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There are more coral species in deep, cold-waters than in tropical coral reefs. This broad-ranging treatment is the first to synthesise current understanding of all types of cold-water coral, covering their ecology, biology, palaeontology and geology. Beginning with a history of research in the field, the authors describe the approaches needed to s...
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... to 1000 m) at high latitudes, and at great depths (up to 4000 m) beneath warm water masses at low latitudes. Approximately 800 species of reef-building scleractinians are described in shallow waters, yet fewer than 10 are known to make substantial deep-water reef frameworks (1,8). Of these, we have an incomplete view of their global distribution (Fig. 2), which remains skewed by the geographically varied levels of research activity and the bias of deep-water mapping initiatives to the developed world. Despite this, some intriguing patterns in their global bio- geography are becoming evident. Cold-water scleractinian species diversity is highest around the Philippines, with global ...
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The Antarctic Cold Reversal (ACR; 14.7 to 13 thousand years ago; ka) phase of the last deglaciation saw a pause in the rise of atmospheric CO2 and Antarctic temperature, that contrasted with warming in the North. A reexpansion of sea ice and a northward shift in the position of the westerly winds in the Southern Ocean are well‐documented, but the r...
Cold-water corals (CWCs) are frequently found at cold seep areas. However, the relationship between fluid seepage and CWC development is not clear. Here, for the first time, we report the occurrences, species identification, mineralogy, carbon and oxygen isotopes, as well as elemental compositions of fossil CWC skeletons from gas-hydrate-bearing se...
The formation of cold-water coral (CWC) mounds is commonly seen as being the result of the sustained growth of framework-forming CWCs and the concurrent supply and deposition of terrigenous sediments under energetic hydrodynamic conditions. Yet only a limited number of studies investigated the complex interplay of the various hydrodynamic, sediment...
Citations
... Each polyp produces a skeleton called corallite with a central cavity, called calyx, in which it lives (Figure 2a). Coral colonies exhibit various shapes (e.g., encrusting, hemispherical, tabular, corymbose and branching; [14]) but colonial stony (scleactinian) cold-water corals are predominantly branching (dendroidal; [33]). Some dendroid cold-water corals commonly show secondary joints, regions in the colony where two different coral branches have grown together, and skeletal strengthening as well as further associated secondary joints related to the presence of worms of the genus Eunice [29]. ...
Herein, we present CoDA, the Coral Dendroid structure Analyzer, a visual analytics suite that allows for the first time to investigate the ontogenetic morphological development of complex dendroid coral colonies, exemplified on three important framework-forming dendroid cold-water corals: Lophelia pertusa (Linnaeus, 1758), Madrepora oculata (Linnaeus, 1758), and Goniocorella dumosa (Alcock, 1902). Input to CoDA is an initial instance segmentation of the coral polyp cavities (calices), from which it estimates the skeleton tree of the colony and extracts classical morphological measurements and advanced shape features of the individual corallites. CoDA also works as a proofreading and error correction tool by helping to identify wrong parts in the skeleton tree and providing tools to quickly correct these errors. The final skeleton tree enables the derivation of additional information about the calices/corallite instances that otherwise could not be obtained, including their ontogenetic generation and branching patterns - the basis of a fully quantitative statistical analysis of the coral colony morphology. Part of CoDA is CoDAGraph, a feature-rich link-and-brush user interface for visualizing the extracted features and 2D graph layouts of the skeleton tree, enabling the real-time exploration of complex coral colonies and their building blocks, the individual corallites and branches. In the future, we expect CoDA to greatly facilitate the analysis of large stony corals of different species and morphotypes, as well as other dendroid structures, enabling new insights into the influence of genetic and environmental factors on their ontogenetic morphological development.
... Lophelia pertusa, Madrepora oculate), which show their highest diversity and 831 population along the NASPG between 200 and 1000 m depth among the global ocean (Roberts 832 et al., 2009). In fact, several studies reported that CWC ecosystems are anticipated to be among 833 the first deep-sea ecosystems to experience acidification threats (Guinotte et al., 2006; Maier 834 et al., 2009;Raven et al., 2005;Roberts et al., 2009; Turley et al., 2007), particularly in the 835 North Atlantic(Perez et al., 2018). The findings presented here contribute to a deeper 836 understanding of the biological impacts of OA along the NASPG. ...
The CO2-carbonate system dynamics in the North Atlantic Subpolar Gyre (NASPG) were evaluated between 2009 and 2019. Data was collected aboard eight summer cruises through the CLIVAR 59.5º N section. The Ocean Acidification (OA) patterns and the reduction in the saturation state of calcite (ΩCa) and aragonite (ΩArag) in response to the increasing anthropogenic CO2 (Cant) were assessed within the Irminger, Iceland and Rockall basins during a poorly-assessed decade in which the physical patterns reversed in comparison with previous well-known periods. The observed cooling, freshening and enhanced ventilation increased the interannual rate of accumulation of Cant in the interior ocean by 50–86 % and the OA rates by close to 10 %. The OA trends were 0.0013–0.0032 units yr-1 in the Irminger and Iceland basin and 0.0006–0.0024 units yr-1 in the Rockall Trough, causing a decline in ΩCa and ΩArag of 0.004–0.021 and 0.003–0.0013 units yr-1, respectively. The Cant-driven rise in total inorganic carbon (CT) was the main driver of the OA (contributed by 53–68 % in upper layers and >82 % toward the interior ocean) and the reduction in ΩCa and ΩArag (>64 %). The transient decrease in temperature, salinity and AT collectively counteracts the CT-driven acidification by 45–85 % in the upper layers and in the shallow Rockall Trough and by <10 % in the interior ocean. The present investigation reports the acceleration of the OA within the NASPG and expands knowledge about the future state of the ocean.
... In shallow-water scleractinian species, certain microbial assemblages are associated with increased thermal tolerance [45][46][47]. Microbiome variation could be significant for mesophotic and deep-sea corals (those living deeper than 50 m) because they often have wider depth and geographic ranges than shallow-water species [48]. ...
... Mesophotic and deep-sea octocorals occur worldwide along continental margins and seamounts, over a wide depth range down to at least 8000 m [48,59]. Light intensity, oxygen concentration, temperature, pressure, pH, salinity, food availability, and habitat structure vary with depth and geography. ...
Background
Coral-associated microbiomes vary greatly between colonies and localities with functional consequences on the host. However, the full extent of variability across the ranges of most coral species remains unknown, especially for corals living in deep waters which span greater ranges. Here, we characterized the microbiomes of four octocoral species from mesophotic and bathyal deep-sea habitats in the northern Gulf of Mexico, Muricea pendula, Swiftia exserta, Callogorgia delta, and Paramuricea biscaya, using 16S rRNA gene metabarcoding. We sampled extensively across their ranges to test for microbiome differentiation between and within species, examining the influence of environmental factors that vary with depth (53–2224 m) and geographic location (over 680 m) as well as the host coral’s genotype using RAD-sequencing.
Results
Coral microbiomes were often dominated by amplicon sequence variants whose abundances varied across their hosts’ ranges, including symbiotic taxa: corallicolids, Endozoicomonas , members of the Mollicutes , and the BD1-7 clade. Coral species, depth, and geographic location significantly affected diversity, microbial community composition, and the relative abundance of individual microbes. Depth was the strongest environmental factor determining microbiome structure within species, which influenced the abundance of most dominant symbiotic taxa. Differences in host genotype, bottom temperature, and surface primary productivity could explain a significant part of the microbiome variation associated with depth and geographic location.
Conclusions
Altogether, this work demonstrates that the microbiomes of corals in deep waters vary substantially across their ranges in accordance with depth and other environmental conditions. It reveals that the influence of depth on the ecology of mesophotic and deep-sea corals extends to its effects on their microbiomes which may have functional consequences. This work also identifies the distributions of microbes including potential parasites which can be used to inform restoration plans in response to the Deepwater Horizon oil spill.
... Most notably, the general feature spaces enabled the distinction of soft and hard substrate habitats, aligning with the distinct visual contrast of these habitat classes. The overlap of Hard Sub. and Reef feature spaces following dimension reduction, particularly within Datasets 2 & 3, is unsurprising given the ecological association of Reef and hard substrates (Howell et al., 2011;Roberts et al., 2009). Larvae of coral species such as Desmophyllum pertusum, responsible for creating the reef framework in the featured datasets, require hard substrate to settle and build their communities (Roberts et al., 2009;Wilson, 1979). ...
... The overlap of Hard Sub. and Reef feature spaces following dimension reduction, particularly within Datasets 2 & 3, is unsurprising given the ecological association of Reef and hard substrates (Howell et al., 2011;Roberts et al., 2009). Larvae of coral species such as Desmophyllum pertusum, responsible for creating the reef framework in the featured datasets, require hard substrate to settle and build their communities (Roberts et al., 2009;Wilson, 1979). Reef is also more commonly associated with topographic highs (created by boulders and bedrock for example) that enable elevation into currents for enhanced filter feeding (Mienis et al., 2007;Roberts et al., 2009;Thiem et al., 2006). ...
... Larvae of coral species such as Desmophyllum pertusum, responsible for creating the reef framework in the featured datasets, require hard substrate to settle and build their communities (Roberts et al., 2009;Wilson, 1979). Reef is also more commonly associated with topographic highs (created by boulders and bedrock for example) that enable elevation into currents for enhanced filter feeding (Mienis et al., 2007;Roberts et al., 2009;Thiem et al., 2006). Imagery classified as Reef will thus likely contain evidence of hard substrates. ...
Automating identification of benthic habitats from imagery, with Machine Learning (ML), is necessary to contribute efficiently and effectively to marine spatial planning. A promising method is to adapt pre-trained general convolutional neural networks (CNNs) to a new classification task (transfer learning). However, this is often inaccessible to a non-specialist, requiring large investments in computational resources and time (for user comprehension and model training). In this paper, we demonstrate a simpler transfer learning framework for classifying broad deep-sea benthic habitats. Specifically, we take an ‘off-the-shelf’ CNN (VGG16) and use it to extract features (pixel patterns) from benthic images (without further training). The default outputs of VGG16 are then fed in to a Support Vector Machine (SVM), a classical and simpler method than deep networks. For comparison, we also train the remaining classification layers of VGG16 using stochastic gradient descent. The discriminative power of these approaches is demonstrated on three benthic datasets (574–8353 images) from Norwegian waters; each using a unique imaging platform. Benthic habitats are broadly classified as Soft Substrate (sands, muds), Hard Substrate (gravels, cobbles and boulders) and Reef (Desmophyllum pertusum). We found that the relatively simplicity of the SVM classifier did not compromise performance. Results were competitive with the CNN classifier and consistently high, with test accuracy ranging from 0.87 to 0.95 (average = 0.9 (+/-
0.04)) across datasets, somewhat increasing with dataset size. Impressively, these results were achieved 2.4–5× faster than CNN training and had significantly less dependency on high-specification hardware. Our suggested approach maximises conceptual and practical simplicity, representing a realistic baseline for novice users when approaching benthic habitat classification. This method has wide potential. It allows automated image grouping to aid annotation or further model selection, as well as screening of old-datasets. It is especially suited to offshore scenarios as it can provide quick, albeit crude, insights into habitat presence, allowing adaptation of sampling protocols in near real-time.
... As neither samples nor sequencing data were available for Oculina virginea (Linnaeus, 1758), the type species of Oculina, Oculina patagonica de Angelis D'Ossat, 1908 was used to represent the genus. Madrepora oculata is a framework building, deep-water azooxanthellate coral that is distributed worldwide, except in polar regions (Roberts et al. 2009). Cladocora caespitosa is an endangered endemic shallowwater zooxanthellate species that is currently restricted to the Mediterranean Basin (Zibrowius 1980) that has been highly affected by climatic and more recent anthropogenic changes extending back to the Pliocene (Peirano et al. 1998). ...
Despite the widespread use of integrative taxonomic approaches, many scleractinian coral genera and species remain grouped in polyphyletic families, classified as incertae sedis or simply understudied. Oculinidae Gray, 1847 represents a family for which many taxonomic questions remain unresolved, particularly those related to some of the current genera, such as Oculina Lamark, 1816 or recently removed genera, including Cladocora Ehrenberg, 1834 and Madrepora Linnaeus, 1758. Cladocora is currently assigned to the family Cladocoridae Milne Edwards & Haime, 1857 and a new family, Bathyporidae Kitahara, Capel, Zilberberg & Cairns, 2024, was recently raised to accommodate Madrepora. However, the name Bathyporidae is not valid because this was not formed on the basis of a type genus name. To resolve taxonomic questions related to these three genera, the evolutionary relationships are explored through phylogenetic analyses of 18 molecular markers. The results of these analyses support a close relationship between the species Oculina patagonica and Cladocora caespitosa, indicating that these may belong to the same family (and possibly genus), and highlighting the need for detailed revisions of Oculina and Cladocora. By contrast, a distant relationship is found between these two species and Madrepora oculata, with the overall evidence supporting the placement of Madrepora in the resurrected family Madreporidae Ehrenberg, 1834. This study advances our knowledge of coral systematics and highlights the need for a comprehensive review of the genera Oculina, Cladocora and Madrepora.
... Cold-water corals (CWCs) occur globally at all latitudes except the high Arctic regions (Davies et al. 2008;Roberts et al. 2009). Cold-water corals are found in a range of seawater depths, from relatively shallow waters (e.g. ...
Modern cold-water corals (CWCs) occur in a wide range of water depths, with Desmophyllum pertusum being one of the most common species. Pleistocene, Holocene, and modern coral mound formation by living CWC reefs have previously been described in the Porcupine Seabight from water depths greater than 700 m in the vicinity of the transitional zone between the Eastern North Atlantic Water and Mediterranean Outflow Water. Here we document occurrence of fossil corals retrieved from two cores at 370 m depth in the Macnas Mounds, a relatively shallow occurrence for mounds on the Irish shelf-edge. Both cores feature D. pertusum restricted to the upper two metres, immediately overlying an erosive surface and a coeval major down-core change in grain size from sand to mud. Radiocarbon dating of coral specimens indicates the CWC mounds initiated 7.82 Cal ky BP. Our study unequivocally documents the existence of Holocene shelf-edge coral mounds in the eastern Porcupine Seabight and highlights the possibility of other occurrences of CWCs in similar settings elsewhere in the northeast Atlantic. Given that no living CWCs were encountered in the study area, we suggest that the area previously experienced more favourable conditions for CWC mound initiation and development along the shelf-edge margin, possibly due to differing conditions in the European Slope Current which flows northward along the continental slope from south of the Porcupine Bank to the Faroe-Shetland Channel.
Graphical Abstract
... Los pólipos se asocian con algas microscópicas (zooxantelas) y gracias a ello liberan oxígeno y secretan carbonato de calcio, siendo por esto conocidos como corales duros o escleractíneos (Prahl y Erhardt, 1985;Cairns, 1999;Díaz et al., 2000;Reyes et al., 2010). Son propios de aguas someras y cálidas, por lo que se les observa más comúnmente alrededor de los trópicos por todo el mundo, principalmente en zonas costeras, pero llegando incluso a tener presencia a los 6.000 m en los que la luz está ausente y por ende sus zooxantelas (Murray-Roberts et al., 2009). Los arrecifes coralinos generan entre otras funciones oxígeno, hábitat, alimento y protección para más del 25% de especies marinas (Príncipe et al., 2011; Alva-Basurto y Arias- González, 2015). ...
El informe está compuesto por 5 capítulos, donde el primero incluye la descripción de los espacios oceánicos y zonas costeras e insulares de Colombia, las unidades de gestión ambiental, establecidas por la Política Nacional Ambiental para el Desarrollo Sostenible de los Espacios Oceánicos y las Zonas Costeras e Insulares de Colombia. El capítulo II presenta avances en el estado del ambiente y de los ecosistemas marinos y costeros mediante el conocimiento del medio abiótico, a partir de estudios
de condiciones oceanográficas, climáticas y dinámica litoral en tres sitos, caracterización general y geomorfológica de la plataforma continental del Caribe, del Pacífico colombiano y territorios insulares, así como la calidad de las aguas marinas y costeras que incluye un análisis en playas turísticas, y también los indicadores de “salud” para arrecifes coralinos, pastos marinos y manglares. En el capítulo III, se describen las causas y tensores del cambio en los ecosistemas marinos y costeros, así como sus servicios de provisión de alimento y aprovechamiento del recurso pesquero, incluyendo la operación estadística de presión pesquera artesanal. El capítulo IV contiene el tema de instrumentos de gestión de los espacios oceánicos y zonas costeras e insulares de Colombina, en el cual se describen los avances en el manejo integrado de la zona costera desde ejercicios de planificación espacial marina desarrollados a escala regional, el avance en el fortalecimiento de capacidades en manejo integrado de zonas costeras y el estado de la gestión de las áreas marinas protegidas, hasta estrategias de capacitaciones en el manejo integrado de zonas costeras mediante diversos cursos, además se presenta el indicador de fortalecimiento de capacidades en manejo integrado. El capítulo V describe y analiza el estado del conocimiento y los vacíos de información que se tienen sobre los ecosistemas marinos y costeros de Colombia, en esta ocasión se presentan las microalgas potencialmente nocivas las cuales causan impactos negativos en los organismos marinos. Adicionalmente, se presenta la contaminación causada por basura marina costera plástica y el indicador de especies bioprospectadas, los servicios ecosistémicos con su respectiva
clasificación. Por último, el capítulo V presenta el potencial de Carbono Azul en Colombia y su importante papel en la mitigación del cambio climático, además de una línea de tiempo de las
investigaciones en Carbono Azul para manglares y pastos marinos; y los avances en las estimaciones de carbono azul en la zona costera colombiana. De esta manera, el INVEMAR sigue contribuyendo activamente a la generación y difusión de conocimiento con el objetivo de apoyar la formulación de políticas y la toma de decisiones que promuevan el bienestar y la calidad de vida de los ciudadanos colombianos.
... Though less well-studied and publicized than their shallow-water counterparts, at least until recent years, deep-sea corals (DSC; i.e., coral species occurring below 50 m depth; Cairns, 2007) correspond to an important part of the diversity of Scleractinians, with 622 of the 7111 azooxanthellate scleractinian species occurring deeper than 50 m (Roberts et al., 2009). DSC develop complex three-dimensional structures, which can support an important biodiversity (Buhl-Mortensen et al., 2017;Henry & Roberts, 2017;Roberts et al., 2009;Rueda et al., 2019). ...
... Though less well-studied and publicized than their shallow-water counterparts, at least until recent years, deep-sea corals (DSC; i.e., coral species occurring below 50 m depth; Cairns, 2007) correspond to an important part of the diversity of Scleractinians, with 622 of the 7111 azooxanthellate scleractinian species occurring deeper than 50 m (Roberts et al., 2009). DSC develop complex three-dimensional structures, which can support an important biodiversity (Buhl-Mortensen et al., 2017;Henry & Roberts, 2017;Roberts et al., 2009;Rueda et al., 2019). The research on DSC in the Mediterranean has already a long history (Evans et al., 2019;. ...
The deep‐sea corals Dendrophyllia ramea and Dendrophyllia cornigera occur in Mediterranean and Atlantic waters. Both species are found in different environmental conditions, and they can colonize hard and soft substrates. These species then display an important ecological plasticity along with morphological plasticity. Nevertheless, there is a large knowledge gap on the genetic characteristics of the two species, including on the relationships between them and the possibility of cryptic species along their range. The recent discovery of Dendrophyllia populations off Cyprus in the eastern Mediterranean Sea raised new questions in this context. These corals were related to D. ramea but had some morphological differences with other known populations of this species. Here, we study the specific status of Dendrophyllia corals from Cyprus on the basis of morphology and genetics. The genetic data are interpreted by comparison with the same analysis performed on two Caryophyllia species. Both morphological and genetic data confirm that corals found off Cyprus belong to the D. ramea species. We further tested the speciation scenario using transcriptome data: the results indicate an absence of current gene flow between D. ramea and D. cornigera and that the divergence occurred more than 3 million years ago. We discuss the possible historical and ecological factors which may have shaped speciation in these species.
... Other relevant variables are temperature and fishing effort. Regarding the first one, it is widely acknowledged that the distribution of CWCs is restricted by temperature instead of depth, and they are most typically found at temperatures ranging from 4°C to 12°C (Roberts, 2009;Maier et al., 2012). They exist in the Mediterranean Sea at temperatures ranging from 12.5°C to almost 14°C, with occasional higher temperatures Castellan et al., 2019). ...
Cold-water corals (CWCs) are bioengineering species that can increase habitat heterogeneity and improve the deep sea’s biological diversity and ecosystem functioning. Knowledge of their distribution provides a critical baseline for assessing the effect of natural and anthropogenic impacts on these important deep-sea habitats. The aims of this study are: i) provide new data on the spatial distribution of six CWCs species in the Strait of Sicily, ii) describe the principal environmental and anthropogenic variables that play a role in shaping their distribution, iii) identify hotspots in which individuals belonging to the various species co-occur. Presence-only data of six CWCs species, ten environmental variables (depth, slope, rugosity, aspect, flowdir, temperature, salinity, north bottom current, east bottom current, chlorophyll-a), and one variable relating to bottom trawling effort (Automatic Information System – AIS) were used to predict the suitable habitats. We used Maximum Entropy modelling (MaxEnt) approach and used the AUC (area under the receiver operating characteristic curve) and TSS (true skill statistics) to evaluate the model performance. The results showed excellent AUC, TSS and AUC’s standard deviation mean values for all six species. The validation show high predictive performance. MaxEnt identified slope, depth, and rugosity as the most important predictors, showing the highest percentage contribution for all six species considered. Throughout the study area, highlyinterspecific persistent density hotspot of CWCs co-occurrence were discovered, with a total extension of 4.05 km² where all species co-occur. Although studies on the effect of environmental and anthropogenic factors that impact the distribution of these species of conservation interest remain scarce, the results of this study offer useful guidance for decision-makers to develop necessary conservation measures.
... In the present study, some of these invertebrates have been found to retain a large amount of drifted thalli of R. okamurae around their bodies. These invertebrates are mainly gorgonians and colonial scleractinians that have polyps that capture small food particles [2,36,37]. Moreover, some of these invertebrates generally have moderate to slow growth rates and can build vulnerable and threatened habitats that are included in regional and international conservation lists under different conventions and directives (e.g., OSPAR, Habitats Directive) [2]. ...
The arrival of a new invasive alga, Rugulopteryx okamurae, in the Strait of Gibraltar (SoG) in 2015 marked an unprecedented milestone in the North African and, later, in the European marine ecosystems. Nowadays, it is colonising vast infralittoral areas and significantly modifying some habitats and associated communities of the southern Iberian Peninsula. In recent expeditions, a high amount of free drifted thalli of this alga has been detected in different circalittoral and bathyal habitats of the northern SoG and the Alboran Sea. The present study combines quantitative data of this alga obtained with the use of a remotely operated vehicle (ROV) and a bottom otter trawl. The coverage–entanglement level of the drifted thalli on circalittoral and bathyal benthic invertebrates (e.g., not covering, covering only the basal part, covering one-third of the invertebrate, etc.) was also annotated from picture frames taken in locations with abundant drifted thalli. In underwater images, drifted thalli were mainly detected in circalittoral and bathyal bottoms of the northern SoG and the north-western Alboran Sea, between 50 to ca. 450 m depth. Nevertheless, abundant drifted thalli were also detected in bottom otter trawl samples from circalittoral bottoms of the north-central and north-eastern Alboran Sea. Small benthic organisms (e.g., encrusting sponges, hydrozoans, etc.) generally displayed low coverage–entanglement levels of drifted thalli. Nevertheless, large sessile and colonial benthic organisms with a complex three-dimensional morphology (e.g., gorgonians, colonial scleractinians) reached high levels of R. okamurae thalli entangled in different parts of their colonies. The drifted R. okamurae thalli entangled in these colonial suspension feeding organisms may hinder their feeding capability in the long term, resulting in habitat deterioration in the near future.
