisher: Springer Science and Business Media LLC
Date: 07-01-2016
Publisher: Wiley
Date: 28-09-2004
Publisher: Springer Science and Business Media LLC
Date: 03-03-2022
DOI: 10.1007/S00227-022-04027-W
Abstract: Population irruptions of Pacific crown-of-thorns starfish ( Acanthaster cf. solaris ) have caused substantial damage to coral reefs, but it is largely unknown how this asteroid will fare in a warmer ocean. We exposed these starfish to one of four thermal treatments, with final temperatures of 26 °C (control, annual average), 28 °C (summer average), 30 °C (summer maximum) and 32 °C (predicted summer maximum by 2100). We measured the righting time, movement rate, standard metabolic rate and probability of survival of the crown-of-thorns starfish at various timepoints over ~ 60 days. We found that while temperature did not affect righting time, it did significantly affect movement rate. The movement rate of starfish increased across the 26 to 30 °C range, with those at 28 °C and 30 °C moving 18 and 27% faster than those at the control temperature. Similarly, the standard metabolic rate of starfish increased from 26 to 30 °C, with metabolism 100% and 260% faster at 28 °C and 30 °C compared to those at the 26 °C control. At 32 °C, in idual starfish exhibited a 14% slower movement rate, a 33% slower metabolic rate, and also exhibited a fourfold lower probability of survival than those at 30 °C. These results indicate that 32 °C is above the thermal optimum of crown-of-thorns starfish, suggesting that prolonged exposure to temperatures that are expected to be regularly exceeded under near-future climate change may be detrimental to this species.
Publisher: Springer Science and Business Media LLC
Date: 18-08-2021
Publisher: Springer Science and Business Media LLC
Date: 06-08-2022
Publisher: Elsevier BV
Date: 08-2008
Publisher: Inter-Research Science Center
Date: 2001
DOI: 10.3354/MEPS216109
Publisher: Inter-Research Science Center
Date: 22-08-2011
DOI: 10.3354/MEPS09172
Publisher: Springer Science and Business Media LLC
Date: 12-01-2018
DOI: 10.1038/S41598-017-19132-W
Abstract: Coral-eating Crown-of-Thorns Sea stars ( Acanthaster spp.) are major contributors to coral reef loss in the Indo-Pacific region. A release from food limitation of their planktotrophic larvae through enhanced pelagic productivity is one of the main hypothesis explaining population outbreaks (‘nutrient limitation hypothesis’). To improve the understanding of these outbreaks we developed an automated flow- through larvae rearing system that maintained food (microalgae) at set levels over the course of four 15d experiments. This resulted in stable food concentrations in experimental tanks. Increased algae concentrations had a significant positive effect on larval development and size at 10 and 15 days post fertilization (dpf). Larvae densities had no effect at 10 dpf. At 15 dpf greater larvae densities were associated with declines in larvae size. Larval development was slowed under higher larvae densities. Thus, the effects of algae concentration and larvae density were additive at 15 dpf, with larvae under low densities at a given algae concentration being further developed than those under higher densities. The development of a flow-through system gives greater insight into the effect of algae and larvae concentrations on Acanthaster development, and the system can be applied to further test the nutrient-limitation hypothesis for present and future outbreaks.
Publisher: Wiley
Date: 11-06-2010
DOI: 10.1111/J.1755-0998.2009.02826.X
Abstract: There are more than 47 species of holothurians used for bêche-de-mer production, many of which are locally overfished. With three exceptions, all bêche-de-mer species are Aspidochirotida and species identification of many of these is difficult. We analysed available genetic information and newly generated sequences to determine if genetic barcoding with the mitochondrial COI gene can be used to identify bêche-de-mer species. Although genetic data were available for ∼50% of bêche-de-mer species, sufficient information and within-species replication were only available for six species. We generated 96 new COI sequences extending the existing database to cover most common species. COI unambiguously identified most bêche-de-mer species providing a genetic barcode for the identification of known species. In addition, conspecific (1.3%) variation and congeneric (16.9%) ergence were well separated ('barcoding-gap') albeit with a small overlap, which may lead to some error if genetic s ling alone was applied for species discovery. In addition to identification of adults, COI sequences were useful to identify juveniles that are often morphologically different. Sequence data showed that large (deep) and small (shallow) morphotypes of Holothuria atra are the same species, but suggested potential cryptic species within this taxon. For bêche-de-mer, the COI barcode proved useful in species clarification and discovery, but further genetic and taxonomic work is essential for several species. Some bêche-de-mer clades were problematic with morphologically disparate specimens sharing the same barcode. Our study indicated the presence of undescribed species (Bohadschia sp.) and species that constitute separate species in the Indian and Pacific Ocean (e.g. Holothuria fuscogilva).
Publisher: Inter-Research Science Center
Date: 2001
DOI: 10.3354/MEPS210125
Publisher: Wiley
Date: 06-2009
Publisher: Public Library of Science (PLoS)
Date: 07-01-2014
DOI: 10.1371/ANNOTATION/B03DC5D7-0CFD-4182-B39D-FB9299275D5C
Publisher: Wiley
Date: 05-09-2003
DOI: 10.1046/J.1365-294X.2003.01954.X
Abstract: The sea cucumber, Holothuria nobilis, has a long-lived planktotrophic larvae, and previous allozyme surveys have suggested that high dispersal is realized. In contrast, recent ecological studies indicate that dispersal is low. To reconcile these data, and to investigate the evolution of this Indo-Pacific species, we screened geographical variation in 559 bp of a mitochondrial gene (COI) in 360 s les from the Australasian region and La Réunion. Sequences from La Réunion differed by > 7% from others and may constitute another species. Haplotype ersity in other s les was high (0.942, SD = 0.007), but haplotypes were closely related (mean nucleotide ersity: 0.0075, SD = 0.0041). AMOVA, pairwise FST values and exact tests did not detect significant population structure. Nested clade analysis showed that one of two main clades was over-represented in west Australia, whereas the other was more common in the northern Great Barrier Reef. Isolation-by-distance was identified as the main determinant of population structure at several clade levels. Contiguous range expansion was inferred for evolutionary older clade levels and this may correspond to a late Pleistocene (88 000-193 000 years ago) population expansion inferred from haplotype mismatch distributions. Thus, the population genetic structures detected are likely to be formed prior to the last ice age, with some indications for high dispersal on shorter time scales.
Publisher: Springer Science and Business Media LLC
Date: 23-11-2015
DOI: 10.1038/SREP16885
Abstract: Coral reefs are in decline worldwide due to a combination of local and global causes. Over 40% of the recent coral loss on Australia’s Great Barrier Reef (GBR) has been attributed to outbreaks of the coral-eating Crown-of-Thorns Seastar (CoTS). Testing of the hypotheses explaining these outbreaks is h ered by an inability to investigate the spatio-temporal distribution of larvae because they resemble other planktotrophic echinoderm larvae. We developed a genetic marker and tested it on 48 plankton s les collected during the 2014 spawning season in the northern GBR and verified the method by PCR lification of single larva. Surprisingly, most s les collected contained CoTS larvae. Larvae were detected 100 km south of current outbreaks of adult seastars, highlighting the potential for rapid expansion of the outbreak. A minimum estimate suggested that larvae numbers in the outbreak area ( 10 ) are about 4 orders of magnitude higher than adults (~10 6 ) in the same area, implying that attempts to halt outbreaks by removing adults may be futile.
Publisher: The Royal Society
Date: 2023
Abstract: Population irruptions of crown-of-thorns starfish (COTS) cause extensive degradation of coral reefs, threatening the structure and function of these important ecosystems. For population irruptions to initiate and spread, large numbers of planktonic larvae have to successfully transition into their benthic life-history stage (i.e. settlement), whereby larval behaviour and the presence of settlement cues may shape spatial patterns of recruitment and adult densities. Our results demonstrate that a wide range of coralline algae species induce COTS larvae to settle however, the capacity to promote settlement success varied manyfold among algal species, ranging from greater than 90% in Melyvonnea cf. madagascariensis to less than 2% in Lithophyllum cf. kotschyanum and two Porolithon species at 24 h. Because many coralline algae species that promote high settlement success are prevalent in shallow reef habitats, our findings challenge the hypothesis that COTS larvae predominantly settle in deep water. Considering both larval behaviour and algal ecology, this study highlights the ecological significance of coralline algae communities in driving recruitment patterns of COTS. More specifically, the local abundance of highly inductive coralline algae (especially, Melyvonnea cf. madagascariensis ) may explain some of the marked spatial heterogeneity of COTS populations and the incidence of population irruptions.
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.MARPOLBUL.2011.09.004
Abstract: Responses of bioindicator candidates for water quality were quantified in two studies on inshore coral reefs of the Great Barrier Reef (GBR). In Study 1, 33 of the 38 investigated candidate indicators (including coral physiology, benthos composition, coral recruitment, macrobioeroder densities and FORAM index) showed significant relationships with a composite index of 13 water quality variables. These relationships were confirmed in Study 2 along four other water quality gradients (turbidity and chlorophyll). Changes in water quality led to multi-faceted shifts from phototrophic to heterotrophic benthic communities, and from erse coral dominated communities to low- ersity communities dominated by macroalgae. Turbidity was the best predictor of biota hence turbidity measurements remain essential to directly monitor water quality on the GBR, potentially complemented by our final calibrated 12 bioindicators. In combination, this bioindicator system may be used to assess changes in water quality, especially where direct water quality data are unavailable.
Publisher: Wiley
Date: 28-05-2021
DOI: 10.1111/GCB.15657
Abstract: Long‐term experimental investigations of transgenerational plasticity (TGP) and transgenerational acclimatization to global change are sparse in marine invertebrates. Here, we test the effect of ocean warming and acidification over a 25‐month period of Echinometra sp. A sea urchins whose parents were acclimatized at ambient or one of two near‐future (projected mid and end of the 21st century) climate scenarios for 18 months. Several parameters linked to performance exhibited strong effects of future ocean conditions at 9 months of age. The Ambient‐Ambient group (A‐A, both F 0 and F 1 at ambient conditions) was significantly larger (21%) and faster in righting response (31%) compared to other groups. A second set of contrasts revealed near‐future scenarios caused significant negative parental carryover effects. Respiration at 9 months was depressed by 59% when parents were from near‐future climate conditions, and righting response was slowed by 28%. At 10 months, a selective pathogenic mortality event led to significantly higher survival rates of A‐A urchins. Differences in size and respiration measured prior to the mortality were absent after the event, while a negative parental effect on righting (29% reduction) remained. The capacity to spawn at the end of the experiment was higher in in iduals with ambient parents (50%) compared to other groups (21%) suggesting persistent parental effects. Obtaining different results at different points in time illustrates the importance of longer term and multigeneration studies to investigate effects of climate change. Given some animals in all groups survived the pathogenic event and that effects on physiology (but not behavior) among groups were eliminated after the mortality, we suggest that similar events could constitute selective sweeps, allowing genetic adaptation. However, given the observed negative parental effects and reduced potential for population replenishment, it remains to be determined if selection would be sufficiently rapid to rescue this species from climate change effects.
Publisher: Wiley
Date: 28-07-2011
Publisher: MDPI AG
Date: 24-11-2016
DOI: 10.20944/PREPRINTS201611.0124.V1
Abstract: Outbreaks of the crown-of-thorns seastar (CoTS) represent a major cause of coral loss on the Great Barrier Reef. Outbreaks might be explained by enhanced larval survival supported by higher phytoplankton availability after flood events, yet little is known about CoTS larvae feeding behaviour, in particular their potential for selective feeding. Here, single- and mixed-species feeding experiments were conducted on CoTS bipinnaria larvae using five algae (Phaeodactylum tricornutum, Pavlova lutheri, Tisochrysis lutea , Dunaliella sp. and Chaetoceros sp.) and two algal concentrations (1000 and 2500 algae mL-1). Cell counts using flow-cytometry at the beginning and end of each incubation experiment allowed us to calculate the filtration and ingestion rates of each species by CoTS larvae. In line with previous studies, CoTS larvae ingested more algae when initial algal concentration was higher. We found evidence for the selective ingestion of some species (Chaetoceros sp., Dunaliella sp.) over others (P. lutheri, P. tricornutum). The preferred algal species had the highest energy content, suggesting that CoTS selectively ingested the most energetic algae. Ultimately, combining these results with spatio-temporal patterns in phytoplankton communities will help elucidate the role of larval feeding behaviour in determining the frequency and magnitude of CoTS outbreaks.
Publisher: Elsevier BV
Date: 08-2012
Publisher: Springer Science and Business Media LLC
Date: 18-07-2023
DOI: 10.1007/S00338-023-02405-4
Abstract: Population irruptions of crown-of-thorns seastar (CoTS, Acanthaster spp.) represent a perennial threat to Indo-Pacific coral reefs. Age determination of CoTS is challenging, thereby hindering understanding and management of this nuisance species. Telomeres, which are protective DNA structure found at the ends of eukaryotic chromosomes that shorten at each cell ision, have been used to estimate age in wild animals. To investigate the use of telomeres in CoTS, we optimized a quantitative PCR protocol to measure relative telomere length (rTL) in CoTS for the first time. Comparing rTL among four age groups (4, 7, 16, 24 months post-settlement), we found that adult CoTS generally exhibit shorter rTL than juveniles, which is the first evidence of age-related telomere attrition in CoTS. However, there was large within-age class variation, and no significant relationships were found between adult CoTS rTL and potential age-indicating external features. Furthermore, we found accelerated telomere attrition under sub-optimal diet, where in iduals that were fed crustose coralline algae for 16 months exhibited shorter rTL than their counterparts fed on coral. A positive correlation was found between rTL of tube feet and pyloric caeca, suggesting synchronization of telomere dynamics across somatic tissues in CoTS. Overall, our results suggest that rTL could be used to classify CoTS into broad age groups, though in idual variation constrains the ability to resolve specific cohorts. The present study contributes to the understanding of telomere dynamics in marine invertebrates, while laying the groundwork for future research into rTL as biomarker for age and potentially stress for CoTS.
Publisher: Springer Science and Business Media LLC
Date: 27-11-2012
Publisher: Springer Science and Business Media LLC
Date: 03-12-2019
Publisher: Springer Science and Business Media LLC
Date: 07-03-2023
DOI: 10.1007/S00338-023-02364-W
Abstract: Crown-of-thorns starfish (CoTS) are a pervasive coral predator prone to population outbreaks that have damaged coral reefs across Australia and the wider Indo-Pacific. CoTS population control through predation has been suggested as a primary mechanism that suppresses their outbreaks. However, the nature and rates of predation on CoTS are poorly resolved, especially for early life-history stages where they are expected to be most vulnerable. Here, we provide results from the first investigation of predators of CoTS during their rubble-dwelling, herbivorous, juvenile phase. We assessed the capacity of 104 common species of the rubble cryptofauna found across Heron Reef, Great Barrier Reef, Australia, to consume early-stage juvenile CoTS (0.8–3.8 mm) using controlled feeding experiments with laboratory-raised juveniles. We identified 26 novel CoTS predators, but only 10 species that regularly consumed juvenile CoTS in their entirety. Most cases of predation resulted in severed bodies and missing arms (i.e. sublethal predation) but not total consumption. We highlight one crustacean predator, Schizophrys aspera , the red decorator crab, which consumed whole juvenile CoTS in 89% of feeding trials and in excess of 5 CoTS d −1 in natural rubble mesocosms with alternative prey. This work emphasises the importance of predators at the critical juvenile stage that may control the build-up of CoTS populations prior to being detectable as an outbreak population.
Publisher: Springer Science and Business Media LLC
Date: 04-05-2016
Publisher: Public Library of Science (PLoS)
Date: 16-03-2012
Publisher: American Society for Microbiology
Date: 11-2012
DOI: 10.1128/AEM.01623-12
Abstract: 16S rRNA gene molecular analysis elucidated the spatiotemporal distribution of bacterial biofilm communities along a water quality gradient. Multivariate statistics indicated that terrestrial runoff, in particular dissolved organic carbon and chlorophyll a concentrations, induced shifts of specific bacterial communities between locations and seasons, suggesting microbial biofilms could be suitable bioindicators for water quality.
Location: Australia
Start Date: 2019
End Date: 2022
Funder: Australian Research Council
View Funded ActivityStart Date: 04-2019
End Date: 12-2022
Amount: $416,000.00
Funder: Australian Research Council
View Funded Activity