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While the distribution patterns of cold-water corals, such as Paragorgia arborea, have received increasing attention in recent studies, little is known about their in situ activity patterns. In this paper, we examine polyp activity in P. arborea using machine learning techniques to analyze high-resolution time series data and photographs obtained from an autonomous lander cluster deployed in the Stjernsund, Norway. An interactive illustration of the models derived in this paper is provided online as supplementary material. We find that the best predictor of the degree of extension of the coral polyps is current direction with a lag of three hours. Other variables that are not directly associated with water currents, such as temperature and salinity, offer much less information concerning polyp activity. Interestingly, the degree of polyp extension can be predicted more reliably by sampling the laminar flows in the water column above the measurement site than by sampling the more turbulent flows in the direct vicinity of the corals. Our results show that the activity patterns of the P. arborea polyps are governed by the strong tidal current regime of the Stjernsund. It appears that P. arborea does not react to shorter changes in the ambient current regime but instead adjusts its behavior in accordance with the large-scale pattern of the tidal cycle itself in order to optimize nutrient uptake., 25 pages

The cold-water gorgonian coral Paragorgia arborea is considered as a foundation species of deep-sea ecosystems in the northern Atlantic and Pacific oceans. To advance lipidomic studies of deep-sea corals, molecular species compositions of diacylglycerol ethers (DAGE), which are specific storage lipids of corals, and structural glycerophospholipids (GPL) including ethanolamine, choline, inositol and serine GPL (PE, PC, PI, and PS, respectively) were analyzed in P. arborea by HPLC and tandem mass spectrometry. In DAGE molecules, alkyl groups (16:0, 14:0, and 18:1), polyunsaturated fatty acids (PUFA), and monounsaturated FA are mainly substituted the glycerol moiety at position sn-1, sn-2, and sn-3, respectively. The ether form (1-O-alkyl-2-acyl) predominates in PE and PC, while PI is comprised of the 1,2-diacyl form. Both ether and diacyl forms were observed in PS. At position sn-2, C20 PUFA are mainly attached to PC, but C24 PUFA, soft coral chemotaxonomic markers, concentrate in PS, PI, and PE. A comparison of non-polar parts of molecules has shown that DAGE, ether PE, and ether PC can originate from one set of 1-O-alkyl-2-acyl-sn-glycerols. Ether PE may be converted to ether PS by the base-exchange reaction. A diacylglycerol unit generated from phosphatidic acid can be a precursor for diacyl PS, PC, and PI. Thus, a lipidomic approach has confirmed the difference in biosynthetic origins between ether and diacyl lipids of deep-sea gorgonians.

In the 10th edition of the Systema Naturae (Linnaeus, 1758), which is the starting point of the Code for Zoological Nomenclature (ICZN Art. 3), Linnaeus named three species of the genus Alcyonium, A. arboreum, A. digitatum, and A. bursa. The genus name Alcyonium was based on the 16th and 17th century pre-Linnaean use for a diversity of marine organisms, including cnidarians, sponges, bryozoans, and algae. In the first valid presentation of the genus name, Linnaeus narrowed this down to comprise two clear cnidarians (A. arboreum, currently Paragorgia arborea, and A. digitatum, still accepted under this name and subsequently assigned as type species), but the pre-Linnaean diversity perhaps explains why the third species, A. bursa, was not recognized as a cnidarian. Linnaeus defined it as ‘Alcyonium acaule pulposum subglobosum. Habitat in O. Europaea.’ (translated as: Alcyonium without stalk, fleshy, semiglobular. From the European Ocean).’ Attempts to fix its identity among contemporary authors at the end of the 18th and beginning of the 19th century followed a checkered course, with opinions varying from algae to tunicates and sponges.

Paragorgia arborea (Linnaeus, 1758) Material examined: BBB 2016: St. 13. Distribution: Western North Atlantic, East Canada to Cape Hatteras; Boreal Eastern Atlantic, northern Mid-Atlantic Ridge; Lusitanian-Mediterranean (Watling & Auster 2005); Norway to Nova Scotia, including Faroes Islands, Iceland and Greenland, 1330 m (Tendal 1992); off Crozet Islands, Indian Ocean (46°05’– 46°24.1’S, 49°37.0’– 50°37.1’E, 140–270 m) (Grasshoff 1979; D’Ambrosio et al. 1984); Aleutian Islands (Heifetz et al. 2005); Makarov Bay, Iturup Island, Sea of Okhotsk (Nedashkovskaya et al. 2005); Southern California (52°17’– 52°22’N, 160°40’– 160°34’E, 659–798 m), New Zealand (33°55’36”S– 52°17’22”S, 159°40’00– 177°54’30”E, 659–1525 m) (Sánchez 2005); Off Patagonia and Malvinas Islands (40°57’– 54°38’S, 56°52’– 63°00’W, 340– 1000 m) (Grasshoff 1979); Burdwood bank (54°31´S, 62°11´W, 330 m) (as Paragorgia sp.) (Auscavitch & Waller 2017); Drake Passage, 57°04´S, 67°30´W, 1400 m (as Paragorgia sp.) (Waller & Robinson 2011); off Staten Island (608 m) (present study). Remarks: According to Sánchez (2005), this species has a disjunct distribution between the Arctic and Antarctic, with no linking records. Auscavitch & Waller (2017) and Waller & Robinson (2011) cited Paragorgia sp. for the Drake passage and Burdwood bank, their identification at genus level is justified since the samplings were made by towed camera surveys. Deichmann (1936) said that according to Verrill (1922) this species is common off the fishing banks off Nova Scotia and Newfoundland., Published as part of Schejter, L., Genzano, G., Pérez, C. D., Acuña, F., Cordeiro, R. T. S., Silva, R. A., Garese, A. & Bremec, C. S., 2020, Checklist of Benthic Cnidaria in the SW Atlantic Ocean (54 ºS- 56 ºS), pp. 201-239 in Zootaxa 4878 (2) on page 222, DOI: 10.11646/zootaxa.4878.2.1, http://zenodo.org/record/4424884, {"references":["Watling, L. & Auster, P. J. (2005) Distribution of deep-water Alcyonacea off the northeast coast of the United States. In: Freiwald, A. & Roberts, J. M. (Eds.), Cold-Water Corals and Ecosystems. Springer-Verlag, Berlin, pp. 279 - 296.","Tendal, O. S. (1992) The North Atlantic distribution of the octocoral Paragorgia arborea (L., 1758) (Cnidaria, Anthozoa). Sarsia, 77, 213 - 217. https: // doi. org / 10.1080 / 00364827.1992.10413506","Grasshoff, M. (1979) Zur bipolaren Verbreitung der Oktokoralle Paragorgia arborea (Cnidaria: Anthozoa: Scleraxonia). Senckenbergiana Maritima, 11 (3 / 6), 115 - 137.","D'Ambrosio, M., Guerriero, A. & Pietra, F. (1984) Arboxeniolide- 1, a New, Naturally Occurring Xeniolide Diterpenoid from the Gorgonian Paragorgia arborea of the Crozet Is. (S. Indian Ocean). Zeitschrift fur Naturforschung C, 39 (11 - 12), 1180 - 1183. https: // doi. org / 10.1515 / znc- 1984 - 11 - 1232","Heifetz, J., Wing, B. L., Stone, R. P., Malecha, P. W. & Courtney, D. L. (2005) Corals of the Aleutian Islands. Fisheries Oceanography, 14, 131 - 138. https: // doi. org / 10.1111 / j. 1365 - 2419.2005.00371. x","Nedashkovskaya, O., Kim, S., Lysenko, A., Frolova, G., Mikhailov, V. & Bae, K. (2005) Bizionia paragorgiae gen. Nov., sp. nov., a novel member of the family Flavobacteriaceae isolated from the soft coral Paragorgia arborea. International Journal of Systematics and Evolutionary Microbiology, 55 (1), 375 - 378. https: // doi. org / 10.1099 / ijs. 0.63381 - 0","Sanchez, J. A. (2005) Systematics of the bubblegum corals (Cnidaria: Octocorallia: Paragorgiidae) with description of new species from New Zealand and the Eastern Pacific. Zootaxa, 1014 (1), 1 - 72. https: // doi. org / 10.11646 / zootaxa. 1014.1.1","Auscavitch, S. & Waller, R. (2017) Biogeographical patterns among deep sea megbenthic communities across the Drake Passage. Antarctic Science, 29 (6), 531 - 543. https: // doi. org / 10.1017 / S 0954102017000256","Deichmann, E. (1936) The Alcyonaria of the western part of the Atlantic Ocean. Memoirs of the Museum of Comparative Zoology at Harvard, 53, 1 - 317.","Verrill, A. E. (1922) Alcyonaria and Actinaria. Report of the Canadian Arctic Expeition, 8 (G), 1 - 164."]}

23 pages, 14 figures, 5 tables, Imaging technologies are being deployed on cabled observatory networks worldwide. They allow for the monitoring of the biological activity of deep-sea organisms on temporal scales that were never attained before. In this paper, we customized Convolutional Neural Network image processing to track behavioral activities in an iconic conservation deep-sea species¿the bubblegum coral Paragorgia arborea¿in response to ambient oceanographic conditions at the Lofoten-Vesterålen observatory. Images and concomitant oceanographic data were taken hourly from February to June 2018. We considered coral activity in terms of bloated, semi-bloated and non-bloated surfaces, as proxy for polyp filtering, retraction and transient activity, respectively. A test accuracy of 90.47% was obtained. Chronobiology-oriented statistics and advanced Artificial Neural Network (ANN) multivariate regression modeling proved that a daily coral filtering rhythm occurs within one major dusk phase, being independent from tides. Polyp activity, in particular extrusion, increased from March to June, and was able to cope with an increase in chlorophyll concentration, indicating the existence of seasonality. Our study shows that it is possible to establish a model for the development of automated pipelines that are able to extract biological information from times series of images. These are helpful to obtain multidisciplinary information from cabled observatory infrastructures, This project is funded by The Norwegian Research Council, Federal Ministry for Economic Affairs and Energy of Germany (03SX464C) and the Helmholtz Gemeinschaft Deutscher Forschungszentren (HGF) project Modular Observation Solutions for Earth Systems (MOSES), Spanish Centre for the Development of Industrial Technology (EXP 00108707/SERA-20181020), and co-funded by European Union’s Horizon 2020 research and innovation program under the framework of European Research Area Network (ERA-NET) Cofund Maritime and Marine Technologies for a new Era (MarTERA), With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

Cold-water corals are habitat-forming species that are also classified as indicators of vulnerable marine ecosystems (VMEs) due to the threat of various anthropogenic impacts, e.g., fisheries and oil/mineral exploration. To best protect VMEs, knowledge of their habitat requirements and distribution is essential. However, comprehensive sampling of the deep sea is difficult due to access and cost constraints, so species distribution modeling (SDM) is often used to predict overall distributions and ecological preferences of species based on limited data. We used Maximum Entropy (Maxent) modeling to predict the probability of presence of the reef-building scleractinian Lophelia pertusa and the octocorals Paragorgia arborea and Primnoa resedaeformis using a total of 2149 coral presence points and 15 environmental predictor variables. The environmental variables used in the analysis were processed to 176 m resolution and included bathymetry, depth, geomorphometric characteristics [slope, aspect, and bathymetric position index (BPI)], oceanography (temperature, salinity, current directions, and speed), surface chlorophyll a concentration, sediment type, and marine landscape type. Comparing presence points with environmental data showed that the temperature and depth range for Lophelia was narrower compared to the gorgonians, and it occurred in shallower, warmer water. Observations showed that Lophelia had a broad, bimodal response to Broad BPI, while the predicted model indicated a more narrow response. Paragorgia tolerated the greatest range of sloping according to the model. All three species were observed with a bimodal pattern along a wide range of mean current speed, while the models indicated a high response to faster current speed. Jackknife tests showed that sediment type was an important predictor for gorgonian corals, while BPI and minimum temperature were more important for Lophelia. The spatial precision of the models could be further increased by applying environmental layers with a higher and uniform spatial resolution. The predicted distribution of corals and their relation to environmental variables provides an important background for prioritizing areas for detailed mapping surveys and will aid in the conservation efforts for these VMEs in Norwegian waters and beyond. publishedVersion

Species composition of the most common species belonging to the taxa of macrozoobenthos - potential indicators of vulnerable marine ecosystems is considered on the data of bottom-sampler and bottom trawl surveys in the Chukotka and Koryak districts of the Bering Sea. The Chukotka district is mostly shallow-water area (prevailing depths 20-60 m) where these taxa-indicators are: sponges ( Myxilla incrustans , Halichondria panicea , and Semisuberites cribrosa ), barnacles ( Chirona evermanni ), ascidians ( Halocynthia aurantium and Boltenia ovifera ), octocorals ( Gersemia rubiformis ), bryozoans ( Cystisella saccata and Flustra foliacea ), and brittle stars ( Gorgonocephalus eucnemis ). Settlements of immobile sestonophages (the first 5 taxa) occupy mainly the hard or mixed bottom grounds in the coastal zone and movable filtrator (the last taxon) is distributed deeper on loose grounds. The Koryak district is deeper (up to 870 m depth); beyond the abovementioned taxa the other common taxa-indicators here are marine whips ( Halipteris willemoesi ), sea lilies ( Heliometra glacialis ), and sea anemones ( Actinostola callosa ) and 3 more species are common for octocorals ( Anthomastus rylovi, Paragorgia arborea , and Paragorgia sp.). The list of taxa-indicators includes immovable or almost immovable sestonophages (octocorals, sponges, ascidians, bryozoans, barnacles, sea whips, and sea lilies), moving filtrators (brittle stars) and predators (sea anemones). All these taxa could be divided onto 3 groups according to the depth of their occurrence: i) continental shelf residents (barnacles, bryozoans, sea squirts Boltenia ovifera and Gersemia rubiformis ); ii) continental slope residents (octocorals, sea whips and sea lilies); iii) interzonal dwellers (sponges, brittle stars, sea squirt Halocynthia aurantium , and sea anemones). The epibenthos is the most abundant in the area between Cape Navarin and Cape Haidin that obviously is the sign of high bioproductivity of this area. The data of long-term observations confirm high stability of distribution patters and abundance of the epibenthic communities in the western Bering Sea.

Species distribution modelling can be applied to identify potentially suitable habitat for species with largely unknown distributions, such as many deep-water corals. Important variables influencing species occurrence in the deep sea, e.g. substrate composition, are often not included in these modelling approaches because high-resolution data are unavailable. We investigated the relationship between substrate composition and the occurrence of the two deep-water octocoral species Primnoa resedaeformis and Paragorgia arborea, which require hard substrate for attachment. On a scale of 10s of metres, we analysed images of the seafloor taken at two locations inside the Northeast Channel Coral Conservation Area in the Northwest Atlantic. We interpolated substrate composition over the sampling areas and determined the contribution of substrate classes, depth and slope to describe habitat suitability using maximum entropy modelling (Maxent). Substrate composition was similar at both sites - dominated by pebbles in a matrix of sand (>80%) with low percentages of suitable substrate for coral occurrence. Coral abundance was low at site 1 (0.9 colonies of P. resedaeformis per 100m2) and high at site 2 (63 colonies of P. resedaeformis per 100m2) indicating that substrate alone is not sufficient to explain varying patterns in coral occurrence. Spatial interpolations of substrate classes revealed the difficulty to accurately resolve sparsely distributed boulders (3-5% of substrate). Boulders were by far the most important variable in the habitat suitability model (HSM) for P. resedaeformis at site 1, indicating the fundamental influence of a substrate class that is the least abundant. At site 2, HSMs identified cobbles and sand/pebble as the most important variables for habitat suitability. However, substrate classes were correlated making it difficult to determine the influence of individual variables. To provide accurate information on habitat suitability for the two coral species, substrate composition needs to be quantified so that small fractions (

Over the past 15 years, multiple areas in the North Atlantic have been closed to destructive fishing practices to protect vulnerable deep-water coral ecosystems, known to provide habitat for diverse associated fauna. Despite the growing number of conservation measures, long-term studies on the recovery of deep-water coral communities from fisheries impacts remain scarce. In the Gulf of Maine, the Northeast Channel Coral Conservation Area (NECCCA)1 was established in 2002 to protect dense aggregations of the two numerically dominant octocoral species in the region, Primnoa resedaeformis and Paragorgia arborea. To evaluate the effectiveness of the conservation measures, we monitored shifts in abundance and size of these two coral species in the shallow section (400–700 m) of the NECCCA for 12 years after the fisheries closure. We also evaluated the appropriateness of the location of the deep boundaries of the NECCCA that were placed based on a precautionary approach with limited information on coral distribution at depths >500 m. Video transects were conducted with ROV “ROPOS” in 2001, 2006, 2010 and 2014. We found potential signs of recovery from fisheries impact at some of the shallow locations in 2014: higher coral abundance and the presence of some very large colonies as well as recruits compared to 2001 and 2006. However, spatial heterogeneity was pronounced and small colonies (

Corals and sponges in rocky deep-sea environments are foundation species postulated to enhance local diversity by increasing biogenic habitat heterogeneity and enriching local carbon cycling. These key groups are highly vulnerable to disturbances (e.g., trawling, mining, and pollution) and are threatened by expansive changes in ocean conditions linked to climate change (acidification, warming, and deoxygenation). Once damaged by trawling or other disturbances, recolonization and regrowth may require centuries or longer, highlighting the need for stewardship of these deep-sea coral and sponge communities (DSCSCs). To this end, the sustainability of DSCSCs may be enhanced not only by protecting existing communities, but also repopulating disturbed areas using active restoration methods. Here, we report one of the first studies to explore methods to restore deep-sea coral populations by translocating coral fragments of multiple coral species. Branches of deep-sea corals were collected by ROV from 800 to 1300 m depth off central California and propagated into multiple fragments once at the surface. These fragments were then attached to “coral pots” using two different methods and placed in the same habitat to assess their survivorship (n = 113 total fragments, n = 7 taxa, n = 7 deployment groups). Mean survivorship for all translocated coral fragments observed within the first 365 days was ∼52%, with the highest mortality occurring in the first 3 months. In addition to an initial temporal sensitivity, survival of coral fragments varied by attachment method and among species. All coral fragments attached to coral pots using zip ties died, while those attached by cement resulted in differential survivorship over time. The latter method resulted in 80–100% fragment survivorship after 1 year for Corallium sp., Lillipathes sp., and Swiftia kofoidi, 12–50% for the bamboo corals Keratoisis sp. and Isidella tentaculum, and 0–50% for the bubblegum corals Paragorgia arborea and Sibogagorgia cauliflora. These initial results indicate differences in sensitivities to transplanting methods among coral species, but also suggest that repopulation efforts may accelerate the recovery of disturbed DSCSCs.

Deep-water corals are significant ecosystem engineers that provide habitat complexity in the deep sea. They are indicator species of vulnerable marine ecosystems because of their slow growth and longevity, characteristics that can prolong recovery from disturbances such as fishing. For populations with discontinuous distributions, such as aggregations of deep-water corals, population connectivity is critical in regulating persistence and recovery and is one of the recommended elements in the design of area-based conservation measures. In this study, we assessed potential pathways of connectivity in the Corsair Canyon Conservation Area, off Nova Scotia, Canada, for populations of the deep-water corals Paragorgia arborea and Primnoa resedaeformis discovered in 2014 and afforded protection in 2016. Corsair Canyon located in the Canadian EEZ, ∼ 20 km from the border between Canada and the United States, is potentially receiving larvae from either the Canadian or US EEZ. In Corsair Canyon, P. arborea was very abundant at depths 484-856 m and some colonies of P. arborea were > 2 m high. These are the locally densest aggregations of P. arborea we have detected on the continental slope off Nova Scotia. We also recorded P. resedaeformis at similar depths. Colonies of both species were most often seen attached perpendicularly to a rock face, and into the current. We assessed hydrodynamic connectivity between Corsair Canyon and other canyons to the northeast and southwest along the continental slope with known occurrences of the two corals, using the ocean model Finite-Volume Community Ocean Model (University of Massachusetts-Dartmouth). Our results indicate that estimated hydrodynamic connectivity originates consistently from canyons to the southwest of Corsair Canyon, particularly Georges, and Heezen Canyons. Of these, only Georges Canyon is within Canada’s EEZ and based on our data has very sparse populations of corals that can supply potential recruits. Predicted connectivity with the Northeast Channel Coral Conservation Area occurs in winter and spring, but the complexity of circulation in those seasons needs to be resolved to confirm the strength of this connection. Our results strongly suggest that cross-boundary coordination is essential in the conservation of aggregations of deep-water corals in the northwest Atlantic, by ensuring larval exchange and connectivity.

Two cold-water coral taxa, Octocorallia in the class Anthozoa and Stylasteridae in the class Hydrozoa, were identified. Deep-water samples were collected in fishing nets at depths ranging between 20 and 200 m along the coasts of the East Sea in Korea from 1976 to 1993. The two species found in this study represent new records for Korea: Paragorgia arborea (Linnaeus, 1758) in the class Anthozoa, and Stylaster profundiporus Broch, 1936 in the class Hydrozoa. Two families, Paragorgiidae and Stylasteridae, are also newly recorded in Korea. Furthermore, the species name of another cold-water gorgonian species, Primnoa pacifica (Kinoshita, 1907) in the family Primnoidae, is amended in this report. The two newly recorded cold-water coral species from Korea are described in detail based on their morphological characteristics. Paragorgia arborea is characterized by its growth form, medulla and cortex, zooid dimorphism, canal system, and spicule composition. Stylaster profundiporus is distinguished by its external skeletal characteristics, such as the coordination of dactylopores and gastropores, presence or absence of gastrostyles and dactylostyles, cyclosystem orientation, ampullar position, gastropore tube shape, and coenosteal texture.

Environmental conditions influence species composition, including the microbial communities that associate with benthic organisms such as corals. In this study we identified and compared bacteria that associate with three common deep-water corals, Lophelia pertusa, Madrepora oculata and Paragorgia arborea, from a reef habitat on the mid-Norwegian shelf. The 16S rRNA gene amplicon sequencing data obtained revealed that >50% of sequences were represented by only five operational taxonomic units. Three were host-specific and unclassified below class level, belonging to Alphaproteobacteria with affiliation to members of the Rhizobiales order (L. pertusa), Flavobacteria affiliated with members of the Elisabethkingia genus (M. oculata) and Mollicutes sequences affiliated with the Mycoplasma genus (P. arborea). In addition, gammaproteobacterial sequences within the genera Sulfitobacter and Oleispira were found across all three deep-water coral taxa. Although highly abundant in the coral microbiomes, these sequences accounted for 200 m), mesophotic (30–200 m) and shallow (

Coral bacterial associates can play important functional roles for the holobiont, such as nitrogen cycling, nutrient processing, and supporting immunity. While bacteria found within the microbiome of corals may benefit the host, they can also be linked to pathogenesis. In the deep-sea, cold-water corals, like their warm shallow-water counterparts, host bacterial communities, but have received little attention due to logistical constraints in sampling. In particular, bacteria associated with surficial mucus of cold-water corals have not yet been investigated. Here, tissue and mucus samples of Paragorgia arborea were collected from three submarine canyons along the continental slope of the Gulf of Maine. Bacterial DNA was extracted from tissue and mucus samples and sequencing of the V6–V8 hypervariable region of the 16S rRNA gene was performed using Illumina MiSeq. The bacterial communities associated with P. arborea compartments (tissue and mucus) and sampling locations (canyon) differed significantly in composition. Proteobacteria, Tenericutes, and Spirochaetes were the dominant phyla across the majority of coral tissue samples, with Gammaproteobacteria and Alphaproteobacteria identified as the largest Proteobacteria contributors across all samples. Operational taxonomic units (OTUs) belonging to the taxa Spirochaeta, Mycoplasma, Flavobacteriaceae, Terasakiellaceae, Campylobacterales, and Rickettsiales were identified as biomarkers (bacterial taxa significantly more abundant in a specific coral microhabitat) of P. arborea tissues, while Paracoccus was a biomarker of P. arborea mucus. Many of the recovered biomarker taxa may be involved in nitrogen cycling. Representatives from several bacterial families (Vibrionaceae, Campylobacteraceae, Rhodobacteraceae, Flavobacteriaceae, and Burkholderiaceae) previously reported in diseased scleractinians, were present in P. arborea as rare bacterial taxa. Characterizing the bacterial associates present in visibly healthy coral colonies provides a benchmark of dominant and rare bacterial groups present in the cold-water coral holobiont. This is the first characterization of bacterial groups associated with P. arborea, examining both tissue- and mucus-specific communities.

Fatty acid (FA) markers are used to trace predator–prey relationships in the marine environment. Soft corals contain tetracosapolyenoic acids (TPA), namely 24:5n-6 and 24:6n-3, which are considered as octocoral FA markers. The nudibranch mollusks are known to feed on soft corals. To check whether TPA are transferred from soft corals to nudibranch mollusks during their nutrition, we determined and compared FA compositions of total lipids of Tochuina tetraquetra and soft corals (Acanella sp., Anthomastus rylovi, Gersemia fruticosa, and Paragorgia arborea) collected together near the Kuril Islands (the depths of 80–550 m). FA compositions of T. tetraquetra, Acanella sp. and A. rylovi were described for the first time. In Acanella sp., G. fruticosa, A. rylovi, and P. arborea, the average contents of TPA were 6.5, 13.4, 5.9, and 12.0 % of total FAs, whereas the 24:5n-6/24:6n-3 ratio was 1.0, 1.4, 5.4, and 2.6, respectively. The high level of TPA (21.7 %) found in T. tetraquetra indicates that 24:5n-6 and 24:6n-3 are transferred from soft corals to the mollusks during their feeding and accumulated in mollusk tissues. The most possible feed source of the mollusk is suggested to be G. fruticosa and/or Acanella sp., because the 24:5n-6/24:6n-3 ratios in T. tetraquetra and these soft corals were similar. Thus, the TPA could be used as FA markers to estimate a proportion of soft corals in feeding of cold-water nudibranch mollusks.

This paper describes the fauna associated with the gorgonians Paragorgia arborea (530 colonies), Primnoa resedaeformis (370 colonies) and Paramuricea placomus (68 colonies) and the sea pens Kophobelemnon stelliferum (584 colonies), Virgularia mirabilis (114 colonies), Funiculina quadrangularis (278 colonies) and Pennatula phosphorea (36 colonies) recorded by video from 18 locations on the Norwegian continental margin. The fauna associated with gorgonians was more diverse than that of the sea pens, with 21 and 12 taxa recorded. P. arborea had the highest number of associates; in total 38% of the colonies had associates on them. Amphipods dominated numerically contributing with 72% to the total number of taxa observed. Shrimps and the basket star Gorgonocephalus sp. were frequently observed on all gorgonian species. Rarefaction analysis indicated that the number of associated taxa was richest for P. resedaeformis. The fauna associated with the sea pens consisted mainly of shrimps and ophiuroids, for which the sea pens play a key role as a shelter and/or as a feeding platform. The ophiuroid Asteronyx loveni was only observed on F. quadrangularis, which is used as a platform to reach better feeding conditions. The squat lobster Munida sp. was often observed close to the sea pen K. stelliferum which presumably offer shelter against predators. We argue that both sea pens and gorgonians play an important role as a habitat, and that a better understanding of their ecological importance is essential to develop sound scientific advice on sustainable habitats and fisheries management of deep-water ecosystems. & 2015 Published by Elsevier Ltd.

The distribution of nine cold-water corals in the cold temperate North Atlantic is described based on existing records. The species studied are Lophelia pertusa, Madrepora oculata, Paragorgia arborea, Primnoa resedaeformis, Paramuricea placomus, Acanella arbuscula, Isidella lofotensis, Radicipes gracilis and Acanthogorgia armata. The compiled number of records were 5,854, of which 4,875 were obtained from databases and 979 from publications. Distribution maps were produced and temperature, broad-scale topography and current patterns were considered to understand the distribution patterns and conditions at which the species thrive. Currents connecting shelves and slopes above 500 m can explain the wide spatial distribution of L. pertusa, P. arborea and P. resedaeformis. However, L. pertusa is scarce on the western side of the North Atlantic, P. arborea has only few records off Iceland and A. arbuscula and A. armata are not found on the Norwegian shelf. The differences in distribution patterns between species indicate that they are differently affected by the topographic barrier between the North Atlantic and the Nordic Seas. Present knowledge of dispersal ability of cold-water corals does not allow a firm causal explanation to the observed distribution patterns. These, however, are indicative of biogeographic provinces relevant to cold-water corals and their habitat requirements.

A multi-disciplinary study of two major submarine canyons, Baltimore Canyon and Norfolk Canyon, off the US mid-Atlantic coast focused on the ecology and biology of canyon habitats, particularly those supporting deep-sea corals. Historical data on deep-sea corals from these canyons were sparse with less than 750 records for the mid-Atlantic region, with most being soft sediment species. This study substantially increased the number of deep-sea coral records for the target canyons and the region. Large gorgonians were the dominant structure-forming coral taxa on exposed hard substrates, but several species of scleractinians were also documented, including first observations of Lophelia pertusa in the mid-Atlantic Bight region. Coral distribution varied within and between the two canyons, with greater abundance of the octocoral Paragorgia arborea in Baltimore Canyon, and higher occurrence of stony corals in Norfolk Canyon; these observations reflect the differences in environmental conditions, particularly turbidity, between the canyons. Some species have a wide distribution (e.g., P. arborea, Primnoa resedaeformis, Anthothela grandiflora), while others are limited to certain habitat types and/or depth zones (e.g., Paramuricea placomus, L. pertusa, Solenosmilia variabilis). The distribution of a species is driven by a combination of factors, which include availability of appropriate physical structure and environmental conditions. Although the diversity of the structure-forming corals (gorgonians, branching scleractinians and large anemones) was low, many areas of both canyons supported high coral abundance and a diverse coral-associated community. The canyons provide suitable habitat for the development of deep-sea coral communities that is not readily available elsewhere on the sedimented shelf and slope of the Mid-Atlantic Bight.

This thesis explores a set of environmental variables may be used to predict the spatial distribution of the three most common cold-water coral (CWC) species in Norway: Lophelia pertusa, Paragorgia arborea, and Primnoa resedaeformis. CWCs are important biogenic habitats that provide substrate and living space for a variety of deep-sea sessile organisms and commercially important fish, but are threatened by various anthropogenic impacts (e.g. bottom trawling, petroleum exploration and mineral mining), leading to increased efforts to appraise and protect them. Deep-sea exploration is difficult due to cost, time and access constraints, so in order to target protection efforts, species distribution models (SDM) can be created to find areas with the highest probability of species presence. The Maximum Entropy (Maxent) 3.4.1 program was used on CWC presence data and several environmental variable layers covering the Norwegian continental shelf from the southern end of Norway to Svalbard. Data on CWC presence positions from MAREANO video records for all three species together with the IMR Lophelia Reef Database with additional Lophelia presence points were used. The environmental variables were: depth and terrain proxies from a bathymetry layer (processed to 176 x 176m resolution) from EMODnet, oceanographic variables from the Norkyst-800 model, surface chlorophyll a concentration from the Ocean Biology Processing Group in NASA, and sediment and marine landscape type as defined by NGU. Data was prepared and visualized in ArcMap 10.5.1 and environmental characteristics at CWC presence points were summarized in Excel prior to modeling. Maxent produced SDMs that indicated high probability of presence especially on the continental margin and along the Norwegian coast and near fjords. Jackknife tests showed that sediment was particularly important for the gorgonian corals, while chlorophyll a uniquely predicted well for Lophelia. Depth, mean current speed, marine landscape, and slope were important individual indicators of presence for all. The hope is that information gained from the modeled distributions and predictor variables used will help conservation efforts for Lophelia, Paragorgia, and Primnoa. Master's Thesis in Biology BIO399

The coral species Paragorgia arborea and Primnoa resedaeformis are abundant and widely distributed gorgonians in North Atlantic waters. Both species add significant habitat complexity to the benthic environment, and support a host of invertebrate species. Mapping their distribution is an essential step in conservation and resource management, but challenging as a result of their remoteness. In this study, three predictive models — Ecological Niche Factor Analysis, Genetic Algorithm for Rule-set Production and Maximum Entropy modeling (MaxEnt) were applied to predict the distribution of species' suitable habitat across a region of Rost Reef (Norwegian margin) based on multiscale terrain variables. All three models were successful in predicting the habitat suitability for both gorgonian species across the study area, and the MaxEnt predictions were shown to outperform other predictions. All three models predicted the most suitable habitats for both species to mainly occur along the ridges and on the upper section of the large slide, suggesting both species preferentially colonize topographic highs. Jackknife tests for MaxEnt predictions highlighted the seabed aspect in relation to P. arborea distribution, and the seabed relative position (curvature) in relation to the distribution of both species. Given the vulnerability of deep-water corals to anthropogenic impacts, further comparative study over a wider study area would be particularly beneficial for the management of the species.

Taphonomic degradation of cold-water gorgonian and antipatharian corals may affect the record of dead or broken corals remaining on the sea floor after damage by deep-sea fisheries. A taphonomic experiment on skeletal degradation of four species of gorgonians and one antipatharian was run in aquaria for 14 months. Paragorgia arborea skeletal fragments, composed of spongy proteins and calcite spicules, were completely degraded within 14 months. Protein-skeletons of Paramuricea and antipatharian fragments gained 10-20% wet weight through hydration of their proteinaceous skeletons. Calcitic gorgonian skeletons of Primnoa resedaeformis and Keratoisis grayi experienced no significant weight change during the experiment. Field observations of dead dislodged and dead skeletons corroborated experimental results. Dislodged and dying P. arborea skeletons were rigid in their live parts, but friable and fragile in their dead parts. Subfossil calcareous gorgonian skeletons up to 2000 years in age have been recovered from the sea floor by trawl bycatch or ROV. Documenting fisheries damage to gorgonian coral forests on the sea floor requires observation within a few months after the fisheries impacts.

Geological features supporting cold-water coral habitat in Atlantic Canada are reviewed and exemplified using qualitative field observations from the Scotian margin and Southwest Grand Banks, Newfoundland, in the context of regional geology of the Atlantic Canadian continental margin. Coral habitats are concentrated in areas of shelf-crossing troughs and trough-mouth fans associated with glacial ice streams. Most habitat types are supported by glacial or glaciomarine depositional features, although some are supported by erosional features, probably related to subglacial meltwater erosion. Shelf-break and upper continental slope moraine deposits, subject to strong currents, form current-swept cobble-boulder pavements, forming the principal habitats for the large gorgonian corals Primnoa resedaeformis and Paragorgia arborea . At greater depths, upper slope till tongues are upper continental slope gravelly mud deposits, exposed at the surface as isolated cobbles and boulders in a muddy sand matrix. Common skeletal corals in these environments include the large long-lived gorgonian Keratoisis ornata , the smaller gorgonian Acanthogorgia armata , and, in muddy sand between rocks, the small gorgonian Acanella arbuscula . Erosional environments including friable Tertiary mudstones and semi-consolidated Quaternary sediments, colonized by large gorgonians and other corals, were observed in The Gully, the Stone Fence, and the Southwest Grand Banks. Weak bedrock strength may limit the size of large gorgonian coral colonies. Authigenic carbonate crusts, possibly related to cold seeps, may be locally important in supporting coral growth. Predictive models of coral distribution should consider Quaternary and surficial geology.

Deep-water corals form unique ecosystems, yet very little is known about factors that regulate their distribution and growth. The abundance and size of two deep-water gorgonian coral species, Paragorgia arborea and Primnoa resedaeformis , and their relationship with depth and substratum cover, were investigated at Northeast Channel, off Nova Scotia, in July 2006. This is the first study to measure abundance and size of these two coral species at depths >500 m in the Canadian Atlantic region. A total of 5 transects between 500 and 1000 m depth were examined using video collected by the remotely operated vehicle ROPOS. Abundance of both species was patchy, but higher at these deeper depths than at P. resedaeformis than for P. arborea , suggesting that factors such as topographic relief may play an additional role in regulating distributions of P. arborea . Maximum colony height was 125 and 240 cm for P. resedaeformis and P. arborea , respectively, and much greater than recorded for depths P. resedaeformis showed a negative relationship with depth, while the opposite was observed for P. arborea , suggesting that the two species are affected differently by factors that vary with depth (e.g. temperature, fishing disturbance). Relationships between colony size and size of attachment stone were stronger for P. arborea , especially for overturned colonies, than for P. resedaeformis , suggesting that availability of suitably coarse substrate may be more important for the long-term persistence of P. arborea colonies.

With the aim of understanding of the trophic ecology of cold-water corals, this paper explores the tissue d 13 C and d 15 N values of 11 ‘coral’ species (8 alcyonacean, 1 antipatharian, 1 pennatulacean, 1 scleractinian) collected along the Newfoundland and Labrador continental slope. Isotopic results delimit species along continua of trophic level and food lability. With an isotopic signature similar to macrozooplankton, Paragorgia arborea occupies the lowest trophic level and most likely feeds on fresh phytodetritus. Primnoa resedaeformis occupies a slightly higher trophic level, likely supplementing its diet with microzooplankton. Bathypathes arctica, Pennatulacea and other alcyonaceans (Acanella arbuscula, Acanthogorgia armata, Anthomastus grandiflorus

Offshore banks and seamounts sustain diverse megafaunal communities, including framework reefs formed by cold-water corals. Few studies have quantified environmental effects on the alpha or beta diversity of these communities. We adopted an interdisciplinary approach that used historical geophysical data to identify topographic highs on Hatton Bank, which were surveyed visually. The resulting photographic data were used to examine relationships between megafaunal communities and macrohabitat, the latter defined into six categories (mud, sand, cobbles, coral rubble, coral framework, rock). The survey stations revealed considerable small-scale variability in macrohabitat from exposed Late Palaeocene lava flows to quiescent muddy habitats and coral-built carbonate mounds. The first reported evidence for coral carbonate mound development in UK waters is presented, which was most pronounced near present-day or former sites of topographic change, suggesting that local current acceleration favoured coral framework growth and mound initiation. Alpha diversity varied significantly across macrohabitats, but not between rock and coral rubble, or between smaller grain sized categories of cobbles, sand and mud. Community composition differed between most macrohabitats, and variation in beta diversity across Hatton Bank was largely explained by fine-scale substratum. Certain megafauna were clearly associated with particular macrohabitats, with stylasterid corals notably associated with cobble and rock habitats and coral habitats characterized by a diverse community of suspension-feeders. The visual surveys also produced novel images of deep-water megafauna including a new photographic record of the gorgonian coral Paragorgia arborea, a species not previously reported from Rockall Plateau. Further interdisciplinary studies are needed to interpret beta diversity across these and other environmental gradients on Hatton Bank. It is clear that efforts are also needed to improve our understanding of the genetic connectivity and biogeography of vulnerable deep-water ecosystems and to develop predictive models of their occurrence that can help inform future conservation measures.

The distribution and abundance of benthic megafauna in areas known to be inhabited by dense gorgonian coral assemblages were examined at Northeast Channel, off Nova Scotia, Canada, in August 2001. Using a remotely operated vehicle, 1–5 video transects during each of 1–2 dives at each of four sites (Rips, Middle Canyon, Hell Hole West and Hell Hole East) were conducted. The relationships in the structure of biological assemblages at three spatial scales: within transects (10s of metres); between dive locations (100s of metres); and among sites (10s to 100s of kilometres) were explored. The most abundant epibenthic taxa included the gorgonians Primnoa resedaeformis and Paragorgia arborea, several suspension feeders (Actinauge verrilli, Bolocera tudiae, an unidentified anemone and encrusting sponge, Ophiacantha abyssicola), the deposit feeder Porania pulvillus insignus and the predatory Solaster endeca. The basket star Gorgonocephalus arcticus was present only on colonies of Paragorgia arborea. Despite large variability in abundance and assemblage composition among transects and dive locations, clear patterns were observed among sites. Mean abundance of most cnidarians and echinoderms was greatest at Hell Hole West. No gorgonians were found at Hell Hole East. The encrusting sponge was most abundant at the Rips and least abundant at Hell Hole East. Cluster analysis and multidimensional scaling (MDS) indicated that, when abundance was averaged across transects for each dive, the megafaunal assemblages fall into groups of dives that separated by site. These differences among sites are most likely related to variability in the physical environment. The epibenthic megafaunal assemblages were as diverse in the presence as in the absence of gorgonian corals, at least at the abundances that we observed. However, the apparent low recruitment and abundance, combined with small population size make these assemblages particularly vulnerable to perturbations.

The morphology of the gorgonian corals Paragorgia arborea and Primnoa resedaeformis was studied from video records and colonies collected from different locations in Atlantic Canada, at depths between 200 and 600 m. Growth was studied by relating colony height to age (number of growth rings) in P. resedaeformis, and from a photographic time-series of a P. arborea colony in a Norwegian fjord. The highest P. resedaeformis and P. arborea colonies were 86 and 180 cm, respectively. The height of P. arborea seemed to be restricted by the size of the boulder it was attached to. When the coral exceeds a critical height (approximately twice the stone size), the drag of strong currents can turn the coral and its substrate over. No limiting factors for the height of P. resedaeformis colonies were identified. P. arborea occurred in three colour varieties: red, salmon red, and white. The red and white contributed 41% to the population each, while 18% of the colonies were salmon red. On average the salmon red P. arborea were taller than the red and white. P. arborea colonies >50 cm were mainly concave fan shaped. The orientation of these indicated a near-bottom current pattern similar to what is known from previous current measurements in the area. P. resedaeformis occurred mainly on the up-current side of boulders, but its bushy morphology does not indicate influence by unidirectional current to the same degree as P. arborea. The different height, morphology, and position on boulders of the two species indicate that they utilize different food sources. P. resedaeformis seems to be adapted to a near-bottom environment with turbulent currents, whereas P. arborea utilize uni- or bidirectional currents higher above bottom by developing planar colonies perpendicular to the current. The oldest P. resedaeformis colony was 61 years. The relationship between height and age indicated an average growth of 1.7 cm year−1 for P. resedaeformis. X-ray images of skeletal sections of P. arborea showed clear growth bands with a maximum band width of 1.3 cm. It is not clear what time scales these bands represent, and they could therefore not be used for indicating age. The limited previously reported data on age and growth of P. arborea indicate an average growth rate of 1 cm year−1. This gives an age of about 180 years for the largest colony in this study. The time-series photographs, however, indicated a much higher growth rate (varying between 2 and 6 cm year−1 within the colony), which may be more representative for colonies of an intermediate size.

The distribution and abundance of deep-water gorgonian corals were investigated along 52 transects at 183–498 m depth in the Northeast Channel, between Georges Bank and Browns Bank in the northwest Atlantic, using a remotely operated vehicle and a towed video-camera system. Three species (Paragorgia arborea, Primnoa resedaeformis, and Acanthogorgia armata) were observed. Primnoa occurred on 35 transects below 196 m depth, with highest local abundance in stands of 104 colonies per 100 m2. Paragorgia was present on 21 transects deeper than 235 m, with highest local abundance of 49 colonies per 100 m2. Acanthogorgia was observed at only four transects between 231 m and 364 m, with a local maximum abundance of 199 colonies per 100 m2. The maximum abundance averaged for whole transects was 19.2 and 6.2 colonies per 100 m2 for Primnoa and Paragorgia, respectively. The corals were more common in the outer part of the channel along the shelf break and slope than on the shelf in the inner part. All three species showed a patchy distribution with no signs of competitive exclusion at any spatial scale. Transects with high abundance of corals were characterised by depths greater than 400 m, maximum temperatures less than 9.2°C, and a relatively high percentage coverage of cobble and boulder (more than 19% and 6%, respectively). High temperatures probably control the upper depth limit of the corals, and Primnoa seems to tolerate slightly higher temperatures than Paragorgia. Abundance of both species was negatively correlated with average temperature and positively with cobbles. Together, temperature, percentage cobble and salinity accounted for 38% of the variance of Primnoa. The comparable figure for Paragorgia was 15%. The observed distribution indicated that the abundance of coral is controlled by additional factors such as larger-scaled topographic features governing the current regimes and thus also the supply of food and larvae.

Paragorgia arborea, or bubblegum coral, occurs in continental slope habitats worldwide, which are increasingly threatened by human activities such as energy development and fisheries practices. From 101 putative loci screened, nine microsatellite markers were developed from samples taken from Baltimore canyon in the western North Atlantic Ocean. The number of alleles ranged from two to thirteen per locus and each displayed equilibrium. These nuclear resources will help further research on population connectivity in threatened coral species where mitochondrial markers are known to lack fine-scale genetic diversity.

15 pages, 8 figures, 4 tables, The spatial variability in the mix of species making up Cold-water coral reef communities is not well known. In this study abundances of a selection of megafauna (Lophelia pertusa, Madrepora oculata, Paragorgia arborea, Primnoa resedaeformis, Mycale lingua, Geodia baretti, Acesta excavata and fish) were quantified throughout 9 manned submersible video transects from 3 reef complexes (Røst Reef, Sotbakken Reef and Traena Reef) on the Norwegian margin. Substrate type (coral structure, rubble, exposed hardground or soft sediment) was also recorded. Variations in the densities of these fauna (with respect to both reef complex and substrate type) were investigated, with spatial covariance between species assessed.For the majority of fauna investigated, densities varied by both reef and substrate. Spatial covariance indicated that some species may be utilising similar habitat niches, but that minor environmental differences may favour colonisation by one or other at a particular reef. Fish densities were generally higher in regions with biogenic substrate (coral structure and coral rubble substrates) than in areas of soft or hardground substrate. Further, fish were more abundant at the northerly Sotbakken Reef at time of study than elsewhere. Community structure varied by reef, and therefore management plans aimed at maintaining the biodiversity of reef ecosystems on the Norwegian margin should take this lack of homogeneity into account. © 2013 Elsevier Ltd., The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007–2013) under the HERMIONE project, grant agreement n° 226354), Statoil and is a CORAMM group collaboration. The captain, crew and on-board scientific party of RV Polarstern ARKXXII/1a cruise are thanked for their assistance, particularly the IFM-GEOMAR JAGO team who provided access to the video data used in this paper. In the first stage of the development of this manuscript, C. Orejas and A. Gori were supported by a post doctoral and Ph.D. I3P contracts, respectively, (Ref. I3P-PC2006L, I3P-BPD2005) from the Consejo Superior de Investigaciones Científicas (CSIC)

Cold-water coral (CWC) reefs are heterogeneous ecosystems comprising numerous microhabitats. A typical European CWC reef provides various biogenic microhabitats (within, on and surrounding colonies of coral species such as Lophelia pertusa, Paragorgia arborea and Primnoa resedaeformis, or formed by their remains after death). These microhabitats may be surrounded and intermixed with non-biogenic microhabitats (soft sediment, hard ground, gravel/pebbles, steep walls). To date, studies of distribution of sessile fauna across CWC reefs have been more numerous than those investigating mobile fauna distribution. In this study we quantified shrimp densities associated with key CWC microhabitat categories at the Røst Reef, Norway, by analysing image data collected by towed video sled in June 2007. We also investigated shrimp distribution patterns on the local scale (Paragorgia arborea microhabitat (43 shrimp m−2, SD = 35.5), live Primnoa resedaeformis microhabitat (41.6 shrimp m−2, SD = 26.1) and live Lophelia pertusa microhabitat (24.4 shrimp m−2, SD = 18.6). In non-biogenic microhabitat, shrimp densities were −2. CWC reef microhabitats appear to support greater shrimp densities than the surrounding non-biogenic microhabitats at the Røst Reef, at least at the time of survey.

Deep-water gorgonian corals are long-lived organisms found worldwide off continental margins and seamounts, usually occurring at depths of ∼200–1,000 m. Most corals undergo sexual reproduction by releasing a planktonic larval stage that disperses; however, recruitment rates and the environmental and biological factors influencing recruitment in deep-sea species are poorly known. Here, we present results from a 4-year field experiment conducted in the Gulf of Maine (northwest Atlantic) at depths >650 m that document recruitment for 2 species of deep-water gorgonian corals, Primnoa resedaeformis and Paragorgia arborea. The abundance of P. resedaeformis recruits was high, and influenced by the structural complexity of the recipient habitat, but very few recruits of P. arborea were found. We suggest that divergent reproductive modes (P. resedaeformis as a broadcast spawner and P. arborea as a brooder) may explain this pattern. Despite the high recruitment of P. resedaeformis, severe mortality early on in the benthic stage of this species may limit the abundance of adult colonies. Most recruits of this species (∼80%) were at the primary polyp stage, and less than 1% of recruits were at stage of 4 polyps or more. We propose that biological disturbance, possibly by the presence of suspension-feeding brittle stars, and limited food supply in the deep sea may cause this mortality. Our findings reinforce the vulnerability of these corals to anthropogenic disturbances, such as trawling with mobile gear, and the importance of incorporating knowledge on processes during the early life history stages in conservation decisions.

Numerous deep-sea species have apparent widespread and discontinuous distributions. Many of these are important foundation species, structuring hard-bottom benthic ecosystems. Theoretically, differences in the genetic composition of their populations vary geographically and with depth. Previous studies have examined the genetic diversity of some of these taxa in a regional context, suggesting that genetic differentiation does not occur at scales of discrete features such as seamounts or canyons, but at larger scales (e.g. ocean basins). However, to date, few studies have evaluated such diversity throughout the known distribution of a putative deep-sea species. We utilized sequences from seven mitochondrial gene regions and nuclear genetic variants of the deep-sea coral Paragorgia arborea in a phylogeographic context to examine the global patterns of genetic variation and their possible correlation with the spatial variables of geographic position and depth. We also examined the compatibility of this morphospecies with the genealogical-phylospecies concept by examining specimens collected worldwide. We show that the morphospecies P. arborea can be defined as a genealogical-phylospecies, in contrast to the hypothesis that P. arborea represents a cryptic species complex. Genetic variation is correlated with geographic location at the basin-scale level, but not with depth. Additionally, we present a phylogeographic hypothesis in which P. arborea originates from the North Pacific, followed by colonization of the Southern Hemisphere prior to migration to the North Atlantic. This hypothesis is consistent with the latest ocean circulation model for the Miocene.

Investigating the relationship between deep-water coral distribution and seabed topography is important for understanding the terrain habitat selection of these species and for the development of predictive habitat models. In this study, the distribution of the deep-water gorgonians, Paragorgia arborea and Primnoa resedaeformis, in relation to terrain variables at multiple scales of 30 m, 90 m and 170 m were investigated at Røst Reef, Traena Reef and Sotbakken Reef on the Norwegian margin, with Ecological Niche Factor Analysis applied. To date, there have been few published studies investigating this aspect of gorgonian distribution. A similar correlation between the distribution of P. arborea and P. resedaeformis and each particular terrain variable was found at each study site, but the strength of the correlation between each variable and distribution differed by reef. The terrain variables of bathymetric position index (BPI) and curvature at analysis scales of 90 m or 170 m were most strongly linked to the distribution of both species at the three geographically distinct study sites. Both gorgonian species tended to inhabit local topographic highs across all three sites, particularly at Sotbakken Reef and Traena Reef, with both species observed almost exclusively on such topographic highs. The tendency for observed P. arborea to inhabit ridge crests at Røst Reef was much greater than was indicated for P. resedaeformis. This investigation identifies the terrain variables which most closely correlate with distribution of these two gorgonian species, and analyzes their terrain habitat selection; further development of predictive habitat models may be considered essential for effective management of these species.

Commonly called “bubblegum coral’, Paragorgia is a genus of cold-water gorgonian coral that has a broad global distribution and is eurybathic from depths of meters to kilometers. Such ecological breadth, however, may be confounded by the presence of cryptic species. In this study the genetic distances of various Paragorgia spp. across their distribution and depth range along the Canadian mid-Atlantic margin using 18S ribosomal DNA sequences were compared. Morphometric and 18S evidence show that although appearing closely related, only one species of cold-water Paragorgia, called P. arborea, predominates in this region. However, 18S evidence from corals collected at deep depths located at one site, called the Stone Fence, indicate that a significant amount of divergence exists and other species may also be present. Such new light provides a need for further genetic testing using alternative methods (e.g. microsatellites), which could reveal new lineages that may have considerable ecological and/or taxonomic importance.

New records of Paragorgia arborea from the Faroes, Iceland and Greenland show that the species has a coherent distribution from the coast of Norway to Nova Scotia. Offshore, P. arborea is always found at depths greater than about 200 m, following water from the North Atlantic Current, generally with a temperature of 4–8° C. Two cooccurring colour forms have been reported from most areas. Colonies about 2.5 m high have been documented, and it seeems likely that considerably larger ones exist.

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 study corals in the deep sea. They consider coral habitats created by stony scleractinian as well as octocoral species. The importance of corals as long-lived geological structures and palaeoclimate archives is discussed, in addition to ways in which they can be conserved. Topic boxes explain unfamiliar concepts, and case studies summarise significant studies, coral habitats or particular conservation measures. Written for professionals and students of marine science, this text is enhanced by an extensive glossary, online resources, and a unique collection of colour photographs and illustrations of corals and the habitats they form.

Three unusual new steroid thioesters, parathiosteroids A-C (1a-3a), were isolated from the 2-propanol extract of the soft coral Paragorgia sp. collected in Madagascar. Their structures, determined by detailed spectroscopic analysis, were confirmed by synthesis and represent the first isolation of natural steroids bearing a C22 thioester in their side chain. These compounds displayed cytotoxicity against a panel of three human tumor cell lines at the micromolar level. The preparation of several analogues revealed structure/activity relationships in this type of steroids, for example, that the XCH2CH2NHCOCH3 moiety (X = S, O, NH) in the side chain is essential for the antiproliferative activity, and a low degree of oxidation in the A-ring results in higher bioactivity. These natural products could be biosynthetic intermediates in the steroid side chain degradation pathway involving activation with CoA and beta-oxidations.

Paragorgia arborea (Linnaeus, 1758) (Figs. 6���9) Alcyonium arboreum Linnaeus 1758: 803. Paragorgia nodosa Koren & Danielsen 1883 (sensu Bayer 1956: 70). Paragorgia pacifica Verrill 1922: G 16. Paragorgia arborea: Broch 1912: 6; Grasshoff 1979: 117 (and references therein). Material examined: NIWA 3308, 33�� 55.6 ���S ��� 167 �� 55.1 ���E, 1225 m, (Waipori, bottom trawling, Z 10987), 23 January 2002, New Zealand; NIWA 3309, (J 217), 33 �� 55.6 ���S ��� 167 �� 54.4 ���E, 955 m, (Waipori 1621 /011, Z 11009) 8 June 2002; NIWA Z 10920 (J 208)/ Z 10956 (J 212), (AEX 0101/080), New Zealand EEZ, exact locality unknown (probably near: 42 �� 47 ���S ��� 179 �� 32 ���E, 1077 m), (Kap Farval), 17 October 2001; NIWA 3310, Z 9862 (J 219), 44 �� 45.0S ��� 174 ��50.0���49.0���E, 687���940 m, (Kap Farval 1278 / 102), 21 October 1999, New Zealand; NIWA 3311, X 700 (J 221), 35 �� 50.447 ������ 49.900 ���S��� 177 �� 54.497���54.644 ���E, ���Southern Havre trough��� (dredge), 1525���1798 m, 12 February 1996, New Zealand; USNM 98045, 52�� 17 ������ 52 �� 22 ���S ��� 160 �� 40 ������ 160 �� 34 ���E, 659���798 m, (Eltanin R/ V 1414, USAP 16, U. Southern California, trawl��blake), 9 February 1965, New Zealand; USNM 52433, 54�� 19 ���N ��� 159 �� 40 ��� W, (Albatross R/V 3338), 1143 m, 28 August 1890, Alaska, USA; USNM 1014919, Davison seamount, 1313 m, California 2003, USA. Diagnostic characters. Surface cortex (including calyx surface) containing small, ornate, radiate sclerites (6, 7, and 8 rays); predominantly 6 radiates with distinctive, labyrinth��like, groove markings in the radiate projections or ornamentations (Figs. 7 C���D and 8 C���D). Description. Robust tree��like colonies up to several meters in height with bubble��like concentrations of autozooids (Fig. 6). Complete specimens exhibiting dense and regular accumulations of autozooid nodules or bulbs on distal or lateral branches, whereas the distal main stem and branches are usually without nodules (Fig. 6 A). Inter��nodular surface with numerous and uniformly distributed tiny siphonozooid apertures giving the colony a granular texture (Fig. 6 D). Medulla perforated by 5���7 main stem canals in terminal branches, surrounded by both red and colorless spindles; outer medulla with colorless sclerites and numerous smaller canals. Polyps completely retracted and enclosed within the calicular (small conical protuberance of the nodule) cortex. Tentacle sclerites are blunt, stubby ovals up to 0.1 mm (Figs. 7 A���B, 8 A���B), commonly found in several Paragorgia spp. (Bayer, 1993), but some of them pointed like a spindle (Fig. 8 A). They have conical ornaments usually arranged bipolarly with a smooth neck, and at the surface exhibit a granular appearance due to microcrystal calcite tips. Radiate sclerites (6 ��radiate) from the surface are small, averaging 0.043 mm length in two different specimens, exhibiting low variation (0.004 SD, n= 10, NIWA 3308; 0.002 SD, n= 10, NIWA Z 10920). Radiates 1.3 times longer than wide, averaging 0.03 mm in width (0.001 SD, n= 10, NIWA 3308; 0.002 SD, n= 10, Z 10920) also occur. The rays are ornamented with distinctive markings (see diagnostic character) and the surface between is smooth. Subsurface rich in diverse radiates and intermediate forms between radiate and spindle attaining larger sizes (Figs. 7 F, 8 E). Medulla sclerites long, slim spindles up to 0.5 mm length with irregular projections, some quite prominent (up to 0.02 mm) and bifurcated (Figs. 7 E, 8 F). Occasionally slightly curved, intermediate forms (short and long ornamented spindles) present between the medulla and subsurface (see Grasshoff, 1979). Morphological variation. Whereas sclerites and ultrastructure variation has been usually low among many specimens and geographical localities (e.g., Grasshoff, 1979), colonial features seem to have a great deal of variation. One New Zealand specimen (NIWA Z 9566) had unusually large siphonozooids and autozooids with eight grooved notches in the aperture not present in the rest of the material, but no scleritic differences were found. Most New Zealand specimens were red except a few paler (pink) specimens. The size of the autozooid nodules was another factor of variation. Some specimens had nodules of less than 20 mm in diameter (e.g., Fig. 6 A���B) and some had up to 30 mm (Fig. 6 C���D), the latter corresponding to the largest specimens from the NIWA collection. However, only one specimen of this morphotype is fairly complete and no correlation with colony size can be made. Similar variation has been recorded in northern latitudes including the presence of white individuals (Tendal 1992), which have not been found in New Zealand. Distribution. P. arborea has one of the most intriguing distributions among octocorals (e.g., Fig. 1), it has been abundantly collected and observed towards the two poles in the North Atlantic and in sub��Antarctic waters (Broch 1912) but no intermediate populations have been found so far. Tendal (1992) provided a complete compilation of P. a r b o re a records in the North Atlantic concluding that the species is usually distributed between 200 and 1330 m in depth and a temperature of 4���8 ��C. In the Southern Hemisphere it has been reported from the Falkland Islands, on the Patagonian shelf. New Zealand records (e.g., 1525 m) are the deepest records for this species. Species comparisons. Broch (1957) reported specimens of P. a r b o re a for the first time in the Southern hemisphere. Grasshoff (1979) reviewed material, including some SEM analyses, from boreal and austral latitudes concluding that they belong to the same species. The material collected and studied from New Zealand waters presented the same diagnostic characters and size variation presented by Grasshoff���s (1979) SEMs. The diagnostic characters of the surface radiate sclerites of P. arborea are not similar to any other Paragorgia species. Other scleritic characteristics are very similar to other Paragorgia spp. such as the polyp (tentacles) and medulla sclerites, but the diversity of forms in the subsurface is richer in P. arborea than in any of the studied species. However, it is still unknown if the boreal and austral populations of P. a r b o re a are indeed the same interbreeding population and if there are stepping��stone populations in the tropics; further genetic testing would help to solve this problem. An important variation within P. a r b o re a ���populations��� is present in the specimens from Alaska in the North Pacific, corresponding to P. pacifica Verrill (1922). The sclerites from a specimen from Alaska have the same diagnostic characters including the particular 6 ��radiates with grooved ornaments (Fig. 9 D) but the sclerites from the medulla seem to be reduced in size and ornamentation with respect to the New Zealand P. arborea (Figs. 7 F, 8 F vs 9 H). The surface sclerites (6 ��radiates) were also found to be smaller than the other Paragorgia species examined (Fig. 3). Paragorgia pacifica was described on the grounds of colony form and as Verrill (1922) stated, ���there may be doubt whether P. pacifica is not a variety of P. arborea ���, because it was described without sclerite examination. Nevertheless, the North Pacific populations of P. arborea seem to be the most derived morphologically, but a more comprehensive revision including type material and genetics is needed before reaching conclusions on P. p a c i �� fica and the differentiation of south vs north P. arborea populations. m); H, sclerites from the colony medulla (scales 100 m)., Published as part of JUAN ARMANDO S��NCHEZ, 2005, Systematics of the bubblegum corals (Cnidaria: Octocorallia: Paragorgiidae) with description of new species from New Zealand and the Eastern Pacific, pp. 1-72 in Zootaxa 1014 on pages 15-20, DOI: 10.5281/zenodo.169657, {"references":["Linnaeus, C. (1758) Systema Naturae, Editio Decima, reformata 1, Holmiae.","Verrill, A. E. (1922) Part G: Alcyonaria and Actiniaria. Report of the Canadian Arctic Expedition 1913 - 18, 8, 1 - 164.","Broch, H. (1912) Die Alcyonarien des Trondhjemsfjordes. II. Gorgonacea. Kongelige Norske Videnskabers Selskabs Skrifter, 2, 1 - 48.","Bayer, F. M. (1993) Two new species of the gorgonacean genus Paragorgia (Coelenterata: Octocorallia). Precious Corals & Octocoral Research, 2, 1 - 40.","Tendal, O. S. (1992) The North Atlantic distribution of the octocoral Paragorgia arborea (L., 1758) (Cnidaria, Anthozoa). Sarsia, 77, 213 - 217.","Broch, H. (1957) The Northern octocoral, Paragorgia arborea (L.), in sub-antarctic waters. Nature, 179, 1356."]}