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Corals and gorgonians play an important role as ecosystem engineers in many sublittoral communities worldwide. However, coral populations are being increasingly impacted by human activities. Active ecological restoration is a popular conservation tool nowadays, widely used to revert degradation in natural populations. Several studies have reported survival and growth success in actively restored corals, but few have studied the long‐term effect of transplantation on coral reproduction. We investigated survival and sexual reproduction of transplanted colonies of the Mediterranean gorgonian Eunicella singularis up to 3 years after being recovered from fishery bycatch and transplanted back to their habitat. Three different colony sizes were tested to explore possible effects of fragmentation on survival and reproduction. Results showed that transplanted colonies suffered a significant mortality during the first 4–5 months (30–35%), independently of fragment size. However, larger fragments showed high survival despite other disturbances, as a bloom of ephemerons filamentous algae occurred during the study. Results also showed that reproductive capacity is negatively affected by transplantation in female colonies. Conversely, male colonies were not directly affected by transplantation but showed an unexpectedly reduced number of spermary sacs both in transplanted and natural control colonies. The trade‐off between investment in reproduction and mortality of transplants highlights that large colony size could be the most appropriate for the active restoration of E. singularis. This study emphasizes the need to explore the long‐term viability and the reproduction investment in transplanted corals as indicators of restoration success, whose populations are sustained by sexual reproduction. [ABSTRACT FROM AUTHOR]

Assisted coral recovery (ACR) initiatives are establishing rapidly in coral reefs worldwide, using a variety of devices and techniques. In the Great Barrier Reef (GBR, the Reef), site-scale ACR field trials are occurring at multiple sites in the Cairns-Port Douglas region through Reef stewardship activities involving GBR tourism operators, Traditional Owners, and not-for-profit organisations. It is hypothesised that these field trials and the presence of ACR devices at reef tourism sites do not negatively affect visitor experiences, and when accompanied by appropriate educational information, can potentially help to raise awareness of Reef stewardship and conservation efforts. We tested these hypotheses using a survey of 708 Reef visitors on five tourism vessels, 346 of whom reported observing ACR devices in situ during their coral reef experience. Ordinal regression tests of survey responses found no statistical relationship between respondents' observation of ACR devices and (i) their overall Reef trip satisfaction, (ii) the perceived aesthetic beauty of the site(s) they visited, and (iii) their concern about the future health of the GBR. However, Reef visitors who observed ACR devices showed significantly lower levels of concern about the use of these devices on the Reef. The perceived quality of educational information presented to respondents was among the significant factors associated with their reef trip satisfaction and perceived beauty of reef sites. Our findings have implications for ACR practitioners and proponents who are concerned about public visibility, perceptions, and support for ACR initiatives, as the scale of such initiatives is expected to increase. [ABSTRACT FROM AUTHOR]

Autonomous Reef Monitoring Structures (ARMS) are used worldwide to assess cryptic diversity, especially on coral reefs. They were developed as standardised tools, yet conditions of deployment, such as immersion duration and/or deployment and retrieval seasons, vary among studies. Here we studied temporal and seasonal variability in coral reef cryptic communities sampled with 15 ARMS on a single coral reef slope site at Reunion Island, Southwest Indian Ocean. Settlement patterns and temporal succession of Eukaryote communities were investigated across three immersion times (6 months, 1 year, 2 years), two immersion seasons (hot vs. cool) and three fractions (500–2000 μm, 106–500 μm, sessile) using two genetic markers (18S, COI). Both markers detected different taxa with different resolutions, but broadly similar patterns of community composition and structure. While OTU diversity of communities did not change with immersion time and season, these parameters significantly affected community structure and composition. Our results showed a decrease of the similarity of ARMS communities with duration of immersion, and a strong temporal turnover of species with only a small proportion of the diversity persisting over time. The small proportion of OTUs assigned at phylum level highlights the uniqueness of the Mascarene cryptobiome. [ABSTRACT FROM AUTHOR]

Coral bleaching, a consequence of stressed symbiotic relationships between corals and algae, has escalated due to intensified heat stress events driven by climate change. Despite global efforts, current early warning systems lack local precision. Our study, spanning 2015–2017 in the Mesoamerican Reef, revealed prevalent intermediate bleaching, peaking in 2017. By scrutinizing 23 stress exposure and sensitivity metrics, we accurately predicted 75% of bleaching severity variation. Notably, distinct thermal patterns—particularly the climatological seasonal warming rate and various heat stress metrics—emerged as better predictors compared to conventional indices (such as Degree Heating Weeks). Surprisingly, deeper reefs with diverse coral communities showed heightened vulnerability. This study presents a framework for coral reef bleaching vulnerability assessment, leveraging accessible data (including historical and real-time sea surface temperature, habitat variables, and species composition). Its operational potential lies in seamless integration with existing monitoring systems, offering crucial insights for conservation and management. A study on the Mesoamerican Reef shows that the climatological rate of seasonal warming and heat stress metrics more accurately predict coral bleaching severity than conventional indices, enhancing regional early warning systems for better conservation strategies. [ABSTRACT FROM AUTHOR]

Countries have committed to conserving and restoring ecosystems after signing the Kunming‐Montreal Global Biodiversity Framework (GBF). The IUCN Red List of Ecosystems (RLE) will serve as a headline indicator to track countries' progress toward achieving this goal. Using Kenyan coral reefs, we demonstrate how nations implementing the GBF can use standardized estimates of ecosystem degradation from RLE assessments to support site‐specific management decisions. We undertook a reef‐by‐reef analysis to evaluate the relative decline of four key ecosystem components over the past 50 years: hard corals, macroalgae, parrotfish, and groupers. Using the two benthic indicators, we also calculated standardized estimates of state to identify reef sites which maintain a better condition through time relative to adjacent sites. Kenya's coral reefs have degraded across all four ecosystem components. At more than half the monitored sites parrotfish and grouper abundance declined by more than 50%, while coral cover and macroalgae‐coral ratio declined by at least 30%. This resulted in an Endangered threat status for coral reefs in Kenya (under criterion D of the RLE). The results can guide management actions related to 9 of the 23 GBF targets. For example, we identified several sites with relatively healthy benthic and fish communities as candidate areas for protection measures under Target 3. The RLE has a key role to play in monitoring and meeting the goals and targets of the GBF, and our work demonstrates how using the wealth of data within these assessments can inform local‐scale ecosystem management and amplify the GBF's impact. [ABSTRACT FROM AUTHOR]

Coral reefs are among the most sensitive ecosystems affected by ocean warming and acidification, and are predicted to collapse over the next few decades. Reefs are predicted to shift from net accreting calcifier-dominated systems with exceptionally high biodiversity to net eroding algal-dominated systems with dramatically reduced biodiversity. Here, we present a two-year experimental study examining the responses of entire mesocosm coral reef communities to warming (+2 ℃), acidification (-0.2 pH units), and combined future ocean (+2 ℃, -0.2 pH) treatments. Contrary to modeled projections, we show that under future ocean conditions, these communities shift structure and composition yet persist as novel calcifying ecosystems with high biodiversity. Our results suggest that if climate change is limited to Paris Climate Agreement targets, coral reefs could persist in an altered state rather than collapse. [ABSTRACT FROM AUTHOR]

ABSTRACT Coral reef ecosystems support high fish biodiversity through ecological interactions with structural complexity across multiple spatial scales including coral colony architecture and the surrounding seascape structure. In an era where the complexity of coral reef ecosystems is being diminished, understanding the importance of structural characteristics beyond single focal patches has the potential to better inform actions for protecting, restoring or creating habitat for reef‐associated species. A seascape ecology approach was applied to explore the associations between multiple scales of seascape structure and fish assemblage response variables within a small (49.6 km2) offshore no‐take MPA, Sir Bu Nair Island Protected Area, in Sharjah, United Arab Emirates. Fish–seascape associations were modelled with single regression trees. Both in situ and remote sensing–derived variables produced the best models with highest contributions from coral cover, amount of hard‐bottom habitat type and structural complexity of the seafloor terrain. Fish species richness was significantly higher where coral cover exceeded 35%. The hard‐bottom areas with coral supported diverse assemblages dominated by carnivorous and omnivorous fishes. The Sir Bu Nair Island Protected Area provides a critical refuge for threatened and regionally overexploited species including those with low resilience to fishing. The ecological success of this protected area is key to safeguarding regional marine biodiversity and recovering fish populations to enhance food security. [ABSTRACT FROM AUTHOR]

Background: Corals are the foundational species of coral reefs and coralligenous ecosystems. Their success has been linked to symbioses with microorganisms, and a coral host and its symbionts are therefore considered a single entity, called the holobiont. This suggests that there may be evolutionary links between corals and their microbiomes. While there is evidence of phylosymbiosis in scleractinian hexacorals, little is known about the holobionts of Alcyonacean octocorals. Results: 16S rRNA gene amplicon sequencing revealed differences in the diversity and composition of bacterial communities associated with octocorals collected from the mesophotic zones of the Mediterranean and Red Seas. The low diversity and consistent dominance of Endozoicomonadaceae and/or Spirochaetaceae in the bacterial communities of Mediterranean octocorals suggest that these corals may have a shared evolutionary history with their microbiota. Phylosymbiotic signals were indeed detected and cophylogeny in associations between several bacterial strains, particularly those belonging to Endozoicomonadaceae or Spirochaetaceae, and coral species were identified. Conversely, phylosymbiotic patterns were not evident in Red Sea octocorals, likely due to the high bacterial taxonomic diversity in their microbiota, but cophylogeny in associations between certain coral and bacterial species was observed. Noteworthy were the associations with Endozoicomonadaceae, suggesting a plausible evolutionary link that warrants further investigations to uncover potential underlying patterns. Conclusions: Overall, our findings emphasize the importance of Endozoicomonadaceae and Spirochaetaceae in coral symbiosis and the significance of exploring host-microbiome interactions in mesophotic ecosystems for a comprehensive understanding of coral-microbiome evolutionary history. [ABSTRACT FROM AUTHOR]

Characteristics such as calcareous morphology and life cycle are used to understand the ecology of calcified rhodophytes. However, there is limited information regarding their chemical profiles and biological activities. Therefore, a systematic review (PRISMA) was conducted to assess the influence of the chemistry of calcareous rhodophytes on ecological interactions in the marine environment. The keywords used were: ["Chemical AND [Ecology OR Interaction OR Response OR Defense OR Effect OR Cue OR Mediated OR Induce]"] AND ["Red Seaweed" OR "Red Macroalgae" OR Rhodophy?] AND [Calcified OR Calcareous] in Science Direct, Scielo, PUBMED, Springer, Web of Science, and Scopus. Only English articles within the proposed theme were considered. Due to the low number of articles, another search was conducted with three classes and 16 genera. Finally, 67 articles were considered valid. Their titles, abstracts, and keywords were analyzed using IRaMuTeQ through factorial, hierarchical and similarity classification. Most of the studies used macroalgae thallus to evaluate chemical mediation while few tested crude extracts. Some substances were noted as sesquiterpene (6-hydroxy-isololiolide), fatty acid (heptadeca5,8,11-triene) and dibromomethane. The articles were divided into four classes: Herbivory, Competition, Settlement/Metamorphosis, and Epiphytism. Crustose calcareous algae were associated with studies of Settlement/Metamorphosis, while calcified algae were linked to herbivory. Thus, the importance of chemistry in the ecology of these algae is evident,and additional studies are needed to identify the substances responsible for ecological interactions. This study collected essential information on calcified red algae, whose diversity appears to be highly vulnerable to the harmful impacts of ongoing climate change. [ABSTRACT FROM AUTHOR]

The coefficient of earth pressure at rest (K0) is a crucial parameter in geotechnical design. In this study, coral sands with various initial relative densities were subjected to K0 consolidation tests and consolidated-drained triaxial compression tests to investigate the impact of the relative density, stress level, and particle breakage on K0. Based on the Mohr–Coulomb failure law and experimental data, a formula for estimating K0 related to the effective stress and effective friction angle was proposed. The results revealed that the K0 of coral sand decreased with an increase in effective stresses, while the impact of the initial relative density on K0 was more obvious. At the same effective stress, the smaller the initial relative density was, the larger the K0 can be. In the tested stress range, minimal particle breakage was observed during the K0 consolidation, whereas a greater degree of particle breakage occurred during triaxial shear. This particle breakage has the potential to undermine the stress-dilatancy and interparticle locking characteristics in coral sands, leading to a diminished effective friction angle and potentially affecting K0. The proposed formula for estimating K0 can be expressed as a function of the effective stresses and effective friction angle, and the effect of initial relative density on K0 can be reflected by the function parameters. This formula provides a reasonable estimate of the K0 value for coral sand within a certain range of relative densities and stress levels. Furthermore, it demonstrates favorable applicability to other types of granular soils, such as quartz sand and rockfills. [ABSTRACT FROM AUTHOR]

The development of trait‐based approaches has accelerated our understanding of how communities assemble, respond to environmental change and may best be managed in the Anthropocene. Understanding the magnitude and pattern of interspecific variability forms a critical underpinning of trait‐based approaches while exploring intraspecific variability can identify the potential of species to adapt to changing environmental drivers. Our work is motivated by the critical need for a novel conceptual framework for understanding the functional ecology of macroalgae, as the current paradigm is still mired in functional group models developed in the 1980s.Our objective was to quantify interspecific and intraspecific functional trait variability in three common and morphologically diverse species of tropical marine macroalgae by exploring traits relating to the ecological functions of resource acquisition, resistance to herbivory, and resistance to physical disturbance and the trade‐offs between them.We quantified intraspecific and interspecific variability of 11 functional traits for three common and morphologically diverse species of tropical macroalgae from five fringing reefs of Mo'orea, French Polynesia that were likely to capture a wide range of environmental variability. Differences in traits among species and sites were determined with PERMANOVA, visualised with non‐metric multidimensional scaling, and trade‐offs between pairs of traits explored with correlation. Finally, spatial patterns among select traits across all species were quantified.Species clustered together in distinctly different trait spaces driven by trade‐offs among suites of functional traits. Two of three species had considerable intraspecific variability, though this variability occurred at different scales, while one clustered tightly. Exploration of individual traits across species and sites revealed trade‐offs between two strategies for resource acquisition, growing tall and strong versus investing in large surface area.Synthesis. We captured novel patterns of interspecific and intraspecific variability for tropical marine macroalgae. We found fundamental differences in traits between species that may represent ecological strategies while considerable intraspecific variability demonstrates a wide range in abilities to respond to environmental drivers. Overall, our work provides novel insights into intra and interspecific trait variation that form an essential underpinning for using a trait‐based framework in a taxon that is increasingly dominant on tropical reefs. [ABSTRACT FROM AUTHOR]

The die‐off of the long‐spined sea urchin Diadema antillarum in the 1980s highlighted its crucial role as a primary grazer in tropical western Atlantic coral reefs. However, natural recovery has been slow, exacerbated by a new die‐off in 2022. Interest in actively restoring D. antillarum populations has grown with the emergence of culture and rearing techniques. Restocking reefs with laboratory‐reared urchins shows potential for enhancing coral reef resilience by reducing algal cover and promoting coral settlement, but success rates vary. Predation and migration contribute to low retention rates, with distinguishing between them is challenging. In this study near Saba, Caribbean Netherlands, we released 200 laboratory‐reared D. antillarum on a reef and monitored for D. antillarum retention and potential D. antillarum predator presence and interaction for 35 days. Only 40% of the urchins were still present on the reef after day one. The Spanish hogfish Bodianus rufus was identified as the primary daytime predator, responsible for nine direct predation events. No nighttime predation was observed, but interaction with a batwing coral crab Carpilius corallinus was noted. These insights can help optimize future restocking attempts and emphasize the importance of assessing predator presence beforehand. Reefs with high abundances of predators such as Spanish hogfish should be avoided for D antillarum restocking. In addition, before being released, lab‐reared animals should be given time to acclimate to conditions in the wild by being placed in protected in situ cages. Here, they could also grow to larger sizes that are less vulnerable to predation. [ABSTRACT FROM AUTHOR]

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]

Root piles exhibit favorable bearing characteristics, rendering them suitable for the foundation of offshore wind power facilities to withstand uplift loads. This study compared the uplift load bearing advantages of root piles to those of equal diameter piles in coral sand foundations. Additionally, it analyzed the effects of relative foundation compaction on the uplift load bearing characteristics of root piles. The tests involved comparing root piles and equal diameter piles in coral sand foundations with relative foundation compaction levels of 0.5, 0.6, 0.7, and 0.8. The results indicate that root piles possess a 62.5% higher pullout capacity than equal diameter piles, with only a 10.7% increase in uplift displacement. As relative compaction increases, the pullout ultimate capacity of root piles initially rises rapidly and then levels off, while the corresponding uplift displacement experiences a sharp decline followed by a relatively stable state. With the increase of relative compaction, the location of the maximum attenuation of axial force and the maximum lateral friction resistance in the root region started to move deeper only under larger loads. Both the implementation of root piles and an increase in relative compaction greatly enhance the pile foundation's ability to resist pullout forces and control deformation. [ABSTRACT FROM AUTHOR]

Pro-environmental media content, such as nature documentary programming, often features awe-inducing scenes of Earth's natural beauty, and exposure to this kind of content has been shown to increase persuasive outcomes. Yet environmental messaging is increasingly likely to portray the tragic impacts of human activities on these natural wonders alongside content about Earth's beauty. How might emotional responses evolve during exposure to sequenced messages that juxtapose positively-valenced (beauty) and negatively-valenced (negative impacts) pro-environmental content? Embracing an emotional flow perspective as our overarching lens, we put forth two accounts for how emotions might shift during sequenced messaging: contrast effects and the elicitation of poignancy. We tested these accounts in a between-subjects experiment with U.S. adults (N = 979), following a 5 (focus: beauty-only, impacts-only, beauty→impacts, impacts→beauty, or control) × 2 (topic: coral reefs or forests) design. We found no evidence for contrast effects in discrete emotion intensity (awe, hope, sadness, or fear). The sequenced messages evoked greater poignancy than the static messages, which in turn predicted greater intentions to share the message. Although the sequenced messages indirectly predicted sharing intentions and policy support via several other emotion-based mechanisms, these outcomes did not differ between the static and sequenced conditions. [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]

With the continuous advancement of marine engineering and coral reef construction, the construction process of using coral reefs and sand as aggregate to make concrete or mortar came into being. Therefore, this study delves into the impact of aggregate type, water–cement ratio (W/C), and sand–cement ratio (S/C) on the workability, shrinkage, and mechanical properties of mortar. Simultaneously, it uses microscopic techniques to elucidate the mechanisms underlying the impact of aggregate type, W/C , and S/C on mortar performance. The results demonstrate that the S/C of coral mortar should be controlled at 1.5–2. The self-shrinkage and drying shrinkage values of coral mortar decrease progressively with higher S/C and increase with increasing W/C. Coral mortar exhibits a smaller self-shrinkage than ordinary mortar. Unlike self-shrinkage, the early drying shrinkage of coral mortar is less than that of ordinary mortar. However, as time progresses, the drying shrinkage of coral mortar becomes notably greater than that of ordinary mortar. The flexural and compressive strengths of coral mortar are inferior to those of ordinary mortar. Coral mortar experiences transcrystalline fracture, in contrast to the intergranular failure observed in ordinary mortar. Moreover, strength exhibits a quadratic power function correlation with the S/C and a negative linear correlation with the W/C. In addition, the construction technology for coral mortar differs from that of ordinary mortar. [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]

Indonesia has a vast marine area with numerous coral reefs located at the center of the global coral triangle, which is crucial for aquatic life. However, these coral reefs face severe threats from climate change, pollution, rising sea temperatures, and human activities. Currently, 85% of Indonesia's coral reefs are at risk. Therefore, monitoring and preserving coral reefs are essential for the sustainability and health of the ocean. Technology such as Convolutional Neural Networks (CNN), which monitor and classify coral reef conditions, is highly beneficial in addressing these challenges. This study shows that the optimization method based on swarm optimization, namely Particle Swarm Optimization (PSO) influenced by declining weighting, effectively improves the performance of CNN by determining the best values for each parameter in the CNN for classifying coral reef conditions. The optimized parameters include Epoch, Dropout, Hidden Size, Learning Rate, Activation Function, and Optimizer. The experimental results indicate that the best parameter values produced by the proposed are Epoch of 9, Dropout of 0.2, Hidden Size of 256, Learning Rate of 0.002, Activation Function as ReLU, and Optimizer as Adam. The proposed shows more consistent and stable performance compared to the Original PSO and Original GWO (Grey Wolf Optimizer) methods, achieving a maximum training accuracy of 82.23% and a testing accuracy of 79.74%. This indicates that the proposed can be considered more reliable and effective for parameter optimization in classifying coral reefs using CNN. [ABSTRACT FROM AUTHOR]

Implementation of coral restoration practices within reef management strategies is accelerating globally to support reef resilience and recovery. However, full costs underpinning restoration project feasibility have historically been underreported yet are critical to informing restoration cost-benefit decision-making. Such knowledge is especially lacking for Australia's Great Barrier Reef (GBR), where a coral restoration program led by reef tourism operators, Coral Nurture Program (CNP), was initiated in 2018 (northern GBR) and continues to scale. Here we describe the early outcomes and costs of implementing similar tourism-led asexual coral propagation and outplanting practices in a new region, the Whitsundays (central GBR) through the CNP. Specifically, we detail the local operational and environmental context of CNP Whitsundays, describe the costs of implementation and continuation of restoration activities, as well as evaluate survivorship of coral outplants across three restoration sites for nine months after project establishment (August 2022 to June 2023). Baseline benthic surveys revealed relatively low hard coral cover at restoration sites (ranging from 3.22-8.67%), which significantly differed in benthic composition from coral collection sites (ranging 16.67-38.06%), supporting strong motivation by tourism operators to undertake restoration activities. Mean coral survivorship of coral outplants in fate-tracked plots differed between the three restoration sites after 267 days (ranging 23.33-47.58%), with declines largely driven by coral detachment. Early-stage cost-effectiveness (costs relative to outplant survival) associated with implementation of restoration activity varied widely from US$33.04-178.55 per surviving coral (n = 4,425 outplants) depending on whether 'in-kind' costs, restoration activity (outplanting only vs. total costs encompassing planning through to monitoring), site-based survivorship, or a combination of these factors, were considered. As coral reef restoration projects continue to be established globally, our results highlight the need for ongoing, long-term monitoring that can inform adaptive practice, and fully transparent costreporting to understand and improve feasibility for any given project. We further highlight the inherent context-dependency of restoration costs, and the importance of considering local social-environmental contexts and their associated cost-benefits in economic rationale for reef restoration projects. [ABSTRACT FROM AUTHOR]

AbstractPorous coral reef limestone (CRL) is characterized by the low strength and developed pore structure, so improving its physico-mechanical properties is important for marine engineering construction work. Chemically consolidated porous CRL was prepared by taking a non-granular chemical grout (sodium silicate) as the main consolidation material. Then, the chemical consolidation effect was evaluated from two aspects (both the physical and mechanical properties) by conducting computed tomography (CT) scanning and quasi-static uniaxial compression tests. The results indicate that the consolidation material can fill the pores in the CRL, which reduces the porosity of specimens by more than 50%. In addition, the peak strength under quasi-static compression is increased by about 20%. The fragments decrease at failure, and fracture plane slip and crack opening are inhibited. Finally, influences of the special banded shape of consolidation material retained in the specimens on the failure process and failure mode of specimens were investigated. The chemical consolidation mechanism of porous CRL was revealed by combining with the scanning electron microscope (SEM) images. Research results indicate that the non-granular chemical material (sodium silicate) improves the physico-mechanical properties of porous CRL. The research provides reference for the foundation treatment in coral reefs and the design of consolidation schemes for surrounding rocks of underground spaces in marine engineering operations. [ABSTRACT FROM AUTHOR]

Reproduction, embryological development, and settlement of corals are critical for survival of coral reefs through larval propagation. Yet, for many species of corals, a basic understanding of the early life‐history stages is lacking. In this study, we report our observations for ex situ reproduction in the massive reef‐building coral Porites cf. P. lobata across 2 years. Spawning occurred in April and May, on the first day after the full moon with at least 2 h of darkness between sunset and moonrise, on a rising tide. Only a small proportion of corals observed had mature gametes or spawned (14–35%). Eggs were 185–311 μm in diameter, spherical, homogenous, and provisioned with 95–155 algal cells (family Symbiodiniaceae). Males spawned before females, and ex situ fertilization rates were high for the first 2 h after egg release. Larvae were elliptical, ~300 μm long, and symbiotic. Just 2 days after fertilization, many larvae swam near the bottom of culture dishes and were competent to settle. Settlers began calcification 2 days after metamorphosis, and tentacles were developed 10 days after attachment. Our observations contrast with previous studies by suggesting an abbreviated pelagic larval period in Porites cf. P. lobata, which could lead to the isolation of some populations. The high thermal tolerance and broad geographic range of Porites cf. P. lobata suggest that this species could locally adapt to a wide range of environmental conditions, especially if larvae are locally retained. The results of this study can inform future work on reproduction, larval biology, dispersal, and recruitment in Porites cf. P. lobata, which could have an ecological advantage over less resilient coral species under future climate change. [ABSTRACT FROM AUTHOR]

Coral reconstruction often serves as a major proxy of high-resolution sea surface temperature (SST) variability beyond the instrumental era. However, coral reconstructions are sparse and are usually studied for interannual variability, with few studies on the monthly features. In this study, we reconstruct the monthly SST spatial field by applying the paleoclimate data assimilation method to the coral records of the latest CoralHydro2k data set for the instrument period of 1880–2000. A comparison with observed SST variability shows that our assimilated tropical SST variability performs reasonably well for the seasonal cycle and monthly ENSO characteristics, notably the phase-locking and onset timing, and more realistic spatial fields relative to the model simulations. This study suggests the feasibility of applying paleoclimate data assimilation to reconstruct the monthly SST in the historical period. [ABSTRACT FROM AUTHOR]

Background: Extensive research on the diversity and functional roles of the microorganisms associated with reef-building corals has been promoted as a consequence of the rapid global decline of coral reefs attributed to climate change. Several studies have highlighted the importance of coral‐associated algae (Symbiodinium) and bacteria and their potential roles in promoting coral host fitness and survival. However, the complex coral holobiont extends beyond these components to encompass other entities such as protists, fungi, and viruses. While each constituent has been individually investigated in corals, a comprehensive understanding of their collective roles is imperative for a holistic comprehension of coral health and resilience. Results: The metagenomic analysis of the microbiome of the coral Oculina patagonica has revealed that fungi of the genera Aspergillus, Fusarium, and Rhizofagus together with the prokaryotic genera Streptomyces, Pseudomonas, and Bacillus were abundant members of the coral holobiont. This study also assessed changes in microeukaryotic, prokaryotic, and viral communities under three stress conditions: aquaria confinement, heat stress, and Vibrio infections. In general, stress conditions led to an increase in Rhodobacteraceae, Flavobacteraceae, and Vibrionaceae families, accompanied by a decrease in Streptomycetaceae. Concurrently, there was a significant decline in both the abundance and richness of microeukaryotic species and a reduction in genes associated with antimicrobial compound production by the coral itself, as well as by Symbiodinium and fungi. Conclusion: Our findings suggest that the interplay between microeukaryotic and prokaryotic components of the coral holobiont may be disrupted by stress conditions, such as confinement, increase of seawater temperature, or Vibrio infection, leading to a dysbiosis in the global microbial community that may increase coral susceptibility to diseases. Further, microeukaryotic community seems to exert influence on the prokaryotic community dynamics, possibly through predation or the production of secondary metabolites with anti-bacterial activity. 5jxNwVcR-vUc4t1YJ-ryph Video Abstract [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]

Coral reefs are facing threats from a variety of global change stressors, including ocean warming, acidification, and deoxygenation. It has been hypothesized that growing corals near primary producers such as macroalgae or seagrass may help to ameliorate acidification and deoxygenation stress, however few studies have explored this effect in situ. Here, we investigated differences in coral growth rates across a natural gradient in seawater temperature, pH, and dissolved oxygen (DO) variability in a nearshore seagrass bed on Dongsha Atoll, Taiwan, South China Sea. We observed strong spatial gradients in temperature (5°C), pH (0.29 pH units), and DO (129 μmol O2 kg-1) across the 1-kilometer wide seagrass bed. Similarly, diel variability recorded by an autonomous sensor in the shallow seagrass measured diel ranges in temperature, pH, and DO of up to 2.6°C, 0.55, and 204 μmol O2 kg-1, respectively. Skeletal cores collected from 15 massive Porites corals growing in the seagrass bed at 4 sites revealed no significant differences in coral calcification rates between sites along the gradients. However, significant differences in skeletal extension rate and density suggest that the dynamic temperature, pH, and/or DO variability may have influenced these properties. The lack of differences in coral growth between sites may be because favorable calcification conditions during the day (high temperature, pH, and DO) were proportionally balanced by unfavorable conditions during the night (low temperature, pH, and DO). Alternatively, other factors were simply more important in controlling coral calcification and/or corals were acclimated to the prevailing conditions at each site. [ABSTRACT FROM AUTHOR]

Summary Coral reefs directly support the well‐being of millions of people across Southeast Asia, however, these critical ecosystems are also under immense pressure, threatening their sustainability. Coral reef restoration has emerged as a promising strategy to contribute to safeguarding these critical ecosystems and securing the socioeconomic benefits they provide to local communities across the region. In this paper, we present the outcomes of a week‐long of deliberations between policymakers, research funders, practitioners and scientists from Indonesia, Philippines, Vietnam and Australia, which identified four strategies for building improved capacity for coral reef restoration in Southeast Asia; (i) the creation of a learning network, (ii) addressing critical research needs, (iii) improved approaches to communication and engagement to diverse audiences and (iv) the establishment of sustainable funding mechanisms. These strategies are discussed in detail with a view of providing a roadmap to help support coral reef restoration processes across Southeast Asia. [ABSTRACT FROM AUTHOR]

Out‐planting corals onto coral reefs as a mechanism to increase coral cover on degraded reef systems is an increasing global activity. Current practices typically focus on asexual out‐planting of coral fragments (coral gardening). Newer sexual reproductive approaches are being developed to out‐plant younger corals produced in aquaculture facilities or sea‐based rearing pools to enable assisted evolution or assisted gene flow conservation genetics approaches. Designing out‐planting deployment operations requires decisions to be made on planting density and location in order to maximize future recruitment on both the out‐planted reefs, and on nearby reefs that are connected through oceanographic transport processes. The thinking presented here seeks to unpack how out‐planting density may be influenced, especially by local oceanographic conditions, in order to guide practitioners undertaking restoration projects. [ABSTRACT FROM AUTHOR]

Florida's coral reefs are facing a multi-year outbreak of stony coral tissue loss disease (SCTLD) with dramatic consequences for coral communities. However, potential anthropogenic and environmental drivers of SCTLD progression and severity remain poorly understood. This study was designed to determine the potential impacts of nutrient amendments on the progression and spread of SCTLD on reefs in Southeast Florida. In situ fertilizer amendments with 30 g of Osmocote™ slow-release fertilizer were used to mimic the effects of agricultural and urban runoff. Fifteen healthy and thirty SCTLD-affected Montastraea cavernosa coral colonies were tagged and divided into three experimental groups: apparently healthy colonies, SCTLD-affected nutrient-amended colonies, and SCTLD-affected control colonies. SCTLD lesion progression, coral tissue loss, and disease prevalence were tracked over a 30-day nutrient amendment period and for an additional 40 days after nutrient amendment removal to determine if there were any latent or recovery effects. Coral tissue loss was tracked over time using Structure-from-Motion photogrammetry and disease prevalence was recorded from diver surveys within a 3-m radius surrounding five centroid colonies from each experimental group. Throughout the experiment, temperature, nutrient concentrations, and SCTLD status of the coral colonies were also monitored. Ultimately, we observed no significant differences in SCTLD progression or surrounding SCTLD prevalence between the nutrient-amended and control groups, suggesting that nutrient amendment had no effect on SCTLD severity during this experiment in Southeast Florida. [ABSTRACT FROM AUTHOR]

Coral reef limestone is a unique type of rock and soil body characterized by high porosity. Its dynamic mechanical properties under impact loads differ significantly from those of conventional land-sourced aggregate concrete.This study utilizes coral reef limestone as both coarse and fine aggregates to prepare C40 strength concrete. The research investigates the effects of dry-wet carbonation cycles on its dynamic mechanical behavior and energy evolution characteristics using a Split Hopkinson Pressure Bar (SHPB) mechanical testing system.The findings reveal that increasing the number of dry-wet carbonation cycles leads to a significant weakening of the internal structural bonding in coral reef limestone concrete. Notably, the degree of phenolphthalein color change diminishes, while uniaxial compressive strength and tensile strength demonstrate an overall downward trend. The reduction in tensile strength is less pronounced than the decrease in compressive strength. Additionally, the relative dynamic elastic modulus gradually decreases, and a size effect is noted, with a rapid acceleration in mass loss. As the number of dry-wet carbonation cycles increases, dynamic compressive strength declines, and failure modes shift from surface cracking to crush-type failure.The dynamic increase factor (DIF) of the coral reef limestone concrete indicates a high sensitivity to strain rate, with a significant rise in DIF value as the strain rate increases. Various energies generated under impact load exhibit clear strain rate effects. Furthermore, the effects of dry-wet carbonation cycling enhance energy dissipation, especially at 30 cycles, where energy dissipation increases sharply, while a hindering effect on transmitted energy is observed. [ABSTRACT FROM AUTHOR]

Accurately identifying tropical fish serves as a crucial indicator, offering an insight into the state of marine biodiversity and the condition of coral reef ecosystems. However, the current detection networks are prone to omission and misidentification due to occlusion between fish and the complex underwater environment. This paper proposes a modified approach named FishFocusNet, in which alterable kernel convolution modules, asymptotic feature pyramid network (AFPN), and Shape‐IoU are integrated into YOLOv8. To extract a more comprehensive set of fish features, AKConv modules with arbitrary kernel sizes are proposed to take the place of the conventional fixed‐shaped kernels in the backbone for downsampling. AFPN is adopted as the feature integration structure in the neck, which enhances feature fusion and adaptive spatial fusion between non‐adjacent layers. In the detector head, Shape‐IoU is employed to achieve precise localization of fish targets. The superiorities of these modifications are proved by ablation experiments and comparative experiments. The experimental results show that the optimized approach obtained an mAP of 81.8% accompanied by 2.4 MB parameters and 3.6 GB FLOPS. Meanwhile, compared with more complicated models of similar scale, the proposed method can enhance recognition accuracy to 84.2% and significantly reduce computational costs. [ABSTRACT FROM AUTHOR]

Understanding how coral reefs respond to disturbances is fundamental to assessing their resistance and resilience, particularly in the context of climate change. Due to the escalating frequency and intensity of coral bleaching events, it is essential to evaluate spatio-temporal responses of coral reef communities to disentangle the mechanisms underlying ecological changes. Here, we used benthic data collected from 59 reefs in the Red Sea over five years (2014–2019), a period that encompasses the 2015/2016 mass bleaching event. Reefs were located within three different geographic regions with different environmental settings: north (Duba; Al Wajh), central (Jeddah; Thuwal), and south (Al Lith; Farasan Banks; Farasan Islands). Coral community responses were region-specific, with communities in the south being more promptly affected than those in the northern and central regions, with hard and soft coral cover dropping drastically in several reefs from around > 40% to < 5% two years after bleaching. Coral bleaching effects were particularly evident in the decrease of cover in branching corals. Overall, we documented a shift towards a dominance of macroalgae, turf algae, and crustose coralline algae (CCA). Using remote sensing data, we analyzed sea surface temperature (SST) regimes at the study sites to infer potential drivers of changes in benthic composition. Both SST and Degree Heating Weeks (DHW) only partially aligned with the responses of benthic communities, highlighting the need for more accurate predictors of coral bleaching in the Red Sea. In times of intense coastal development along Saudi Arabia's Red Sea coast, our study provides crucial baseline information on developments in coral reef community composition, as well as to guide decision-making, namely restoration efforts. [ABSTRACT FROM AUTHOR]

Coral microbiomes play crucial roles in holobiont homeostasis and adaptation. The host's ability to populate broad ecological niches and to cope with environmental changes seems to be related to the flexibility of the coral microbiome. By means of high-throughput DNA sequencing we characterized simultaneously both bacterial (16S rRNA) and Symbiodiniaceae (ITS2) communities of four reef-building coral species (Mussismilia braziliensis, Mussismilia harttii, Montastraea cavernosa, and Favia gravida) that differ in geographic distribution and niche specificity. Samples were collected in a marginal reef system (Abrolhos, Brazil) in four sites of contrasting irradiance and turbidity. Biological filters governed by the host are important in shaping corals' microbiome structure. More structured associated microbial communities by reef site tend to occur in coral species with broader geographic and depth ranges, especially for Symbiodiniaceae, whereas the endemic and habitat-specialist host, M. braziliensis, has relatively more homogenous bacterial communities with more exclusive members. Our findings lend credence to the hypothesis that higher microbiome flexibility renders corals more adaptable to diverse environments, a trend that should be investigated in more hosts and reef areas. [ABSTRACT FROM AUTHOR]

Cold-water corals form vast reefs that are highly valuable habitats for diverse deep-sea communities. However, as the deep ocean is warming, it is essential to assess the resilience of cold-water corals to future conditions. The effects of elevated temperatures on the cold-water coral Lophelia pertusa (now named Desmophyllum pertusum) from the north-east Atlantic Ocean were experimentally investigated at the holobiont level, the coral host, and its microbiome. We show that at temperature increases of + 3 and + 5 °C, L. pertusa exhibits significant mortality concomitant with changes in its microbiome composition. In addition, a metagenomic approach revealed the presence of gene markers for bacterial virulence factors suggesting that coral death was due to infection by pathogenic bacteria. Interestingly, different coral colonies had different survival rates and, colony-specific microbiome signatures, indicating strong colony-specific variability in their response to warming waters. These results suggest that L. pertusa can only survive a long-term temperature increase of < 3 °C. Therefore, regional variations in deep-sea temperature increase should be considered in future estimates of the global distribution of cold-water corals. [ABSTRACT FROM AUTHOR]

This study analyzed the horizontal and vertical distribution characteristics of temperature and salinity in the central and eastern regions of the Beibu Gulf, based on conductivity measurements in summer 2022, temperature, and depth (CTD) measurement data from the Sino–Vietnamese cooperative project "Demonstration Study on Ecological Protection and Management in Typical Bays: Seasonal Survey of the Beibu Gulf". Furthermore, the study utilized the computational results from the numerical Finite-Volume Coastal Ocean Model (FVCOM) to elucidate the intrinsic patterns that formed the temperature and salinity distribution characteristics in August 2022 from both thermodynamic and dynamic perspectives. The circulation in the Beibu Gulf drives external seawater to move northward from the bay mouth. During this movement, numerous upwelling areas are created by lateral Ekman transport. The formation of different scales of cyclonic and anticyclonic vortices and current convergence zones is influenced by topography, runoff, and the water flux from the Qiongzhou Strait, which are key factors in the formation of upwelling and downwelling. The surface circulation in August 2022 significantly differed from the 20-year average surface circulation, with an influx of 1.15 × 104 m3/s more water entering the Beibu Gulf compared to the multi-year average. The water flux from the Qiongzhou Strait is a critical factor affecting the circulation patterns in the Beibu Gulf. The northeastern waters of the Beibu Gulf are characterized by current convergence zones, where extensive upwelling occurs. The rich nutrient salts in these areas promote the reproduction and growth of phytoplankton and zooplankton, making this the most favorable ecological environment in the Beibu Gulf and serving as a natural reserve for fisheries, coral reefs, dugongs, and Bryde's whales. [ABSTRACT FROM AUTHOR]

Introduction: Predictive models based on environmental proxy data are being used to predict biodiversity on large and even global scales. Yet, some of the underlying assumptions about the relationship between proxy variables and predictions require investigations and testing the consequences of using model alternatives, data sources, variables choices, and scales, extent, and overlap among the predictions. Mozambican coral reefs provide a good case study to test these assumptions given the paucity of field data, its long coastline, and transitions from tropical to temperate environments. Methods: Three modelling formulations and 5 specific models were made using satellite and shipboard measurements and extensive fish and corals field data to test their performance in predicting numbers of fish species and coral taxa from field data. Model predictions were mapped for the 1180 ~6.25 km[sup 2] Mozambican coral reef cells. Predictions were made and mapped 1) based on ~1000 field sites in the Western Indian Ocean (WIO) faunal province model, 2) using environmental variable selected in the WIO model (WIOMOD) but trained only with Mozambican field data (<113 sites), and 3) using only Mozambican environmental and field data and standard variable redundancy and selection procedures. Results and discussion: Training and testing cross validation of models indicated modest predictive ability (R[sup 2]~0.42-0.56%) and reasonable transferability. Consequently, there was unexplained variation likely due to small-scale environmental variability finer than the mapped cell scale. Differences between model predictions were caused by different variable rankings and response relationship. For example, the Mozambique-only model predicted more fish but fewer coral taxa, a larger role of water quality and sediments, habitats, and temperature variation, and a lesser role of human influence than the WIOMOD. Therefore, differences between models indicate that large scale models (i.e. provincial or global) can contribute to understanding gross patterns but miss important local environmental and human drivers in transitional environments. Nevertheless, 79% of the fish and 88% of coral taxa cell-level predictions of taxonomic diversity had standardized coefficients of variations of <10%. [ABSTRACT FROM AUTHOR]

The composition of coral-reef sediments is highly variable across space and time, and differences in the life histories of the dominant calcifying organisms on reefs contribute to the heterogeneity of reef sediments. Previous studies have suggested that variations in coral-reef bioerosion can influence spatial and temporal variations of sedimentary assemblages: elevated erosion rates of dead coral skeletons can trigger a pulse of coral-derived sediments and cause a shift in the dominance of sedimentary grains from coralline algae, such as Halimeda, to coral. We assessed the variability of the sedimentary composition and bioerosion rates of reefs at different spatial scales to determine the association between these two variables. We surveyed the benthic assemblages on reefs exhibiting different ecological states and collected samples of the associated sediments. We calculated the carbonate budget for each site and compared their variability at different hierarchical levels to the variability of their respective sedimentary assemblages. At the scale of sites (1–10 km), Halimeda cover was a significant predictor of the relative abundance of Halimeda grains. Both the relative abundance of coral grains and reef bioerosion rates varied significantly at the scale of locality (tens to hundreds of km), with high abundances of coral grains in the sediments coinciding with high rates of bioerosion. The main drivers of bioerosion at our localities were parrotfish assemblages dominated by large size classes of excavating species such as Sparisoma viride. Reef sediments may reflect the gross degree of bioerosion pressure that reefs experience, and historical changes in bioerosion rates could potentially be assessed by examining the sediments across temporal scales. [ABSTRACT FROM AUTHOR]

Promoting resilience is highly relevant to preserving biodiversity and ecosystem functioning. For coral reefs, parrotfish protection emerged as a mainstream action for reversing the degradation experienced by these systems. The rationale is that restoring their populations will increase grazing activity and reinforce control of fast‐growing macroalgae, facilitating coral cover recovery. A lack of a link between parrotfish trends and macroalgae and coral cover trends at a large scale has, however, often been the case. Suggesting more complex underlying dynamics that should be reexamined. In this review, we discuss how lumping parrotfish species as if they were functionally redundant may obscure trends. And how a lack of appreciation of other functions around the parrotfish paradigm, specifically bioerosion, may have unforeseen and potentially adverse effects on degraded reefs. We show that bioerosion responded more directly and quickly to spatial and temporal changes in parrotfish assemblages than macroalgae consumption, arguably due to the varying vulnerability among Caribbean parrotfishes to fisheries and habitat loss. For highly degraded reefs, positive changes in parrotfish populations could hence compromise the remaining coral skeleton structures and the reef framework, further accentuating reef degradation, where increases in macroalgae consumption could not necessarily compensate for higher rates of bioerosion. [ABSTRACT FROM AUTHOR]

The Halimedineae are marine green macroalgae that play crucial roles as primary producers in various habitats, including coral reefs, rocky shores, embayments, lagoons, and seagrass beds. Several tropical species have calcified thalli, which contribute significantly to the formation of coral reefs. In this study, we investigated the codon usage patterns and the main factors influencing codon usage bias in 16 chloroplast genomes of the suborder Halimedineae. Nucleotide composition analysis revealed that the codons of these species were enriched in A/U bases and preferred to end in A/U bases, and the distribution of GC content followed a trend of GC1 > GC2 > GC3. 30 optimal codons encoding 17 amino acids were identified, and most of the optimal codons and all of the over-expressed codons preferentially ended with A/U. The neutrality plot, effective number of codons (ENc) plot, and parity rule 2 (PR2) plot analysis indicated that natural selection played a major role in shaping codon usage bias of the most Halimedineae species. The genetic relationships based on their RSCU values and chloroplast protein-coding genes showed the closely related species have similar codon usage patterns. This study describes, for the first time, the codon usage patterns and characterization of Halimedineae chloroplast genomes, and provides new insights into the evolution of this suborder. [ABSTRACT FROM AUTHOR]

ABSTRACT The current rapid climate warming is expected to cause an ocean temperature increase of 3°C–5°C by 2100, leading to deoxygenated and acidified tropical seas. Without mitigation measures, the total loss of tropical corals is inevitable. Already, one‐third of tropical reefs are considered permanently lost. Coral bleaching initiated by the loss of symbionts, the photosynthetic zooxanthellae, is the main process whereby corals respond to thermal stress, followed by recovery. However, increased thermal stress and frequency of bleaching have caused widespread coral recovery failure. Zooxantheallae of the genus Symbiodinium are considered the thermally vulnerable part of the coral symbiosis. In recent decades, warming has displaced genotypes of lower thermal resilience to subtropical latitudes; few genotypes of higher temperature tolerance remain abundant in tropical seas, but these will not withstand warming predictions either. Interestingly, high temperatures in the Red Sea have selected for exceptionally heat‐resistant coral genotypes and for the highest known thermal resilience in endemic zooxanthellae at the same time. Actions to overcome the coral bleaching crisis have been proposed by combining coral ecophysiology and mass culturing of thermally resilient Red Sea symbionts for naturalisation to the global tropical ocean, including restoration of collapsed reefs using corals with thermally resilient symbiont genotypes. [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]

The Great Barrier Reef (GBR), Australia, has a long history of palaeoenvironmental coral research. However, it can be logistically difficult to find the relevant research and records, which are often unpublished or exist as "grey literature". This hinders researchers' abilities to efficiently assess the current state of coral core studies on the GBR and thus identify any key knowledge gaps. This study presents the Great Barrier Reef Coral Skeletal Records Database (GBRCD), which compiles 208 records from coral skeletal research conducted since the early 1990s. The database includes records from the Holocene, from ∼8000 years ago, to the present day; records are from the northern, central, and southern GBR from inshore and offshore locations. Massive Porites spp. coral records comprise the majority (92.5 %) of the database, and the remaining records are from Acropora, Isopora, or Cyphastrea spp. The database includes 78 variables, with Sr/Ca , U/Ca , and Ba/Ca being the most frequently measured. Most records measure data over 10 or more years and are at monthly or lower resolution. The GBRCD is machine readable and easily searchable so that users can find records relevant to their research, e.g. by filtering for site name, time period, or coral type. It is publicly available as comma-separated values (CSV) data and metadata files with entries linked by the unique record ID and as Linked Paleo Data (LiPD) files. The GBRCD is publicly available from the NOAA National Center for Environmental Information World Data Service for Paleoclimatology at 10.25921/hqxk-8h74 (Arzey et al., 2024). The intention is to update the GBRCD annually, depending on the availability of relevant new GBR records or submission of legacy records to the GBRCD for archiving. The collection and curation of existing GBR coral research data provide researchers with the ability to analyse common proxies such as Sr/Ca across multiple locations and/or examine regional to reef-scale trends. The database is also suitable for multi-proxy comparisons and combination or composite analyses to determine overarching changes recorded by the proxies. This database represents the first comprehensive compilation of coral records from the GBR. It enables the investigation of multiple environmental factors via various proxy systems for the GBR, northeastern Australia, and potentially the broader Indo-Pacific region. [ABSTRACT FROM AUTHOR]

Tropical reef ecosystems are strongly influenced by the composition of coral species, but the factors influencing coral diversity and distributions are not fully understood. Here we demonstrate that large variations in the relative abundance of three major coral species across adjacent Caribbean reef sites are strongly related to their different low O2 tolerances. In laboratory experiments designed to mimic reef conditions, the cumulative effect of repeated nightly low O2 drove coral bleaching and mortality, with limited modulation by temperature. After four nights of repeated low O2, species responses also varied widely, from > 50% bleaching in Acropora cervicornis to no discernable sensitivity of Porites furcata. A simple metric of hypoxic pressure that combines these experimentally derived species sensitivities with high‐resolution field data accurately predicts the observed relative abundance of species across three reefs. Only the well‐oxygenated reef supported the framework‐building hypoxia‐sensitive Acropora cervicornis, while the hypoxia‐tolerant weedy species Porites furcata was dominant on the most frequently O2‐deplete reef. Physiological exclusion of acroporids from these O2‐deplete reefs underscores the need for hypoxia management to reduce extirpation risk. [ABSTRACT FROM AUTHOR]

Microplastic pollution is an emerging stressor of concern to coral reef ecosystems, which are already threatened by additional global and local level anthropogenic stressors. The effects of ingesting microplastics alone on corals have been well studied, but the effects of the chemical composition of these particles have been understudied. Many microplastic-associated chemicals are endocrine disrupters potentially posing a threat to organismal reproduction. Therefore, the goal of this study was to determine if differences exist between the effects of microplastics themselves and microplastic leachate on Montipora capitata fertilization due to changes in fatty acid quantity and composition. Assays were conducted two years in a row which exposed M. capitata gamete bundles to either one of four types of recently manufactured, virgin microspheres (nylon, polypropylene, high-density polyethylene, or low-density polyethylene) at three concentrations (50, 100, or 200 particles/L) or microplastic leachates, presumably including plastic additives from these microspheres. Gamete fertilization was not impacted by microplastic particles themselves, but some of the microplastic leachate treatments with the same polymer type significantly reduced fertilization rates for M. capitata. Additionally, a total of 17 fatty acids were seen in both years, but neither fatty acid quantity nor composition correlated with observed declines in fertilization. Instead, fertilization and fatty acid data independently varied by concentration and polymer type, likely due to the presence of different chemicals. This study is the first to directly test the toxicity of microplastic leachate to coral reproduction. These findings show that microplastic-associated chemicals are an important stressor affecting successful coral fertilization and fatty acid quantity and composition and provide evidence for the negative effects of microplastic leachate to coral reproduction. Thus, plastic additives could pose an additional threat to coral replenishment and persistence in coral reef ecosystems. [ABSTRACT FROM AUTHOR]

Coral reefs are at risk due to various global and local anthropogenic stressors that impact the health of reef ecosystems worldwide. The most recent climate models predict that climate change will increase the frequency and intensity of tropical storms. This increased storm occurrence and strength will likely compromise coral reef structures and habitats for reef-dwelling organisms, including across the Florida Keys Reef Tract (FKRT), the most extensive tropical reef system along the US coast. While several recent studies reveal the chronic impacts of tropical storms on corals, relatively little is known about the effects of major storm events on coral growth and how these effects vary over spatiotemporal scales. Here, I characterize the skeletal growth of two common Caribbean reef-building coral species, Siderastrea siderea and Pseudodiploria strigosa , before and after Hurricane Irma to investigate the storm's impact on coral skeletal growth on inner and outer reefs of the FKRT. Coral cores were extracted from both species at four inner and four outer reef sites in May 2015, before Hurricane Irma struck the Florida Keys in September 2017. Subsequently, 33 micro-cores were collected in May 2019, two years after the storm traversed our previously cored coral colonies. A three-way ANOVA model with storm, species, and reef location as the three factors was used to assess the impact of the storm on each of three growth parameters: skeletal density, linear extension, and calcification rates. Results reveal no difference in the coral annual skeletal growth parameters pre- and post-Hurricane Irma, although previously quantified differences in these growth parameters across species and location were observed. However, analysis of the "yearly" change in annual skeletal growth parameters showed significant differences in skeletal density across groups before and after Hurricane Irma, but not for linear extension and calcification rates. Our findings improve an understanding of the impacts of tropical storms on coral skeletal growth and offer new insights into how we can employ corals' innate growth capacities to help conserve coral reefs under climate change. [ABSTRACT FROM AUTHOR]

Global ocean warming is affecting keystone species distributions and fitness, resulting in the degradation of marine ecosystems. Coral reefs are one of the most diverse and productive marine ecosystems. However, reef-building corals, the foundational taxa of coral reef ecosystems, are severely threatened by thermal stress. Models predict 40–80% of global coral cover will be lost by 2100, which highlights the urgent need for widespread interventions to preserve coral reef functionality. There has been extensive research on coral thermal stress and resilience, but 95% of studies have focused on adult corals. It is necessary to understand stress during early life stages (larvae, recruits, and juveniles), which will better inform selective breeding programs that aim to replenish reefs with resilient stock. In this review, we surveyed the literature on coral thermal resilience in early life stages, and we highlight that studies have been conducted on relatively few species (commonly Acropora spp.) and in limited regions (mainly Australia). Reef-building coral management will be improved by comprehensively understanding coral thermal resilience and fitness across life stages, as well as in diverse species and regions. [ABSTRACT FROM AUTHOR]

Coral mucus, teeming with organic matter, releases nutrients and microorganisms, affecting element cycling and microbial communities in coral reefs. While terrestrial ecosystems exhibit well‐studied priming effects from root exudates, the influence of mucus in marine environments, particularly in coral reefs, remains underexplored. We hypothesize that coral mucus, through its nutrients and microbes, stimulates the surrounding microorganisms, regulating carbon metabolism and thus contributing to high coral reef productivity. Initially, natural samples (Acropora pruinosa mucus, seawater, and sediment) were collected for metagenomic assessment of microbial communities and functions. Results showed significant differences in microbial diversity, community structures, co‐occurrence modes, and unique functions among mucus, seawater, and sediment. Subsequent laboratory experiments demonstrated mucus's substantial influence on surrounding microorganisms. Analyses, including 16S rRNA sequencing and Eco‐plate results, revealed that mucus regulates microbial composition and activities. Quantitative gene‐chip analysis showed significant increase in the functional genes related to carbon fixation (e.g., the 3‐hydroxypropionate cycle) and degradation (e.g., pectin and hemicellulose hydrolysis) by 55.81% and 65.48%, respectively. Partial least squares path modeling identified mucus nutrients and microbial community composition as key contributors to carbon metabolic potential. This research confirms that mucus acts as a trigger, reshaping microbial profiles around corals and enhancing carbon utilization efficiency, highlighting its essential role in carbon metabolism and the maintenance of high productivity in coral reef ecosystems. [ABSTRACT FROM AUTHOR]

Algal turf on coral reefs can transition from short productive forms to longer less productive forms that often form a persistent degraded state. We evaluated whether adjacent communities, such as stands of the macroalga Turbinaria ornata, can drive these transitions in Moorea, French Polynesia. We first found that T. ornata stands that overhang turf reduced growth as restricting canopy movement increased turf height compared to controls, implying an overhanging T. ornata canopy shades or abrades adjacent turf. Second, we manipulated T. ornata presence (intact/completely removed) and herbivore access (uncaged/caged) and found that, in the presence of herbivores, removal of stands reduced the height of adjacent turf compared to plots adjacent to intact Turbinaria stands. The presence of intact stands also deterred grazing, demonstrating they provide a refuge for adjacent turf. Thus, algal turf derives both benefits and costs of proximity to macroalgal stands. It is imperative to explore the relative strengths of these costs and benefits as these interactions may drive local transitions to degraded algal states. [ABSTRACT FROM AUTHOR]

The elemental composition of coral skeletons supplies essential information about palaeoceanographic reconstructions. The present work aims to optimize the neutron activation analysis (NAA) protocol for determining Ca-substituting elements in coral skeletons, which can be considered as a potential indicator for reconstructing past climate variability. Conventional and epithermal NAA schemes have been applied to determine 22 elements. The results reveal that the use of epithermal NAA significantly improved the limits of detection, up to 10 times, for specific elements, e.g. As, Ba, Cd, Mn, Sr, etc. The Compton suppression counting regime yielded an additional improvement in the limits of detection. [ABSTRACT FROM AUTHOR]

Describing living community compositions is essential to monitor ecosystems in a rapidly changing world, but it is challenging to produce fast and accurate depiction of ecosystems due to methodological limitations. Morphological methods provide absolute abundances with limited throughput, whereas metabarcoding provides relative abundances of genes that may not correctly represent living communities from environmental DNA assessed with morphological methods. However, it has the potential to deliver fast descriptions of living communities provided that it is interpreted with validated species‐specific calibrations and reference databases. Here, we developed a quantitative approach to retrieve from metabarcoding data the assemblages of living large benthic foraminifera (LBF), photosymbiotic calcifying protists, from Indonesian coral reefs that are under increasing anthropogenic pressure. To depict the diversity, we calculated taxon‐specific correction factors to reduce biological biases by comparing surface area, biovolume and calcite volume, and the number of mitochondrial gene copies in seven common LBF species. To validate the approach, we compared calibrated datasets of morphological communities from mock samples with bulk reef sediment; both sample types were metabarcoded. The calibration of the data significantly improved the estimations of genus relative abundance, with a difference of ±5% on average, allowing for comparison of past morphological datasets with future molecular ones. Our results also highlight the application of our quantitative approach to support reef monitoring operations by capturing fine‐scale processes, such as seasonal and pollution‐driven dynamics, that require high‐throughput sampling treatment. [ABSTRACT FROM AUTHOR]