10 research outputs found

    The Composition of Spesies and Changes in Reef Fishes Community at Ecoreef Rehabilitation Site, Manado Tua Island, Bunaken National Park

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    The study conducted from 2006 to 2012 with an interval of every two years in the ecoreef area of ā€‹ā€‹ Manado Tua island found 2,936 individual reef fishes of 181 species that include into 32 families. Species composition value of the 10 dominant species of reef fishes was 55.48% of the total species. The highest number of species was Plotosus lineatus with schooling behavior which only discovered in 2010 at a depth of 3 meters. Ecoreef area of Manado Tua island, when analyzed from the abundance and biomass of reef fishes exhibited a succession of reef fish that have been stable, with peak abundance and higher biomass in 2008 and 2010. Reef fish found in ecoreef seemed to start a new living and become a new habitat for them. These were indicated by the highest biomass during the previous year but the number of individuals and spesies were decline. There was no change in the structure of reef fish communities in the ecoreef area of Manado Tua Island, which characterized by non significant different ecological index between the years. Cluster analyses grouped reef fish species into 2 groups i.e., the group of 2006 and the group of 2008, 2010, and 2012. Early survey in 2006 showed lower abundance of reef fish species for allegedly associated with low ecoreef organisms

    A New Northernmost Distribution Record of the Reef Coral Duncanopsammia axifuga at Birdā€™s Head Peninsula, West Papua, Indonesia

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    Duncanopsammia axifuga (Scleractinia: Dendrophylliidae) is reported for the first time from Indonesia. A population was found in 5-m deep, murky water on a sediment-rich, inshore reef at Birdā€™s Head Peninsula, West Papua. Some corals were attached to dead coral and others were loose fragments living on sediment. One attached specimen was observed to be damaged as a result of direct contact with an adjacent Goniopora coral. Free-living specimens on sand are more likely able to escape competition for space. These observations may help to better understand the northernmost range limit and the natural environment of D. axifuga, a species that is popular in the international aquarium trade, but has not been studied very well in the field

    Growth responses of branching versus massive corals to ocean warming on the Great Barrier Reef, Australia

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    As oceans continue to warm under climate change, understanding the differential growth responses of corals is increasingly important. Scleractinian corals exhibit a broad range of life-history strategies, yet few studies have explored interspecific variation in long-term growth rates under a changing climate. Here we studied growth records of two coral species with different growth forms, namely branching Isopora palifera and massive Porites spp. at an offshore reef (Myrmidon Reef) of the central Great Barrier Reef (GBR), Australia. Skeletal growth chronologies were constructed using a combination of X-radiographs, gamma densitometry, and trace element (Sr/Ca) analysis. General additive mixed-effect models (GAMMs) revealed that skeletal density of I. palifera declined linearly and significantly at a rate of 1.2% yr between 2002 and 2012. Calcification was stable between 2002 and 2009, yet declined significantly at a rate of 12% yr between 2009 and 2012 following anomalously high sea surface temperatures (SST). Skeletal density of massive Porites exhibited a significant non-linear response over the 11-year study period (2002āˆ’2012) in that density was temporarily reduced during the 2009ā€“2010 anomalously hot years, while linear extension and calcification showed no significant trends. Linear extension, density and calcification rates of I. palifera increased to maximum growth of 26.7ā€“26.9 Ā°C, beyond which they declined. In contrast, calcification and linear extension of Porites exhibited no response to SST, but exhibited a significant linear decline in skeletal density with increasing SST. Our results reveal significant differences in coral growth patterns among coral growth forms, and highlight both the resistant nature of massive Porites and sensitivity of branching I. palifera. Future research should target a broad range of coral taxa within similar environments to provide a community-level response of ocean warming on coral reef communities

    Long-term growth trends of massive Porites corals across a latitudinal gradient in the Indo-Pacific

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    Previous studies have reported recent substantial declines in the growth rates of massive Porites corals under warming oceans. However, the majority of these reports are from inshore reefs, and few have explored growth responses in offshore reefs from remote locations with low levels of pollution, sedimentation or nutrient loading. Here, we examined continuous growth records of massive Porites from remote locations spanning a 25 degrees latitudinal gradient in the Indo-Pacific, including Palau, central Sulawesi, West Papua and the central Great Barrier Reef (GBR). Between 1982 and 2012, no significant changes in calcification or extension anomalies were observed at any study location, despite significant increases in sea surface temperature (SST) at all sites. Skeletal density increased linearly by similar to 0.4 % yr(-1) in Palau, but no change was found in Sulawesi, yet skeletal density showed a significant nonlinear change in West Papua and the GBR. Skeletal density displayed a significant positive linear relationship with SST at Palau and West Papua, whereas no relationship was observed in Sulawesi. In the GBR, skeletal density exhibited a nonlinear parabolic relationship with SST, with strong negative anomalies occurring following major thermal events. Unlike the ongoing declines in growth rates of inshore corals that have been widely reported, we found that calcification and extension anomalies of the majority of Porites from offshore remote locations do not appear to be exhibiting negative growth responses to warming SST. Our results suggest that reefs experiencing low levels of local stressors may show increased resilience to warming SST in an era of rapidly warming oceans

    Coral restoration can drive rapid reef carbonate budget recovery

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    Restoration is increasingly seen as a necessary tool to reverse ecological decline across terrestrial and marine ecosystems. Considering the unprecedented loss of coral cover and associated reef ecosystem services, active coral restoration is gaining traction in local management strategies and has recently seen major increases in scale. However, the extent to which coral restoration may restore key reef functions is poorly understood. Carbonate budgets, defined as the balance between calcium carbonate production and erosion, influence a reef's ability to provide important geo-ecological functions including structural complexity, reef framework production, and vertical accretion. Here we present the first assessment of reef carbonate budget trajectories at restoration sites. The study was conducted at one of the world's largest coral restoration programs, which transplants healthy coral fragments onto hexagonal metal frames to consolidate degraded rubble fields. Within 4 years, fast coral growth supports a rapid recovery of coral cover (from 17% Ā± 2% to 56% Ā± 4%), substrate rugosity (from 1.3 Ā± 0.1 to 1.7 Ā± 0.1) and carbonate production (from 7.2 Ā± 1.6 to 20.7 Ā± 2.2 kg m yr ). Four years after coral transplantation, net carbonate budgets have tripled and are indistinguishable from healthy control sites (19.1 Ā± 3.1 and 18.7 Ā± 2.2 kg m yr , respectively). However, taxa-level contributions to carbonate production differ between restored and healthy reefs due to the preferential use of branching corals for transplantation. While longer observation times are necessary to observe any self-organization ability of restored reefs (natural recruitment, resilience to thermal stress), we demonstrate the potential of large-scale, well-managed coral restoration projects to recover important ecosystem functions within only 4 years

    Integrative carbonate budget model of the Great Barrier Reef

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    This project synthesizes and refines the carbonate budget produced for the Great Barrier Reef (GBR) in Wolfe et al. (2019). Here, we present robust methodological advances to facilitate the calculation of carbonate budgets for the GBR, including:1. The first method to quantify carbonate budgets using percent-cover data, alleviating the requirement for detailed in-situ census-based approaches to quantifying structural complexity and carbonate production (e.g., rugosity).2. Development of a carbonate budget model for the GBR that allows for site-specific conversions of coral cover to produce estimates of carbonate production.3. Inclusion of ecologically-relevant parameterisation of parrotfish bioerosion using an integrative modelling approach and GBR-specific parameter estimates.4. Explicit consideration of uncertainty surrounding production and erosion processes across spatial and temporal dimensions.5. A consequent R package (ā€œcaRbsā€) for use by scientists and managers.Using the Australian Institute of Marine Scienceā€™s (AIMS) Long-Term Monitoring Program (LTMP) data on coral cover and fish biomass between 2016ā€“2020 to parameterise the caRbs package, we quantified spatial and temporal patterns in carbonate production and bioerosion and identified the thresholds in coral cover required to maintain a positive carbonate budget for the GBR. Results highlighted the importance of Acropora sp. as the primary contributor to the carbonate budget, although massive Porites sp. were identified as key framework builders to maintain carbonate production. Carbonate production varied latitudinally, with higher calcification rates at low latitudes, while there were no clear spatial or temporal trends in primary bioerosion on the GBR. Parrotfish (Chlororus microrhinus) was the primary driver of bioerosion on fore-reef habitats. The study concluded that overall estimates of the carbonate budget on the GBR ranged between -4.9 and 28.4 kg m-2 yr-1 (~73% of sites had net positive budgets), and the threshold of coral cover to maintain a positive carbonate budget on the GBR were estimated at ~17%.Key take home messages from a management perspective are:1. For mid and outer shelf reef slope communities, overall coral cover needs to exceed 17% for reefs to have a positive carbonate budget.2. We do not yet have a corresponding threshold for inshore reefs where a number of processes, including bioerosion and biogeochemistry, can be quite different.3. The fact that an individual reef may sit below the 17% threshold does not necessarily indicate that there is a problem; it may just be in an early stage of recovery.4. The caRbs package presents an important tool to evaluate trends of reef state over time, asking how the proportion of reefs sitting below and above the 17% threshold is changing and to ask whether one region has a higher proportion of ā€˜positive reefsā€™ than another.5. A positive carbonate budget is a pre-requisite for many reef services but does not necessarily imply that all services, including accretion with sea-level rise and provision of high-quality habitat for fish and coastal protection, will occur at historical rates. Further work is needed to link carbonate budget trends explicitly to ecosystem functions. This work has started by linking carbonate budgets to reef accretion (Perry et al. 2018) but there is more to do

    CORDAP R&D Technology Roadmap for Understanding the Natural Adaptation and Assisted Evolution of Corals to Climate Change

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    Experts release a roadmap for harnessing the potential of assisted evolution to help save corals. The IPCC predicts that if warming reaches 2Ā°C, 99% of all coral reefs will be lost in less than 30 years. It is clear that to ensure the future of corals, the highest priority must be reducing global greenhouse gas emissions. However, even with swift and substantial reductions in emissions, corals will continue to face increasing temperatures for the foreseeable future, which can result in extensive coral mortality and local extinction of some coral species. While recent studies have shown that corals may exhibit some degree of adaptation to ocean warming, it is unclear whether corals are able to survive the rate of temperature change during heat waves that will become more frequent under several climate change scenarios. If corals lack what it takes to naturally rapidly adapt to new environmental regimes, they may fail to survive a warming ocean. This is where assisted evolution could be a game-changer. Growing our understanding of the power of adaptation In January 2023, we held a workshop on assisted evolution co-organized with the Australian Institute of Marine Sciences (AIMS) as part of CORDAPā€™s Scoping Studies (a series of planning sessions and technology roadmap studies to shape our funding priorities). Our aim was to develop a visionary roadmap, offering recommendations on how to prioritise assisted evolution in R&D investment in the future. Assisted evolution is the use of human interventions to speed up the natural evolutionary process. It may allow coral species to adapt faster than they would if left unaided, allowing reefs and corals to keep better pace with the oceanā€™s environmental changes. The first step in creating this strategy was to pinpoint where we are now in our understanding regarding the potential and impacts of assisted evolution on enhancing coral tolerance to stress conditions like ocean warming. Our experts unanimously agreed that assisted evolution methods cannot be understood and evaluated without a solid foundational understanding of natural adaptation, and identified some knowledge gaps that can be closed with relatively minimal effort and others that will require substantial investment of time and resources. Key Findings: - Standardising methods, experimental designs, species selection guidelines, and terminologies will help to understand natural adaptation and assisted evolution more rapidly. - Long-term funding is critical to facilitate multigenerational studies, which are needed to deliver essential but largely missing information about coral evolution. Building the best pathway for research and investment This roadmap sets out tangible recommendations for future investment and research, to help fill critical knowledge gaps that could assist natural adaptation and evolution of coral reefs in a warming world. Overall, the roadmap recommends investment in a mixed portfolio of R&D, ranging from technologies with lower perceived risks to those with higher percieved risks and longer R&D horizons. This strategy is advised because of the uncertainty around future heating trajectories and thus requirements for enhancement of tolerance. The roadmap outlined four main areas of work that need to be undertaken: 1. Leading global coordination and synthesis. Recommendation: Building global infrastructure to support research would dramatically accelerate the generation of knowledge around the natural and assisted evolution of corals. This could include compiling and committing to a set of standards and methods that will allow more studies to be used in predictive models, as well as establishing a global resource-sharing network and database to facilitate meta-analysis and synthesis. 2. Optimising generation and use of knowledge. Recommendation: Make sure new studies are well designed and timely. Optimize published and future studies by characterizing relationships between heat stress metrics and other facets of coral fitness. Having funding set aside to be able to quickly respond to bleaching events will ensure vital knowledge is captured rather than lost if and when those events occur. 3. Filling critical knowledge gaps in multigenerational coral data in the laboratory and field. Recommendation: Given the slow-growing nature of coral, longer-term funding would allow researchers to gain critical knowledge needed to estimate the multi-generational benefits and risks of implementing assisted evolution methods in the wild. Standardised approaches repeated in different parts of the world would add confidence to generalise those results. 4. Supporting the advance of existing and new technologies. Recommendation: Methods that may yield a larger effect (e.g., gene editing, hybridisation between species, and assisted migration) are also potentially of greater risk and would need considerable R&D. Expanding support for some of the riskier long-term projects currently being overlooked, could potentially offer a greater return on investment, but should be balanced with continued investment in less risky technologies. CORDAP will be using these recommendations to prepare new accelerator program and we believe that they will assist academia in understanding gaps and needs for future research as well as helping to guide funding agencies on where their money will be most effective. The roadmap identifies the funding structures and research priorities that are most likely to yield the knowledge needed to ensure that assisted evolution methods can be implemented effectively. Ultimately, conserving and restoring coral reefs in warming climates will require an inclusive infrastructure involving many partners at a local, national, and international level
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