Search

Earth's ecological assemblages are rapidly being driven towards unprecedented, novel states. We know little about ecological novelty in our oceans, limiting our ability to detect, contextualise, and manage substantive anthropogenic change. This is especially true for novel states with altered functional compositions. Here, we provide a quantitative assessment of taxonomic and functional ecological novelty in historical coral communities across the east Australian coast, capturing changes in the composition of coral taxa and their traits over the past 1500 years. Taxonomically novel communities emerged more frequently and often unaccompanied by substantial trait compositional change while functional novelty was commonly observed alongside significant genus turnover. Novel coral communities themselves were rare, context‐dependent, and often associated with transitions in dominant genera. Our preliminary trait‐based community classifications complement classical taxonomic methods to uncover a history of ecological change in east Australian coral communities, helping provide important context for their present states and inform future responses under ongoing and intensifying human‐driven change. [ABSTRACT FROM AUTHOR]

Ecologists have long sought general explanations for the co‐occurrence of ecologically similar taxa. Niche theory explains co‐occurrence via functional differences among taxa that reduce competition and promote resource partitioning. Alternatively, the unified neutral theory of biodiversity and biogeography suggests that co‐occurrence can be attributed to stochastic processes, and thus, presupposes that ecologically similar species that occur in sympatry are functionally analogous. We test these hypotheses using the most diverse crustacean‐sea anemone symbiosis from coral reefs in the Tropical Western Atlantic. δ13C and δ15N stable isotope analyses of six crustacean symbionts that co‐occur around the host anemone Bartholomea annulata exhibit highly differentiated isotopic niche space spanning several trophic levels. As multiple crustacean species within the symbiosis have been documented as cleaners that remove parasites from reef fishes, we extended our investigation into the broader cleaner community. Our stable isotope analyses of cleaners shows that Pederson's cleaner shrimp Ancylomenes pedersoni exhibits the highest δ15N isotopic values‐ significantly higher than all other putative cleaner species and consistent with expectations of a dedicated cleaning lifestyle. However, for other species previously described or observed to clean reef fishes, including Periclimenes yucatanicus, Stenopus hispidus and Stenorhynchus seticornis, δ15N isotopic values were substantially lower, raising questions about the degree to which these species rely on cleaning interactions to meet their nutritional requirements. Taken together, our data are consistent with the expectations of niche theory: co‐occurring symbiotic crustaceans have highly partitioned niche space with low levels of functional redundancy. [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]

Major trade-offs often manifest as axes of diversity in organismal functional systems. Overarching trade-offs may result in high trait integration and restrict the trajectory of diversification to be along a single axis. Here, we explore the diversification of the feeding mechanism in coral reef fishes to establish the role of trade-offs and complexity in a spectacular ecological radiation. We show that the primary axis of variation in the measured musculo-skeletal traits is aligned with a trade-off between mobility and force transmission, spanning species that capture prey with suction and those that bite attached prey. We found weak or no covariation between about half the traits, reflecting deviations from the trade-off axis. The dramatic trophic range found among reef fishes occurs along the primary trade-off axis, with numerous departures that use a mosaic of trait combinations to adapt the feeding mechanism to diverse challenges. We suggest that morphological evolution both along and independent of a major axis of variation is a widespread mechanism of diversification in complex systems where a global trade-off shapes major patterns of diversity. Significant additional diversity emerges as systems use weak integration and complexity to assemble functional units with many trait combinations that meet varying ecological demands. The diversity of coral reef fishes' feeding apparatus aligns with the trade-off between mobility and force transmission, but weak trait covariation and complexity allow jaw traits to evolve independently to adapt to diverse ecological challenges. [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]

Caribbean coral reefs face unprecedented decline due to anthropogenic and environmental stressors, necessitating active restoration efforts. Among the strategies to conserve and restore reef ecosystems, land‐based sexual propagation of corals is crucial for preserving genetic diversity and population resilience. This study explores the efficacy of utilizing native sea urchin herbivory to control benthic macroalgal proliferation and enhance coral growth in land‐based propagation systems. Three captive‐reared urchin species—Lytechinus variegatus, Tripneustes ventricosus, and Diadema antillarum—were evaluated for their influence on algal cover and growth of sexually propagated brain coral Pseudodiploria strigosa. Juveniles of each urchin species were co‐cultured with 6‐month‐old coral colonies over a 105‐day experiment. Results indicated that all urchin treatments effectively reduced algal cover compared to controls; however, only T. ventricosus significantly increased coral growth rate, while the other urchin species did not have a notable effect. Despite differences in growth, coral survival was consistently high across all treatments. Benthic community analysis revealed shifts in algal composition, with D. antillarum grazing associated with increased crustose coralline algae. However, overgrazing by D. antillarum may have resulted in mild peripheral tissue damage to some corals. Urchin survival remained high, suggesting potential for downstream utilization in restoration (e.g. urchin population enhancement). This study highlights the potential of native urchins as biocontrol agents in coral propagation, emphasizing the importance of species‐specific interactions in shaping benthic communities and promoting coral resilience. [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]

Understanding of non-geniculate coralline algal (NGCA) diversity, prevalence, and distribution in the tropical western North Atlantic is currently limited by reliance on morphological and anatomical features that are inadequate for species identifications. Reef surveys from two study sites, the Florida Keys (Florida, USA) and Roatán (Honduras), provided prevalence data for the main benthic organisms as well as relative abundance for NGCA genera. NGCA collected during these surveys and from additional sites and depths were identified using DNA sequences from two plastid genes, psbA and rbcL, and two nuclear genes, SSU and LSU, and supported by morphological and anatomical descriptions. Bayesian and Maximum Likelihood phylogenetic analyses, along with species delimitation and genetic distance methods, resolved 11 genera within two orders. Within the Corallinales, the genera Dawsoniolithon, Porolithon and Spongites each had one species, Harveylithon and Lithophyllum had two, Titanoderma three, Hydrolithon four, Neogoniolithon eight, and an unknown genus within the subfamily Neogoniolithoideae had 11 putative species. Within the Hapalidiales, the genera Phymatolithon and Roseolithon each had one species. This study reinforces the inability of morphological and anatomical features to distinguish NGCA species in the tropical western North Atlantic, resulting in substantial underestimations of species richness and diversity. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim Location Method Results Main Conclusion As climate change increasingly threatens the world's coral reefs, enhancing their resilience by improving population connectivity for key reef species is crucial for ensuring their persistence. Here, we evaluate the population genomic structure of two common coral species, Pocillopora acuta and Porites sp., chosen due to their divergent life histories. Thousands of single‐nucleotide polymorphisms (SNPs) were sequenced and analysed to infer regional connectivity patterns in Southeast Asia, a region that harbours a tremendous diversity of marine life.Coasts of the Malay Peninsula and northern Borneo, covering ~1 million km2.NextRAD genotyping‐by‐sequencing of 185 Porites sp. and 221 Pocillopora acuta colonies. Libraries were prepared and sequenced on Illumina NovaSeq 6000. Genotyping involved initial quality controls, allele frequency filtering and checks for contamination. Genetic structure was assessed with Bayesian clustering, and relationships between genetic variation and environmental factors were studied through redundancy analysis. Contemporary gene flow was estimated using BayesAss.We observed panmixia among the broadcasting Porites sp. populations, while for the brooding Pocillopora acuta, the Malay Peninsula acts a strong barrier to dispersal between the Malacca Strait and the southern South China Sea. Moreover, its genomic structure seems to follow current marine ecoregion delineation. By analysing contemporary migrant movement, we can prioritise reef localities for conservation. In particular, localities at the Andaman Coral Coast are contemporarily isolated from the other localities, and Tioman is identified as a major larval source for both species.Our analyses highlight contrasting population differentiation patterns between the two species that can be explained by the disparity in their reproductive strategies. These findings are important for biodiversity managers in Southeast Asia; incorporation of regional connectivity considerations into conservation planning can help safeguard ecosystem resilience and persistence. [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]

With the projected escalation of extreme storm events, coastal ecosystems risk undergoing catastrophic shifts and losing essential ecosystem services. Subtidal soft‐bottom mussel beds, vital components of these ecosystems, are particularly vulnerable to hydrodynamically‐induced dislodgement (i.e., detachment of mussel clumps from the bed), especially during storms. However, the mechanisms underlying the resilience—comprising both resistance and recovery—of these beds to storms remain unclear, despite being essential for informed management.This study addresses this knowledge gap regarding subtidal soft‐bottom mussel beds by: (i) quantifying their dislodgement threshold (i.e., the hydrodynamics causing widespread dislodgement of mussel clumps) using novel in situ monitoring methodologies in a representative region, namely the Dutch Wadden Sea; (ii) unveiling the influence of prior life history (here, wave exposure extent) and storm durations on their dislodgement thresholds through a flume study; and (iii) assessing the impacts of repeated storms and prior life histories (here, wave exposure extent and substrate types) on their recovery (i.e. mussel re‐aggregation) through mesocosm experiments.Integrated experimental evidence indicates that: (i) hydrodynamic‐induced dislodgement is a sudden process characterized by distinct near‐bed orbital velocity thresholds, which were identified at our study site to be between 0.45 and 0.50 m s−1; (ii) peak storm intensity, rather than storm duration, primarily drives the dislodgement of subtidal soft‐bottom mussel beds, and prior wave exposure extent regulates the dislodgement threshold; (iii) repeated storms do not seem to affect the recovery of these beds following storm‐related disturbances when the conditions between storms are conducive to mussel re‐aggregation, whereas substrate type significantly impacts recovery.Synthesis and applications. Overall, concerns regarding subtidal soft‐bottom mussel beds degradation primarily stem from increasing storm intensity and their limited resistance to such events. The methodology we developed enables low‐cost quantification of mussel resistance thresholds across broad spatiotemporal scales, facilitating the pinpointing of vulnerable areas. Our findings inform strategic management by highlighting the influential role of prior life histories in shaping mussel bed resistance and the potential to accelerate mussel bed recovery through substrate modification (e.g., shell additions). Both our methodology and findings hold promise for application in comparable ecosystems, such as oyster and coral reefs. [ABSTRACT FROM AUTHOR]

Coral reefs face escalating pressures leading to unprecedented declines in the populations of reef-building corals. 1,2 Conservation genomic studies are critical in understanding and formulating interventions to reverse such declines but thus far have only focused on a handful of broadcast-spawning species in shallow waters. 3,4 The recent International Union for Conservation of Nature (IUCN) reclassification of six different brooding corals as "critically endangered" 5 indicates that such species are equally threatened. However, we lack a thorough understanding of the factors underlying their decline. Here, we comprehensively examine the genetic impacts of a severe population decline in the brooding coral Helioseris cucullata , once a major contributor to Caribbean reefs but now critically endangered. 6,7,8 Genome-wide sequencing of colonies across five locations revealed the presence of two distinct species, indicating that the remaining population sizes are even smaller than previously estimated. Using an exhaustive, spatially explicit sampling approach (across a total of ∼2.5 hectares), we observed extremely low genetic diversity and identified how localized dispersal, excessive inbreeding, and prevalent asexual reproduction may contribute to an extinction vortex. However, we also found evidence for recent hybridization and introgression, providing an avenue for the reintroduction of genetic diversity into both lineages. With many brooding species now under threat, these results highlight the critical need to assess the genetic processes associated with their declines so that these can be harnessed or mitigated to deliver effective conservation outcomes. [Display omitted] • Critically endangered Caribbean coral represents two ecologically distinct species • The remaining populations have very low genetic diversity and small population sizes • Both species exhibit localized dispersal, high inbreeding, and asexual reproduction • Recent hybridization may provide an avenue for reintroducing genetic diversity Using a combination of genomics and photogrammetric mapping, Hernández-Agreda et al. uncover that the critically endangered coral Helioseris cucullata consists of two ecologically distinct species. Although characterized by extremely low genetic diversity, genome-wide sequencing indicates that recent hybridization may be reintroducing diversity. [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]

Population surges of crown‐of‐thorns starfish (COTS) (Acanthaster spp.) are a leading cause of coral cover loss on Australia's Great Barrier Reef (GBR). While COTS culling has been undertaken since 2012 little is known about how the public perceive COTS culling or how perceptions vary among social groups. Drawing on survey data collected in 2018 and 2022 we test the relative influence of demographic variables, social and institutional variables, and beliefs concerning the risks and benefits of culling, on public acceptance for the culling of COTS on the GBR. In contrast with previous research suggesting a polarization of views, we found limited opposition to culling (12% in 2018 and 8% in 2022). Remaining respondents, however, were almost equally divided between those who agreed or strongly agreed with culling and those who were neutral or only slightly in agreement. The strongest predictors of support, in terms of standardized mean odds ratios, were the perceived social, environmental, and ethical responsibility of culling (1.57), the manageability of culling risks (1.46), the personal importance of the GBR to the respondent (1.33), trust in science to deliver solutions (1.30), confidence in management of the GBR (1.26), and how much of a threat respondents believed COTS posed to the Reef (1.25). These findings suggest public communications about COTS culling might usefully focus on how scientific understanding, ongoing research, ecosystem monitoring, and partnerships with Reef Traditional Owners and stakeholders guide operations. [ABSTRACT FROM AUTHOR]

Habitat structural complexity is an emergent property of ecosystems that directly shapes their biodiversity, functioning and resilience to disturbance. Yet despite its importance, we continue to lack consensus on how best to define structural complexity, nor do we have a generalised approach to measure habitat complexity across ecosystems. To bridge this gap, here we adapt a geometric framework developed to quantify the surface complexity of coral reefs and apply it to the canopies of tropical rainforests. Using high‐resolution, repeat‐acquisition airborne laser scanning data collected over 450 km2 of human‐modified tropical landscapes in Borneo, we generated 3D canopy height models of forests at varying stages of recovery from logging. We then tested whether the geometric framework of habitat complexity – which characterises 3D surfaces according to their height range, rugosity and fractal dimension – was able to detect how both human and natural disturbances drive variation in canopy structure through space and time across these landscapes. We found that together, these three metrics of surface complexity captured major differences in canopy 3D structure between highly degraded, selectively logged and old‐growth forests. Moreover, the three metrics were able to track distinct temporal patterns of structural recovery following logging and wind disturbance. However, in the process we also uncovered several important conceptual and methodological limitations with the geometric framework of habitat complexity. We found that fractal dimension was highly sensitive to small variations in data inputs and was ecologically counteractive (e.g. higher fractal dimension in oil palm plantations than old‐growth forests), while rugosity and height range were tightly correlated (r = 0.75) due to their strong dependency on maximum tree height. Our results suggest that forest structural complexity cannot be summarised using these three descriptors alone, as they overlook key features of canopy vertical and horizontal structure that arise from the way trees fill 3D space. Keywords: Forest disturbance, LiDAR, logging, recovery, remote sensing, structural complexity [ABSTRACT FROM AUTHOR]

Community engagement has been identified as a key component for successful conservation efforts. According to community members, key stakeholders, and coral reef restoration practitioners in the Seaflower Marine Protected Area (MPA), the most effective way to engage communities in coral reef restoration is by building local capacity. We used a mixed‐methods approach including interviews, strengths, weaknesses, opportunities, and threats analysis, and surveys to assess strategies employed in the Seaflower MPA to involve local communities in coral reef restoration and the motivations and possible barriers that hinder community engagement. The community residing in the Seaflower MPA demonstrated awareness of the importance of coral reefs and their role in their livelihoods. They identified the main challenges to restoration as social dysfunctionality, administrative barriers, and environmental threats, along with a lack of opportunities for the community to participate in coral reef restoration. Our findings identified building trust, promoting equity, transparency, and accountability, fostering collaboration, and improving communication as essential to overcoming these challenges. Empowering local communities through capacity‐building initiatives such as educational programs, economic incentives, equity and inclusion measures, formal certifications, and local leadership would enhance support for coral reef restoration in the Seaflower MPA. In addition to building local capacity, our research identified the need for strategic planning, budgeting, and effective policies for enhancing community efforts in coral reef restoration. [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]

Cabral, A.P. and Noernberg, M.A., 2024. Morphological characteristics of an open shelf ridge at Rio Grande do Norte continental shelf, NE Brazil. Journal of Coastal Research, 40(6), 1166–1181. Charlotte (North Carolina), ISSN 0749-0208. This paper describes for the first time the occurrence of an open shelf ridge (OSR) in the South Atlantic Ocean, evidencing morphological differences with respect to occurrences in other regions. The unique configuration of this OSR derives from the characteristics of the shallow continental shelf frontal to the Calcanhar Cape, Rio Grande do Norte State, Brazil, where it is located. It is a shallow, narrow, stepped shelf with an escarpment corresponding to a drowned shoreline around the 35 m isobath. There are extensive siliciclastic and carbonate sand deposits, sand ribbons, subaqueous dune fields, coral reefs, and calcareous algae patches. The high transparency of the water allows the use of multitemporal optical satellite images from remote sensors in the bathymetric modeling and morphodynamic description, in conjunction with echo sounder surveys, in situ sampling, and modeling. The metocean conditions of the region were determined from current and wind data obtained in situ, as well as data from the Hybrid Coordinate Ocean Model (HYCOM) and Regional Ocean Modeling System (ROMS) numerical models. Combining these data allowed the identification, characterization, and analysis of the metocean patterns over the OSR. Superimposed onto the OSR, there is a field of asymmetric subaqueous dunes transverse to the ridge axis with wavelengths between 150 m and 2 km and heights between 2.5 m and 9 m, with a tendency for sediment transport offshore northwestward of the OSR crest. The synergistic effect of the dominant NE winds and the North Brazil Current with tidal currents drives the main metocean forcings. The hydrodynamic pattern for the main sedimentary deposit areas is described, and the effect of the OSR on general subaqueous dune field configuration is presented. [ABSTRACT FROM AUTHOR]

Stony coral tissue loss disease (SCTLD) has swept through Florida reefs and caused mass mortality of numerous coral species. In the wake of these losses, efforts are underway to propagate coral species impacted by SCTLD and promote population recovery. However, numerous knowledge gaps must be addressed to effectively grow, outplant, and restore populations of the slower growing, massive species that were lost. Here, we used sexual recruits of Diploria labyrinthiformis spawned in captivity to understand how conditioning, coral size, and nutritional status at outplanting affect coral survivorship, growth, and susceptibility to predation. We found that ex situ conditioning with supplemental feeding increased coral growth rates, resulting in larger sized corals at the time of outplanting. In turn, these corals had higher growth rates in the field and a lower probability of being removed by predators than outplants that were conditioned in in situ nurseries. Additionally, we found that coral size was an important predictor of survivorship, suggesting that hastening the speed at which young corals grow and outplanting larger juveniles can improve restoration outcomes. Taken together, our results suggest that providing supplemental food to corals at ex situ facilities confers benefits that could help restore populations of massive coral species impacted by SCTLD. [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 buried diagenesis and dolomitization in the deep stratum of coral reef island enable the Coral reef limestone (CRL) to exhibit a significant distinction compared with the calcified coral skeleton in mechanical properties. This paper utilized the Split Hopkinson Pressure Bar and X-ray computed tomography to investigatethe dynamic mechanical characteristics of deep CRL, revealing the effect of free water on stress–strain behaviors and the energy evolution law of CRL under high-rate impact. Furthermore, the concept of pore tensor proposed in our previous investigation was introduced to modify the dynamic constitutive model. The results indicate that the dynamic compressive strength (DCS) of CRL specimens is strongly related to stress rate, whereas the dynamic elastic modulus and DCS are independent of strain rate. The peak strains of dry specimens are significantly greater than those of saturated ones at comparative loading rates, and the viscosity effect of free water at a high loading rate impedes the deformation of CRL specimens. Moreover, the energy absorption efficiency of CRL is significantly higher than that of Bohus granite and Solnhofen limestone. Dry specimens have higher energy absorption efficiency under the same energy input, but the dynamic increase factor (DIF) of saturated specimens is larger under the same energy absorption efficiency. For the determination of DIF, this paper adopted the Back Propagation Neural Network model trained by pore tensor to predict the quasi-static compressive strength of CRL specimens, which solved the problem of considerable discreteness in mechanical parameters of CRL. The critical transition value of input energy proportion that the DIF increases rapidly is about 30%. In addition, the constitutive model modified by pore tensor reflects the influence of pore structure and water content of CRL specimens, and well describes the characteristics of dynamic elastic modulus and peak strain of deep CRL independent of loading rate. Highlights: Dynamic compressive strength of coral reef limestone strongly correlates with stress rate and weakly correlates with strain rate. The machine learning-based method for predicting quasi-static strength improves the determination accuracy of dynamic increase factor of coral reef limestone. The critical transition value of input energy proportion that the dynamic increase factor increases rapidly is about 30%. The modified constitutive model reflects the effects of pore structure and water content of coral framework limestone. [ABSTRACT FROM AUTHOR]

The single published record of centipedes from the Chagos Archipelago, British Indian Ocean Territory, is for the scolopendrid Rhysida longipes Newport, 1845, from Eagle Island. Recent collections from Diego Garcia atoll include new records of R. longipes as well as four other centipede species, including the first records of the orders Lithobiomorpha and Geophilomorpha. A new species of the lithobiid Australobius Chamberlin, 1920, A. chagosensissp. n., is closely allied to species described from southern India, Sri Lanka and the Maldives. The henicopid Lamyctes is represented by two geographically widespread species, L. mauriesi Demange, 1981 and L. tristani (Pocock, 1893), from which sequence data for the COI barcode marker are presented and analysed phylogenetically. The types of Lamyctes albipes (Pocock, 1894), and L. tristani, from Java and Tristan da Cunha, respectively, are illustrated for the first time to facilitate taxonomic comparisons with Chagos material. Specimens of Mecistocephalus are identified as Mecistocephalus lohmanderi Verhoeff, 1939, closely resembling specimens from the Seychelles. Collections from the archipelago in 1971–1972 also included Mecistocephalus angusticeps (Ribaut, 1914), and Nycternyssa dekania dekania (Verhoeff, 1938). The Chagos centipede fauna reveals affinities to those of the southern Indian Subcontinent, East Africa, Madagascar, the Maldives, the Seychelles, and Java. [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]

The article discusses the threats faced by coral reefs due to climate change, including bleaching and aggressive algal blooms. Scientists are working on ways to track and analyze reef health, as well as constructing artificial reefs to protect these ecosystems. Additionally, research shows that playing healthy reef sounds can encourage coral larvae to recolonize damaged reefs, offering hope for reef restoration efforts. French researchers have developed a non-invasive device to analyze dissolved compounds in seawater, providing insights into ecosystem health. [Extracted from the article]

The back-reef depressions, or lagoons, of Reunion Island (western Indian Ocean) host a high abundance of organisms living amongst the coral reefs and are critical sites for artisanal fishing, tourism, and shoreline stability for the island. Over time, increasing degradation of Reunionese reefs has been observed due to overexploitation, beach erosion and eutrophication. Efforts to mitigate the impact of these pressures on aquatic organisms include biodiversity surveys primarily performed through visual censuses that can be logistically complex and may unintentionally overlook organisms. Surveys integrating environmental DNA (eDNA) collections have provided rapid biodiversity assessments, while helping to circumvent some limitations of visual surveys. The present study describes the results of an exploratory eDNA survey, which aims to characterize metazoan communities of four Reunionese lagoons located along the west coast of the island. As eDNA surveys first require deliberate study design and optimization for each new context, we sought to establish a modernized workflow implementing specialized equipment to collect and preserve samples to facilitate future studies in these lagoons. During the austral summer of 2023, samples were pumped directly from surface and bottom depths at each site through self-preserving filters which were then processed for DNA metabarcoding using regions of the 12S ribosomal RNA (12S), small ribosomal subunit 18S (18S) and Cytochrome Oxidase I (COI) genes. The survey detected high species richness that varied by site, and in a single collection period, recovered the presence of 60 teleost families and numerous invertebrate taxa, including members of the coral faunal community that are less studied in Reunion. Distinct biological communities were observed at each site, and within a single lagoon, suggesting that these differences are due to site-specific factors (e.g., environmental variables, geographic distance, etc.). Although continued protocol optimization is needed, the present findings demonstrate the successful application of an eDNA-based survey for biodiversity assessment within Reunionese lagoons. [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]

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]

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]

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 cost-reporting 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]

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]

Anthropogenic climate change has significantly altered terrestrial and marine ecosystems globally, often in the form of climate-related events such as thermal anomalies and disease outbreaks. Although the isolated effects of these stressors have been well documented, a growing body of literature suggests that stressors often interact, resulting in complex effects on ecosystems. This includes coral reefs where sequential associations between heat stress and disease have had profound impacts. Here we used the model cnidarian Exaiptasia diaphana to investigate mechanisms linking prior heat stress to increased disease susceptibility. We examined anemone pathogen susceptibility and physiology (symbiosis, immunity, and energetics) following recovery from heat stress. We observed significantly increased pathogen susceptibility in anemones previously exposed to heat stress. Notably, prior heat stress reduced anemone energetic reserves (carbohydrate concentration), and activity of multiple immune components. Minimal effects of prior heat stress on symbiont density were observed. Together, results suggest changes in energetic availability might have the strongest effect on pathogen susceptibility and immunity following heat stress. The results presented here provide critical insight regarding the interplay between heat stress recovery and pathogen susceptibility in cnidarians and are an important first step towards understanding temporal associations between these stressors. The anemone Exaiptasia diaphana is more susceptible to pathogenic challenge following exposure to prior heat stress, even after two weeks of recovery at ambient temperatures. [ABSTRACT FROM AUTHOR]

The back-reef depressions, or lagoons, of Reunion Island (western Indian Ocean) host a high abundance of organisms living amongst the coral reefs and are critical sites for artisanal fishing, tourism, and shoreline stability for the island. Over time, increasing degradation of Reunionese reefs has been observed due to overexploitation, beach erosion and eutrophication. Efforts to mitigate the impact of these pressures on aquatic organisms include biodiversity surveys primarily performed through visual censuses that can be logistically complex and may unintentionally overlook organisms. Surveys integrating environmental DNA (eDNA) collections have provided rapid biodiversity assessments, while helping to circumvent some limitations of visual surveys. The present study describes the results of an exploratory eDNA survey, which aims to characterize metazoan communities of four Reunionese lagoons located along the west coast of the island. As eDNA surveys first require deliberate study design and optimization for each new context, we sought to establish a modernized workflow implementing specialized equipment to collect and preserve samples to facilitate future studies in these lagoons. During the austral summer of 2023, samples were pumped directly from surface and bottom depths at each site through self-preserving filters which were then processed for DNA metabarcoding using regions of the 12S ribosomal RNA (12S), small ribosomal subunit 18S (18S) and Cytochrome Oxidase I (COI) genes. The survey detected high species richness that varied by site, and in a single collection period, recovered the presence of 60 teleost families and numerous invertebrate taxa, including members of the coral faunal community that are less studied in Reunion. Distinct biological communities were observed at each site, and within a single lagoon, suggesting that these differences are due to site-specific factors (e.g., environmental variables, geographic distance, etc.). Although continued protocol optimization is needed, the present findings demonstrate the successful application of an eDNA-based survey for biodiversity assessment within Reunionese lagoons. [ABSTRACT FROM AUTHOR]

The article delves into the correlation between maritime traffic and economic growth in Guangdong Province, China's coastal area. By utilizing GIS technology and mathematical models, the study examines the advantages of maritime traffic, such as network density and port proximity, and quantitatively evaluates the economic development of each region. The research categorizes the regions into four zones based on a coupling-coordination model, offering practical recommendations for enhancing maritime traffic and economic progress in the area. The study underscores the significance of spatial analysis in understanding the interplay between maritime traffic and economic advancement, particularly in regions like the Pearl River Delta, where cities like Zhuhai, Shenzhen, and Guangzhou exhibit high levels of economic development. [Extracted from the article]

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]

The 1997/1998 El Niño event caused mass coral bleaching and mortality in many tropical and subtropical regions, including corals on Green Island, Taiwan, in the northwestern Pacific Ocean. This study analyzed coral carbon isotope ratios (δ13C), oxygen isotope ratios (δ18O), and Sr/Ca ratios for 29 years, including the 1997/1998 El Niño period, to examine how high water temperature events are recorded in coral geochemical indicators. Sr/Ca ratios in coral skeletons from Green Island show the lowest peak, means the highest temperature during the 1997/1998 El Niño period. However, we couldn't observe high-temperature events on δ18O. Furthermore, a negative δ13C shift was observed after El Niño events. The regime shift of δ13C might have been caused by temporal bleaching and/or a decrease in symbiotic algae due to high water temperature stress under the continuous decrease in δ13C in DIC due to the Suess effect. [ABSTRACT FROM AUTHOR]

The services provided by the world's coral reefs are threatened by increasingly frequent and severe marine heatwaves. Heatwave-induced degradation of reefs has often been inferred from the extent of the decline in total coral cover, which overlooks extreme variation among coral taxa in their susceptibility and responses to thermal stress. Here, we provide a continental-scale assessment of coral cover changes at 262 shallow tropical reef sites around Australia, using ecological survey data on 404 coral taxa before and after the 2016 mass bleaching event. A strong spatial structure in coral community composition along large-scale environmental gradients largely dictated how coral communities responded to heat stress. While heat stress variables were the best predictors of change in total coral cover, the pre-heatwave community composition best predicted the temporal beta-diversity index (an indicator of change in community composition over time). Indicator taxa in each coral community differed before and after the heatwave, highlighting potential winners and losers of climate-driven coral bleaching. Our results demonstrate how assessment of change in total cover alone may conceal very different responses in community structure, some of which showed strong regional consistency, and may provide a telling outlook of how coral reefs may reorganize in a warmer future. [ABSTRACT FROM AUTHOR]