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Shallow coral reefs are being increasingly degraded as a result of natural and anthropogenic threats. Mesophotic coral ecosystems (MCEs) are an extension of shallow reefs at depths of ∼30–150 m that harbor depth generalists and specialists, acclimatized to changes in physical factors. A faunal break in MCEs occurs between upper (∼30–60 m) and lower (∼60–150 m) depths, representing transitional and endemic communities, respectively. The trophic ecology of MCEs shifts from autotrophic to heterotrophic processes with increasing depth, and trade-offs in the utilization of dissolved organic matter and particulate organic matter. While dispersal of MCE larvae could reseed degraded shallow reefs, genetic evidence is equivocal, suggesting site-specific connectivity patterns; anthropogenic disturbances at mesophotic depths indicate that MCEs may be as susceptible to stressors as shallow reefs are. The function and stability of mesophotic coral ecosystems (MCEs) have been extensively studied in recent years. These deep reefs are characterized by local physical processes, particularly the steep gradient in irradiance with increasing depth, and their impact on trophic resources. Mesophotic reefs exhibit distinct zonation patterns that segregate shallow reef biodiversity from ecologically unique deeper communities of endemic species. While mesophotic reefs are hypothesized as relatively stable refuges from anthropogenic stressors and a potential seed bank for degraded shallow reefs, these are site-specific features, if they occur at all. Mesophotic reefs are now known to be susceptible to many of the same stressors that are degrading shallow reefs, suggesting that they require their own specific conservation and management strategies. [ABSTRACT FROM AUTHOR]

Animal transport of energy and nutrients through food webs and across ecosystem boundaries is highly dynamic in time and space, challenging our ability to quantify ecological processes. Energy and nutrient flux in individual animals can be measured with data on growth, biochemistry, and trophic ecology, but scaling individual processes up to entire animal communities is inherently difficult. On coral reefs, new frameworks have been developed to predict growth rates, nutrient cycling, micronutrient concentrations, and energy sources in fishes, helping to uncover ecosystem functions and services. Filling data gaps and comparing flux frameworks with existing ecosystem tools will improve quantitative predictions and help ecologists trace energy and nutrient flux in other aquatic systems. The movement of energy and nutrients through ecological communities represents the biological 'pulse' underpinning ecosystem functioning and services. However, energy and nutrient fluxes are inherently difficult to observe, particularly in high-diversity systems such as coral reefs. We review advances in the quantification of fluxes in coral reef fishes, focusing on four key frameworks: demographic modelling, bioenergetics, micronutrients, and compound-specific stable isotope analysis (CSIA). Each framework can be integrated with underwater surveys, enabling researchers to scale organismal processes to ecosystem properties. This has revealed how small fish support biomass turnover, pelagic subsidies sustain fisheries, and fisheries benefit human health. Combining frameworks, closing data gaps, and expansion to other aquatic ecosystems can advance understanding of how fishes contribute to ecosystem functions and services. [ABSTRACT FROM AUTHOR]

Shallow water benthic habitats have been significantly degraded and seriously threatened by intensifying climate changes and anthropogenic stressors. Benthic reflectance (R b λ ) of optically shallow waters (OSWs) is a key parameter for remote sensing of benthic habitats' composition and health status. The remote sensing reflectance (R rs λ ) just above the water surface contains the coupled spectral information of the water column and seabed in OSWs, which makes our effort challenging to separate the signals between seabed and water column properties. Due to too many unknowns of the water column and seabed optical properties, the current approaches are inaccurate or inadequate to retrieve benthic reflectance spectra over a large area from remotely sensed data. In this study, we proposed an enhanced large-scale benthic reflectance (LSBR) retrieval model from satellite data in OSWs with only input of R rs λ . A new spectral library of benthic reflectance was built upon multi-source reflectance datasets obtained from several open-source field measurements. Then, the specific relationship between R b 443 n m and R b 490 n m was developed. By combining a semi-analytical benthic reflectance (SABR) model based on radiative transfer simulations and this relationship, water-column chlorophyll concentration (chl) was determined. Moreover, large-scale water depth was estimated by R rs λ through satellite-derived bathymetry (SDB) technologies. Finally, benthic reflectance was retrieved with the inputs of the satellite-derived R rs λ , chl , and water depth. In this way, the LSBR model fulfills the R b λ retrieval with only input of satellite-derived R rs λ . The new model was successfully applied to Sentinel-2/MSI data in the seagrass region of Xincun Bay and the coral region of Huaguang Reef and further verified by using field measurements and results of the along-track benthic reflectance (ATBR) retrieval model, which combined active lidar and passive high-resolution satellite images. Additionally, to gain insights into the long-term evolution of benthic communities, a typical application of the LSBR model for detecting benthic changes was conducted using eight years of Sentinel-2/MSI data in Heron Reef, depicting a similar consistency between the probable deterioration and restoration region and the sea surface temperature (SST) anomalies. The results demonstrated the robustness and accuracy of the LSBR model in retrieving benthic reflectance at large scales. The LSBR model should be helpful for further investigating benthic changes which can enhance the ability to monitor and assess the health status of submerged ecosystems in OSWs. [ABSTRACT FROM AUTHOR]

Atolls islands are biogenic landforms that are intrinsically capable of adjusting their size, position, and elevation to changing sea levels. The vulnerability of atoll islands to sea level rise is not intrinsically due to their low elevation but primarily due to the loss of their island building capacity. The geophysical processes that control atoll island accretion are being impacted on global and local scales. Protecting and restoring the natural geophysical processes of atoll island accretion through local conservation actions is key to unlocking nature-based opportunities for enhancing atoll resilience to global change. Atoll islands are often perceived as inevitably lost due to rising sea levels. However, unlike other islands, atoll islands are dynamic landforms that have evolved, at least historically, to vertically accrete at a pace commensurate with changing sea levels. Rather than atoll islands' low elevation per se , the impairment of natural accretion processes is jeopardising their persistence. While global marine impacts are deteriorating coral reefs, local impacts also significantly affect accretion, together potentially tipping the scales toward atoll island erosion. Maintaining atoll island accretion requires intact sediment generation on coral reefs, unobstructed sediment transport from reef to island, and available vegetated deposition sites on the island. Ensuring the persistence of atoll islands must include global greenhouse gas emission reduction and local restoration of accretion processes. [ABSTRACT FROM AUTHOR]

The Symbiodiniaceae have been coral symbionts for over 200 million years, yet they retain a facultative lifestyle because both the symbiotic and free-living stages offer unique selective advantages that ensure persistence of the algal lineage. There exists a dynamic competition and interaction between the coral host and algal symbionts that ensures survival of both under fluctuating environmental conditions. If algal symbiont-derived redox stress does not explain coral host bleaching, then it is possible that either or both partners generate a chemical cue that precipitates algal expulsion independent of malfunctions in their electron transport chains. We propose the 'stepping-stone model' as an explanation for the long-term and successful association between coral animals and their facultative algal symbionts, which in a stepwise manner creates novel Symbiodiniaceae lineages worldwide. The photosynthetic symbionts of corals sustain biodiverse reefs in nutrient-poor, tropical waters. Recent genomic data illuminate the evolution of coral symbionts under genome size constraints and suggest that retention of the facultative lifestyle, widespread among these algae, confers a selective advantage when compared with a strict symbiotic existence. We posit that the coral symbiosis is analogous to a 'bioreactor' that selects winner genotypes and allows them to rise to high numbers in a sheltered habitat prior to release by the coral host. Our observations lead to a novel hypothesis, the 'stepping-stone model', which predicts that local adaptation under both the symbiotic and free-living stages, in a stepwise fashion, accelerates coral alga diversity and the origin of endemic strains and species. [ABSTRACT FROM AUTHOR]

Marine heat waves are having unprecedented impacts on reef-building corals worldwide. Corals within the same species have different sensitivity to heat stress, and part of this variation is due to genetic adaptation. Finding coral genotypes that underpin heat adaptation would allow the identification of adapted populations so that reef managers could protect and promote the spread of these adapted populations. Seascape genomics identifies candidate adaptive genotypes by associating variation in genotype frequencies across a reef system with historical thermal conditions. CRISPR/Cas9-based gene editing could assess and validate the functional roles of putative adaptive genotypes, and validated genotypes could then be used in conservation. Mass coral bleaching is one of the clearest threats of climate change to the persistence of marine biodiversity. Despite the negative impacts of bleaching on coral health and survival, some corals may be able to rapidly adapt to warming ocean temperatures. Thus, a significant focus in coral research is identifying the genes and pathways underlying coral heat adaptation. Here, we review state-of-the-art methods that may enable the discovery of heat-adaptive loci in corals and identify four main knowledge gaps. To fill these gaps, we describe an experimental approach combining seascape genomics with CRISPR/Cas9 gene editing to discover and validate heat-adaptive loci. Finally, we discuss how information on adaptive genotypes could be used in coral reef conservation and management strategies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Corals support coral reef biodiversity by acting as hosts for symbionts. • Four major taxa of coral parasites were compared for their host specificity. • Totals of 203 coral-associated invertebrates and 335 host coral species were recorded. • Coral barnacles and gall crabs are more host-specific than serpulids and date mussels. • Coral symbionts in the Indo-Pacific are more host-specific than those in the Atlantic region. Coral-associated fauna predominantly consists of invertebrates and constitutes an important component of coral reef biodiversity. The symbionts depend on their hosts for food, shelter and substrate. They may act as parasites by feeding on their hosts, by overgowing their polyps, or by excavating their skeletons. Because some of these species partly reside inside their hosts, they may be cryptic and can easily be overlooked in biodiversity surveys. Since no quantitative overview is available about these inter-specific relationships, this present study adresses variation in host ranges and specificity across four large coral-associated taxa and between the Atlantic and Indo-Pacific oceans. These taxa are: coral barnacles (Pyrgomatidae, n = 95), coral gall crabs (Cryptochiridae, n = 54), tubeworms (Serpulidae, n = 31), and date mussels (Lithophaginae, n = 23). A total of 335 host coral species was recorded. An index of host specificity (S TD) was calculated per symbiont species, based on distinctness in taxonomic host range levels (species, genus, family, etc.). Mean indices were statistically compared among the four associated taxa and the two oceanic coral reef regions. Barnacles were the most host-specific, tubeworms the least. Indo-Pacific associates were approximately 10 times richer in species and two times more host-specific than their Atlantic counterparts. Coral families varied in the number of associates, with some hosting none. This variation could be linked to host traits (coral growth form, maximum host size) and is most probably also a result of the evolutionary history of the interspecific relationships. [ABSTRACT FROM AUTHOR]

An important, yet overlooked form of anthropogenic pollution is sensory pollution, and one of the most pervasive forms of sensory pollution is artificial light at night (ALAN). Despite the growing use of ALAN across the globe, limited research has examined the impacts of ALAN on coral reef fish. This study aims to further our understanding of the behavioural impacts of light pollution on fish by exposing the humbug damselfish (Dascyllus aruanus) to ALAN (∼15–25 lux, white LED light) over a period of 14 days, in situ. We assessed nocturnal activity, and diurnal shelter use and emergence time following a simulated threat in natural (control) and ALAN conditions. D. aruanus colonies exposed to ALAN were active at night and were lacking cryptic colouration observed in control fish, however this altered nocturnal activity did not appear to impact the diurnal behaviours we measured. Our findings provide critical insight into the impact of ALAN exposure to nocturnal behaviour of a diurnal fish and highlight the potential for increased risk of nocturnal predation under ALAN. Further studies with a longer ALAN exposure time will help illuminate the extent of behavioural changes and implications caused by ALAN in shallow coral reef systems. [Display omitted] [ABSTRACT FROM AUTHOR]

Dark fermentative hydrogen production by Enterobacter aerogenes in a packed bed bioreactor using three immobilization supports was studied. The effects of glucose concentrations (20, 10, 5, 2.5, and 1.5 g/L) and support matrixes (Persian Gulf dead coral, ceramic saddle, and ceramic ball) on the hydrogen yield (HY) and hydrogen production rate (HPR) at low hydraulic retention time (HRT) were investigated. According to the achieved results, glucose concentration, porosity and shape support, and bed voidage affected hydrogen production. The HYs were increased with decreasing glucose concentration and at 2.5 g/L glucose concentration, the maximum HYs of 3.11, 2.86 and 2.79 mol hydrogen/mol glucose were obtained for dead coral, ceramic ball, and ceramic saddle, respectively. The results indicated that at the HRT of 0.6 h, the bioreactor packed with dead coral resulted in higher HY (3.11 mol H 2 /mol glucose) and HPR (173 mL/L.h) representing 8–11%, and 8–15%, enhancement compared to the bioreactor packed with ceramic supports. Besides, based on the acquired results, the HY and HPR of the ceramic ball were higher than the ceramic saddle. • Dead coral was used as support in a packed bed bioreactor for hydrogen production. • Reactor packed with dead coral resulted in higher HY and HPR compared to ceramic supports. • The HY and HPR of the ceramic ball were higher than the ceramic saddle. • Porosity and shape support and bed voidage affect the immobilization process and hydrogen production. [ABSTRACT FROM AUTHOR]

Precipitation of marine biogenic CaCO 3 minerals occurs at specialist sites, typically with elevated pH and dissolved inorganic carbon, and in the presence of biomolecules which control the nucleation, growth, and morphology of the calcium carbonate structure. Here we explore aragonite precipitation in vitro under conditions inferred to occur in tropical coral calcification media under present and future atmospheric CO 2 scenarios. We vary pH, Ω Ar and pCO 2 between experiments to explore how both HCO 3 − and CO 3 2− influence precipitation rate and we identify the effects of the three most common amino acids in coral skeletons (aspartic acid, glutamic acid and glycine) on precipitation rate and aragonite morphology. We find that fluid Ω Ar or [CO 3 2−] is the main control on precipitation rate at 25 °C, with no significant contribution from HCO 3 − or pH. All amino acids inhibit aragonite precipitation at 0.2–5 mM and the degree of inhibition is inversely correlated with Ω Ar and, in the case of aspartic acid, also inversely correlated with seawater temperature. Aspartic acid inhibits precipitation the most, of the tested amino acids (and generates changes in aragonite morphology) and glycine inhibits precipitation the least. Previous work shows that ocean acidification increases the amino acid content of coral skeletons and probably reduces calcification media Ω Ar , both of which can inhibit aragonite precipitation. This study and previous work shows aragonite precipitation rate is exponentially related to temperature from 10 to 30 °C and small anthropogenic increases in seawater temperature will likely offset the inhibition in precipitation rate predicted to occur due to increased skeletal aspartic acid and reduced calcification media Ω Ar under ocean acidification. [ABSTRACT FROM AUTHOR]

Sun glint presents a significant challenge in marine ecological remote sensing by obscuring valuable features of benthic communities, thus hindering accurate monitoring of these communities. More specifically, sun glint leads to inaccurate coral reef identification when it comes to utilize the high-resolution marine Unmanned Aerial Vehicle (UAV) imagery. Despite the availability of many physical models that address this problem using ocean remote sensing satellite images, there is still a lack of effective sun glint correction solutions for high-resolution RGB imagery obtained by consumer-grade UAVs in marine ecological monitoring, particularly at the centimeter level. In this study, an innovative sun glint correction pipeline combining a Foreground Attention-based Semantic Segmentation Network (FANet) with optical flow-based pixel propagation has been proposed, aiming to achieve accurate sun glint detection and restoration of real texture of coral reefs. To further understand the inner mode of sun glint segmentation FANet model, we conduct explainable analysis to ensure that it learns the informative sun glint features and makes reliable decisions. According to the comprehensive experimental evaluation using three datasets, our FANet model exhibits accurate and effective sun glint detection, achieving an I o U range of 70.86%–83.96%. Moreover, the sun-glint free images processed by our sun glint correction method have been employed for large-scale image stitching and shallow-water coral reef habitat semantic mapping. The results demonstrate that our sun glint correction approach successfully restores the texture of coral reefs and prepares a reliable foundation for subsequent downstream applications. We believe that our method as an open-source sun glint correction solution in high-resolution marine UAV RGB images is able to enhance the accuracy and efficiency of various marine ecological remote sensing tasks at a low-cost. The relevant code can be found in https://github.com/jyqinnn/Sun-glint-correction. [ABSTRACT FROM AUTHOR]

Coral skeletal boron geochemistry offers opportunities to probe the pH of the calcification media (pH CM) of modern and fossil specimens, to estimate past changes in seawater pH and to explore the biomineralisation response to future ocean acidification. In this research we grew 2 Stylophora pistillata coral microcolonies over glass coverslips to allow analysis of the pH sensitive dye SNARF-1, in the extracellular calcification medium at the growing edge of colonies where the first aragonite crystals are formed, under both light and dark conditions. We use secondary ion mass spectrometry (SIMS) to measure the boron isotopic composition (δ11B) of the skeleton close to the growth edge after 2 to 3 days of additional calcification had enlarged the crystals until they joined, generating a continuous sheet of aragonite. Mean skeletal δ11B-pH CM estimates are higher than those by SNARF-1 by 0.35–0.44 pH units. These differences either reflect real variations in the pH of the calcification media associated with each measurement technique or indicate other changes in the biomineralisation process which influence skeletal δ11B. SNARF-1 measures directly the pH of the extracellular calcification medium while skeletal δ11B analyses aragonite potentially formed via both extracellular and intracellular biomineralisation pathways. Analysis of a third coral specimen, also growing on a glass slide but with a 5 cm long branch, indicated good agreement between the δ11B value of the apex of the branch and the skeletal growth edge. The tissues overlying both these regions were transparent indicating they had low symbiont densities. This suggests that the biomineralisation process is broadly comparable between these sites and that studies growing corals over glass slides/coverslips provide representative data for the colony apex. [ABSTRACT FROM AUTHOR]

The systematics of the coral assemblages of the Vršatec Limestone from the Pieniny Klippen Belt (Western Carpathians) that inhabited the NW Tethyan margin during the Bajocian is revisited here based on a new and extensive sampling of coral specimens collected at four outcrops. The assemblage consists of 12 genera and 13 species, including the new species Proaplophyllia slovakensis and the first Bajocian occurrence of the genus Enallhelia. Morphometric analyses also allow us to synonymize multiple species citations of the genus Thecosmilia into a single species. A quantitative study shows that five genera tend to be most common at all outcrops, namely Cladophyllia , Dendraraea , Isastrea , Periseris , and Thecosmilia , documenting relatively high homogeneity in the qualitative generic composition of coral assemblages but quantitative differences among the four outcrops. Coral specimens are frequently affected by macroborings (Gastrochaenolites , Entobia , and Trypanites) and coated by microbialitic components. We suggest that these reefs grew in the optimum of the Bajocian reefal window (i.e., shallow-water photic environments above storm wave base). We also identify three traps (typological, nominal, and induction traps) that led in the past to the false stratigraphic attribution of these reefs, when they were erroneously assigned to the Oxfordian rather than to the Bajocian. [ABSTRACT FROM AUTHOR]

The impact of changing nutrient conditions on scleractinian coral-based geochemical proxies is poorly understood, despite the nutrient balance in many coral reefs being disturbed by anthropogenic activity. Here, the geochemical responses of tropical corals Acropora polystoma and Porites lichen to nutrient enrichment and depletion are examined following growth under cultured conditions, to assess the impact of nutrients on traditional geochemical proxies for both temperature and the coral internal carbonate system. The corals were exposed to four different nutrient treatments over a period of 140 days: (1) a replete treatment with optimal levels of nitrate (∼4.5 μM) and phosphate (∼0.6 μM), (2) a nutrient depleted treatment with negligible nitrate and phosphate, (3) a treatment with high nitrate (∼73 μM) and negligible phosphate, and (4) a treatment with high phosphate (∼5.7 μM) and negligible nitrate. Results suggest nutrients play a hitherto under-appreciated role in coral skeleton elemental (Li/Ca, B/Ca, Mg/Ca, Sr/Ca, Li/Mg) and isotopic (δ11B) composition, with the internal carbonate chemistry also impacted. For example, Mg/Ca and Sr/Ca are lower, and Li/Mg higher, in the nutrient imbalanced and deplete treatments compared to the replete treatment for both species. Disruption to the carbonate system in corals cultured under imbalanced nutrient conditions is best explained by a decrease in dissolved inorganic carbon flux to the extracellular calcifying medium. Variations in nutrient concentration — or nutrient imbalance — can have dramatic consequences on both reconstructed sea surface temperatures and ocean or calcification pH, with reconstructed temperatures varying from −7°C to +52 °C, and δ11B-derived pH by up to 0.13 pH units. The impact from anthropogenically-induced nutrient disturbances should therefore be considered when generating temporal records of environments using coral skeletal archives. [ABSTRACT FROM AUTHOR]

Tropical seabirds exert key roles in reef ecosystems but face growing threats from climate change, especially on coral reef islands (CRIs). Therefore, we advocate for a more comprehensive, global data exchange on CRIs and CRI-dependent seabirds and outline steps for improving their study and conservation. [ABSTRACT FROM AUTHOR]

Deep-sea bamboo corals (family Isididae) have been used as archives for reconstructing changes in the past ocean. However, uncertainties remain regarding the interpretation of geochemical signals from their organic nodes, specifically the water depth of the signals recorded by the coral. Here we explore this question by measuring radiocarbon (14C) and nitrogen (15N) isotopic compositions of the organic nodes in six bamboo corals collected from the central and eastern tropical Atlantic between 700 m and 2000 m water depth. By comparing coral 14C to measured seawater data, regional shallow-water coral records and climate-model outputs, we find contrasting results between the two regions. Our bamboo coral 14C results from the eastern tropical Atlantic support previous studies that suggest organic node carbon is sourced primarily from the mixed layer of the ocean. By contrast, the 14C of bamboo coral organic nodes from the oligotrophic central Atlantic better correlates with the 14C content of the subsurface deep chlorophyll maximum layer rather than the surface mixed layer. Combined with nitrogen isotope data, this observation suggests that sinking and/or ambient zooplankton feeding on phytoplankton from the deep chlorophyll maximum layer can contribute a significant proportion of the diet of bamboo corals. These results suggest that the carbon source for bamboo corals organic nodes may not always reside in the mixed layer, especially in oligotrophic regions, which has implications for 14C-based age model development in bamboo corals. [ABSTRACT FROM AUTHOR]

Seaweeds are a primitive type of plant and macro algae, which usually grow in the regions of backwaters, estuaries, and seas, especially in shallow water. They are typically formed, attached, and visualized to the coral reef, rocks, and other substrata wherever available. The seaweeds are collected from the Kanyakumari region and processed for methanol production. The methanol is extracted from the processed seaweed using the Saccharification method. The physicochemical properties of methanol are determined as per ASTM standards. The yield (%) of methanol production depends on the concentration of the substrate and the time duration (24, 48, and 72 h). It is observed that for a substrate concentration of 15%, a maximum yield of methanol is observed. In contrast, when the substrate concentrations lie below 10%, there is a decrease in the methanol yield for all the time durations investigated. Therefore, the maximum yield (51.2%) of methanol is obtained for a substrate concentration of 15% with a time period of about 48 h. The present work concentrated on producing methanol from a high concentration and choice of seaweed (Sargassum wightii). [ABSTRACT FROM AUTHOR]

The stable (δ18O and δ13C) and clumped (Δ 47) isotope compositions of coral carbonate are valuable archives for paleoclimate reconstructions. However, the Δ 47 -temperature relationships of warm and cold-water corals deviate from that of inorganic carbonate precipitated at equilibrium. Dual clumped isotope thermometry of carbonates (i.e., simultaneous Δ 47 and Δ 48 measurements on a single carbonate) has the potential to achieve more accurate paleotemperature reconstruction, identifying and correcting for kinetically driven isotopic disequilibrium. Here we present the first extensive dual clumped isotope dataset of coral carbonate, spanning a broad range of cold and warm-water coral species. We confirm that corals are enriched in Δ 47 and depleted in Δ 48 relative to equilibrium, a pattern corresponding to the mixing of an equilibrium DIC pool with kinetically derived HCO 3 – produced by hydration and hydroxylation of CO 2. Dual clumped isotope measurements of cold-water corals fall on the initial linear portion of model (IsoDIC) predicted departure from equilibrium. The dual clumped isotope composition of cold-water corals, corrected by the model-predicted Δ 47 /Δ 48 offset slope (−0.78), yield accurate reconstruction of coral growth temperature with a precision of <3 °C at the 68% confidence level. In contrast, disequilibrium offsets in the Δ 47 and Δ 48 of warm-water corals correspond to precipitation from a more equilibrated DIC pool, which we attribute to the action of carbonic anhydrase in the calcifying fluid. It may be possible to correct warm-water coral growth temperatures, using an empirically derived correction (Δ 47 / Δ 48 offset slope of −0.4). Dual clumped isotope thermometry of coral carbonate opens new possibilities to reconstruct both sea surface temperatures and ocean dynamics of intermediate to deep water masses. [ABSTRACT FROM AUTHOR]

One of the most widespread coral diseases linked to anthropogenic activities and recorded on reefs worldwide is characterized by anomalous growth formations in stony corals, referred to as coral growth anomalies (GAs). The biological functions of GA tissue include limited reproduction, reduced access to resources, and weakened ability to defend against predators. Transcriptomic analyses have revealed that, in some cases, disease progression can involve host genes related to oncogenesis, suggesting that the GA tissues may be malignant neoplasms such as those developed by vertebrates. The number of studies reporting the presence of GAs in common reef-forming species highlights the urgency of a thorough understanding of the pathology and causative factors of this disease and its parallels to higher organism malignant tissue growth. Here, we review the current state of knowledge on the etiology and holobiont features of GAs in reef-building corals. Growth anomalies (GAs) can appear in various morphotypes and be initiated by different causative agents including parasite infections and water pollution. When GAs are present, the whole colony carries the burden of the disease and its biological functions are impaired. Human density adjacent to coral reefs and the presence of GAs are positively correlated. The biological responses characterizing the gross morphology of GAs can also be detected at the molecular level in the expression of genes involved in morphogenesis, osteogenesis, and organogenesis. [ABSTRACT FROM AUTHOR]

Stony corals are ecologically and economically important marine organisms. Coral aquaculture is essential to provide live coral materials for the marine ornamental trade, reef restoration programs, and environmental education. This study sought to establish coral farms in Taiwan. To culture corals, we adopted an abandoned abalone farming pond built along the northeastern coast of Taiwan, and investigated whether it is possible to propagate corals in this artificial environment. Stainless steel underwater tables were anchored to the pond floor, and fragments of Acropora tumida , Pocillopora damicornis , Stylophora pistillata , Favites pentagona , and Porites lobata were cultured on the tables for one year. Environmental factors in the pond were also monitored. The mean surface temperature was 23.07 °C, ranging from >30 °C in summer to 18 °C in winter. The mean salinity and pH were about 35 ppt and 8.14, respectively. Survivorship of these five species after one year ranged from 100% to 67%, with a 1.37–1.51-fold increase in weight and a 3.22–3.38-fold increase in area, demonstrating that although environmental factors fluctuate depending on the season and weather, long-term and stable asexual propagation of corals is feasible in the pond. For further optimization of culture conditions, the effects of initial fragment size for culture on subsequent survival and growth were investigated. Fragments of 3 sizes (1.5, 3.0, and 4.5 cm) were prepared from parental colonies of A. tumida , P. damicornis , and S. pistillata and cultured for 6 months by hanging them under the table. There were no significant differences in survivorship among these sizes. Differences were observed in biomass (weight) increase. In A. tumida , 3-cm fragments showed significantly more weight gain than other lengths, while 1.5-cm fragments showed a significant weight increase in P. damicornis. In S. pistillata , no significant difference in weight increase was observed among size groups, suggesting the necessity to optimize the initial fragment size for culture for each species before mass culture. Histological analysis showed that mature gametes were formed in some cultured corals, suggesting that sexual propagation may also be possible in the future. The established coral farm, which is culturing >4000 coral fragments now, will be able to support not only basic and applied coral research, but also sustainable reef development and marine ornamental trade. • There are many ponds built for abalone farming along Taiwan's north coast. • A coral farm was established using one of the abandoned ponds. • Five coral species were cultured for >1 year with high survivorship and growth. • The established farm will promote coral studies and conservation. [ABSTRACT FROM AUTHOR]

Parabens, bisphenols (BPs), and triclosan (TCS) are common environmental phenols widely applied in industrial products, pharmaceuticals, and personal care products. They are endocrine disruptors and pervade the natural environment, causing significant detrimental impacts on ecosystems, including marine habitats. Therefore, in this study, 40 samples comprising coral polyps, algae, and sediments were collected from Sanya, Hainan Province, China, in which the presence and compositional profiles of parabens, BPs, and TCS were examined to identify their fate in the oceans. The results unveiled the ubiquitous occurrence of at least one paraben or bisphenol in all samples, with TCS detected in over 80% of cases. Notably, coral samples contained the most contaminants (median concentration: 9.42 ng/g dry weight-dw), followed by sediment samples (5.95 ng/g dw) and algal samples (3.58 ng/g dw). Attributed to their broadest application, methylparaben (MeP) and propylparaben (PrP) emerged as the primary paraben constituents. MeP displayed the highest median concentration in coral samples (4.42 ng/g dw), probably related to its high-water solubility and the filtration mechanism employed by the coral polyps during seawater intake. Intriguingly, bisphenol P (BPP) superseded bisphenol A (BPA) as the dominant bisphenol, especially in the algal samples, probably owing to the lipophilic character of BPP and the enhanced biodegradability of BPA within aquatic environments. The highest concentration of TCS (3.44 ng/g dw) was found in the sediment samples, associated with its long half-life in the sediments. Furthermore, the correlation between multiple parabens and TCS implies their co-use to augment antimicrobial efficacy. Future research should prioritize the examination of these phenols in diverse marine environmental media. Corresponding toxicological experiments should be conducted to visualize their transport dynamics, degradation byproducts, and toxicity to marine biota to gain insights into the risks they pose to the marine ecosystem. [Display omitted] • Parabens and BPs are extensively distributed in coral and algal samples. • The highest concentrations of contaminants were found in coral samples. • BPP was the most abundant BPs instead of BPA. • MeP, BPP, and TCS dominated in coral, algal, and sediment samples, respectively. [ABSTRACT FROM AUTHOR]

As an effective means of coordinating sea use conflicts and promoting ecological conservation, Marine Spatial Planning (MSP) has been well-known by more and more countries. The study has developed an issue-oriented solution for Koh Sichang and its surrounding sea areas in Thailand. Through multi-source data collection and on-site survey, the characteristics of abundant coral reef resources, numerous waterways and mooring areas have been identified. Then, corresponding thematic studies and zoning were conducted, including cassava scatter risk prediction, habitat risk assessment, demarcation of aquaculture priority areas, and scenario analysis. The results show that: (1) Cassava powder accumulates northeast of Koh Sichang and adjacent areas and distributes as high as 84%, with significant diffusion under south wind. Suggest strengthening maritime transport supervision; (2) Human activities have led to a 100% moderate risk for coral reefs around Koh Sichang. While under conservation pattern, the proportion could be reduced to 30%, highlighting the urgency of protective measures; (3) Contrasting the protection and development patterns reveals the double-edged sword effect of the development of tourism and transportation industries on the environment, emphasizing the need to uphold the concept of sustainable development and ecosystem-based management. • An issue-oriented solution for rapid MSP assessment was built. • The probability of cassava powder accumulating northeast of Koh Sichang is as high as 84%. • Human activities have led to a 100% moderate risk for coral reefs around Koh Sichang. • The zoning and suggestions have been adopted by local authorities through trade-offs. [ABSTRACT FROM AUTHOR]

Coral reef limestone (CRL) commonly undergoes dynamic tension when underground structures of island reefs encounter impacts, explosions, or seismic activities. Given the complexity of biological pores, the dynamic tensile fracture characteristics of CRL are poorly understood. Therefore, the dynamic tensile fracture behaviors of deep CRL were systematically observed by Split Hopkinson Pressure Bar tests and digital image techniques. Comparing to traditional rocks, the macro-pores near failure band would significantly change cracking path. The failure patterns are dominated by loading rate. The strongly dependence of dynamic tensile strength and dynamic crack initiation toughness on loading rate suggests the two indices overcome the effect of CRL macro-pores under dynamic impacts. At low loading rates, tensile fractures predominantly follow intergranular cracks, whereas transgranular cracks dominate at higher rates. The fractal dimension of fracture surface decreases with increasing crack propagation velocity, loading rate, and dynamic crack initiation toughness. Due to the unique marine sedimentary environment, the mechanical heterogeneity in multiple scales distinguishes CRL from terrestrial rock materials. The insights into underlying mechanisms of dynamic tension provide support to optimization of blasting scheme and stability assessments for island underground engineering. • The dynamic tensile strength of coral reef limestone is strongly dependent on the loading rate. • Comparing to traditional rocks, the macro-pores near failure band would significantly change cracking path. • At lower loading rates, cleavage induced transgranular cracks consume less fracture energy than intergranular cracks. • Coral reef limestone element better represents corresponding rock mass properties than granite or sandstone. [ABSTRACT FROM AUTHOR]

Caribbean spiny lobsters are known to undergo migration as adults, but the dispersal and homing ability of subadults and juveniles is not well characterized. Given that settlement habitat for juveniles is inshore seagrass / hardbottom and reproductive habitat is offshore coral reefs, dispersal during ontogeny serves as a bottleneck potentially limiting adult population density. Previous studies have examined factors associated with movement and den selection by juvenile lobsters such as shelter type, predators, and conspecific density. Their attraction to odors of healthy conspecifics plays a significant role in aggregation of lobsters in casitas and traps. But what is unknown is whether juvenile lobsters possess the map and compass orientation found in adults. To examine the ontogeny of homing ability, we conducted multiple mark / displace tracking studies using acoustic telemetry in juvenile hardbottom and subadult coral patch reef habitats. All lobsters regardless of size tend to relocate to new crevice shelters when handled, even if returned to their original shelter. Thus, for non-displaced lobsters tagged and returned to their point of capture, distance and angle travelled appears to be random with distance increasing as function of body size. However, for juvenile and subadult lobsters tagged and displaced away from their point of capture, the distance and angle travelled when released is significantly directed toward the point of capture. Thus, it appears that the map and compass ability of Caribbean spiny lobsters appears early in ontogeny and may allow for individuals to safely explore unfamiliar locations while retaining knowledge of how to return to known shelter. This ability to expand their known habitat map while maintaining knowledge of critical diurnal shelter locations is expected to facilitate their ontogenetic dispersal to adult habitat. [ABSTRACT FROM AUTHOR]

Nearshore coral reefs face an increasing abundance of fleshy macroalgae, an indicator of degradation and threat to ecosystem functioning. Removal of macroalgae is proposed to assist coral recovery, though the ecological and physical impacts have not been studied. Nearshore reefs are also confronted with sedimentation stress, influencing reef dynamics including algal turfs, with flow-on impacts to coral recruitment, fish diets, and trophic cascades. In this study, the interplay between macroalgal canopies, sediment deposition and algal turf environments was investigated on the nearshore Great Barrier Reef. Removal of fleshy macroalgae over two years had no significant effect on the amount or composition of sediment deposited on proxy coral (SedPods) and algal turf (TurfPods) surfaces, nor was the height of algal turfs impacted. Deposition on TurfPods was greater with high-energy currents, likely due to retention of sediment within turfs. Therefore, macroalgae removal is unlikely to exacerbate nor alleviate sediment-related stress on benthic communities. [Display omitted] • Fleshy macroalgae are increasing in abundance on coral reefs globally. • Removing macroalgal canopies has no effect on sediment deposition or composition. • Turf algae communities unaffected by macroalgal canopy presence. • Reef restoration via sea-weeding will not exacerbate nor alleviate sediment stress. [ABSTRACT FROM AUTHOR]

This study investigated microplastic and other micro-debris pollution in sediment, seawater, sea cucumbers, and corals from fringing and patch reefs in Kāneʻohe Bay, Oʻahu, Hawaiʻi, USA. Microplastic pollution in Kāneʻohe Bay Bay was low compared to other tropical coral reefs. Microplastics were detected in sediments (29 %), sea cucumbers (9 %), and coral (0–2 %) samples but were not quantifiable. Seawater had quantifiable microplastic (< 0.5 mm) and macroplastic (> 0.5 mm) pollution, with mean concentrations ranging from 0.0061 to 0.081 particles m−3. Most particles detected in seawater samples were larger, floating plastic debris consisting mostly of polyethylene, polypropylene fragments, and fibers. Across the other matrices, the most detected particles were polyester, polypropylene, and cotton fibers. These results provide baseline data for this important coral reef ecosystem, and further monitoring is recommended to understand the seasonal and long-term trends in microplastic pollution and its potential future impacts. [Display omitted] • First assessment of microplastic pollution in coral reefs of Kāne'ohe Bay. • Multiple matrices examined: sediment, seawater, sea cucumbers, and corals. • Pollution of other anthropogenic particles assessed in addition to microplastics. • Rigorous LOD/LOQ methods used to account for sample contamination. • Microplastics and other anthropogenic particles were detected in very few samples. [ABSTRACT FROM AUTHOR]

The heavy metal load in coral reefs of Singapore has not been comprehensively assessed since 1994. Here, we repeated the surveys conducted 27 years ago to quantify the levels of Cd, Cu, Cr, Fe, Pb, Ti, Zn in sediment and the sea urchin Diadema setosum from seven reefs. Cu and Cd showed significant reductions, Pb and Cr remained stable, while Fe, Ti and Zn had increased significantly. Overall, based on the Pollution Load Index (PLI), Singapore's reefs would not be considered polluted. Nevertheless, elevated concentrations of Cu, Pb and Zn were detected in sediment, with Cu and Pb exceeding the Threshold Effect Level. The spatial distribution of metal loads between sediment and sea urchin tissues were decoupled, underscoring the complexity of metal uptake and bioavailability. We reveal a mixed temporal trend among the heavy metals examined, each presenting different toxicity potentials and hence risks to local marine assemblages. [Display omitted] • Heavy metals in coral reef sediment and sea urchin tissues were compared to 1994 levels. • A mixed temporal trend was revealed, with varying toxicity potentials among metals. • Heavy metals in sea urchin tissues showed distinct spatial and temporal trends. • Urchin gonads exhibited significant Cd bioaccumulation. • Sex and reproductive status significantly affected metal accumulation in sea urchin gonads. [ABSTRACT FROM AUTHOR]

The crude oil contamination along the Brazilian Northeast coast significantly impacted reef ecosystems. This study assessed polycyclic aromatic hydrocarbons (PAHs) in seawater, fluorescence of bile PAHs, and biochemical biomarkers in damselfish Stegastes fuscus across four coral reef areas pre- and post-oil contamination. Serrambi (SE) and Japaratinga (JP1) were identified as suitable reference areas. PAH concentrations significantly increased in water post-contamination, predominantly 2 to 3 ring parent and alkylated PAHs. Biliary PAHs naphthalene, phenanthrene, chrysene, pyrene and benzo(a)pyrene increased on Paiva post-spill versus pre-spill to 173 %, 449 %, 334 %, 331 % and 131 %, respectively. Significant increases in ethoxy-resorufin-O-deethylase (EROD) (852 %), catalase (CAT) (139 %) and decrease in lipid peroxidation (LPO) (40 %) and acetylcholinesterase (AChE) (75 %) were verified in Paiva samples. Biliary PAHs and biochemical biomarkers were altered in S. fuscus after exposure to PAHs dissolved from the oil. Stegastes fuscus emerges as a promising sentinel organism for coastal reef oil pollution monitoring. [Display omitted] • PAHs dissolved from emulsified oil and contaminated water in 3 coral reef ecosystems. • PAHs in bile of reef fish Stegastes fuscus increased. • Fish bile PAHs and biochemical biomarkers characterized the oil impact in coral reefs. • Stegastes fuscus is a viable sentinel species to monitor oil effects in reef areas. [ABSTRACT FROM AUTHOR]

Little is known about microplastics (MPs) in corals from the Indian Ocean. We compared MP concentrations, morphotypes, size, colours, and polymer compositions in six coral genera from three remote Mascarene islands (Rodrigues, St. Brandon's Atoll, and Agalega) of the Republic of Mauritius, on a 1200 km transect located in the South Equatorial Current (SEC). The mean MP concentration was 0.78 n/g (53 % fibres) with no significant differences between islands. Polymers were polypropylene (78 %) and polyethylene (18 %). We conclude that the SEC's MP concentrations and compositions have homogenized over thousands of kilometres across the Indian Ocean. We discuss the lack of hazardous polyurethane MPs in coral samples given obvious sources on St Brandon. To the best of our knowledge, this study is the first to report on MPs in coral from the Western Indian Ocean and the Mascarene Islands providing a baseline for further research, monitoring, mitigation, and policy development. [Display omitted] • Nothing is known about microplastics (MPs) in coral from the Western Indian Ocean. • We analysed MPs from hard and soft corals from three Mascarene islands, a 1200 km transect. • The mean concentration was 0.78 n/g (53 % fibres) with no significant differences between islands. • Polymers were polypropylene (78 %) and polyethylene (18 %). • Compositions homogenized over thousands of kilometres across the Indian Ocean. [ABSTRACT FROM AUTHOR]

Numerous studies have investigated the occurrence of plastic additives in marine biota. Yet, their main vector of transfer into organisms tissues remains unknown. We explored seven common additives in benthic coral reef invertebrates residing on natural/plastic substrates in a protected marine reserve versus an unprotected reef to ascertain whether additives transfer by substrate leaching. Samples of three coral-reef species were extracted and analyzed by GCMS and HPLC. Of the seven chemical additives investigated, dibenzylamine and bis(2-ethylhexyl) phthalate were detected. No significant association was found between additives and substrate type, possibly because these plastics have been submerged for years, and the majority of additives within them have leached. The marine reserve had fewer samples with additives, highlighting the importance of active management. Understanding the transfer vectors of plastic additives into biota is essential for assessing the risk they pose and devising effective management tools for protecting coral reefs. [Display omitted] • Plastic additives were identified in 52 % of the samples. • Additives found in organisms from pristine coral reefs of the Gulf of Aqaba. • No difference in the occurrence of additives in organisms from various substrates • Dibenzylamine and DEHP were identified in corals and sponges from the Red Sea. • Marine reserves play a role in the mitigation of chemical and plastic pollution. [ABSTRACT FROM AUTHOR]

Coral reefs provide a variety of ecosystem services to humans, but are also degrading due to human activities such as damage from boat anchoring. Anchoring on reef could occur intentionally, because boaters prioritize other considerations that outweigh any desire to not anchor on reef, or unintentionally, because they lack true awareness of the seabed habitat. We conducted structured interviews, informed by the Theory of Planned Behavior, with 130 boaters in the British Virgin Islands to uncover the motivations and awareness underlying their anchoring behavior. Perceived awareness is rarely ground-truthed, so we checked interview responses of anchored boats by snorkeling to observe the seabed underlying their anchor and anchor chain. All respondents stated a strong aversion to anchoring on coral reef. The few boats we observed anchored on reef did so unintentionally due to a mismatch between their perceived and actual awareness of the seabed habitat. Potential management actions to reduce anchoring on reef thus include measures that increase awareness of seabed habitats. Mooring buoys are an alternative to anchoring at some sites, so increased use of moorings is another option because it should decrease the proportion of boats that anchor, which, in turn, should reduce unintentional anchoring on coral. The decision to use a mooring rather than anchor is, however, multifaceted. Boaters are less likely to choose moorings if they perceive moorings as inconvenient to pre-book, do not trust the moorings are secure, or prefer more secluded areas. Boaters also noted that, during peak boating season, the option to moor is reduced because moorings are sometimes fully occupied. Despite this complexity, our findings suggest several local management options that could further reduce the minority of boats anchoring on coral. • Anchoring on coral reef is unintentional. • Anchoring on reef occurs due to a lack of actual awareness of the bottom type. • Increasing boaters' awareness of seabed habitat should reduce anchoring on reef. • Increased use of moorings instead of anchoring should reduce anchoring on reef. [ABSTRACT FROM AUTHOR]

The relationship between the 2004 Indian Ocean Tsunami (IOT) with the Maldivian reef remains unclear. Following the tsunami event, some field-based studies suggest that specific reef areas offered protection against the tsunami waves. However, a quantitative study is lacking to assess the buffering role of this reef system. Considering its significance for fisheries and tourism, there is an urgent need to understand the reef dynamics during the IOT. Here, we aim to address the scientific gaps related to the reef impact on the tsunami waves in North Male Atoll. Our findings indicate that the coral cover contributed to a marginal reduction in energy flux along approximatively 90% of Eastern North Male shoreline. Over 80% of the area experienced a 60% decrease in tsunami energy flux due to the presence of the reef platform. The distance reef-island, the proportion of reef coverage relative to island and the tsunami wavelength also play a role in influencing tsunami energy flux. This research not only addresses a critical knowledge gap regarding the reef dynamic during a tsunami event, but also emphasizes the importance of considering coral reefs in the context of sustainable coastal management, disaster preparedness and anthropogenic climate change stressors. • Tsunami numerical modelling of the 2004 Indian Ocean Tsunami in the Maldives. • Relationship between the 2004 event and the Maldivian coral reef system. • Evaluating the buffering ability of the coral cover and the reef platform against tsunami waves. • Highlighting the significance of sustainable coastal reef management and associated disaster preparedness. [ABSTRACT FROM AUTHOR]

Historical information serves as a crucial foundation for understanding past natural ecosystems, enabling us to track changes in biodiversity. It plays an indispensable role in both biodiversity conservation and restoration ecology. In the Brazilian Province, there is still an absence of historical accounts relative to the coral assemblage diversity. We compiled historical and modern information on coral species and mapped coral diversity in the Brazilian Province over the past 150 years. Using abundance data, we contrasted the functional structure of coral assemblages sampled 40 years apart (1960–2000) in the Abrolhos Bank, the largest reef complex of the Southwestern Atlantic Ocean. The number of species records increased over time, especially after the 1960's, with the Abrolhos region amassing numerous historical accounts and harboring the greatest coral richness. This increase in species records reflects the recent accumulation of knowledge about these marginal reefs. Historical declines of two major reef building species, Millepora alcicornis and Mussismilia braziliensis , resulted in temporal changes in their relative contributions to the functional structure of coral assemblages in the Abrolhos Bank. The erosion of such assemblages within the past 40 years highlights the importance of considering historical information to adjust environmental baselines, setting proper conservation and restoration targets. • Historical data is crucial for tracking shifts in Brazilian coral diversity. • Comparison between historical and modern data revealed changes over 150 years. • Abrolhos Bank had an increase in coral species records post-1960s. • Abundance declines in major reef-building species reshape coral assemblages. • Importance emphasized of historical data for setting conservation targets. [ABSTRACT FROM AUTHOR]

The liquefaction of coral sands caused by the accumulation of excess pore-water pressure is a major factor contributing to catastrophic events on coral reefs, and accurately estimating this excess pore-water pressure accumulation holds significant importance. High-quality laboratory test results are essential for analytical or numerical calculations. In this study, a new test method is employed to conduct a series of undrained, multi-staged, stress-controlled multidirectional hollow cylinder tests on saturated coral sand under complex loading conditions. The concept of threshold strain (γ t) and the method for determining γ t of saturated coral sand specimens under complex loading conditions are proposed. The test results demonstrate that γ t of saturated coral sand remains insensitive to cyclic loading conditions (including frequency, stress path, and mode) but increases with increasing relative density. The range of volumetric threshold strain, degradation threshold strain, and flow threshold for saturated coral sand under different initial states and cyclic loading conditions are 0.0183%–0.0341%, 0.0242%–0.0454%, and 1.006%–1.614%, respectively. This research provides a novel approach for accurately determining input parameters required for resolving and implementing coupled models in numerical modeling. • The concept and determination method for strain threshold of coral sand under complex loading conditions are proposed. • The new test method precisely determines the strain threshold range of saturated coral sand at various relative densities. • The strain threshold increases with higher relative density, unaffected by cyclic loading frequency, mode, and stress paths. [ABSTRACT FROM AUTHOR]

The bearing capacity and deformation behavior of coral sand foundations, a geotechnical structure commonly employed in coastal and island construction, are investigated in this study. Coral sand presents unique challenges due to its angularity and crushability, which affect interparticle interactions. Model tests and three-dimensional discrete-continuous coupled numerical simulations are performed to understand these complexities, focusing on the impacts of relative density, footing size and shape, and particle crushing on the foundation performance. The testing and numerical simulation data reveal that the bearing capacity of coral sand foundations significantly improves with increasing relative density and footing size. Compared with square footings, circular footings exhibit superior bearing performance at a 70% relative density. However, increased particle crushing reduces the bearing capacity. These findings are evaluated and compared with the theoretical ultimate bearing capacities. Intense crushing and occlusions are observed directly beneath the footing, with marked increases in particle fragments, microscopic contact forces, and coordination numbers within this core region. Additionally, the deformation analysis reveals a symmetrical failure pattern in the coral sand foundations. This study delves into the microscopic interactions between particle crushing and its influence on the bearing and settlement performance, offering insights into the interplay between crushing, stress, and deformation. • A three-dimensional discrete-continuous coupled numerical method is developed. • Bearing and deformation laws under multiple effects are revealed. • The correlation between stress and crushing is described. • Calculations of ultimate bearing capacity are discussed. • Macro- and fine-scale mechanisms of failure deformation are analyzed. [ABSTRACT FROM AUTHOR]

To investigate the effects of cyclic loading frequency (f) and loading patterns (90° jump of principal stress, JPS, and continuous rotation of principal stress, CRPS) on the stiffness characteristics of saturated marine coral sands, a series of undrained cyclic shear tests were conducted. π– plane is introduced as the analytical plane. We propose generalized deviator strain evolution (ζ q) to quantify the evolution of global strain, and introduce generalized dynamic modulus (K) to evaluate the soil's global stiffness. K and maximum generalized dynamic modulus (K 0) exhibited a strong correlation with loading direction angle (α σ), maximum loading direction angle (α σmax), and f. Both patterns showed an increase in K 0 with increasing f. Under JPS, the K 0 initially decreased and then increased as α σ increased, reaching its minimum value at α σ = 45°. Normalizing the effect of f and α σ , we establish a unified empirical formula for K 0. Under CRPS, K 0 continuously decreased with increasing α σmax. The global level of K 0 is higher under CRPS compared to JPS. Additionally, the K / K 0 curve was significantly influenced by α σ but remained insensitive to f. A modified generalized Davidenkov model was developed to describe the recession properties of marine coral sands over a wide strain range. • A new method for calculating the evolution of generalized deviator strain(ζ q) is proposed. • A new index (generalized dynamic modulus, K) is proposed in characterizing the global stiffness of soil. • The variation of K in saturated marine coral sand under seismic and traffic stress is investigated, and the prediction models of K 0 and K / K 0 under JPS is established. • K achieves the comparison of soil stiffness induced by JPS and CRPS, and enabling the feasibility of conducting stiffness studies under complex loading conditions. [ABSTRACT FROM AUTHOR]

Analysis of bacterial carbohydrate-active enzymes (CAZymes) contributes significantly to comprehending the response exhibited by coral symbionts to the external environment. This study explored the impact of bleaching on the bacteria and their CAZymes in coral Favites sp. through metagenomic sequencing. Notably, principal coordinates analysis (PCoA) unveiles substantial difference in bacterial communities between bleached and unbleached corals. Proteobacteria, Actinobacteria, Acidobacteria, Bacteroidota, and Chloroflexi, exhibit noteworthy alterations during coral bleaching. CAZymes profiles in bleached coral disclosed a significant increase in Glycosyltransferases (GTs) abundance, suggesting an intensified biosynthesis of polysaccharides. Conversely, there is a marked reduction in other CAZymes abundance in bleached coral. Proteobacteria, Bacteroidota, Chlorobi, and Planctomycetota exhibit greater contributions to CAZymes in bleached corals, with Rhodobacterales, Cytophagales, Burkholderiales, Caulobacterales, and Hyphomicrobiales being the main contributors. While Acidobacteria, Actinobacteria, and Chloroflexi demonstrate higher contributions to CAZymes in unbleached corals. The changes in bacteria and their CAZymes reflect the ecological adaptability of coral holobionts when facing environmental stress. The alterations in CAZymes composition caused by bleaching events may have profound impacts on coral nutrient absorption and ecosystem stability. Therefore, understanding the dynamic changes in CAZymes is crucial for assessing the health and recovery potential of coral ecosystems. • Substantial difference in bacterial communities between bleached and unbleached corals. • A significant increase in the abundance of GT in bleached coral. • Marked reduction in the abundance of GH, CE, AA, CBM, and PL in bleached coral. • Proteobacteria, Bacteroidota, Chlorobi, and Planctomycetota exhibit greater contributions to CAZymes in bleached corals. [ABSTRACT FROM AUTHOR]

The South China Sea (SCS), located at the intersection of two major tectonic plates and near the Manila Fault Zone, is a region highly susceptible to earthquakes and tsunami activities. To develop a more comprehensive and reliable understanding of tsunami behaviours over coral reefs, this study employs the actual topography of a coral reef in the SCS and N-wave theory for the numerical simulation, encompassing the entire tsunami life cycle. Utilizing the open-source solver OlaFlow, driven by the Reynolds-averaged Navier-Stokes (RANS) equations, this study performs a series of numerical simulations of N-wave tsunamis considering the measured topography of the coral reef, as well as the real dimension of an engineering defence structure on the top of the coral reef. The adopted tsunami parameters are equivalent to an earthquake with a moment magnitude of 7.1. The simulations focus on the impact of wave profiles and initial static water levels on the propagation and evolution of tsunamis. Numerical simulations reveal that tsunami profiles, water depth, and topography significantly influence the tsunami dynamics, notably in the waveform transformation, the relationship between wave height and trough-to-peak ratio, and the topographic effects on the wave energy dissipation. These results highlight the critical need to incorporate factors such as tsunami profiles, dispersion, and realistic topography into tsunami predictive models for the purpose of more reliable hazard evaluation and the development of effective coastal defences. • Tsunamis are finely modelled numerically by adopting N-wave theory and RANS equations. • Evolution and interaction of tsunamis with a coral reef and revetment breakwater are explored. • The measured topography of coral reef and the real dimension of engineering structure are utilized. • Seawater overtopping would bring great threat to the ecosystem of reclaimed lands on coral reefs. • Impact forces of tsunamis on engineering structures is insufficient to threaten their stability. [ABSTRACT FROM AUTHOR]

The Red Sea Coast near Hurghada City is under continuous development in the tourism sector because of its natural heritage of corals reefs. This region is one of the favorite destinations of leisure tourism throughout the world. These activities lead to high environmental stress that affects the water quality and growth of coral reefs. The Foraminifera in Reef Assessment and Monitoring index (FoRAM Index) is one of the cost effective and fast results methods of bio-monitoring. The FoRAM Index is applied in the Makadi and Ras Disha Bays near to Hurghada. Topographic analysis shows that the tourist facilities are concentrated at the outlet of the low gradient valleys especially at Makadi bay. The FoRAM Index is supported with a statistical analysis of the foraminiferal association that resulted in the identification of three microtypes. These microtypes are stress tolerant rich Microtype 1, heterotrophic foraminifera rich Microtype 2 and symbionts-bearing foraminifera Microtype 3. The foraminiferal population pattern in these microtypes is similar to the groupings of the FoRAM Index. The values of the FoRAM Index range between 3.8 and 6.8 and these values reflect healthy water that supports the growth of coral reefs. However, a degradation gradient occurs in Makadi Bay indicating the impact of concentrated tourism activity on the water quality. The values observed in Ras Disha Bay can be considered as background for spatial and future studies. The FoRAM Index is a highly recommended application for economic and rapid bio-monitoring. The results are valuable for stakeholders planning for sustainable development and management of ecotourism. • The coral reef health in Hurghada on Red Sea Coast is assessed based on FoRam Index. • The bio-monitoring followed the standardized method for FoRam Index calculation. • Three foraminiferal association microtypes are found in the study region. • The FoRam Index reflects healthy water that supports the growth of coral reefs. • A degradation gradient occurs in Makadi Bay resulting from concentrated tourism activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • A Co/Mo co-doped NVP composite with unique cluster porous structure is prepared. • Doping Co2+ provides p-type effect, broadens ionic channel and reinforces crystal structure. • Mo6+ doping results in n-type effect and brings more electrons to increase electronic concentration. • Coral cluster porous structure increases contacting areas with electrolyte and withstands the stress. • Ex-situ XRD/XPS/SEM analysis demonstrates the improved crystal stability of NVCMP0.15. Na 3 V 2 (PO 4) 3 (NVP) is suffered from poor conductivities and terrible structure stability. Herein, Co/Mo co-doped NVP with unique cluster porous structure is prepared. Notably, Co2+ replacing V3+ provides useful p-type effects, manufacturing more acceptor levels and generating equal hole carriers, which facilitates the ionic conductivity. Moreover, the larger ionic radius of Co2+ significantly enlarges the interplanar spacing to broaden ionic migration channel. The doped Co2+ can function as pillar ions to reinforce the crystal structure, further improving structure stability. Meanwhile, Moderate Mo6+ is introduced to keep charge balance, resulting in beneficial n-type doping effects, which can bring more electrons and increase the electronic concentration to speed up electronic conduction. Notably, a unique coral cluster porous structure is formed after controlling the added Co/Mo contents. This distinctive morphology allows active materials expose more contact areas with electrolyte to enhance infiltration effects, increasing the active sites to release more reversible capacity. Moreover, the porous construction withstands the stress resulting from the volume contraction during Na+ de-insertion. Comprehensively, NVCMP0.15 exhibits a value of 90.7 mAh g−1 at 50C and retains 68.5 mAh g−1 after 2000 cycles with retention ratio of 75.52 %. Ex-situ XRD/XPS/SEM after cycling indicate great improvements in crystal stability of NVCMP0.15. [ABSTRACT FROM AUTHOR]

The increase in climate-related extreme events and ecosystem degradation demands consistent and sustainable climate mitigation efforts. Seagrass playing a key role in nature-based carbon sequestration mitigation strategy. Here, we investigated the role of coral reef connectivity in blue carbon dynamics with seagrass meadows with coral reef connectivity (SC areas) and without coral reef connectivity (SG areas) in Palk Bay, India. The high sediment organic carbon was recorded in SC areas (90.26 ± 25.68 Mg org.C/ha) and lower in SG areas (66.96 ± 12.6 Mg org.C/ha). The maximum above-ground biomass (AGB) was recorded in Syringodium isoetifolium (35.43 ± 8.50) in SC areas and the minimum in Halophila ovalis (7.59 ± 0.90) in SG areas, with a similar trend observed in below-ground biomass (BGB). Our findings highlight the importance of coral reefs in enhancing the blue carbon potential of seagrass ecosystems and underscore the need for integrated conservation and restoration strategies for coral reefs and seagrasses. • Study reveals the site-specific habitat for SC & SG of carbon storage in Palk Bay • The mean above-ground biomass of Syringodium isoetifolim was 35.43 ± 8.50 g dwt/m2. • The sediment organic carbon stock of Cymodocea rotundata was 84.79 ± 1.37 Mg org.C/ha • Coral reef–seagrass habitat identified as potential climate change mitigation hotspot [ABSTRACT FROM AUTHOR]

Chemical pollution is a threat to coral reefs. To preserve them, it is crucial to monitor novel contaminants and assess the related risks. The occurrence of active pharmaceutical ingredients (APIs) in coral reefs has been poorly investigated until now. Under this light, we tested the use of the marine sponge Cf. Hyrtios as bio-monitors and conducted a pilot study in the Faafu Atoll (Maldives). Analyses were carried out by in vivo solid-phase microextraction (SPME) and liquid chromatography (LC) electrospray ionization (ESI) tandem mass spectrometry (MS/MS). Twelve APIs were selected for method optimization. Limits of quantitation (LOQs) were in the 0.6 and 2.5 ng/g range, accuracy between 86.5 % and 104.7 %, and precision between 3.0 % and 14.9 %. All the sponges located in the inner reefs resulted contaminated with at least one API. Gabapentin and Carbamazepine displayed the highest detection rates, while Ketoprofen had the highest concentration (up to 15.7 ng/g). [Display omitted] • Marine sponges were tested as bio-monitors of APIs in coral reefs. • ESI-SPME-LC-MS/MS method conditions have been optimized for 12 APIS. • LOQs were in the 0.6 and 2.5 ng/g range and accuracy between 86.5 % and 104.7 %. • A survey was conducted in the Faafu Atoll (Maldives). • APIs were primarily detected in the lagoon in concentrations up to 15.7 ng/g. [ABSTRACT FROM AUTHOR]

As relatively independent ecological units, islands have unique characteristics that are different from marine and continental ecosystems. Island ecosystems are even more sensitive and fragile due to the influence of both human activities and coastal effects. However, there is still a lack of studies on ecosystem service trade-off relationships in island terrestrial areas, and few studies have included coastal ecosystems and measured coastal vulnerability. Therefore, this study aimed to analyze the spatial and temporal evolution patterns of carbon storage, water yield, soil conservation, and habitat quality ecosystem services in Hainan Island in 2000, 2010, and 2020 based on the Invest model. The strength of the ecosystem service trade-offs in the island's terrestrial area was measured using correlation analysis and the ecosystem service trade-off coordination degree method. In addition, this study considered the impact of coastal ecosystems on coastal vulnerability. The study showed that (1) all four ecosystem services had a decreasing trend at both scales, with the most pronounced impairment of services at low elevations and in areas of high human activity, where the natural topography and land use types greatly influenced ecosystem service change. (2) The four services showed overall synergistic effects at two scales, and this synergistic effect decreased with the decrease in the scale. There was a trade-off state locally at the county scale. (3) Mangrove, coral reef, and swampy wetland ecosystems provided great protective services for the coast of Hainan Island. (4) Recreation and tourism cultural services had a broad trade-off with the four services, and the cultural services on Hainan Island may be compromised to some extent by an increase in the terrestrial ecosystem services. The findings can provide a theoretical basis for realizing the harmonious coexistence of "island-city-people" on the island. The synthesis of terrestrial and coastal ecosystem services provides suggestions for the sustainable development of island-wide ecosystems. [ABSTRACT FROM AUTHOR]

Boron isotopes (δ 11B) in coral skeletons of Porites have been widely applied to reconstruct past seawater pH (pH SW) on decadal to centennial timescales. However, due to biological regulation within corals, an additional transfer function is required to estimate ambient seawater chemistry during the skeleton growth under the calcification site fluid pH. Temperature may also interfere with coral calcification fluid pH (pH CF) due to changes in kinetics of coral aragonite precipitation, or buffering capacity in coral calcification fluid. To decipher how coral Porites adjusts pH CF in response to pH SW from complex environmental controls, long-term records from sites with least fluctuations in environmental conditions other than pH SW are essential. Here we present a 37-year record of coral δ 11B and B/Ca ratios derived from a coral core collected from southern Maldives, the tropical Indian Ocean. Our results show no clear seasonality in the coral δ 11B and B/Ca ratios between monsoons, but a long-term decline in coral pH CF is evident across the entire record. When applying different existing transfer functions, we also observe discrepancies among the calculated pH CF values, model results and short-term instrumental data. Calculated calcification fluid dissolved inorganic carbon concentration ([DIC] CF) values are relatively low compared to literature, suggesting that coral calcification fluid carbonate chemistry may be under different levels of control, even within the same coral taxa. Thus, coral records from a wider geographic range are required to better quantify coral response to ocean acidification, and our results can serve as a baseline for future comparisons. • This is the first coral's carbonate chemistry record in the tropical Indian Ocean. • Porites calcification pH is sensitive to ocean acidification, but the transfer function to seawater pH needs re-evaluation. • A different internal energy/dissolved inorganic carbon (DIC) supply might explain the lower [DIC] CF observed in Maldives corals. • Data from a wider geographic range is required to constrain the impacts of ocean acidification on corals. [ABSTRACT FROM AUTHOR]

Accurately evaluating the dynamic mechanical properties of coral reef limestone (CRL) is crucial for the safety and stability of island underground engineering structures. A Split Hopkinson Pressure Bar (SHPB) testing system was employed to conduct dynamic impact tests on four different types of CRL under dry and saturated conditions. Additionally, CT scanning and three-dimensional (3D) reconstruction techniques were used to characterize the pore structure of the CRL samples. The results indicate that the dynamic parameters, energy dissipation density, and fracture morphology of CRL are positively correlated with the loading rate. The dynamic compressive strength, dynamic elastic modulus, and energy absorption capacity of the saturated samples are all lower than those of the dry samples. Damage in CRL typically occurs along biocomponent boundaries with poor cementation and areas with abundant through-pores. For dense types of CRL (RW and RD), damage primarily involves skeletal expansion and penetration, exhibiting brittle splitting failure modes with blocky fracture patterns. In contrast, loose types of CRL (CW and CP) primarily undergo perforation propagation, exhibiting crushing failure modes with strip-shaped debris formed along coral growth lines. This study provides valuable insights for the application of CRL in island underground engineering projects. • The dynamic compressive strength of CRL showed a non-linear increase with increasing strain rate. • The degree of fragmentation of CRL is positively correlated with strain rate and incident energy. • The rate effect of compressive failure patterns to coral reef limestone. • The presence of water deteriorates the strength and stiffness of coral reef limestones. [ABSTRACT FROM AUTHOR]

[Display omitted] • Coral microbiome shows higher abundance and diversity than seawater microbiome. • Different habitats may cause contrasting microbial assembly mechanisms. • Separated microbes may associate with their competition and cooperation. • Distinctly microbial indicators existed between corals and the surrounding seawater. Coral reefs are among the most energetic marine ecosystems, taking a place in ecological balance. Microbes participate in the energy exchange in coral ecosystems, which may affect coral resistance and resilience. However, there is still a lack of understanding regarding the microbial structure between corals and seawater. In this study, microbial structure and interactions in coral and seawater were studied using quantitative PCR and high-throughput sequencing. We found that the abundance and diversity of microbes in corals were higher than those in seawater. Corals, as nonfluidic ecosystems, limited the dispersal of microbes, causing broader stochasticity in the ecological shaping process, whereas ecological drift and homogeneous selection were the most important assembly mechanisms in seawater. The microbial niche width was larger in the coral group than in the seawater group, indicating strong adaptability. A group of microbes (e.g., Caldilineaceae , Burkholderiaceae , and Nitrosopumilaceae) may become microbial indicators which differentiate seawater samples (e.g., SAR11 and SAR86 clades, Cryomorphaceae), which may be due to separated habitats and nutrition. Coral microbes may participate in nitrogen-metabolism to maintain a nitrogen limited microenvironment. Nodes linked in the coral co-occurrence network showed coexisting interactions and higher complexity based on the comparison of topological values. Collectively, significant differences in microbial fractions were demonstrated observed in terms of diversity, composition, co-occurrence patterns, assembly processes and predicted functions between coral and seawater samples, showing potential microbial interactions and providing in-depth insights into the metacommunity diversity in coral reef ecosystems. [ABSTRACT FROM AUTHOR]

Fjords provide unique habitats for large cold-water coral (CWC) reefs, typically growing on sills and vertical walls. Fjord reefs are among the most thriving CWC reefs in Norway. Yet, these reefs, especially the wall reefs, are notoriously understudied. Here, we mapped the biomass, total carbon (C) stocks and C turnover (as respiration) of the reef-building coral Lophelia pertusa (syn. Desmophyllum pertusum), and dominant, large CWC reef-associated suspension feeders (the sponges Geodia barretti and Mycale lingua , the CWC Madrepora oculata and the bivalve Acesta excavata) within the Hardangerfjord, Norway. Remotely Operated Vehicle (ROV) recorded videos from wall and sill reefs were used to estimate species-specific biomass. Coupled with high resolution terrain data (2 × 2 m), predictive maps of species biomass were produced using a random forest (RF) model. The resulting biomass data were integrated with species-specific C content and C respiration rates from literature to estimate C stocks and C turnover of wall versus sill reefs. Area-specific results from the RF models reveal that wall reefs had a higher habitat suitability for all species except L. pertusa , which was more dominant on the sills. Accordingly, the wall reefs supported an up to 11 times higher biomass, C stock, and turnover for all species, except for L. pertusa , which had two-fold higher values on the sill reef. As a result, the wall reefs showed a 1.5 to 4.8 times higher total mean C turnover by dominant suspension feeders (all studied species) compared to the sill reefs. With their high C turnover and their presumably wide distribution in Norwegian fjords and globally, benthic wall reef megafauna may have a substantial, but overlooked biomass and functional role within CWC reef systems. • We provide a first insight into cold-water coral reef biomass within a fjord. • Fjordic walls may play a distinct, overlooked role as cold-water coral reef habitat. • Fjordic sill reefs have higher Lophelia pertusa biomass than the walls. • Compared to the sill, wall reefs host higher overall biomass and carbon turnover. • Some reef-associated suspension feeders may prefer walls over sill habitat. [ABSTRACT FROM AUTHOR]

Crown-of-thorns seastars (COTS, Acanthaster spp.) are a major contributor to coral mortality across the Indo-Pacific and can cause extensive reef degradation. The diet preferences of COTS can influence coral community structure by predation on fast-growing genera such as Acropora and avoidance of rare coral genera. In non-outbreaking populations, this preference can increase species diversity. The feeding biology of Acanthaster cf. solaris was compared at two sites (Shark Alley and Second Lagoon) on One Tree Island reef, located in the southern Great Barrier Reef, to determine whether the availability of Acropora influences differences in COTS movement, feeding preference and feeding rates within the same reef system. Acanthaster cf. solaris were tracked daily for five days across both sites, with measurements of movement, feeding scars and coral composition recorded over this time. While Shark Alley and Second Lagoon have similar live coral cover (40 and 44 % respectively), Shark Alley has significantly lower Acropora availability than Second Lagoon (2 vs 32 %). The feeding rate of COTS was significantly different between Shark Alley and Second Lagoon (259.8 and 733.8 cm2 of coral per day, respectively), but did not differ between seastar size (25–40 cm and >40 cm). Acanthaster cf. solaris showed preference for Pocillopora , Seriatopora , Acropora and Isopora and an avoidance of Porites at both sites. The results suggest that for coral reef sites where Acropora is not dominant, COTS outbreaks may be less likely to initiate, with comparatively low feeding rates found in comparison to coral reefs where Acropora is dominant. • Feeding behaviour of crown-of-thorns seastars (COTS) were compared across two sites. • Feeding rates were higher in sites with high Acropora availability. • Movement rates and feeding preferences did not differ between sites. • Feeding preferences are similar between stable and outbreaking populations. • Reefs where Acropora is rare are less able to support COTS outbreaks. [ABSTRACT FROM AUTHOR]

Coral bleaching detection is vital for assessing coral reef health. This paper introduces FCOS_EfficientNET, an improved model that enhances accuracy, recall, and real-time performance in coral bleaching detection. Utilizing EfficientNet as the backbone, the model optimizes parameter throughput. We adopt the ReLU activation function and utilize cosine similarity and softmax to assign weights to datasets, modifying the attention structure to reduce memory consumption. The model also integrates BiFPN for better feature extraction and employs an improved training method to enhance detection accuracy. To cater to different scenarios, we have developed four variants: FCOS_EfficientNETb0, FCOS_EfficientNETb1, FCOS_EfficientNETb2, and FCOS_EfficientNETb3. Experimental results on the MS COCO dataset show that FCOS_EfficientNETb3 achieves a mean average precision (mAP) of 48.5%, while FCOS_EfficientNETb0 reaches a frame rate of 167.17 fps, highlighting the superior performance of the series. On a custom coral bleaching detection dataset, FCOS_EfficientNETb3 achieves 81.5% accuracy and a 59.3% recall rate, demonstrating the effectiveness of the model. FCOS_EfficientNETb1 and FCOS_EfficientNETb2 offer a balance between operations per second, frame rate, and mAP, making them suitable for mobile and edge computing. These models effectively track movement or changes in marine traffic around coral reefs with moderate fps and recall rates. • Deep learning replaces artificial coral underwater photography for bleaching detection. • Four coral bleaching detection models were designed to meet the needs of different scenarios and tasks. • Combining FCOS and EfficientNet, we developed a mobile-friendly model to monitor coral reefs, balancing real-time tracking, moderate complexity, and high recall. [ABSTRACT FROM AUTHOR]

In ecosystems, natural radionuclides are present in the environment and living organisms. The 238U natural decay chain produces multiple radioactive elements, such as 234U, 226Ra, 210Pb, and 210Po. These radionuclides can be found in air, water, rocks, soil, and other biotic and abiotic components, mainly derived from minerals, such as zircon and apatite. In this study, we determined the activity concentration of radionuclides from the 238U decay chain in the sediment of a coastal ecosystem on the southern Mexican coast in the western Caribbean, an ecosystem minimally affected by industrial activities. Methods included high-resolution gamma-ray spectrometry and alpha-particle spectrometry. Results showed that the sediment samples had an activity concentration range of 18.2–36.6 Bq/kg for 238U, 25.0–41.4 Bq/kg for 234U, 10.1–37.3 Bq/kg for 210Pb, and 29.9–46.0 Bq/kg for 210Po. Water samples ranged between 17.9 and 36.3 mBq/L and 27.9–66.0 mBq/L for 238U and 234U, respectively. The activity concentration of these radionuclides in the sediment and water of this area is compared with that of other coral reefs worldwide, providing a radiometric baseline for comparison purposes. [Display omitted] • Radiometric baseline of 238U natural decay chain in a pristine coastal ecosystem. • 18.2–36.6 Bq/kg in coral reef sediment and 17.9–36.3 mBq/L in water for 238U. • Non-secular equilibrium in all 238U decay chain; absence of radium. [ABSTRACT FROM AUTHOR]