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In major harbors and ports in the United States and its territories, the US Army Corps of Engineers maintains federal navigation channels in proximity to coral reefs (e.g., Honolulu Harbor, HI; Miami Harbor, FL; Apra Harbor, Guam) and other sensitive habitats. To effectively predict potential adverse impacts from dredging activities near these sensitive habitats, a holistic approach to improve understanding of the pressures on these habitats is needed to foster a more complete prediction of risk drivers. To achieve this, risk-based frameworks that account for the full range of natural and anthropogenic impacts need to be adapted and applied specifically for assessing and managing indirect dredging impacts on sensitive environments. In this article, we address this need by incorporating a drivers-pressures-stressors-condition-response (DPSCR 4 ) conceptual framework to broaden a comprehensive conceptual model of the coupled human-ecological system. To help understand these complex interactions, DPSCR 4 was applied to evaluate dredging and other unrelated environmental pressures (e.g., terrestrial runoff) in a proof-of-concept dredging project in Honolulu Harbor, Hawai'i, USA, with a focus on the indirect effects of dredge plumes. Particle tracking models and risk-based tools were used to evaluate sediment resuspended during a hypothetical mechanical dredging activity near sensitive coral habitats. Stoplight indicators were developed to predict indirect sediment plume impacts on coral and then compared to exposure modeling results. The strengths and limitations of the approach are presented and the incorporation of the risk framework into environmental management decisions is discussed. Integr Environ Assess Manag 2024;20:547-561. Published 2023. This article is a U.S. Government work and is in the public domain in the USA., (Published 2023. This article is a U.S. Government work and is in the public domain in the USA.)

Microplastic (MP) pollution has been detected in coral reefs, raising concerns regarding its global impact. Although they cover a small portion (<1%) of the total area of the world's oceans, coral reefs are geological and biological structures that trap MPs and disproportionately enhance their accumulation. In this review, we attempted to understand how coral reefs act as short- and long-term sinks for MPs. We describe five characteristics that lead to the enrichment of microplastics in coral reefs: 1) adhesion on reef-building corals at distinct depths; 2) ingestion by reef organisms (e.g., suspension feeders, such as sponges, ascidians, and corals), bioconcentration, and formation of short-term (i.e., years to decades) biological sinks for MPs; 3) formation of long-term (i.e., centuries) MP sinks in coral skeletons and unconsolidated subsurface sediments; 4) reduction of sediment resuspension and seafloor turbulent kinetic energy by complex marine forest architecture that reduces bottom shear stress, facilitates the retention, and deposition of small (<0.5 mm) and high-density floating MPs; and 5) diagenesis of Anthropocene sedimentary rocks containing MPs. We estimate that reef processes may remove more than 10% of floating MPs in shallow tropical waters yearly. Statistical results show that microplastic abundance for reef-building corals are higher than values found in reef sediments and especially in seawater. Moreover, pellets, films, foams and mainly fragments and fibers have been found. These field-based data support our hypothesis of sinks in the reef sediments and organisms. We highlight the role of these seascapes in the interception of MPs as traps and sinks in reef sediments, biota, and carbonate frameworks. As coral reefs are prone to MP accumulation and can become pollution hotspots, global initiatives are necessary to conserve these rich ecosystems and prevent rapidly increasing plastic pollution., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Ocean warming (OW) and acidification (OA) are two of the greatest global threats to the persistence of coral reefs. Calcifying reef taxa such as corals and coralline algae provide the essential substrate and habitat in tropical reefs but are at particular risk due to their susceptibility to both OW and OA. OW poses the greater threat to future reef growth and function, via its capacity to destabilise the productivity of both taxa, and to cause mass bleaching events and mortality of corals. Marine heatwaves are projected to increase in frequency, intensity, and duration over the coming decades, raising the question of whether coral reefs will be able to persist as functioning ecosystems and in what form. OA should not be overlooked, as its negative impacts on the calcification of reef-building corals and coralline algae will have consequences for global reef accretion. Given that OA can have negative impacts on the reproduction and early life stages of both coralline algae and corals, the interdependence of these taxa may result in negative feedbacks for reef replenishment. However, there is little evidence that OA causes coral bleaching or exacerbates the effects of OW on coral bleaching. Instead, there is some evidence that OA alters the photo-physiology of both taxa. Tropical coralline algal possess shorter generation times than corals, which could enable more rapid evolutionary responses. Future reefs will be dominated by taxa with shorter generation times and high plasticity, or those individuals inherently resistant and resilient to both marine heatwaves and OA., (© 2022 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society and the Royal Society of Biology.)

The reduction in benthic light from natural sediment resuspension events, dredging activities and clouds was quantified over multiple time periods (days to weeks) from a 3-year in-situ field study in the inshore turbid-zone coral communities of the Great Barrier Reef. The results were then used to examine the tolerance levels of three coral species and a sponge to light reduction and associated changes in spectral light quality (in conjunction with elevated sediment concentrations) in a 28-day laboratory-based study. All species survived the exposures but sub-lethal responses involving changes in pigmentation, lipids and lipid ratios were observed. A pocilloporid coral was the most sensitive taxon, with a 28-d EC10 value for bleaching (dissociation of the symbiosis) of 2.7 mol photons m 2 d -1 . The possibility of such light reduction levels occurring naturally and/or during maintenance dredging activities was then examined using the 3-year in-situ field study as part of a risk assessment., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Ocean warming and acidification threaten the future growth of coral reefs. This is because the calcifying coral reef taxa that construct the calcium carbonate frameworks and cement the reef together are highly sensitive to ocean warming and acidification. However, the global-scale effects of ocean warming and acidification on rates of coral reef net carbonate production remain poorly constrained despite a wealth of studies assessing their effects on the calcification of individual organisms. Here, we present global estimates of projected future changes in coral reef net carbonate production under ocean warming and acidification. We apply a meta-analysis of responses of coral reef taxa calcification and bioerosion rates to predicted changes in coral cover driven by climate change to estimate the net carbonate production rates of 183 reefs worldwide by 2050 and 2100. We forecast mean global reef net carbonate production under representative concentration pathways (RCP) 2.6, 4.5, and 8.5 will decline by 76, 149, and 156%, respectively, by 2100. While 63% of reefs are projected to continue to accrete by 2100 under RCP2.6, 94% will be eroding by 2050 under RCP8.5, and no reefs will continue to accrete at rates matching projected sea level rise under RCP4.5 or 8.5 by 2100. Projected reduced coral cover due to bleaching events predominately drives these declines rather than the direct physiological impacts of ocean warming and acidification on calcification or bioerosion. Presently degraded reefs were also more sensitive in our analysis. These findings highlight the low likelihood that the world's coral reefs will maintain their functional roles without near-term stabilization of atmospheric CO 2 emissions., Competing Interests: The authors declare no competing interest., (Copyright © 2021 the Author(s). Published by PNAS.)

Artificial Light at Night (ALAN), which is the alteration of natural light levels as the result of anthropogenic light sources, has been acknowledged as an important factor that alters the functioning of marine ecosystems. Using LEDs light to mimic ALAN, we studied the effect on the physiology (symbiont and chlorophyll contents, photosynthesis, respiration, pigment profile, skeletal growth, and oxidative stress responses) of two scleractinian coral species originating from the Red Sea. ALAN induced the photoinhibition of symbiont photosynthesis, as well as an overproduction of reactive oxygen species (ROS) and an increase in oxidative damage to lipids in both coral species. The extent of the deleterious effects of ALAN on the symbiotic association and coral physiology was aligned with the severity of the oxidative stress condition experienced by the corals. The coral species Sylophora pistillata, which experienced a more severe oxidative stress condition than the other species tested, Turbinaria reniformis, also showed a more pronounced bleaching (loss of symbionts and chlorophyll content), enhanced photoinhibition and decreased photosynthetic rates. Findings of the present study further our knowledge on the biochemical mechanisms underpinning the deleterious impacts of ALAN on scleractinian corals, ultimately shedding light on the emerging threat of ALAN on coral reef ecology. Further, considering that global warming and light pollution will increase in the next few decades, future studies should be taken to elucidate the potential synergetic effects of ALAN and global climate change stressors., Competing Interests: Declaration of competing interest The authors declare no competing financial interests., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Reef-building coral taxa demonstrate considerable flexibility and diversity in reproduction and growth mechanisms. Corals take advantage of this flexibility to increase or decrease size through clonal expansion and loss of live tissue area (i.e. via reproduction and mortality of constituent polyps). The biological lability of reef-building corals may be expected to map onto varying patterns of demography across environmental contexts which can contribute to geographic variation in population dynamics. Here we explore the patterns of growth of two common coral taxa, corymbose Pocillopora and massive Porites, across seven islands in the central and south Pacific. The islands span a natural gradient of environmental conditions, including a range of pelagic primary production, a metric linked to the relative availability of inorganic nutrients and heterotrophic resources for mixotrophic corals, and sea surface temperature and thermal histories. Over a multi-year sampling interval, most coral colonies experienced positive growth (greater planar area of live tissue in second relative to first time point), though the distributions of growth varied across islands. Island-level median growth did not relate simply to estimated pelagic primary productivity or temperature. However, at locations that experienced an extreme warm-water event during the sampling interval, most Porites colonies experienced net losses of live tissue and nearly all Pocillopora colonies experienced complete mortality. While descriptive statistics of demographics offer valuable insights into trends and variability in colony change through time, simplified models predicting growth patterns based on summarized oceanographic metrics appear inadequate for robust demographic prediction. We propose that the complexity of life history strategies among colonial reef-building corals introduces unique demographic flexibility for colonies to respond to a wide breadth of environmental conditions., (© 2020 Elsevier Ltd. All rights reserved.)

Due to extremely high rates of evaporation and low precipitation in the Persian Gulf, discharges from desalination plants (DPs) can lead to ecological stresses by increasing water temperatures, salinities, and heavy metal concentrations, as well as decreasing dissolved oxygen levels. We discuss the potential ecological impacts of DPs on marine organisms and propose mitigating measures to reduce the problems induced by DPs discharges. The daily capacity of DPs in the Persian Gulf exceeds 11 million m 3 per day, which is approximately half of global daily freshwater production; multistage flash distillation (MSF) is the dominant desalination process. Results from field and laboratory studies indicate that there are potentially serious and chronic threats to marine communities following exposure to DP discharges, especially within the zoobenthos, echinodermata, seagrasses, and coral reefs. DP discharges can lead to decreases in sensitive species, plankton abundance, hard substrate epifauna, and growth rates of seagrasses. However, the broad applicability of any one of these impacts is currently hard to scale because of the limited number of studies that have been conducted to assess the ecological impacts of DP discharge on Persian Gulf organisms. Even so, available data suggest that appropriately sited, designed, and operated DPs combined with current developments in impingement and entrainment reduction technology can mitigate many of the negative environmental impacts of DPs., (© 2019 John Wiley & Sons Ltd.)

If we are to ensure the persistence of species in an increasingly warm world, of interest is the identification of drivers that affect the ability of an organism to resist thermal stress. Underpinning any organism's capacity for resistance is a complex interplay between biological and physical factors occurring over multiple scales. Tropical coral reefs are a unique system, in that their function is dependent upon the maintenance of a coral-algal symbiosis that is directly disrupted by increases in water temperature. A number of physical factors have been identified as affecting the biological responses of the coral organism under broadscale thermal anomalies. One such factor is water flow, which is capable of modulating both organismal metabolic functioning and thermal environments. Understanding the physiological and hydrodynamic drivers of organism response to thermal stress improves predictive capabilities and informs targeted management responses, thereby increasing the resilience of reefs into the future., (© 2019 WILEY Periodicals, Inc.)

Corals require efficient heat and mass transfer with the overlying water column to support key biological processes, such as nutrient uptake and mitigation of thermal stress. Transfer rates are primarily determined by flow conditions, coral morphology and the physics of the resulting fluid-structure interaction, yet the relationship among these parameters is poorly understood especially for wave-dominated coral habitats. To investigate the interactive effects of these factors on fluxes of heat and mass, we measure hydrodynamic characteristics in situ over three distinct surface morphologies of massive stony corals in a Panamanian reef. Additionally, we implement a numerical model of flow and thermal transport for both current and wave conditions past a natural coral surface, as well as past three simplified coral morphologies with varying ratios of surface roughness spacing-to-height. We find oscillatory flow enhances rates of heat and mass transfer by 1.2-2.0× compared with unidirectional flow. Additionally, increases in Reynolds number and in surface roughness ratio produce up to a 3.3× and a 2.0× enhancement, respectively. However, as waves begin to dominate the flow regime relative to unidirectional currents, the underlying physical mechanisms mediating transfer rates shift from predominantly turbulence-driven to greater control by inertial accelerations, resulting in larger heat and mass transfer for small surface roughness ratios. We show that for rough corals in wave-dominated flows, novel trade-off dynamics for heat and mass transfer exist between broadly spaced roughness that enhances turbulence production versus narrowly spaced roughness that produces greater surface area. These findings have important implications for differential survivorship during heat-induced coral bleaching, particularly as thermal stress events become increasingly common with global climate change.

We investigate the correlation between stress-related compounds produced by corals of the Great Barrier Reef (GBR) and local atmospheric properties-an issue that goes to the core of the coral ecosystem's ability to survive climate change. We relate the variability in a satellite decadal time series of fine-mode aerosol optical depth (AOD) to a coral stress metric, formulated as a function of irradiance, water clarity, and tide, at Heron Island in the southern GBR. We found that AOD was correlated with the coral stress metric, and the correlation increased at low wind speeds, when horizontal advection of air masses was low and the production of non-biogenic aerosols was minimal. We posit that coral reefs may be able to protect themselves from irradiance stress during calm weather by affecting the optical properties of the atmosphere and local incident solar radiation.

Corals are considered one of the most complex microbial biospheres studied to date, hosting thousands of bacterial phylotypes in species-specific associations. There are, however, substantial knowledge gaps and challenges in understanding the functional significance of bacterial communities and bacterial symbioses of corals. The ubiquitous nature of some bacterial interactions has only recently been investigated and an accurate differentiation between the healthy (symbiotic) and unhealthy (dysbiotic) microbial state has not yet been determined. Here we review the complexity of the coral holobiont, coral microbiome diversity, and recently proposed bacterial symbioses of corals. We provide insight into coupling the core microbiome framework with community ecology principals, and draw on the theoretical insights from other complex systems, to build a framework to aid in deciphering ecologically significant microbes within a corals' microbial soup., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Bacterial assemblages associated with the hermatypic corals Pocillopora damicornis and P. verrucosa, the surrounding seawater and the sediment at six coral reef sites in the north section of the Tropical Eastern Pacific were assessed using MiSeq Illumina sequencing of the V4 region of the 16S rDNA. The bacterial microbiota in both coral species, seawater and sediment were stable to seasonal variations. Bacterial assemblages between the same substrates were not significantly different from each other in the six sites sampled. Interestingly, the bacterial composition between substrates within the same site was significantly different, or not, depending on the conservation status of the site. Moreover, we found species-specific bacterial OTUs in both coral species. Analyzing the relationship between bacterial composition and environmental variables revealed a positive correlation between bacterial assemblages and dissolved oxygen, ammonium and silicate., (© FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

To date, studies of ocean acidification (OA) on coral reefs have focused on organisms rather than communities, and the few community effects that have been addressed have focused on shallow back reef habitats. The effects of OA on outer barrier reefs, which are the most striking of coral reef habitats and are functionally and physically different from back reefs, are unknown. Using 5-m long outdoor flumes to create treatment conditions, we constructed coral reef communities comprised of calcified algae, corals, and reef pavement that were assembled to match the community structure at 17 m depth on the outer barrier reef of Moorea, French Polynesia. Communities were maintained under ambient and 1200 μatm pCO2 for 7 weeks, and net calcification rates were measured at different flow speeds. Community net calcification was significantly affected by OA, especially at night when net calcification was depressed ~78% compared to ambient pCO2 . Flow speed (2-14 cm s(-1) ) enhanced net calcification only at night under elevated pCO2 . Reef pavement also was affected by OA, with dissolution ~86% higher under elevated pCO2 compared to ambient pCO2 . These results suggest that net accretion of outer barrier reef communities will decline under OA conditions predicted within the next 100 years, largely because of increased dissolution of reef pavement. Such extensive dissolution poses a threat to the carbonate foundation of barrier reef communities., (© 2015 John Wiley & Sons Ltd.)

There is a need to develop water quality thresholds for dredging near coral reefs that can relate physical pressures to biological responses and define exposure conditions above which effects could occur. Water quality characteristics during dredging have, however, not been well described. Using information from several major dredging projects, we describe sediment particle sizes in the water column/seabed, suspended sediment concentrations at different temporal scales during natural and dredging-related turbidity events, and changes in light quantity/quality underneath plumes. These conditions differ considerably from those used in past laboratory studies of the effects of sediments on corals. The review also discusses other problems associated with using information from past studies for developing thresholds such as the existence of multiple different and inter-connected cause-effect pathways (which can confuse/confound interpretations), the use of sediment proxies, and the reliance on information from sediment traps to justify exposure regimes in sedimentation experiments., (Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.)

Coral reefs face threats from climate change and local pressures that lead to reductions in their physical structure, impacting biodiversity by limiting habitat availability. Despite many efforts to actively restore damaged reefs, few projects provide thorough evaluations of their success. This study measured the success of the "Reef Star" method at the Mars Coral Reef Restoration Project in Indonesia in reestablishing the physical structure of reef habitats that were destroyed by blast fishing. We used photogrammetry surveys to measure the physical habitat structure of 17 large sites (1000 m2 each), calculating three complementary measures of small‐ and large‐scale habitat complexity across degraded, restored, and naturally healthy coral reefs. We demonstrate that the restoration efforts have successfully restored small‐scale habitat complexity, as described by surface complexity metrics (3.22 ± 0.27 on restored reefs; 2.85 ± 0.26 on healthy reefs) and fractal dimension (2.27 ± 0.02 on restored reefs; 2.24 ± 0.02 on healthy reefs). This demonstrates the capacity for restored reefs to recover important ecosystem functions that are lost in degradation. However, while restoration has delivered some increases in large‐scale habitat complexity compared to degraded reefs, restored reefs still exhibit lower values of maximum vertical relief than healthy reefs, due to a lack of large physical structures. This lack of available large‐scale habitat might impact fish populations, meaning that restored reefs with limited large‐scale complexity may only support a restricted range of ecosystem functions. Effective reef restoration strategies must use a mixture of different methods that target the recovery of structural complexity at multiple scales. [ABSTRACT FROM AUTHOR]

The zoantharian genus Umimayanthus consists largely of species that live in obligate symbioses with sponges. Although zoantharians have often been overlooked in field collecting campaigns and in research, sponges are usually well-collected, and many natural history museums harbor numerous sponge specimens. Thus, these sponge collections may also include previously overlooked zoantharian species. Such is the case in this research, in which we examined sponge specimens in museum collections from Western Australia and eastern Indonesia. Based on our morphological and molecular analyses, we herein describe six species of Umimayanthus new to science, and redescribe another species described over a century ago. These species can be distinguished by their sponge associations, gross polyp and colony morphology, and depth ranges. Based on these findings, it appears that the Central Indo-Pacific region of Western Australia and Indonesia can be considered a hotspot for sponge-associated zoantharian diversity. We provide a key for the identification of all formally described species in the genus, but caution that there are likely more Umimayanthus species awaiting discovery. [ABSTRACT FROM AUTHOR]

Bioerosion plays a crucial factor in shaping the structure and function of coral reef ecosystems, with bioeroders actively altering both the physical and ecological dynamics of coral substrates. Despite their importance, studying internal bioeroders in corals presents significant challenges owing to their cryptic nature within the skeletal structures. Additionally, invasive methods are often required to reveal the subtle and microscopic bioerosive alterations they induce in calcium carbonate substrates. Here, we demonstrate the effectiveness of high-resolution micro-computed tomography (mCT) in quantifying the abundance, size, distribution, and growth directions of coral bioeroders such as cryptic calcareous bivalves in the northern Red Sea. We scanned three coral species inhabited by bioeroders, followed by the utilization of three-dimensional image analysis software to identify, count, and measure each bivalve within the coral skeleton, along with quantifying boring cavity volumes. We revealed that mCT captures small boring cavities (< 1mm), providing more accurate abundance estimates of live and dead boring bivalves than the skeleton decalcification technique, with the added benefits of being rapid and non-destructive in contrast to traditional methods. Furthermore, measurements of empty cavity volumes enabled the estimations of the contribution of bioeroders to the overall coral skeletal porosity. Overall, our study highlights mCT as a practical and effective tool for studying cryptic coral bioeroders, providing novel ecological insights into bioeroder population ecology and coral-bioeroder interactions. [ABSTRACT FROM AUTHOR]

The collection of a dead specimen of the coral Heterocyathus cf. sulcatus on a sandy beach in southern Odisha highlights the importance of exploring offshore waters along this coast. The specimen was identified based on prominent taxonomic characters and association with coral boring worm. This genus was previously known to occur along the eastern coast of India, from the Gulf of Mannar/Palk Bay and off the Chennai coast. The presence of rocky offshore outcrops and a sandy substratum in the vicinity suggests that the specimen likely originated from that location. [ABSTRACT FROM AUTHOR]

ABSTRACT Giant clams are invertebrates that form mutualistic associations with Symbiodiniaceae dinoflagellates. Despite their ecological significance, gaps persist regarding our understanding of their trophic ecology. Specifically, it is unknown whether Symbiodiniaceae‐derived photosynthates are metabolized differently according to species and organ. Therefore, we maintained Tridacna derasa and T. noae for 3 months in a well‐lit recirculated system without food supply. Samples were taken from eight organs and underwent lipid extraction and fatty acid esterification before analysis of three symbiont‐derived fatty acids (stearidonic acid, docosapentaenoic acid, and docosahexaenoic acid—SDA, DPA, and DHA, respectively) using gas chromatography. Results show considerable variation in fatty acids concentration among species and organs. SDA was found in higher concentrations in T. noae, especially in the adductor muscle. DPA was detected in low concentrations across T. noae organs and absent for T. derasa. DHA did not vary significantly among species and organs. Our findings indicate that Symbiodiniaceae supply clams with fatty acids, which are stored differentially according to species and organs. This demonstrates that these compounds are translocated to multiple organs throughout the complex giant clam anatomical system, in contrast to simpler hosts like corals. These results advance our understanding of the physiological dynamics of the mollusk‐algae association. [ABSTRACT FROM AUTHOR]

This review comprehensively covers the development of viable unmanned underwater vehicles based on their technical capabilities, in particular those designed to conduct research exploration in underwater ecosystems and address environmental issues through analysis of coral reef vulnerability. The most important elements to be obtained are in situ data samples for analysis and characterization, supported by molecular biomarkers and marine ecology indicators. The following aspects are considered in this study: first, the geographic distribution of coral reefs for the study of marine ecology and molecular biological approaches for the detection of biomarkers to evaluate the vulnerability of coral reefs are detailed; then, the technologies currently available for the study of coral reefs are briefly described, ranging from large-scale capture to local-scale capture directly in the study region, taking advantage of remote sensing systems assisted by aerial technologies, marine vehicles, and artificial intelligence for the mapping, monitoring, and management of coral reefs as well as the characterization of their vulnerability; following this, existing marine vehicle technologies are generally explained, including a categorical description and an updated and highlighted list of innovative and robust marine vehicles that have been used in coral reef applications; the technical capabilities of such vehicle throughout the missions they have been subjected to are presented based on bibliographic references; finally, this review promotes multidisciplinary work to integrate the developments in the associated knowledge areas in order to obtain synergies in the face of challenges related to the massive scale of coral reef degradation worldwide. [ABSTRACT FROM AUTHOR]

Coral reefs are among the most diverse and productive ecosystems, teeming with life and providing many benefits to marine life and human communities. Coral reef classification is popular for many important reasons, such as assessing biodiversity, prioritizing conservation actions to protect vulnerable species and their habitats, and many other objectives related to scientific research and interdisciplinary studies on marine ecosystems. Classifying images of coral reefs is challenging due to their great diversity and subtle differences in morphology. Manually classifying them is a time-consuming process, especially when dealing with large datasets. This can limit the scalability and efficiency of scientific research and conservation efforts. This study proposes an automated classification approach using computer vision and deep learning techniques to address these challenges, employing models such as YOLOv5l, YOLOv8l, and VGG16 to classify images of coral reefs. The dataset, comprising 1,187 images of five coral species, was augmented for robustness. YOLOv8l demonstrated superior performance with an accuracy of 97.8%, significantly outperforming the other models in terms of speed and accuracy. These results demonstrate the potential of advanced deep-learning models to improve coral reef monitoring and conservation efforts. This approach aims to streamline classification processes, improving the efficiency and scalability of coral reef research and conservation initiatives worldwide. [ABSTRACT FROM AUTHOR]

Periodic outbreaks of crown‐of‐thorns starfish have led to severe coral reef degradation, with one hypothesized cause being eutrophication. Phosphorus (P) is one of the driving factors for eutrophication, but researches on the spatiotemporal distributions of P in coral reefs are limited, impeding our understanding of the P cycling in coral reefs and its correlation with starfish outbreaks. This study undertook an analysis of various P species, migration and transformation in seawater, sediments, and crown‐of‐thorns starfish within the coral reefs of the Xisha Islands, northern South China Sea. The results show that in seawater, P predominantly existed in the dissolved phase, with organic P constituting the largest fraction (>67%). Conversely, in sediments, P primarily existed as inorganic form (43%−95%), with calcium‐bound P comprising the majority (26%−46%). Notably, exchangeable P accounted for a relatively smaller fraction (9%−20%) but played a significant role as a source of P released from sediments into seawater (0.01−0.17 mmol m−2 hr−1). During starfish outbreaks, starfish (1,000 individuals per hectare) assimilated P from seawater via phytoplankton or corals, resulting in substantial accumulation of both organic and inorganic P in their tissues (69−315 μmol g−1). Meanwhile, starfish excretion released P back into the seawater, which contributes to the migration and transformation of various P forms. Historical data also show a close relationship between P content and starfish density. These findings highlight the interactions between starfish and P cycling within coral reefs, and provide valuable insights into conservation and restoration on coral reefs, especially those severely affected by starfish outbreaks. Plain Language Summary: The coral reefs of the Xisha Islands, northern South China Sea have experienced periodic outbreaks of crown‐of‐thorns starfish, causing severe degradation of the coral reefs. However, the reasons for the outbreak of starfish remain unclear. This study aims to investigate the relationship between P content and starfish outbreaks, and examines where and how P migrates and transforms in seawater, sediments, and crown‐of‐thorns starfish. This study discovered that the majority of P in seawater existed in a dissolved state, primarily as organic compounds. In sediments, P existed mostly in inorganic forms, particularly bound to calcium, which is commonly found in coral reef sediments. The proportion of exchangeable P which can easily migrate from the sediments into the seawater was the least. During starfish outbreaks in the Xisha Islands, the density of starfish can hit 1,000 individuals per hectare. These starfish assimilated P from seawater via phytoplankton or corals, resulting in significant amounts of both organic and inorganic P within their tissues. Yet, starfish excretion releases P back into the seawater. This study linked starfish outbreaks to DIP levels, which helps us understand the P cycling in coral reefs and provides some outlooks on coral reef conservation in the context of starfish outbreaks. Key Points: Water P in Xisha's coral reefs mainly existed in DOP, as a significant DIP source via degradationPorous calcium carbonate boosted Ca‐P and Ex‐P proportion and DIP release in reef sedimentsCrown‐of‐thorns starfish stored and released OP and IP, affecting P cycle and starfish outbreaks [ABSTRACT FROM AUTHOR]

ABSTRACT Ostreobium comprises endolithic algae commonly seen in conjunction with scleractinian corals. In the past, it was solely recognized as a coral skeleton bioeroder. Their relationship with corals is critical because they give photosynthetic byproducts and help the coral when it loses its primary symbionts due to stress. The variety of these algae in coral species of the genus Porites in the Tropical Eastern Pacific and western Atlantic was investigated. Ostreobium samples from seven Porites species including two from the Tropical Eastern Pacific (TEP) (P. panamensis and P. lobata) and five from the Caribbean (P. furcata, P. porites, P. colonensis, P. branneri, and P. astreoides) were extracted. Published rbcL sequences from algae found within various coral species from other parts of the world were also compared. A biogeographic analysis and two methodologies, PTP (Poisson tree process) and GMYC (general mixed Yule‐coalescent), were used to delineate the different species. The findings revealed a significant degree of genetic diversity within Ostreobium, with more than 15 groups of not more than three individuals and 40 individual lineages. Its origins date back to the Ordovician, 500 Ma, and it does not appear to preserve host specificity. The sampled locations still have a wide variety of Ostreobium. Biogeographically patterns were also confirmed, making it impossible to pinpoint the precise origins of most clades. The ancestry analyses revealed convergent events for not only the emergence of Ostreobium in a few genera of local corals, but also the phenomenon occurred in genera from far‐off places. [ABSTRACT FROM AUTHOR]

The coral reef ecosystem is one of the most productive ecosystems in the ocean, and is also an important calcium carbonate deposition region. Because excess production is very low in coral reefs, organic carbon reservoirs are very limited. During the calcification process, each mole of CaCO3 will produce 1 mol of CO2, approximately 60% of which will be released into the atmosphere through the sea-air interface. This causes coral reefs to be large inorganic carbon reservoirs, but at the same time, most coral reefs act as atmospheric CO2 sources (which also act as sinks in some coral reefs). Therefore, clarifying the sea-air CO2 exchange flux and carbon storage is critical for understanding the carbon cycle in coral reef ecosystems. In this paper, we summarize the carbon cycle processes in the coral reefs of the South China Sea (SCS) and estimate the total CO2 budget and carbon reserves. According to current research, the coral reefs in this area act as a source of atmospheric CO2, releasing 0.37-1.59 × 1011 g C a-1 into the atmosphere. Owing to their extremely high biological productivity and carbonate productivity, the carbon reserves of coral reefs in the SCS range from 1.66-3.78 × 1012gCa-1, which is an order of magnitude greater than the CO2 emissions at the sea-air interface. Overall, coral reefs in the SCS are important carbon storage areas. As the current results are still approximate, a more comprehensive and indepth investigation is needed to clarify the carbon source/sink processes, regulatory mechanisms, and carbon storage capacity of SCS coral reefs. [ABSTRACT FROM AUTHOR]

Adaptation of reef-building corals to global warming depends upon standing heritable variation in tolerance traits upon which selection can act. Yet limited knowledge exists on heat-tolerance variation among conspecific individuals separated by metres to hundreds of kilometres. Here, we performed standardized acute heat-stress assays to quantify the thermal tolerance traits of 709 colonies of Acropora spathulata from 13 reefs spanning 1060 km (9.5° latitude) of the Great Barrier Reef. Thermal thresholds for photochemical efficiency and chlorophyll retention varied considerably among individual colonies both among reefs (approximately 6°C) and within reefs (approximately 3°C). Although tolerance rankings of colonies varied between traits, the most heat-tolerant corals (i.e. top 25% of each trait) were found at virtually all reefs, indicating widespread phenotypic variation. Reef-scale environmental predictors explained 12–62% of trait variation. Corals exposed to high thermal averages and recent thermal stress exhibited the greatest photochemical performance, probably reflecting local adaptation and stress pre-acclimatization, and the lowest chlorophyll retention suggesting stress pre-sensitization. Importantly, heat tolerance relative to local summer temperatures was the greatest on higher latitude reefs suggestive of higher adaptive potential. These results can be used to identify naturally tolerant coral populations and individuals for conservation and restoration applications. [ABSTRACT FROM AUTHOR]

The intensifying loss of coral reefs from global climate change and local stressors has seen international commitments targeted at conservation and repair, for example the Kunming–Montreal Global Biodiversity Framework. Fulfilling these targets requires decisions to be made on where, when, and how to act, ultimately dictating where limited resources will be deployed. Every choice on action or inaction toward our ocean has direct and indivisible consequences not only for the health of marine ecosystems but also for the health of humans, particularly those who directly depend on marine habitats, both culturally and economically. The well‐being of the environment, humans, and animals is interlinked, co‐dependent, and even co‐produced, as has already been acknowledged by One Health approaches, which endorse a cross‐ and trans‐disciplinary view to health. Coral reefs epitomie how tightly intertwined ecosystem health and the fate of the human and nonhuman communities that depend on them are. A field that thus far remains poorly considered is a human rights‐based approach to coral reef protection. A human rights‐based approach implements human rights obligations, including the recently affirmed right to a clean, healthy, and sustainable environment, while embedding principles of accountability, nondiscrimination, participation, and empowerment for local and Indigenous communities that ensure effectiveness and meaningful stakeholder engagement. Tying the protection of coral reef ecosystems to human rights emphasises the importance of healthy ecosystems to human well‐being and thus the inevitable connection between nonhuman and human life. The general failure to consider coral reef protection through a human rights‐based approach is a missed opportunity to expedite reef protection while simultaneously advancing climate justice for both humans and nonhumans. [ABSTRACT FROM AUTHOR]

Ecosystem responses to disturbance depend on the nature of the perturbation and the ecological legacies left behind, making it critical to understand how climate‐driven changes in disturbance regimes modify resilience properties of ecosystems. For coral reefs, recent increases in severe marine heat waves now co‐occur with powerful storms, the historic agent of disturbance. While storms kill coral and remove their skeletons, heat waves bleach and kill corals but leave their skeletons intact. Here, we explored how the material legacy of dead coral skeletons modifies two key ecological processes that underpin coral reef resilience: the ability of herbivores to control macroalgae (spatial competitors of corals), and the replenishment of new coral colonies. Our findings, grounded by a major bleaching event at our long‐term study locale, revealed that the presence of structurally complex dead skeletons reduced grazing on turf algae by ~80%. For macroalgae, browsing was reduced by >40% on less preferred (unpalatable) taxa, but only by ~10% on more preferred taxa. This enabled unpalatable macroalgae to reach ~45% cover in 2 years. By contrast, herbivores prevented macroalgae from becoming established on adjacent reefs that lacked skeletons. Manipulation of unpalatable macroalgae revealed that the cover reached after 1 year (~20%) reduced recruitment of corals by 50%. The effect of skeletons on juvenile coral growth was contingent on the timing of settlement relative to the disturbance. If corals settled directly after bleaching (before macroalgae colonized), dead skeletons enhanced colony growth by 34%, but this benefit was lost if corals colonized dead skeletons a year after the disturbance once macroalgae had proliferated. These findings underscore how a material legacy from a changing disturbance regime can alter ecosystem resilience properties by disrupting key trophic and competitive interactions that shape post‐disturbance community dynamics. [ABSTRACT FROM AUTHOR]

Compact bushy and expansive branching Acropora survival rates were compared in an experimental restoration setting. Coral fragments were sourced as corals of opportunity (CoPs) or refragmented from CoPs reared on a floating mid‐water rope nursery. Fragments were attached in single‐species and mixed‐species aggregations to modular substrate stabilization structures (reef stars) on degraded, unconsolidated dead coral rubble slopes in Wakatobi Marine National Park, central Indonesia. In total, 1440 Acropora fragments were outplanted to 96 reef stars across five experimental restoration blocks at 14 m depth. Fragment survival was recorded 40–44 months post‐attachment. Survival had a significant relationship with fragment morphology (p < 0.001) and aggregation type (p < 0.01). Sourcing fragments as CoPs or from the nursery did not have a significant relationship with survival. No significant relationships were found with fragment survival for any interactions between morphology, outplanted aggregation, and source. Survival rates for bushy Acropora were 3.44 times and 5.25 times higher than for expansive species for direct CoP outplants and nursery‐reared corals, respectively. The results demonstrate the potential efficacy of returning complex bushy branching Acropora morphologies to mid‐depth reef slopes previously dominated by the genus, using single‐species aggregations interspersed with mixed‐species aggregations. The study also supports using mid‐water nurseries to create a closed or semi‐closed nursery cycle to scale up restoration, and proposes introducing the term "biomass production system" to distinguish this as a process distinct from other coral nursery approaches. [ABSTRACT FROM AUTHOR]

Sea hares are cryptic, herbivorous sea slugs present on many coral reefs worldwide. Although they are known to consume high quantities of macroalgae, they are rarely considered or quantified in assessing algal suppression. Their role as algal suppressors is not well understood, therefore this study sought to quantify sea hare herbivory on the abundant red algal genus Laurencia. The sea hares Aplysia dactylomela, Dolabella auricularia and Dolabella sp. were collected and used in herbivory trials in aquaria at Heron Island on the Southern Great Barrier Reef to quantify their rate of consumption. A. dactylomela consumed 76.9 g partially dried weight of Laurencia per 24-h, which was significantly more than the other species, with D. auricularia consuming an average of 22.5 g and Dolabella sp. consuming 37.4 g partially dried weight. Consumption of Laurencia by A. dactylomela increased with body size, with the exception of the smallest animals, which ate up to 12.5 times their body weight. D. auricularia consumed significantly more algae than was lost in control tanks. Although we observed Dolabella sp. feeding on Laurencia, the amount consumed was not significantly different to loss of algae in control tanks. The rate of herbivory on Laurencia by A. dactylomela is comparable or greater than that of more commonly studied reef herbivores such as fishes and urchins, which suggests that they may contribute to algal suppression on coral reefs and further studies are warranted to evaluate their possible role in coral-algal phase shift dynamics. [ABSTRACT FROM AUTHOR]

While a record-high in situ water temperature of 38.4 °C on July 24, 2023, has been measured from a local site in Florida's Manatee Bay, satellite images revealed more extensive record-high water temperature in South Florida estuaries and the Florida Keys Reef Tract in July 2023 as a response to the 2023 heatwave, with an average sea surface temperature (SST) anomaly of 1.59 °C above the 2003–2022 mean. Long-term annual SST anomalies and long-term SST trend components of the time series both show significant warming trends in these regions between 2003 and 2023 (0.70 °C/decade), which is 67% higher than in the Gulf of Mexico (0.42 °C/decade). Furthermore, the warming trend appears to have accelerated over the past decade. In the context of global warming in the twenty-first century, such a warming trend and response to heatwaves may lead to more heat stress on the precious coral reefs and seagrasses both in and downstream from these already fragile estuaries. [ABSTRACT FROM AUTHOR]

Recurrent climate-driven warming events, which can induce severe coral bleaching and mortality on tropical reefs, are predicted to cause homogenisation of coral communities and loss of ecosystem functions in shallow reef systems (< 30 m). However, data documenting the variation in coral carbonate production across depth are limited. Here we explore differences in coral cover, community composition, coral colony size structure and carbonate production rates between two depths (10 m and 17.5 m) across four atolls in the remote Chagos Archipelago. We show higher coral carbonate production rates at 10 m (4.82 ± 0.27 G, where G = kg CaCO3 m−2 yr−1) compared to sites at 17.5 m (3.1 ± 0.18 G). The main carbonate producers at 10 m consisted of fast-growing branching and tabular corals (mainly Acroporids) and massive corals (mainly Porites), with high abundances of medium- and large-sized colonies. In contrast, coral carbonate production at 17.5 m was driven by slow-growing encrusting and foliose morphotypes and small colony sizes. Utilising a dataset following 6–7 years of recovery after the 2015–2017 bleaching event, our results show that depth-homogenisation of coral communities was temporary and carbonate production rates at 10 m depth recovered quicker at 3 of 4 studied atolls. The exception is Great Chagos Bank where slower recovery of branching and tabular corals at 10 m has led to a longer-lasting depth-homogenisation of carbonate production rates. The latter example cautions that more frequent bleaching events may drive increasing homogenisation of carbonate production rates across depth gradients, with implications for vital reef geo-ecological functions. [ABSTRACT FROM AUTHOR]

Reef-building corals live in close mutualism with dinoflagellate algae (family Symbiodiniaceae), which play key roles in coral physiological performance and survival. Association patterns between host species and endosymbiont algae and their significance are still not fully understood, but they seem to affect the ability of hosts to inhabit different environments and their resilience to climate change. In this work, we used next-generation sequencing of the Internal Transcribed Spacer 2 region of ribosomal DNA to determine the diversity and composition of the Symbiodiniaceae community in Pocillopora corals from Colombia, in the Eastern Tropical Pacific (ETP). We sampled 243 colonies from four localities characterized by distinct sea surface temperature, turbidity, and proximity to the coast. Two genera of Symbiodiniaceae, Durusdinium and Cladocopium were found associated with Pocillopora mitochondrial Open Reading Frame (mtORF) types. Cladocopium latusorum was highly specific to Pocillopora mtORF type 1, while C. pacificum was found exclusively associated with Pocillopora mtORF type 3. In contrast, Durusdinium glynnii was found in both Pocillopora mtORF types. Furthermore, a Cladocopium-dominated symbiont community occurred in cooler and less turbid localities, while a Durusdinium- dominated community was found in localities with high sea surface temperature and high water turbidity, irrespective of mtORF type. These results suggest that Pocillopora mtORF lineages associate with different Symbiodiniaceae genera in response to local environmental conditions. The ability to associate with a different partner under particular environmental conditions (Pocillopora-Durusdinium combination), and also maintain a specific partnership (Cladocopium species and Pocillopora mtORF types) may be key to understanding the resilience of the genus Pocillopora on ETP coral reefs. [ABSTRACT FROM AUTHOR]

Coral reef fishes are usually assumed to be most strongly associated with reef-building corals. However, sponges can be a significant structural component of coral reef ecosystems and their framework can enhance the local abundance and biodiversity of fish assemblages. Little is known regarding the range of fish species using complex sponges as either shelter or feeding substrata. Here we use a combination of stationary video cameras and focal animal sampling to document fish species positively associated with complex sponges in Kimbe Bay, Papua New Guinea. Stationary cameras identified 45 fish species using the sponges for either shelter, feeding substrata or as sites for ambush predation. A guild of 10 individual fish species from five families (Blenniidae, Chaetodontidae, Gobiidae, Labridae and Pomacentridae) were observed to quantify sponge and other habitat use and compared with habitat availability to determine the level of sponge selectivity. One species, Pleurosicya elongata (the Slender Spongegoby), lived in obligate association with Ianthella basta (Elephant Ear sponge), and there was a positive relationship between sponge size and number of resident fish, however this was not significant for all life stages. Five other fish species appeared to preferentially select sponges as habitat (Amblyglyphidodon aureus, Chaetodon kleinii, Coradion chrysozonus, Escenius prooculis and Pomacentrus nigromanus), while for others, sponge use appeared incidental. When selectivity indices were calculated for specific sponge species it was apparent that some fishes exhibited preferences for particular sponge species or growth forms. These results suggest more fish species may be reliant on sponges than is widely appreciated. [ABSTRACT FROM AUTHOR]

Climate‐driven alterations to disturbance regimes are increasingly disrupting patterns of recovery in many biomes. Here, we examine the impact of disturbance and subsequent level of recovery in live hard coral cover on the Great Barrier Reef (GBR) across the last three decades. We demonstrate that a preexisting pattern of infrequent disturbances of limited spatial extent has changed to larger and more frequent disturbances, dominated by marine heatwaves and severe tropical cyclones. We detected an increase in the impact (measured as coral loss) across 265 individual disturbance impacts on 131 reefs in a 36‐year dataset (1985–2022). Additionally, the number of survey reefs impacted by disturbance has increased each decade from 6% in the 1980s to 44% in the 2010s, as has the frequency of mass coral bleaching across the GBR, which has increased between 19% and 28% per year, and cyclones (3%–5% per year), resulting in less time for recovery. Of the 265 disturbance impacts we recorded, complete recovery to the highest levels of coral cover recorded earlier in this study (the "historical benchmark") occurred only 62 (23%) times. Of the 23% of disturbance impacts that resulted in complete recovery to historical benchmarks, 34/62 recovered to their benchmark in 2021 or 2022. Complete recovery was more likely when the historical benchmark was <25% live hard coral cover. The lack of recovery was attributed to recovery time windows becoming shorter due to increases in the frequency of cyclones and of thermal stress events that result in mass coral bleaching episodes. These results confirm that climate change is contributing to ecosystem‐wide changes in the ability of coral reefs to recover. [ABSTRACT FROM AUTHOR]

In the 20th century, Australia's Great Barrier Reef emerged as a political battleground when governing bodies planned to turn its coral territories into a vast mining zone. But in the 21st century, as the temporalisation of the Reef exerts increasing influence on the governance, securitisation and anticipation of planetary futures, coral time has emerged as a new site of political and imaginative conflict. Responding to this shift from territory to temporality, how can we pay closer attention to those skilfully making coral time? In this article, I introduce 'dimensional friction' as a tool for considering how the temporal structure of corals intersects with the temporal structure of global climate science in a coring laboratory. Based on my fieldwork at the Australian Institute of Marine Science, I analyse simultaneously discursive, technical, and imaginative problems that emerge when scientists transform the mineral skeletons of corals into time data. Dimensional friction appears whenever this skeletal matter is manipulated, surfacing the lab-based production of vertical time-depth but also suggesting other ways of temporalising (and corporally appropriating) coral time. Viewed in this way, coral cores might be better understood as 'temporal volumes' rather than chronostratigraphic records amenable to linear timelines and trajectories. [ABSTRACT FROM AUTHOR]

Algal ridges are protective features for coral reefs that form through the accretion and encrustation of reef rubble and debris by crustose coralline algae (CCA) and processes of diagenetic cementation. Carbonate precipitation and dissolution dynamics on and within algal ridge frameworks are poorly understood. We studied the surface and subsurface geochemistry of the algal ridge framework at One Tree Island, Australia. Measurable quantities of hydrogen sulphide were detected in most porewater samples collected from bores, indicating a largely anoxic ridge framework. Total alkalinity (TA) and pH measurements indicate that the precipitation of carbonate minerals within the interior of the ridge framework occurs under largely anoxic conditions and is likely to be driven by TA changes associated with sulphate-reducing bacteria. Modelling of porewater hydrogen sulphide concentrations in combination with TA and dissolved inorganic carbon (DIC) indicates anoxic respiration processes produce alkalinity within the algal ridge framework. However, significantly more TA is removed via the precipitation of mineral carbonate, resulting in porewater TA concentrations falling below the open seawater values. The precipitation of mineral carbonate also lowers interstitial water pH, such that pH changes are not solely from organic carbon diagenesis. The simultaneous precipitation and dissolution of carbonate minerals within the algal ridge framework are key to forming and cementing algal ridges, which are important physical protective features for coral reefs. [ABSTRACT FROM AUTHOR]

Background: Marine benthic prokaryotic communities play crucial roles in material recycling within coastal environments, including coral reefs. Coastal sedimentary microbiomes are particularly important as potential reservoirs of symbiotic, beneficial, and pathogenic bacteria in coral reef environments, and therefore presumably play a core role in local ecosystem functioning. However, there is a lack of studies comparing different environments with multiple sites on the island scale, particularly studies focusing on prokaryotic communities, as previous investigations have focused mainly on a single site or on specific environmental conditions. In our study, we collected coastal sediments from seven sites around Okinawa Island, Japan, including three different benthic types; sandy bottoms, seagrass meadows, and hard substratum with living scleractinian corals. We then used metabarcoding to identify prokaryotic compositions and estimate enzymes encoded by genes to infer their functions. Results: The results showed that the three substrata had significantly different prokaryotic compositions. Seagrass meadow sites exhibited significantly higher prokaryotic alpha-diversity compared to sandy bottom sites. ANCOM analysis revealed that multiple bacterial orders were differentially abundant within each substratum. At coral reef sites, putative disease- and thermal stress-related opportunistic bacteria such as Rhodobacterales, Verrucomicrobiales, and Cytophagales were comparatively abundant, while seagrass meadow sites abundantly harbored Desulfobacterales, Steroidobacterales and Chromatiales, which are common bacterial orders in seagrass meadows. According to our gene-coded enzyme analyses the numbers of differentially abundant enzymes were highest in coral reef sites. Notably, superoxide dismutase, an important enzyme for anti-oxidative stress in coral tissue, was abundant at coral sites. Our results provide a list of prokaryotes to look into in each substrate, and further emphasize the importance of considering the microbiome, especially when focusing on environmental conservation. Conclusion: Our findings prove that prokaryotic metabarcoding is capable of capturing compositional differences and the diversity of microbial communities in three different environments. Furthermore, several taxa were suggested to be differentially more abundant in specific environments, and gene-coded enzymic compositions also showed possible differences in ecological functions. Further study, in combination with field observations and temporal sampling, is key to achieving a better understanding of the interactions between the local microbiome and the surrounding benthic community. [ABSTRACT FROM AUTHOR]

Introduction: In 2023, a comprehensive survey was conducted at Qiziwan National Marine Park (QZW) to assess marine environmental variables, coral communities, and ecosystem parameters. This study aimed to evaluate the current state of coral ecosystems across different regions within the park. Methods: The survey covered 19 sampling stations distributed among four regions: Xiaojiao Park, Zhongjiao Park, Dajiao Park, and Shayutang Village. Various marine environmental parameters were measured, and coral species were identified and recorded. Results: A total of 67 species of reef-building corals belonging to 25 genera were identified. Dominant species included Porites lutea, Goniopora columna, Platygyra sinensis, Favites flexuosa, Galaxea fascicularis, and Acropora millepora. Coral coverage was found to be low at Xiaojiao Park, with high levels of turbidity and dissolved inorganic nitrogen, likely due to the nearby Changhua Port. Dajiao Park's sandy substrate made it unsuitable for coral survival. In contrast, Zhongjiao Park and Shayutang Village exhibited the best coral ecosystems. Redundancy analysis indicated that turbidity and substrate types were significant factors influencing coral distribution. Discussion: The live coral coverage at Xiaojiao Park, parts of Zhongjiao Park, and Dajiao Park declined from 14.03% in 2017 to 11.73% in 2023. This decline is potentially attributed to frequent marine construction and land use changes. Anthropogenic disturbances appear to have worsened environmental conditions, undermining coral reef survival at QZW. [ABSTRACT FROM AUTHOR]

Macrozoobenthos communities play significant ecological roles in coral reef ecosystems. However, they are frequently overlooked due to their cryptic appearance, and their diversity remains undiscovered, particularly in Indonesia. This comprehensive review of publications on the macrozoobenthos in the coral reef ecosystems of Java - the most populated island in Indonesia, was conducted to compile a species list and gain an overview of its community composition. We also assessed the existence of species that are frequently reported, endemic, protected, and threatened. Data analysis was performed with data from 53 publications appearing from the 1980s to 2022. In total, 482 species belonging to 4 phyla and 9 classes have been recorded. Mollusca is the most speciose phylum (n = 321), followed by Echinodermata (n = 106), Arthropoda (n = 49), and Platyhelminthes (n = 6). Generally, the northern part of Java is well studied and has larger numbers of recorded phyla and species. The highest species number (n = 266) has been recorded off the northern coast of West Java, while there are around 25–99 species in other regions. Echinoderms species such as Culcita novaeguineae, Diadema setosum, Echinothrix calamaris, and Holothuria atra had relatively higher occurrences than other taxa. We also noted the occurrence of giant clam Hippopus hippopus, which is protected by Indonesian law. This review provides fundamental knowledge of macrozoobenthic diversity in the coral reefs of Java, making it available to global audiences. However, it revealed a lack of research on benthic fauna in several areas with moderate to good coral cover conditions. Further research is needed to explore macrozoobenthic species richness in this region thoroughly, and periodic monitoring is essential to provide early warnings of possible changes and biodiversity loss. [ABSTRACT FROM AUTHOR]

Hundreds of studies now document positive relationships between biodiversity and critical ecosystem processes, but as ecological communities worldwide shift toward new species configurations, less is known regarding how the biodiversity of undesirable species will shape the functioning of ecosystems or foundation species. We manipulated macroalgal species richness in experimental field plots to test whether and how the identity and diversity of competing macroalgae affected the growth, survival, and microbiome of a common coral in Mo'orea, French Polynesia. Compared to controls without algal competitors, coral growth was significantly suppressed across three macroalgal monocultures, a polyculture of the same three macroalgae, and plots containing inert seaweed mimics; coral mortality was limited and did not differ significantly among treatments. One macroalga suppressed coral growth significantly less than the other two, but none differed from the inert mimic in terms of coral suppression. The composition, dispersion, and diversity of coral microbiomes in treatments with live macroalgae or inert plastic mimics did not differ from controls experiencing no competition. Microbiome composition differed between two macroalgal monocultures and a monoculture versus plastic mimics, but no other microbiome differences were observed among macroalgal or mimic treatments. Together, these findings suggest that algal diversity does not alter harmful impacts of macroalgae on coral performance, which could be accounted for by physical structure alone in these field experiments. While enhancing biodiversity is a recognized strategy for promoting desirable species, it would be worrisome if biodiversity also enhanced the negative impacts of undesirable species. We documented no such effects in this investigation. [ABSTRACT FROM AUTHOR]

Instrumental neutron activation analysis (INAA) is a well-accepted technique that has the ability to simultaneously determining 30–40 elements. INAA is also capable of determining major, minor, and trace elements as well as rare earth elements. It was utilised to determine the concentration of heavy elements and elemental contents of coral reef samples collected from three locations on the Red Sea coast of Egypt. The coral reef samples were prepared with their standard materials and together irradiated in Egypt Second Research Reactor (ETRR-2). For short and long irradiations, samples were separately irradiated at a convenient thermal neutron flux 4 × 1011cm−2s−1 for 2 min in a pneumatic rabbit system and samples were irradiated at a thermal neutron flux 1.5x1014cm−2s−1 for 32 mins, respectively. All samples were counted two times in a HPGe detector with a relative efficiency of 100% for short and long irradiations. The following elements have been determined Al, Ti, Na, K, Mg, V, Cl, Ca, Mn, Cr, As, Co, Zn, Ni, Fe, Br, Tb, Zr, Hf, Sb, Ba, Sc, Nd, La, Sm, Ce, Eu, Yb, Ta, U, and Th. In the Quseir harbour, the maximum concentration of Al, Fe, Mn Zn, U, and Th were 3487 ± 74, 2007 ± 22, 33 ± 0.5, 119 ± 0.5, 4 ± 0.3, and 0.52 ± 0.04 mg/kg, respectively. These concentrations were higher for these elements compared to other areas. The present work is concerned to achieve precise information about the elemental content in coral reef samples along the Red Sea coast in specific locations and the effect of detected concentrations on the surrounding environment. [ABSTRACT FROM AUTHOR]

Gobiodon spadix sp. nov. is described on the basis of 37 specimens from Kyushu, and the Osumi and Tokara Islands, southern Japan. The new species is characterized by the following combination of characters: dorsal-fin rays VI-I, 9–11 (modally 9); anal-fin rays I, 8 or 9 (8); pectoral-fin rays 19–21 (20); body depth at pelvic-fin origin 32.4–38.3% (mean 36.0%) of standard length; distance between first dorsal-fin origin to dorsal-most point of pectoral-fin base 50.4–64.8% (55.2%) of head length (HL); pectoral fin relatively long, its length 90.6–112.5% (100.8%) of HL; groove between isthmus and interopercle absent; body uniformly reddish-brown; coloration of all fins darker than that of body; and five narrow vertical bluish stripes on lateral surface of head. The new species is currently known from southern Japan, Papua New Guinea, and northeastern Australia. [ABSTRACT FROM AUTHOR]

Anthropogenic stressors like overfishing, land based runoff, and increasing temperatures cause the degradation of coral reefs, leading to the loss of corals and other calcifiers, increases in competitive fleshy algae, and increases in microbial pathogen abundance and hypoxia. To test the hypothesis that corals would be healthier by moving them off the benthos, a common garden experiment was conducted in which corals were translocated to midwater geodesic spheres (hereafter called Coral Reef Arks or Arks). Coral fragments translocated to the Arks survived significantly longer than equivalent coral fragments translocated to Control sites (i.e., benthos at the same depth). Over time, average living coral surface area and volume were higher on the Arks than the Control sites. The abundance and biomass of fish were also generally higher on the Arks compared to the Control sites, with more piscivorous fish on the Arks. The addition of Autonomous Reef Monitoring Structures (ARMS), which served as habitat for sessile and motile reef-associated organisms, also generally significantly increased fish associated with the Arks. Overall, the Arks increased translocated coral survivorship and growth, and exhibited knock-on effects such as higher fish abundance. [ABSTRACT FROM AUTHOR]

Mutualistic interactions between branching scleractinian corals and aggregating damselfishes on coral reefs create positive feedback loops, that enhance coral processes and functioning on local scales. However, the duration and stability of fishes' occupations of individual coral colonies are poorly understood. In situ short- (17 days) and long-term (355 days) assessments of the occupation of Pocillopora damicornis coral colonies by adult damselfish Dascyllus aruanus were conducted within a reef lagoon on the southern Great Barrier Reef. Results revealed that across multiple sites, high average occupancy stability (> 85% of colonies maintained their status) and low levels of change in occupancy (only 10–15%) were observed and documented over both short- and long-term time frames. After experimentally removing fish from P. damicornis colonies during short-term occupancy quantification, re-colonization of previously occupied colonies occurred rapidly (< 3 days). Overall stability of coral occupancy over both short- and long-term periods provides novel insight into the functional significance, mutualistic nature, and resiliency of this interspecific interaction. [ABSTRACT FROM AUTHOR]

This research explores the condition of coral reefs in Berau Regency, Indonesia, and the impact of human activities on these ecosystems. Coral reefs are considered crucial assets in supporting the well-being of local communities, especially in the context of tourism and fisheries resources. However, the increasing economic growth and human activities around coastal areas have pressured coral reefs, threatening their sustainability and preservation. This study employs a descriptive method utilising primary and secondary data and interviews with relevant stakeholders. The findings reveal that coral reefs in Berau Regency exhibit varied conditions, ranging from very good to poor. Threats to coral reefs include human activities such as unsustainable fishing practices, the use of explosives in fishing, and the development of tourism infrastructure. The research also underscores the importance of integrating environmental capacity into the development of Derawan Island as a coastal conservation tourism destination. Collaboration among the government, private sector, non-governmental organisations, and local communities is essential to maintain the sustainability of coral reef ecosystems while supporting the well-being of local communities. [ABSTRACT FROM AUTHOR]

Feeding habits of herbivorous fishes play an important role in shaping the form and function of coastal marine ecosystems. Rabbitfishes (Siganidae) are important consumers of macroalgae on Indo‐West Pacific coral reefs. However, it is unclear how their diet varies among and within species at biogeographical scales, casting doubt on their precise functional roles across different regions. The present study assessed the inter‐ and intra‐specific diet variation of four rabbitfishes (Siganus trispilos, Siganus corallinus, Siganus virgatus and Siganus doliatus) factored by morphological relatedness among populations from Ningaloo Reef (western Australia), the Great Barrier Reef (GBR, eastern Australia) and the Yaeyama Islands (Okinawa Prefecture, Japan). Results showed that the region had a strong effect on diet, effectively reducing the expected effect of morphologic similitude. While intra‐specific differences were only significant when populations inhabited different regions; interspecific differences were not as predicted, with different morphotypes having similar diets when populations inhabited the same regions. Rabbitfishes consumed more corticated and filamentous macroalgae on the GBR, more foliose and membranous macroalgae at the Yaeyama Islands, and more leathery macroalgae at Ningaloo Reef. The findings indicate that rabbitfishes have high diet plasticity, and hence their functional role as mediators of competition between macroalgae and corals can change across biogeographic regions. Local context is therefore important when assessing the diet and functional role of herbivorous fishes. As climate change unfolds, shifts in the distribution, trophic behaviour and function of species are expected, making the study of trophic plasticity more important. [ABSTRACT FROM AUTHOR]

Despite the limited coverage of coral reefs in the world's oceans, they play a crucial role in global marine biodiversity and providing essential ecosystem services. This study explores the influence of chlorophyll-a (Chl-a) concentration in the water column on the estimation of bottom reflectance (rb) in coral reefs monitored by the Allen Coral Atlas coral reef monitoring system, using satellite imagery from a Sentinel-2 MSI sensor. We conducted a comprehensive analysis, considering Chl-a global distribution and variability, and its combined effect with water column depth over rb calculation. Our results demonstrated that the impact of Chl-a on rb estimation becomes significant when the water column depth exceeds 3 m. While suggesting the optionality of using regional Chl-a values, our study highlights potential overestimations of Chl-a in optically complex environments, such as along the Brazilian coast. This research contributes to refining coral reef monitoring systems and underscores the importance of accurate Chl-a assessments for robust environmental evaluations. [ABSTRACT FROM AUTHOR]

Since reef-building corals rely on both heterotrophy and endosymbiotic dinoflagellate autotrophy to meet their metabolic needs, it is necessary to consider both food supply and light levels, respectively, when optimizing their cultivation ex situ. Herein nubbins of the model reef coral Pocillopora acuta cultured in recirculating aquaculture systems at photosynthetically active radiation levels of 370 or 670 μmol quanta m−2 s−1 were fed Artemia nauplii at concentrations of either 33 or 78 individuals mL−1 in a separate feeding tank for 6 hr in the dark thrice weekly. A subset of nubbins was experimentally wounded at the outset of the 84-day experiment to assess recovery, and 100% fully healed within 2–4 weeks. All cultured corals survived, and unwounded corals (1) grew at a specific growth rate approaching 0.5% day−1 and (2) demonstrated a mean total linear extension of 0.2% day−1 (~6–8 cm year−1); these are far higher than growth rates normally documented in situ. In the feeding tank, corals tolerated nitrate levels up to 25 mg L−1, but once concentrations reached 50 mg L−1 by day 84, tissue necrosis began to occur in nubbins of one tank. This highlights the importance of feeding in separate tanks during long-term culture of corals, and bio-filtration could reduce the possibility of organic matter accumulation in future coral culture studies. [ABSTRACT FROM AUTHOR]

Though a previous study in Sudan confirmed the existence of a living hybrid of an oceanic manta ray (Mobula birostris) and a reef manta ray (M. alfredi), courtship behaviors between the two closely related species have never been documented. Here we report the first observation of courtship behaviors between two male M. birostris and a female M. alfredi at a manta ray cleaning station on a shallow coral reef seamount in Misool, Raja Ampat, Indonesia. The observed courtship event lasted for approximately 45 min and involved one male oceanic manta actively chasing the mature reef manta female around the cleaning station and repeatedly bumping her on the left wing tip with his right cephalic lobe, while the second male continuously flanked the female to seemingly prevent her retreat from the cleaning station and potential evasion of the pursuing male. Notably, the female exhibited a rapid coloration change, likely indicative of courtship-related stress, transitioning from the striking pale hue she exhibited throughout the courtship activity to a normal chevron pattern once the males departed. [ABSTRACT FROM AUTHOR]