Search

Understanding and preserving the deep sea ecosystems is paramount for marine conservation efforts. Automated object (deep-sea biota) classification can enable the creation of detailed habitat maps that not only aid in biodiversity assessments but also provide essential data to evaluate ecosystem health and resilience. Having a significant source of labelled data helps prevent overfitting and enables training deep learning models with numerous parameters. In this paper, we contribute to the establishment of a significant deep-sea remotely operated vehicle (ROV) image classification dataset with 3994 images featuring deep-sea biota belonging to 33 classes. We manually label the images through rigorous quality control with human-in-the-loop image labelling. Leveraging data from ROV equipped with advanced imaging systems, our study provides results using novel deep-learning models for image classification. We use deep learning models including ResNet, DenseNet, Inception, and Inception-ResNet to benchmark the dataset that features class imbalance with many classes. Our results show that the Inception-ResNet model provides a mean classification accuracy of 65%, with AUC scores exceeding 0.8 for each class. [ABSTRACT FROM AUTHOR]

Healthy coral reefs provide diverse habitats for marine life, playing a crucial role in marine ecosystems. Coral health is under threat due to global climate change, ocean pollution, and other environmental stressors, leading to coral bleaching. Coral bleaching disrupts the symbiotic relationship between corals and algae, ultimately impacting the entire marine ecosystem. Processing complex underwater images manually is time-consuming and burdensome for marine experts. To rapidly locate and monitor coral health, deep neural networks are employed for identifying coral categories, which can facilitate the automated processing of extensive underwater imaging data. However, these classification networks may overlook critical classification criteria like color and texture. This paper proposes a multi-local perception network (ML-Net) for image classification of healthy and bleached corals. ML-Net focuses on local features of coral targets, leveraging valuable information for image classification. Specifically, the proposed multi-branch local adaptive block extracts image details through parallel convolution kernels. Then, the proposed multi-scale local fusion block integrates features of different scales vertically, enhancing the detailed information within the deep network. Residual structures in the shallow network transmit local information with more texture and color to the deep network. Both horizontal and vertical multi-scale fusion blocks in deep networks are used to capture and retain local details. We evaluated ML-Net using six evaluation metrics on the Bleached and Unbleached Corals Classification dataset. In particular, ML-Net achieves an ACC result of 86.35, which is 4.36 higher than ResNet and 8.5 higher than ConvNext. Experimental results demonstrate the effectiveness of the proposed modules for coral classification in underwater environments. [ABSTRACT FROM AUTHOR]

Coral reefs occupy only ~ 0.1% of the oceans habitat, but are the most biologically diverse marine ecosystem. In recent decades, coral reefs have experienced significant global declines due to a variety of causes, one of the major being widespread coral bleaching events. During bleaching the coral expels its symbiotic algae losing its main source of nutrition generally obtained through photosynthesis. While recent coral bleaching events have been extensively investigated, there is no scientific data on historical coral bleaching prior to 1979. In this study, we employ high-resolution femtosecond Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS) to demonstrate a distinct biologically-induced decline of boron (B) isotopic composition (δ11B) as a result of coral bleaching. These findings and methodology offer a new use for a previously developed isotopic proxy to reconstruct paleocoral bleaching events. Based on a literature review of published δ11B data and our recorded "vital effect" of coral bleaching on the δ1111B signal, we also describe at least two possible coral bleaching events since the Last Glacial Maximum. The implementation of this bleaching proxy holds the potential of identifying occurrences of coral bleaching throughout the geological record. A deeper temporal view of coral bleaching will enable scientists to determine if it occurred in the past during times of environmental change and what outcome it may have had on coral population structure. [ABSTRACT FROM AUTHOR]

Coral reef bleaching events have become more frequent all over the world and pose a serious threat to coral reef ecosystems. Therefore, there is an urgent need for better detection of coral reef bleaching in a time- and cost-saving manner. In recent years, remote sensing technology has often been utilized and gained recognition for coral reef bleaching detection. However, bleaching corals in the water always have weak spectral change signals, causing difficulties in using remote sensing data. Additionally, uneven change samples make it challenging to adequately capture the details of coral reef bleaching detection and produce thematic maps. To resolve these problems, a novel method named coral reef bleaching detection by positive-unlabeled bagging (CBD-PUB) is proposed in this paper. To test the capacity of the method, a series of multi-temporal Sentinel-2 remote sensing images are utilized, and Lizard Island in Australia is taken as a case study area. The pseudo-invariant feature atmospheric correction (PIF) algorithm is adopted to improve coral reef bleaching spectral signals. After that, CBD-PUB is employed to effectively explore coral reef bleaching variation and its corresponding influence relations. The experimental results show that the overall accuracy of bleaching detection by the proposed algorithm reaches 92.1% and outperforms the traditional method. It fully demonstrates the feasibility of the model for the field of coral reef bleaching detection and provides assistance in the monitoring and protection of coral environments. [ABSTRACT FROM AUTHOR]

Impairment of the photosynthetic machinery of the algal endosymbiont ("zooxanthellae") is the proximal trigger for the thermal breakdown of the coral-algae symbiosis ("coral bleaching"). Yet, the primary site of thermal damage is not well resolved. In this perspective essay, I consider further a recent hypothesis which proposes an energetic disruption to the carbon-concentrating mechanisms (CCMs) of the coral host, and the resultant onset of CO2-limitation within the photosynthetic "dark reactions", as a unifying cellular mechanism. The hypothesis identifies the enhanced retention of photosynthetic carbon for zooxanthellae (re)growth following an initial irradiance-driven expulsion event as the cause of the energetic disruption. If true, then it implies that the onset of the bleaching syndrome and setting of upper thermal bleaching limits are emergent attributes of the coral symbiosis that are ultimately underpinned by the characteristic growth profile of the intracellular zooxanthellae; which is known to depend not just on temperature, but also external (seawater) nutrient availability and zooxanthellae genotype. Here, I review this proposed bleaching linkage at a variety of observational scales, and find it to be parsimonious with the available evidence. This provides a new standpoint to consider the future prospects of the coral symbiosis in an era of rapid environmental change, including the now crucial importance of reef water quality in co-determining thermal bleaching resistance. [ABSTRACT FROM AUTHOR]

The article discusses the interaction between climate change and anthropogenic pressures in the eutrophication process. Eutrophication, which is the excessive supply of nutrients to estuarine and coastal regions, poses a significant threat to ecosystems worldwide. The article explores the complex link between climate change and eutrophication, highlighting the potential exacerbation of eutrophication and its negative impacts due to climate-driven factors such as temperature changes, wind patterns, and sea level rise. The research topic also covers various themes related to eutrophication assessment, biogeochemical consequences, anthropogenic pressures, climate variability, ecosystem comparisons, and the effects of eutrophication on ecosystem services. The volume includes six papers contributed by scientists from different countries, providing insights into the effects of different factors on marine ecosystems. [Extracted from the article]

Coral bleaching driven by ocean warming is one of the most visible ecological impacts of climate change and perhaps the greatest threat to the persistence of reefs in the coming decades. In the absence of returning atmospheric greenhouse gas concentrations to those compatible with ocean temperatures below the mass coral bleaching temperature thresholds, the most straightforward means to reduce thermal-stress induced bleaching is to cool water at the seabed. The feasibility of reducing the seabed temperature through cool-water injections is considered first by analysing the feasibility of doing so on 19 reefs with differing physical environments using a simple residence time metric in 200 m resolution hydrodynamic model configurations. We then concentrate on the reefs around Lizard Island, the most promising candidate of the 19 locations, and develop a 40 m hydrodynamic model to investigate the effect of the injection of cool water at differing volumetric rates. Injecting 27°C seawater at a rate of 5 m³ s-1 at 4 sites in early 2017 cooled 97 ha of the reef by 0.15°C or more. The power required to pump 5 m³ s-1 through a set of pipes over a distance of 3 km from a nearby channel is*466 kW. This power applied at 4 sites for 3 months achieves a 2 Degree Heating Weeks (DHWs) reduction on 97 ha of reef. A more precise energy costing will require further expert engineering design of the pumping equipment and energy sources. Even for the most physically favourable reefs, cool-water transported through pipes and injected at a reef site is energy expensive and cannot be scaled up to any meaningful fraction of the 3,100 reefs of the GBR. Should priority be given to reducing thermal stress on one or a few high value reefs, this paper provides a framework to identify the most promising sites. [ABSTRACT FROM AUTHOR]

In this initial study of a research project, this paper seeks to understand the thermal conditions in the cities of Lisbon and Munich, specifically focusing on Urban Heat Island intensity and on thermal comfort using the Universal Thermal Climate Index modeling data at the Local Climate Zone scale. Based on these datasets, Munich has exhibited more unfavourable thermal conditions than Lisbon. In terms of UHII, both cities have shown that low, medium, and high rise compact urban areas and bare rock or paved areas have the highest values, while sparsely built areas have the lowest. These results differ from the UTCI, which indicates that in Lisbon and Munich, these sparsely built areas as well as areas with low plants and vegetation are the most uncomfortable. In Munich, the population was exposed to very strong heat stress, while Lisbon experienced strong heat stress conditions. Conversely, low, medium, and high rise compact urban areas and densely wooded areas in Munich, and scattered trees areas and large low-rise urban areas in Lisbon, have demonstrated the lowest monthly mean and average maximum values. These results will be further explored in future studies in the city of Lisbon and cross-checked with data obtained from roving missions. This will enable a more detailed temporal and local analysis. [ABSTRACT FROM AUTHOR]

The recent widespread and recurrent coral bleaching events over the Great Barrier Reef, the largest coral reef system on Earth and a hotspot of marine biodiversity, are a reminder of the vulnerability of reef ecosystems to human activities and a warming world. Protection of the Great Barrier Reef and similar reef ecosystems across Oceania requires a better understanding of environmental and socio-economic pressures, as well as the development of integrated management strategies. The rapid expansion of Earth Observation technologies and data has greatly advanced our capability to map and monitor reef habitats, ecological processing and exposure risk, providing spatially rich data essential to support and evaluate management and conservation strategies. However, these technologies are proportionally still under-utilized, and it is important to synthesise remote-sensing-derived tools and methods currently available for mapping reef ecosystems in Oceania to facilitate their intake in coral reefs studies. Publications in this Special Issue contribute toward filling this gap and explore recent advances in remote sensing of the Great Barrier Reef and other reef ecosystems in Oceania, from novel methodological approaches (sensors, algorithm development and improved thematic classification) to applications for environmental monitoring and management. [ABSTRACT FROM AUTHOR]

The paper exposes the experience of València in applying climate-resilient thinking to the current revision of the city's General Urban Development Plan. A semi-quantitative, indicator-based risk assessment of heat stress was carried out on the 23 functional areas of the city sectorized by the Plan, including modeling and spatial analysis exercises. A data model of 18 indicators was built to characterize vulnerability. A thermal stress map was developed using the URbCLim model and a heat index was then calculated using Copernicus hourly data (air temperature, humidity, and wind speed) for the period of January 2008–December 2017 at a spatial resolution of 100 m × 100 m. General recommendations at the city level as well as guidelines for development planning in the functional areas at risk are provided, with specifications for the deployment of nature-based solutions as adaptation measures. From a planning perspective, the study positively informs the General Urban Development Plan, the City Green and Biodiversity Plan, and contributes to City Urban Strategy 2030 and City Missions 2030 for climate adaptation and neutrality. Applying the same approach to other climate change-related hazards (i.e., water scarcity, pluvial flooding, sea level rise) will allow better informed decisions towards resilient urban planning. [ABSTRACT FROM AUTHOR]

Turbid reefs have traditionally been described as degraded systems, characterised by low coral cover and diversity, and high bioerosion rates with reduced reef complexity and reef accretionary potential. The six papers in the Special Issue focus on two important marginal reef systems, which may have the potential to serve as climate change refugia: turbid reefs and high-latitude reefs. Marginal coral reefs live under sub-optimal environmental conditions (e.g., low light, high sediment inputs, and variable temperatures) and include turbid and mesophotic reefs, high-latitude reefs, high-temperature reefs, and high CO SB 2 sb seep reefs near volcanic vents. [Extracted from the article]

Coral reefs play important roles in the marine ecosystem, from providing shelter to aquatic lives to being a source of income to others. However, they are in danger from outbreaks of species like the Crown of Thorns Starfish (COTS) and the widespread coral bleaching from rising sea temperatures. The identification of COTS for detecting outbreaks is a challenging task and is often done through snorkelling and diving activities with limited range, where strong currents result in poor image capture, damage of capturing equipment, and are of high risks. This paper proposes a novel approach for the automatic detection of COTS based Convolutional Neural Network (CNN) with an enhanced attention module. Different pre-trained CNN models, namely, VGG19 and MobileNetV2 have been applied to our dataset with the aim of detecting and classifying COTS using transfer learning. The architecture of the pre-trained models was optimised using ADAM optimisers and an accuracy of 87.1% was achieved for VGG19 and 80.2% for the MobileNetV2. The attention model was developed and added to the CNN to determine which features in the starfish were influencing the classification. The enhanced model attained an accuracy of 92.6% while explaining the causal features in COTS. The mean average precision of the enhanced VGG-19 with the addition of the attention model was 95% showing an increase of 2% compared to only the enhanced VGG-19 model. [ABSTRACT FROM AUTHOR]

The results from these and other research efforts are used by the Intergovernmental Panel on Climate Change (IPCC) to regularly publish state-of-the-art climate change updates, such as the recent special report on the ocean and cryosphere in a changing climate (IPCC [14]). Theme: Climate change impacts At the frontier of climate change: Red alert from the European Alps, the Arctic and coral reefs: This article belongs to Ambio's 50th Anniversary Collection. The effects of climate change are also evident in coral reefs around the world, where rising sea surface temperatures cause increasingly frequent and damaging bleaching events (Goreau and Hayes [8]). [Extracted from the article]

Marine heatwaves are discrete and prolonged periods of anomalously warm seawater temperature which have devastating ecological and socioeconomic impacts. Being part of the center of marine biodiversity and a fisheries-dependent country, the Philippines is vulnerable to the threats of marine heatwaves, but these extreme events remain understudied in the country. It is, therefore, crucial to investigate the development of marine heatwaves and to assess and predict the impacts of these events in the Philippine seas. In this perspective paper, we aim to put forward the research direction for advancing our understanding of marine heatwaves and their impacts in the Philippines. The limited studies on marine heatwaves in the Philippines highlight the need for progress in understanding the spatiotemporal patterns, physical processes, and impacts of marine heatwaves in the country. Advancing our knowledge of marine heatwaves will help us formulate mitigating strategies for ocean warming in fisheries management and marine biodiversity conservation in the Philippines. [ABSTRACT FROM AUTHOR]

Desmosomes, strong cell--cell junctions of epithelia and cardiac muscle, link intermediate filaments to cell membranes and mechanically integrate cells across tissues, dissipating mechanical stress. They comprise five major protein classes -- desmocollins and desmogleins (the desmosomal cadherins), plakoglobin, plakophilins and desmoplakin -- whose individual contribution to the structure and turnover of desmosomes is poorly understood. Using live-cell imaging together with fluorescence recovery after photobleaching (FRAP) and fluorescence loss and localisation after photobleaching (FLAP), we show that desmosomes consist of two contrasting protein moieties or modules: a very stable moiety of desmosomal cadherins, desmoplakin and plakoglobin, and a highly mobile plakophilin (Pkp2a). As desmosomes mature from Ca2+ dependence to Ca2+- independent hyper-adhesion, their stability increases, but Pkp2a remains highly mobile. We show that desmosome downregulation during growth-factor-induced cell scattering proceeds by internalisation of whole desmosomes, which still retain a stable moiety and highly mobile Pkp2a. This molecular mobility of Pkp2a suggests a transient and probably regulatory role for Pkp2a in desmosomes. This article has an associated First Person interview with the first author of the paper. [ABSTRACT FROM AUTHOR]

1 Goreau-Hayes Coral Reef Bleaching Hot Spot Map from the NOAA Coral Reef Watch Daily 5 km coral bleaching record (coralreefwatch.noaa.gov/product/5 km), Accessed September 26, 2020. Global warming triggers coral reef bleaching tipping point: This article belongs to Ambio's 50th Anniversary Collection. The sudden outbreak of mass coral reef bleaching around the world in the 1980s was unprecedented, the first natural ecosystem threat from global warming, and an urgent alarm call for concerted efforts to reverse global warming. There has been minimal progress towards enhancement of local reef management capacity in coral reef countries by documenting environmental history, understanding the causes of present changes, and preparing for future developments while coral reef science represents scientific tourism rather than local priorities. [Extracted from the article]

CORrelation ALignment (CORAL) is an unsupervised domain adaptation method that uses a linear transformation to align the covariances of source and target domains. Deep CORAL extends CORAL with a nonlinear transformation using a deep neural network and adds CORAL loss as a part of the total loss to align the covariances of source and target domains. However, there are still two problems to be solved in Deep CORAL: features extracted from AlexNet are not always a good representation of the original data, as well as joint training combined with both the classification and CORAL loss may not be efficient enough to align the distribution of the source and target domain. In this paper, we proposed two strategies: attention to improve the quality of feature maps and the p-norm loss function to align the distribution of the source and target features, further reducing the offset caused by the classification loss function. Experiments on the Office-31 dataset indicate that our proposed methodologies improved Deep CORAL in terms of performance. [ABSTRACT FROM AUTHOR]

The health and condition of the world's reefs are in steep decline. This has triggered the development of fledgling micro-scale coral reef restoration projects along many reef coastlines. However, it is increasingly recognised that the scale and productivity of micro-scale coral gardening projects will be insufficient to meet the growing global threats to reefs. More recently, efforts to develop and implement restoration techniques for application at regional scales have been pursued by research organisations. Coral reefs are mostly located in the unindustrialised world. Yet, most of the funding, and scientific and engineering method development for larger-scale methods will likely be sourced and created in the industrialised world. Therefore, the development of the emerging at-scale global reef restoration sector will inevitably involve the transfer of methods, approaches, finances, labour and skills from the industrialised world to the unindustrialised world. This opens the door to the industrialised world negatively impacting the unindustrialised world and, in some cases, First Nations peoples. In Western scientific parlance, ecological imperialism occurs when people from industrialised nations seek to recreate environments and ecosystems in unindustrialised nations that are familiar and comfortable to them. How a coral reef 'should' look depends on one's background and perspective. While predominately Western scientific approaches provide guidance on the ecological principles for reef restoration, these methods might not be applicable in every scenario in unindustrialised nations. Imposing such views on Indigenous coastal communities without the local technical and leadership resources to scale-up restoration of their reefs can lead to unwanted consequences. The objective of this paper is to introduce this real and emerging risk into the broader reef restoration discussion. [ABSTRACT FROM AUTHOR]

Abstract The state of coral reefs has been of great concern, as documented in the growing amount of primary literature. These reports on coral health have accumulated, resulting in reviews of the primary studies (i.e. secondary literature). Recently, such reviews have also accumulated, creating an opportunity to review the secondary literature. Second‐order syntheses (reviews of secondary literature) provide an overview of the field, which can be used to guide future research. Based on our previously published protocol, we compiled peer‐reviewed secondary literature on coral health from Scopus and Web of Science databases. We synthesised 335 secondary literature papers on coral health, 35 of which underwent critical appraisal and 333 of which also underwent bibliometric analysis. The secondary literature consisted primarily of qualitative reviews (78%). Over 80% of papers stated informing coral conservation as the review's purpose. Climate change (50%) and coral resilience (42%) were the most studied topics, and bioerosion was the least (3.6%). Critically appraised papers scored poorly on Collaboration for Environmental Evidence Synthesis Assessment Tool criteria (studies did not meet standards 55% of the time). The authors of the secondary literature were highly interconnected (with 30% of the authors having more than 15 coauthors within our dataset) and included authors from countries with coral reefs (predominantly in Australia and USA; 79% of papers). The secondary literature on coral health had a median Altmetric score of 5.27. We have revealed key gaps in coral health topics for further review (e.g. coral range shifts and microbial biodiversity), particularly when considering conservation policy. Incorporating research in policy could be improved through greater research accessibility and continuing to gather public interest in coral reefs. We further recommend broadening research collaborations to include even more researchers from countries with coral reefs (e.g. Maldives). Finally, the secondary literature on coral health needs better reporting transparency (e.g. publishing code). Our second‐order synthesis is timely, pushing coral health research in a new direction—one which produces research of higher quality, collaboration, and efficiency. As coral reefs decline, we should also aim to rebuild public trust in research and strengthen the evidence base for conservation.

The decline of marine ecosystems poses a substantial threat to the viability of local economies that are reliant on marine life for their continued survival. Artificial intelligence (AI) and machine learning (ML) are two of the several developing technologies that have the ability to address environmental challenges. In particular, ML may be used to better analyse the oceans, keep track of shipping, maintain track of debris in the ocean, unregulated and unreported (IUU) fishing, ocean mining, reduce coral bleaching, and stop the spread of marine diseases. In this paper, we examine the rising prospects and concerns related with the application of AI in the maritime environment, as well as their potential scalability for larger results, using some use-cases to illustrate our points. The results that were obtained when the model prediction was applied to random images are evidence that the model that was suggested provides better outcomes with fewer data points. [ABSTRACT FROM AUTHOR]

Students were introduced to the scenario that a young student, Maya, had sent mail with pictures of what she suspects to be coral in a cliff (see NSTA Connection). For the Exploration section, if students are working in a virtual setting, students could be placed in a breakout group and each group could be assigned one sheet of fossil data to examine collaboratively. Next, we defined fossils as evidence of life in the past that was at least 10,000 years old and asked students "What things could become fossils?" They reasoned that they did not think the coral was a recently living organism since coral "lives in warmer climates" and living coral would look physically different from coral fossils. [Extracted from the article]

Estimating variability across spatial scales has been a major issue in ecology because the description of patterns in space is extremely valuable to propose specific hypotheses to unveil key processes behind these patterns. This paper aims to estimate the variability of the coral assemblage structure at different spatial scales in order to determine which scales explain the largest variability on β-diversity. For this, a fully-nested design including a series of hierarchical-random factors encompassing three spatial scales: (1) regions, (2) localities and (3) reefs sites across the Venezuelan territory. The variability among spatial scales was tested with a permutation-based analysis of variance (Permanova) based on Bray-Curtis index. Dispersion in species presence/absence across scales (i.e., β-diversity) was tested with a PermDisp analysis based on Jaccard’s index. We found the highest variability in the coral assemblage structure between sites within localities (Pseudo-F = 5.34; p-value = 0.001, CV = 35.10%). We also found that longitude (Canonical corr = 0.867, p = 0.001) is a better predictor of the coral assemblage structure in Venezuela, than latitude (Canonical corr = 0.552, p = 0.021). Largest changes in β-diversity of corals occurred within sites (F = 2.764, df1= 35, df2 = 107, p = 0.045) and within localities (F = 4.438, df1= 6, df2 = 29, p = 0.026). Our results suggest that processes operating at spatial scales of hundreds of meters and hundreds of kilometers might both be critical to shape coral assemblage structure in Venezuela, whereas smaller scales (i.e., hundreds of meters) showed to be highly-important for the species turnover component of β-diversity. This result highlights the importance of creating scale-adapted management actions in Venezuela and likely across the Caribbean region. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide solutions have been used for more than 100 years as industrial bleach for various wood, paper, textile, leather products, as well as for hair whitening. Since the same time, hydrogen peroxide solutions and sodium bicarbonate solutions have been widely used in medicine as antiseptic and disinfectants to remove pus from purulent wounds. Less than this period, hydrogen peroxide solutions are successfully used for bleaching fish and various seafood. However, until the early 21st century, the combination of hydrogen peroxide with sodium bicarbonate was not used as a bleaching cleaner for surfaces contaminated with blood and/or pus stains. The use of hydrogen peroxide solution in combination with sodium bicarbonate as a universal bleaching and dissolving medical cleaner was first proposed in the last 20 years in Russia. It was during these years that a new group of drugs was discovered in pharmacology: drugs, bleaching and dissolving blood stains and a mass of thick pus. It is proved that the local application of various mixtures of baking soda, hydrogen peroxide and warm water provides a safe urgent dissolution and discoloration of the dense biological masses. It is established that purification, bleaching and removal of organic pollutants is achieved due to their hyperthermal softening, cavitation loosening, alkaline saponification and dissolution, as well as due to oxidative discoloration of pigments. It is proposed to use the created Arsenal of biomedical alkaline bleaching cleaners for the analysis and development of new effective and safe ceramic bleaches in everyday life. [ABSTRACT FROM AUTHOR]

The Caribbean Sea and adjacent land areas are highly sensitive to the projected impacts of global climate change. The countries bordering the Caribbean Sea depend heavily on coastal and marine assets as a major source of livelihood support. Rising sea surface temperatures (SSTs) are known to be associated with coral bleaching, ocean acidification, and other phenomena that threaten livelihoods in the region. The paucity of SST systematic observations in both the Caribbean Sea and adjoining Western Atlantic waters is a limiting factor in the projection of future climate change impacts on the region's marine resources. Remote sensing of SST by satellites began only within the last three decades and although the data collected so far might be insufficient to provide conclusive definitions of long-term SST variations in the Caribbean waters, these data along with the output from climate model simulations provide a useful basis for gaining further insights into plausible SST futures under IPCC SRES scenarios. In this paper, we examine the recent SST records from the NESDIS AVHRR satellite data and NOAA Optimum Interpolation (OI) sea surface temperature V2 and provide a comparative analysis of projected SST changes for the Caribbean Sea up to the end of the twenty-first century, under the SRES A2 and B2 scenarios' simulations of the sea surface skin temperatures (SSsT) using the Hadley Centre's regional model, PRECIS. The implications of these projected SST changes for bleaching of coral reefs, one of the region's most valuable marine resource, and for rainfall are also discussed. [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]

Light is critical to coral growth through endosymbiont photosynthesis but can also act with elevated temperatures to cause coral bleaching. When more light is absorbed than can be used for photosynthesis, elevated irradiance can damage symbiont photosynthetic machinery. Hence, solar-radiation management through shading has been suggested to alleviate coral bleaching during marine heatwaves. Acropora divaricata and Acropora kenti were tested at two temperatures with 30% shading and an unshaded control to determine the relative impacts of light and temperature on coral bleaching severity. The coral bleaching response was assessed by photochemical (pulse amplitude modulated fluorometry), physiological (symbiont density, chlorophyll a concentration, catalase activity, and lipid peroxidation), and physical (mean intensity of grey or 'percentage whiteness') markers. Shading significantly reduced the bleaching response in A. divaricata, whilst for some parameters A. kenti responded negatively to shade. In A. divaricata, shading prevented photochemical collapse up to the experiment's maximum 4.4 degree-heating weeks (DHW). Biomarkers of coral bleaching stress responded to shade and water temperature at 4.4 DHW; catalase activity was greatest in the shaded and ambient temperature treatment. Shading did not reduce the effects of bleaching in A. kenti; the mean intensity of grey and light saturation coefficient was greatest in the shaded treatment. Shading did, however, reduce lipid peroxidation at 3 DHW. Our results suggest shading during thermal stress may only protect some coral species, highlighting the need to consider species-specific responses when evaluating the potential efficacy of coral bleaching interventions. [ABSTRACT FROM AUTHOR]

Assisted sexual coral propagation, resulting in greater genet diversity via genetic recombination, has been hypothesized to lead to more adaptable and, hence, resilient restored populations compared to more common clonal techniques. Coral restoration efforts have resulted in substantial populations of 'Assisted sexual Recruits' (i.e., juvenile corals derived from assisted sexual reproduction; AR) of multiple species outplanted to reefs or held in in situ nurseries across many locations in the Caribbean. These AR populations provided context to evaluate their relative resilience compared to co-occurring coral populations during the 2023 marine heat wave of unprecedented duration and intensity that affected the entire Caribbean. Populations of six species of AR, most ranging in age from 1–4 years, were surveyed across five regions during the mass bleaching season in 2023 (Aug-Dec), alongside co-occurring groups of corals to compare prevalence of bleaching and related mortality. Comparison groups included conspecific adult colonies as available, but also the extant co-occurring coral assemblages in which conspecifics were rare or lacking, as well as small, propagated coral fragments. Assisted sexual recruits had significantly lower prevalence of bleaching impacts (overall pooled ~ 10%) than conspecific coral populations typically comprised of larger colonies (~ 60–100% depending on species). In addition, small corals derived from fragmentation (rather than sexual propagation) in two regions showed bleaching susceptibility intermediate between AR and wild adults. Overall, AR exhibited high bleaching resistance under heat stress exposure up to and exceeding Degree Heating Weeks of 20°C-weeks. As coral reefs throughout the globe are subject to increasingly frequent and intense marine heatwaves, restoration activities that include sexual reproduction and seeding can make an important contribution to sustain coral populations. [ABSTRACT FROM AUTHOR]

Abstract The health of coral reef ecosystems is declining. As research examining this decline has grown, review articles (secondary literature) have emerged. Secondary literature can include narrative reviews, systematic reviews, and bibliometric analyses. Synthesizing secondary literature can influence research directions, as syntheses visualize both the current state of knowledge and trends in research. Therefore, we propose to use the combination of bibliometric mapping and systematic mapping techniques to synthesize the secondary literature on coral health and coral reef decline. We will examine secondary literature on coral health published in peer‐reviewed journals and indexed in Scopus or Web of Science databases. After screening the title, abstract, and keywords of each paper, we will extract information that encompasses the type and purpose of the review, the identified factors affecting coral health, and the health‐related outcomes on coral reefs. We will also conduct a critical appraisal using the Collaboration for Environmental Evidence Synthesis Assessment Tool (CEESAT) criteria for papers that are self‐reported to be systematic reviews. We will also extract bibliometric data to identify author affiliations, collaboration networks, and journals. We will communicate our results from systematic and bibliometric mapping using visualizations and tabulations. Our systematic map aims to reveal gaps and clusters of topics in review articles on coral health. These findings can guide future research into coral health in both primary and secondary literature. Our critical appraisal will evaluate the robustness of systematic reviews, informing researchers on how to identify and conduct high‐quality reviews. Our bibliometric map will uncover the extent and connectivity of researchers synthesizing evidence on coral health, highlighting the diversity (or lack thereof) of those engaging in coral health research.

Coral reefs are one of the world's most threatened ecosystems, with global and local stressors contributing to their decline. Excessive sea-surface temperatures (SSTs) can cause coral bleaching, resulting in coral death and decreases in coral cover. A SST threshold of 1°C over the climatological maximum is widely used to predict coral bleaching. In this study, we refined thermal indices predicting coral bleaching at high-spatial resolution (1 km) by statistically optimizing thermal thresholds, as well as considering other environmental influences on bleaching such as ultraviolet (UV) radiation, water turbidity, and cooling effects. We used a coral bleaching dataset derived from the web-based monitoring system Sango Map Project, at scales appropriate for the local and regional conservation of Japanese coral reefs. We recorded coral bleaching events in the years 2004-2016 in Japan. We revealed the influence of multiple factors on the ability to predict coral bleaching, including selection of thermal indices, statistical optimization of thermal thresholds, quantification of multiple environmental influences, and use of multiple modeling methods (generalized linear models and random forests). After optimization, differences in predictive ability among thermal indices were negligible. Thermal index, UV radiation, water turbidity, and cooling effects were important predictors of the occurrence of coral bleaching. Predictions based on the best model revealed that coral reefs in Japan have experienced recent and widespread bleaching. A practical method to reduce bleaching frequency by screening UV radiation was also demonstrated in this paper. [ABSTRACT FROM AUTHOR]

In recent years, with the advancement of marine resources and environment research, the ecological functions of reef-building coral reef ecosystems distributed in warm shallow waters of the ocean are being continuously discovered and valued by people. It is important for ecosystem protection to monitor the population of marine animals. Besides, many projects of Autonomous Underwater Vehicle (AUV) also need technology to perceive and understand environment information in real-time for better decision-making. Therefore, marine animal detection has become a challenge for researchers to study nowadays. Deep neural network models have been used to solve fish-related tasks and gained encouraging achievements, but there are still many problems in this field. In this paper, several YOLO-based methods are chosen for comparison. Experiment results indicate that these methods can recognize the marine animals in coral reef quickly and accurately. Finally, several recommendations for model improvement according to assessment results are presented. [ABSTRACT FROM AUTHOR]

Climate change is transforming coral reefs by increasing the frequency and intensity of marine heatwaves, often leading to coral bleaching and mortality. Coral communities have demonstrated modest increases in thermal tolerance following repeated exposure to moderate heat stress, but it is unclear whether these shifts represent acclimatization of individual colonies or mortality of thermally susceptible individuals. For corals that survive repeated bleaching events, it is important to understand how past bleaching responses impact future growth potential. Here, we track the bleaching responses of 1,832 corals in leeward Maui through multiple marine heatwaves and document patterns of coral growth and survivorship over a seven-year period. While we find limited evidence of acclimatization at population scales, we document reduced bleaching over time in specific individuals that is indicative of acclimatization, primarily in the stress-tolerant taxa Porites lobata. For corals that survived both bleaching events, we find no relationship between bleaching response and coral growth in three of four taxa studied. This decoupling suggests that coral survivorship is a better indicator of future growth than is a coral's bleaching history. Based on these results, we recommend restoration practitioners in Hawaiʻi focus on colonies of Porites and Montipora with a proven track-record of growth and survivorship, rather than devote resources toward identifying and cultivating bleaching-resistant phenotypes in the lab. Survivorship followed a latitudinal thermal stress gradient, but because this gradient was small, it is likely that local environmental factors also drove differences in coral performance between sites. Efforts to reduce human impacts at low performing sites would likely improve coral survivorship in the future. [ABSTRACT FROM AUTHOR]

Local meteorology over the Great Barrier Reef (GBR) can significantly influence ocean temperatures, which in turn impacts coral ecosystems. While El Niño–Southern Oscillation (ENSO) provides insight into the expected synoptic states, it lacks details of anticipated sub‐seasonal weather variability at local scales. This study explores the influence of the Madden‐Julian oscillation (MJO) on Australian tropical climate, both independently and in combination with ENSO, focusing on GBR impacts. We find that during El Niño periods, including the summer of 2009/10, faster propagating MJO patterns can disrupt background warm, dry conditions, and potentially provide cooling relief via increased cloud cover and stronger winds. In La Niña periods, such as the summer of 2021/22, the MJO tends to be prevented from passing the Maritime continent, forcing it to remain in a standing pattern in the Indian Ocean. This leads to decreased cloud cover and weaker winds over the GBR, generating warm ocean anomalies. Plain Language Summary: Bleaching is likely when tropical corals are exposed to ocean temperatures above a threshold for a prolonged period. In austral summer, tropical weather over the Great Barrier Reef (GBR) can vary from hot and sunny to stormy with rain and strong winds. During El Niño, summer weather over the GBR is typically warm, still, and dry, increasing the likelihood of coral bleaching due to increased exposure to solar radiation and decreased mixing. During La Niña, tropical storms, with cooling effects through increased rainfall and cloud cover, are more typical. The Madden‐Julian oscillation (MJO) is an eastward moving storm pattern near the equator that can also influence the background climate over the GBR. We find that the MJO can significantly influence the weather variability over the GBR, altering the expected states of El Niño and La Niña periods. Key Points: Composite maps show how the Madden‐Julian oscillation (MJO) can change meteorological patterns on the Great Barrier ReefCluster analysis is used to show the types of MJO propagation patterns likely to occur during El Niño and La Niña periodsOcean temperature variability is discussed with El Niño/La Niña phases as the background states and the MJO as a sub‐seasonal modulator [ABSTRACT FROM AUTHOR]

This article discusses an innovative approach to science education focused on engaging students through authentic learning experiences and hands-on activities. It emphasizes the importance of linking classroom instruction with real-world science research practices, particularly in the context of coral reef ecosystems through an authentic learning opportunity. The article shares insights from piloting a coral reef ecosystem lesson with high school biology students, noting their enthusiastic engagement and skill development in data interpretation and communication. The lab activity is an opportunity for students to simulate underwater research techniques and analyze authentic data to assess the health of coral reef ecosystems. The article underscores the urgency of educating students about threats facing coral reefs, including climate change, pollution, and human activities. Whether we live near an ocean or far away it is important to help students understand how the ocean is connected to our daily lives. By integrating ocean literacy principles into the curriculum, educators can empower students to understand the interconnectedness of marine ecosystems and human behaviors, encouraging informed citizenship and environmental stewardship. This article advocates for transformative science education that cultivates critical thinking, scientific inquiry, and a deeper appreciation for the natural world. [ABSTRACT FROM AUTHOR]

Global warming has enduring consequences in the ocean, leading to increased sea surface temperatures (SSTs) and subsequent environmental impacts, including coral bleaching and intensified tropical storms. It is imperative to monitor these trends to enable informed decision-making and adaptation. In this study, we comprehensively examine the methods for extracting long-term temperature trends, including STL, seasonal-trend decomposition procedure based on LOESS (locally estimated scatterplot smoothing), and the linear regression family, which comprises the ordinary least-squares regression (OLSR), orthogonal regression (OR), and geometric-mean regression (GMR). The applicability and limitations of these methods are assessed based on experimental and simulated data. STL may stand out as the most accurate method for extracting long-term trends. However, it is associated with notably sizable computational time. In contrast, linear regression methods are far more efficient. Among these methods, GMR is not suitable due to its inherent assumption of a random temporal component. OLSR and OR are preferable for general tasks but require correction to accurately account for seasonal signal-induced bias resulting from the phase–distance imbalance. We observe that this bias can be effectively addressed by trimming the SST data to ensure that the time series becomes an even function before applying linear regression, which is named "evenization". We compare our methods with two commonly used methods in the climate community. Our proposed method is unbiased and better than the conventional SST anomaly method. While our method may have a larger degree of uncertainty than combined linear and sinusoidal fitting, this uncertainty remains within an acceptable range. Furthermore, linear and sinusoidal fitting can be unstable when applied to natural data containing significant noise. [ABSTRACT FROM AUTHOR]

Transcriptome data are frequently used to investigate coral bleaching; however, the factors controlling gene expression in natural populations of these species are poorly understood. We studied two corals, Montipora capitata and Pocillopora acuta, that inhabit the sheltered Kāne'ohe Bay, Hawai'i. M. capitata colonies in the bay are outbreeding diploids, whereas P. acuta is a mixture of clonal diploids and triploids. Populations were sampled from six reefs and subjected to either control (no stress), thermal stress, pH stress, or combined pH and thermal stress treatments. RNA‐seq data were generated to test two competing hypotheses: (1) gene expression is largely independent of genotype, reflecting a shared treatment‐driven response (TDE) or, (2) genotype dominates gene expression, regardless of treatment (GDE). Our results strongly support the GDE model, even under severe stress. We suggest that post‐transcriptional processes (e.g., control of translation, protein turnover) modify the signal from the transcriptome, and may underlie the observed differences in coral bleaching sensitivity via the downstream proteome and metabolome. [ABSTRACT FROM AUTHOR]

Coral reefs off the coast of the Republic of Sudan are still considered to be among the most pristine reefs in the central Red Sea. The complex coastal fringing reefs, offshore banks, and shoals of Dungonab Bay in the north and Sanganeb atoll situated further to the south, about 23 km off the Sudanese mainland coast, were inscribed on the UNESCO World Heritage List in 2016. Due to their remote location and limited access, monitoring of the status of the reefs has been sporadic. Here, we present the results of a repeated large area photomosaic survey (5 m × 5 m plots) on the Sanganeb atoll, first established and surveyed in 1980, and revisited in 1991 and most recently in 2019. The 2019 survey recovered and reinstated the four original monitoring plots. Evaluation of photographic and video records from one photomosaic plot on the seaward slope of the atoll revealed general continuity of the overall community structure and composition over 39 years. Individual colonies of Echinopora gemmacea and Lobophyllia erythraea were recorded in the exact same positions as in the 1980 and 1991 plots. The genera Acropora and Pocillopora remain dominant, although in altered proportions. Shifts in composition were detected at the species level (e.g., increase in Pocillopora verrucosa, Stylophora pistillata, Acropora hemprichii, Dipsastraea pallida, and Echinopora gemmacea, decrease in Acropora cytherea and A. superba), in addition to changes in the extent of uncolonized substrate (e.g., increase from 43.9% in 1980 to 52.2% in 2019), and other scleractinian, hydrozoan, and soft coral living cover. While the temporal resolution only includes three sampling events over 39 years (1980, 1991, 2019), this study presents one of the longest time series of benthic community surveys available for the entire Red Sea. A semi-quantitative estimate of vertical reef growth in the studied test plot indicates a reduction in net accretion rates of more than 80%, from 2.27 to 2.72 cm/yr between 1980 and 1991 to 0.28–0.42 cm/yr between 1991 and 2019. We carefully conclude that the changes observed in the coral community in the plot in 2019 (Acropora–Pocillopora shift, increase in Montipora and calcareous algae) are representative of impacts at the community level, including rising sea surface temperatures and recent bleaching events. [ABSTRACT FROM AUTHOR]