Black Coral Research Articles

Perspectives on working underwater with black coral nubbins (Cnidaria: Antipatharia): The case of Cirrhipathes anguina (Dana, 1846)

In order to test the feasibility of transplantation of the whip black coral species Cirrhipathes anguina (Dana, 1846) from Madagascar, transplants were installed on cultivation tables in two sites (the North Pass and the Grande Vasque) characterized by distinct environmental conditions. Following transplantation, the transplants were followed for short-term (20 days) healing capacities and medium-term (200 days) mortality and growth rates. Results show a successful transplantation in both sites with 0% mortality (except in the form of missing fragments) and a certain growth over 200 days. Maximum growth rates were 3.4 cm/month and 2.0 cm/month in the North Pass and in the Grande Vasque, respectively. In addition, mean time to total healing was delayed in the Grande Vasque compared to the transplants in the North Pass (10 days). Differences between sites are likely to be related to differences in environmental parameters. Altogether, the promising results obtained with the easy protocol used in this study encourage the use of black coral transplants in further in situ experiments and restoration projects.

Bosques de coral negro del Área de Conservación Guanacaste, Costa Rica: especies y distribución

Introduction: Little is known about the antipatharians in Costa Rica, only three species are known from the Pacific and the occurrence of coral forests was previously reported only for Isla del Coco. Black coral forests were observed at several sites in the north Pacific of the country, within the Guanacaste Conservation Area (ACG), which are reported and characterized in this study.
 Objective: To determine the species of black corals present in the ACG Marine Sector and its surroundings, and geographically locate the sites where black coral forests grow.
 Methods: Visual censuses were made by diving, samples were taken and analyzed in the laboratory for identification.
 Results: These black coral forests are composed of two species: Myriopathes panamensis and Antipathes galapagensis, these species are described and illustrated. The coral forests were found within and outside ACG marine protected areas. Myriopathes panamensis was found between 15-35 m depth and A. galapagensis at 30-45 m. Associated macrofauna was observed among the branches of M. panamensis, their ecological importance and status have not been determined.
 Conclusions: The species found did not have morphological variations with those described in other similar regions. Associated fauna was found (mainly the anemone Nemanthus californicus, the bivalve Pteria sterna and the longnose hawkfish Oxycirrhithes typus) and needs to be studied to determine its role on black corals. The importance of the ACG as a marine biodiversity conservation site is emphasized.

Morphology and molecular phylogeny of three black corals (Antipatharia, Schizopathidae) from seamounts in the Western Pacific Ocean, with description of a new species

Morphology and molecular phylogeny of three black corals (Antipatharia, Schizopathidae) from seamounts in the Western Pacific Ocean, with description of a new species

Habitat suitability mapping of the black coral Leiopathes glaberrima to support conservation of vulnerable marine ecosystems

The black coral Leiopathes glaberrima is an important habitat forming species that supports benthic biodiversity. Due to its high sensitivity to fishing activities, it has been classified as indicator of Vulnerable Marine Ecosystems (VMEs). However, the information on its habitat selection and large-scale spatial distribution in the Mediterranean Sea is poor. In this study a thorough literature review on the occurrence of L. glaberrima across the Mediterranean Sea was undertaken. Predictive modelling was carried out to produce the first continuous map of L. glaberrima suitable habitat in the central sector of the Mediterranean Sea. MaxEnt modeling was used to predict L. glaberrima probability of presence as a function of seven environmental predictors (bathymetry, slope, aspect North–South and East–West, kinetic energy due to currents at the seabed, seabed habitat types and sea bottom temperature). Our results show that bathymetry, slope and aspect are the most important factors driving L. glaberrima spatial distribution, while in less extent the other environmental variables. This study adds relevant information on the spatial distribution of vulnerable deep water corals in relation to the environmental factors in the Mediterranean Sea. It provides an important background for marine spatial planning especially for prioritizing areas for the conservation of VMEs.

Black Coral Distribution in the Italian Seas: A Review

Antipatharian corals are important structural and complex members of benthic communities inhabiting the Italian seafloor. In this study, the distribution of black corals in Italy is reported and mapped for the first time. This review has permitted the identification of occurrences of such vulnerable marine ecosystems along the Italian coasts in a bathymetric range of 42 m to 790 m. Black corals appear to be most conspicuous and widely distributed in the mesophotic zone (from around 60 to 300 m depth), with a major occurrence on the rocky bottom and shoals. This review also highlights that these communities suffer direct damage from anthropogenic impacts (fishing activity and lost garbage). Finally, this study provides evidence that the reported Italian submarine sites associated with the occurrence of black corals probably represent only a small portion of their real distribution. This finding urges the need to increase monitoring efforts to support the protection and the conservation of these pristine species assemblages.

Correction to: Population genomic structure of the black coral Antipathella subpinnata in Mediterranean Vulnerable Marine Ecosystems

Correction to: Population genomic structure of the black coral Antipathella subpinnata in Mediterranean Vulnerable Marine Ecosystems

Observations of sea anemones (Hexacorallia: Actiniaria) overgrowing black corals (Hexacorallia: Antipatharia)

Despite being crucial for habitat provision and being able to inhabit most oceans and all depths, documentation of threats affecting antipatharian corals (known as black corals) is very limited. We provide the second report of sea anemones in the genus Nemanthus overgrowing antipatharian corals causing the death of either entire colonies or sections of them. Our observations are from shallow and mesophotic reefs at the epicentre of marine biodiversity in Indonesia. Other instances exist where Nemanthus sp., as well as various species of zoanthids, have been reported to be in ‘association’ with antipatharians from other regions, which suggests that this could be a widespread threat to antipatharians. It is urgent to investigate the causes and to document the long-term effects that the sea anemones and zoanthids are having, in order to understand how this phenomenon will affect antipatharian populations and the fauna they support.

Potential Distribution and Environmental Niche of the Black Corals Antipathes galapagensis and Myriopathes panamensis in the Eastern Tropical Pacific1

Antipathes galapagensis and Myriopathes panamensis are black coral species (Order Antipatharia) distributed in the Eastern Pacific from the Gulf of California to the coasts of Peru, at depths from -10 m to -200 m for A. galapagensis and to -50 m for M. panamensis. Antipatharians have great ecological importance as engineer species and major constituents of “coral forests,” which are recognized as vulnerable marine ecosystems. Antipathes galapagensis has been a target of fisheries in several countries and has frequently been overexploited. Thus, the aim of this study was to compile a database of georeferenced records of A. galapagensis and M. panamensis, and use distribution data and environmental variables to construct habitat suitability models with Maxent software, in order to better understand black coral environmental requirements and potential distributions in the Eastern Tropical Pacific. The models showed good fit and performance (AUC > 0.9); key variables that drive the potential distribution of both species were chlorophyll a, nutrient concentration, and seawater temperature. The models did not predict occurrences beyond the recognized distribution range limits of the species; notwithstanding, they indicated that the Pacific coast of the Baja California Peninsula and the central and southern coasts of the Mexican Pacific have areas of high suitability for the presence of these corals. To our knowledge, no black coral records from these sites exist in the literature to date; thus, field validations are needed to verify the model predictions. With these results, it is possible to offer suggestions of new conservation sites for black corals based on the areas with the highest probability of occurrence of the species.

Description of two new genera and two new species of antipatharian corals in the family Aphanipathidae (Cnidaria: Anthozoa: Antipatharia).

Two new genera and two new species of black corals are recognized in the family Aphanipathidae. The new genus Anozopathes, with the species A. hawaiiensis sp. nov. and A. palauensis, sp. nov. is characterized by a sparsely and irregularly branched corallum with relatively long branches which can be straight, curved or crooked. The genus Aphanostichopathes, with the type species Cirripathes paucispina Brook, is characterized by an unbranched corallum with a long, curved stem with loose distal coils. Mitochondrial DNA data (nad5-IGR-nad1 for Anozopathes and cox3-cox1 for Aphanostichopathes) indicate that both taxa are related to the genera Aphanipathes, Phanopathes and Acanthopathes in the family Aphanipathidae, and morphologically they both share the characteristic of having spines with distinct conical tubercles. The two new species of Anozopathes are separated primarily by differences in colony growth form and in the size and shape of the skeletal spines. Species of Aphanostichopathes are separated primarily by differences in the size and shape of the spines and by size and density of the tubercles on the surface of the spines.

The Interactive Role of Hydrocarbon Seeps, Hydrothermal Vents and Intermediate Antarctic/Mediterranean Water Masses on the Distribution of Some Vulnerable Deep-Sea Habitats in Mid Latitude NE Atlantic Ocean

In this work, we integrate five case studies harboring vulnerable deep-sea benthic habitats in different geological settings from mid latitude NE Atlantic Ocean (24–42° N). Data and images of specific deep-sea habitats were acquired with Remoted Operated Vehicle (ROV) sensors (temperature, salinity, potential density, O2, CO2, and CH4). Besides documenting some key vulnerable deep-sea habitats, this study shows that the distribution of some deep-sea coral aggregations (including scleractinians, gorgonians, and antipatharians), deep-sea sponge aggregations and other deep-sea habitats are influenced by water masses’ properties. Our data support that the distribution of scleractinian reefs and aggregations of other deep-sea corals, from subtropical to north Atlantic could be dependent of the latitudinal extents of the Antarctic Intermediate Waters (AAIW) and the Mediterranean Outflow Waters (MOW). Otherwise, the distribution of some vulnerable deep-sea habitats is influenced, at the local scale, by active hydrocarbon seeps (Gulf of Cádiz) and hydrothermal vents (El Hierro, Canary Island). The co-occurrence of deep-sea corals and chemosynthesis-based communities has been identified in methane seeps of the Gulf of Cádiz. Extensive beds of living deep-sea mussels (Bathymodiolus mauritanicus) and other chemosymbiotic bivalves occur closely to deep-sea coral aggregations (e.g., gorgonians, black corals) that colonize methane-derived authigenic carbonates.

Genetic Divergence and Polyphyly in the Octocoral Genus Swiftia [Cnidaria: Octocorallia], Including a Species Impacted by the DWH Oil Spill

Mesophotic coral ecosystems (MCEs) are recognized around the world as diverse and ecologically important habitats. In the northern Gulf of Mexico (GoMx), MCEs are rocky reefs with abundant black corals and octocorals, including the species Swiftia exserta. Surveys following the Deepwater Horizon (DWH) oil spill in 2010 revealed significant injury to these and other species, the restoration of which requires an in-depth understanding of the biology, ecology, and genetic diversity of each species. To support a larger population connectivity study of impacted octocorals in the GoMx, this study combined sequences of mtMutS and nuclear 28S rDNA to confirm the identity of Swiftia sea fans in the GoMx, compare these markers for different polyp colors in the GoMx and Atlantic, and examine the phylogeny of the genus. Two mtMutS haplotypes were identified, one seemingly endemic to the northern GoMx. Compared to other North Atlantic Swiftia, S. exserta, the type of the genus was found to be extremely divergent and distinct from the two other Swiftia at both loci, with strong evidence of polyphyly in the genus. This information refines our understanding of the geographical distribution of injured coral and highlights how little is known about MCEs. Substantial taxonomic revisions may be needed for several taxa injured by the DWH oil spill.

Population genomic structure of the black coral Antipathella subpinnata in Mediterranean Vulnerable Marine Ecosystems

Antipathella subpinnata (Ellis and Solander 1786) is one of the most frequently observed black corals at mesophotic depths (60–200 m) of the Mediterranean Sea, particularly in the northwestern part of the basin, where its populations can reach high densities and create forest-like aggregations, both along the coast and in offshore locations such as seamounts. Similar to other marine underwater forests, black coral gardens host a rich associated fauna and attract numerous species of commercial interest. As such, these corals are targeted by recreational and artisanal fisheries and are vulnerable to human impact due to their arborescent morphology and low growth rates. Genetic connectivity can provide valuable insight into the processes of population maintenance and replenishment following environmental disturbance and is often used as a proxy for population resilience. In our study, a restriction-site associated DNA analysis (2bRAD) was used to evaluate fine-scale population structure of the Mediterranean black coral A. subpinnata, and to understand which populations could serve as a potential source of genetic diversity for adjacent populations. Colonies from two offshore localities (a Ligurian seamount and a Tyrrhenian canyon) and four coastal populations from Liguria and Sicily were sampled and genotyped. Significant genetic differentiation was recorded between coastal and offshore localities. Moreover, offshore localities were genetically distinct from one another, while all coastal populations were characterized by panmixia. This indicates that offshore A. subpinnata gardens are potentially less resilient to human impact (i.e., demersal fishing activities) due to a limited influx of larvae from adjacent habitats. In addition, they are unlikely to supply coral propagules to coastal populations. Overall, this study highlights the vulnerability of Mediterranean A. subpinnata forests, and the importance of enforcing conservation and management measures to achieve Good Environmental Status (GES, EU Marine Strategy Framework Directive) of these valuable marine ecosystems.

Evaluating the distribution of priority benthic habitats through a remotely operated vehicle to support conservation measures off Linosa Island (Sicily Channel, Mediterranean Sea)

Abstract Explorations of the Mediterranean deep sea using remotely operated vehicles have shown that the sea bed hosts rich habitats, supporting high biodiversity. However, there have been only a few studies dealing with the southern part of the basin, leading to limited protection and conservation efforts in this area. This study aimed to explore the sea bed off Linosa Island (Sicily Channel, southern Mediterranean Sea), which is considered a ‘sentinel area’ for alien species and global environmental changes owing to its geographic position, thus deserving special attention. Remotely operated vehicle surveys, carried out in 2016 and 2017, were analysed to provide the first ecological characterization of benthic assemblages at depths −19 – −384 m around Linosa Island. Communities were dominated by three priority habitats, amounting to 39% of the almost 5 km of the sea floor that was surveyed. These are represented in the euphotic zone by Posidonia oceanica meadows and, at greater depth, by newly discovered dense coral forests and extended rhodolith/maërl beds. Sixteen habitat‐forming species included in the Red List of the International Union for Conservation of Nature (e.g. gorgonians Eunicella cavolini and Paramuricea clavata, and black corals Antipathella subpinnata and Leiopathes glaberrima) were recorded, as well as individuals of Sargassum sp. at −100 m depth. The volcanic island of Linosa represents a small, naturally preserved area, with very limited human pressure, hosting rich marine benthic biodiversity. Given the high species and habitat richness, we recommend its inclusion in the Special Protected Areas of Mediterranean Importance project (United Nations Environment Programme) and suggest a redefinition of the existing marine protected area extension.

Iron speciation and annual records in black coral as new proxy for mining and environmental impacts.

Iron (Fe) is a micronutrient and plays an important role in regulating ocean primary production and consequently changing oceanic CO2 uptake. However, approaches for high-resolution of Fe records in marine environment has been a great challenge. In this study, we report for the first time an annual Fe record on black coral organic skeleton from the northern South China Sea (SCS) as an archive to study the environmental change during the past century. In situ micro-Raman, synchrotron micro X-ray absorption near edge spectroscopy (μ-XANES) and synchrotron micro X-ray fluorescence (μ-XRF) were applied to investigate the Fe speciation and the radial Fe profile in black coral. The preliminary results from micro-Raman and synchrotron micro XANES analysis demonstrated that Fe in black coral was mainly combined with 3,4-dihydroxyphenylalanine (dopa) as tris-DOPA-Fe complex. Such spatial coordination structure of complexation makes Fe have high affinity with dopa in black coral. Furthermore, elevated Fe concentration in Fe profile recorded on synchrotron μ-XRF spectra with 2.5μm resolution corresponded well to the exploitation history of the adjacent onshore Tiandu Iron Mine (Sanya, China) from 1939 to 1960. Other distinct Fe peak coincides with the war activities in 1970s. The findings presented in this work indicate that the high-resolution iron record with low annual growth rate (~17.8μmyear-1) of black coral may serve as a proxy of marine environmental record.

Sclerobionts associated with Orbiramus from the Early Ordovician of Hubei, China, the oldest known trepostome bryozoan

In addition to a marked rise in marine biodiversity, the Ordovician witnessed the most profound increase in the complexity of marine ecosystems in the history of the earth, including the expansion of tiering and enhanced biotic interactions. In order to understand these changes, it is important to study palaeoecological relationships among organisms at the commencement of the Great Ordovician Biodiversification Event (GOBE). Here, we describe sclerobionts associated with one of the earliest bryozoans in the fossil record, the oldest known trepostome, Orbiramus from the Fenhsiang Formation (late Tremadocian) of Hubei Province, China. These sclerobionts are diverse and include borings (e.g. Trypanites and Sanctum), bioclaustrations of vermiform organisms, and syn-vivo fouling by the putative black coral Sinopathes and other bryozoans. Diverse sclerobiotic associations and intricate palaeoecological relationships had already been established between bryozoans and other metazoans by the Tremadocian, showing the early onset of the ‘hard substrate revolution’ during the GOBE.

Stable isotopes (δ13C and δ15N) in black coral as new proxies for environmental record

Stable isotopes (δ13C and δ15N) in marine ecosystem are useful proxies for environmental record. In this study, a time-series analysis of δ13C and δ15N in two black coral samples collected from off-shore and near-shore environment was performed to investigate variations in climate and environment changes over the last 110 years. The results showed a decreasing trend of δ13C in both samples, implying an increase of fossil fuel consumption in modern age - the Suess effect. Meanwhile, a difference in δ15N between the offshore and nearshore black coral samples can be attributed to atmospheric transport of natural terrigenous source input and local anthropogenic activities. This study demonstrates that black coral has advantages as an environmental proxy compared with other traditional ones, and suggests that δ13C and δ15N in black coral can be used as new proxy indicators for climate changes related to anthropogenic activities.

ITS1 variation among Stichopathes cf. maldivensis (Hexacorallia: Antipatharia) whip black corals unveils conspecificity and population connectivity at local and global scales across the Indo-Pacific

Due to the dearth of molecular markers variable enough to distinguish species of black corals, species delimitation in Antipatharia is still mainly based on morphological traits. One of the few markers available, the internal transcribed spacer (ITS) region located in ribosomal DNA, has already been used several times to infer phylogenetic relationships among antipatharians. However, this region was never considered in population-scale studies of shallow-water black corals till now. Here, we sampled two phenotypic variants of 41 specimens of the shallow-water antipatharian Stichopathes cf. maldivensis along the SW of Madagascar. The sampling area represents 200 km of shore and encompasses the runoffs of three rivers. We used direct sequencing to determine the main ITS1 types present in the genomes of the collected specimens and retrieved sequences from GenBank for Indonesian specimens. Then, we constructed a haploweb to visualize possible species boundaries using the criterion of mutual allelic exclusivity. With this method, we confirm that the previously described phenotypic variants belong to a single species that apparently extends from Indonesia to Madagascar. Likewise, the three rivers that pour freshwater in southwestern Madagascar do not appear to act as a barrier for the larval dispersal of this species. This study highlights the usefulness of ITS markers within antipatharians at both species and population levels.

Polyp bailout and reattachment of the abundant Caribbean octocoral Eunicea flexuosa

Anthozoans exhibit great plasticity in their responses to stressful conditions, including decreasing individual size, detaching from the substratum and relocating, and releasing endosymbiotic microalgae. Another response to stress used by some colonial anthozoans is polyp bailout, in which the coenenchyme breaks down and individual polyps detach from the colony. We observed polyp bailout in the common Caribbean gorgonian Eunicea flexuosa after 8 h of aerial exposure. After 9 days, 28% of bailed-out polyps reattached, although none opened to resume feeding. Polyp bailout is a costly and high-risk escape response, but reattachment indicates that this can be a genet-saving behavior in cases where whole-colony mortality is likely. While it has been described in two octocorals, several species of scleractinians, and one black coral, we still do not know how widespread this behavior is in anthozoans.

Deep-sea habitat characterization using acoustic data and underwater imagery in Gazul mud volcano (Gulf of Cádiz, NE Atlantic)

Gazul is the shallowest mud volcano (MV) within the Shallow Field of Fluid Expulsion (SFFE) of the northeastern Gulf of Cádiz (NE Atlantic; 300–1200 m depth). The SFFE represents an important geo- and biodiversity area that was designated as a Site of Community Importance under the European Habitats Directive in 2014. In this study, geological features, habitats and associated biodiversity, as well as anthropogenic impacts, were characterized at Gazul MV from underwater imagery and multibeam bathymetry. Multivariate methods using the Bray-Curtis similarity index identified six main habitats, each of which harbored a characteristic faunal assemblage that included: (1) sandy ripple bottoms typified by the actiniarian Actinauge richardi; (2) sandy, muddy, coarse sand and bioclastic bottoms dominated by the solitary coral Flabellum chunii; (3) coarse sand and bioclastic bottoms, together with soft sediments covered by scattered methane-derived authigenic carbonates (MDACs) (mixed bottoms), characterized by the echinoid Cidaris cidaris; (4) hard bottoms comprising MDACs dominated by a wide variety of sponges and gorgonians; (5) coral-rubble bottoms typified by the presence of colonial scleractinian communities dominated by Madrepora oculata; and (6) mixed bottoms characterized by the presence of a styelid ascidian. Slope and water depth were the main factors explaining assemblages’ distribution, which was also supported by the presence of MDACs such as slabs, crusts and chimneys on the seafloor, as well as by the geomorphologic diversity of Gazul MV. The results highlight Gazul MV as an eco-biologically important area harboring different vulnerable marine ecosystem (VME) elements with indicator taxa such as scleractinians, sponges, gorgonians and black corals. ROV images revealed abandoned or lost fishing gears and marine debris on the seafloor, indicating anthropogenic impacts in Gazul MV and adjacent areas. Indeed trawling fisheries activities have also been detected in Vessel Monitoring System datasets. A fishery restricted area is recommended in Gazul MV due to the occurrence of diverse VMEs and species included in different conservation directives and conventions.

Multidisciplinary Scientific Cruise to the Northern Mid-Atlantic Ridge and Azores Archipelago

This work presents the preliminary result of the multidisciplinary cruise EXPLOSEA2 surveying the northern Mid-Atlantic Ridge and Azores Archipelago from 46° 30′ N to 38° 30′ N aboard the R/V Sarmiento de Gamboa and ROV Luso over 54 days (June 11 to July 27, 2019). In this cruise report, we detail the geophysical, hydrographic, geological, oceanographic, ecological, and microbiological data acquired and a brief of main findings. The cruise addressed the exploration and comprehensive characterization of venting sites, including the water column, the sediments and rocks that host the hydrothermal activity, and the associated mineralizations, biology, and microbiology. Deep hydrothermal chimneys and massive sulfide deposits (up 3,000 m in depth) within the Moytirra hydrothermal active field were identified on slopes that had not been explored previously. Another striking finding made during the EXPLOSEA2 cruise was the field of carbonate chimneys named the “Magallanes-Elcano” field, a potentially relict ultramafic-hosted hydrothermal site sourced by abiotic methane. This field is related to a serpentinite and gabbro rock outcropping on a dome-shaped massif named the “Iberian Massif.” An outstanding finding of the EXPLOSEA2 survey was the identification of the first garden of soft corals growing after active submarine eruptions were reported in the Azores Archipelago composed by a high density of soft corals the suborder Alcyoniina at the summit and flanks of a recent volcanic cone at 160 m water depth developed during the 1957–1958 eruption of Capelinhos. Several cold-water coral habitats formed by colonial scleractinians (e.g., Lophelia pertusa and Madrepora oculata), coral gardens composed of mixed assemblages of black corals (Leiopathes sp.), and octocorals and dense aggregations of the glass sponge Pheronema carpenteri that may be classified as vulnerable marine ecosystems (VMEs) have been discovered during the EXPLOSEA2 cruise along the northern Mid-Atlantic Ridge. This work reveals the importance of multidisciplinary surveys to the knowledge of deep-sea environments.