Bathymetric Distribution Research Articles

Distribution of modern agglutinated foraminifera along an inner neritic- to mid-bathyal transect in Saros Bay (northern Aegean Sea)

Agglutinated benthic foraminifera were investigated in the central Northern Aegean Sea. Eighteen samples were collected along a neritic to mid-bathyal transect in Saros Bay at water depths ranging from 15 to 500m in March 2003. This study documents for the first time in detail, agglutinated foraminiferal species and their bathymetric distribution in this area.Atotal of 96 species belonging to 51 genera were recognised. Statistical analyses (CA and PCA) allowed us to identify different assemblages that can be related to bathymetric depth and trophic level and, in turn, to different hydrological zones. The shallowest assemblage (15m) is characterised by the lowest species richness that might result from the influence of the Black Sea outflow into Saros Bay. The shallow assemblages stations (21–70m) are characterized by relatively low diversity and higher dominance values. On the other hand, assemblages from intermediate water (80–200m) are characterised by high diversity values and the dominance of elongate keeled forms associated with elongated tapered forms, providing evidence of mesotrophic conditions. The deepest assemblages, including stations ranging from water depths of 200 to 500m, are very well-diversified and mainly represented by epifaunal taxa. The dominance of tubular morphogroup might be due to the low food supply, which acts as a limiting factor for more eutrophic dependent taxa and meso-oligotrophic conditions might be inferred.

Diversity and bathymetric distribution of decapod crustaceans attracted to baited traps from the middle slope of the northern Aegean Sea

We sampled the decapod crustaceans inhabiting the depth zone between 500 and 1500 m off Gökçeada Island (northern Aegean Sea) from May 2010 to November 2011. The deep-slope decapod fauna of the northern Aegean Sea was sampled with baited traps. A total of 23 species of decapods have been identified at 32 stations. The results were analysed in terms of composition and distribution of benthic and benthopelagic bait-attracted species between regions. In addition, they were compared between stations in relation to the depth gradient. The results are discussed in relation to previous studies carried out in the eastern and western Mediterranean. Also, the use of traps is commented for different regions and the effects of the sampler on benthic species are discussed. The most common species was the penaeid shrimp, Parapenaeus longirostris in samples taken between 500 and 600 m. It is followed by Polycheles typhlops and the pandalid shrimp Plesionika martia martia. These species constitute more than 50% of all decapods. Differences among the strata at 500-1500 m depth were tentatively explained using the Shannon-Weaver diversity index (H′). The highest H′ value was found for the 800-1000 m depth strata. The lowest number of species was observed between 1000 and 1500 m, which lowered the diversity index values (H′). The results of similarity percentage analysis (SIMPER) showed a change in the decapod fauna below 1000 m depth. The present results are preliminary; further data collection and analysis will be required to evaluate the role of palaeoecolgical conditions and trophic factors, and how these could be supposed to interact.

First record of the oceanic hyperiid Platyscelus armatus (Amphipoda: Platyscelidae) in the Canary Islands (subtropical north-eastern Atlantic)

Three specimens of Platyscelus armatus (Crustacea: Amphipoda: Hyperiidea: Platyscelidae) are reported from coastal waters of the Canary Islands, Spain; these are the first records from these waters. The specimens were collected south-west of Tenerife and El Hierro Islands during the ‘CETOBAPH 2012' (April 2012) oceanographic cruise. Morphological and morphometric measurements of the specimens, geographical and bathymetric distribution of this species and a key to species of the genus reported in the Canary Islands are provided.

Aglaopheniid hydroids (Cnidaria: Hydrozoa: Aglaopheniidae) from bathyal waters of the Flemish Cap, Flemish Pass, and Grand Banks of Newfoundland (NW Atlantic).

Five species of aglaopheniid hydroids (Aglaophenopsis cornuta, Cladocarpus diana, C. formosus, C. integer, and Nematocarpus ramuliferus) were collected from the Flemish Cap, Flemish Pass, and Grand Banks of Newfoundland during surveys with bottom trawls, rock dredges, and scallop gear. All are infrequently reported species, with C. diana being discovered for the first time since its original description from Iceland. We document here the southernmost collections of C. diana and N. ramuliferus, both previously unknown in the western Atlantic. Each of the five species is described and illustrated based on fertile material, a key is provided for their identification, and bathymetric distributions are noted. Known depth ranges are extended for A. cornuta, C. diana, and C. integer. Aglaophenopsis and Nematocarpus are recognized as genera distinct from the polyphyletic Cladocarpus, based on the unique structure of the phylactocarp in the former, and the existence of appendages with nematothecae (ramuli) on almost all thecate internodes of hydrocladia in the latter. These appendages occur even in the absence of gonothecae, and are here considered defensive structures that protect the hydranths. In differing from typical phylactocarps, we accept the contention that they are characters of generic value.

Two new species of Halichondrida (Demospongiae) and the first record of Phycopsis and Ciocalapata for Brazil.

Two new species of the genera Phycopsis and Ciocalapata are described from the shallow waters off the Brazilian coast. This is the first record of Phycopsis in South Atlantic, with Phycopsis styloxeata sp. nov. being the only species of the genus that presents three categories of spicules: two of styles and one of oxeas. Ciocalapata, here represented by Ciocalapata minuspiculifera sp. nov., displays smaller oxeas and styles when compared to its congeneric C. amorphosa (Ridley & Dendy, 1886). The definition of this genus was modified and its geographical and bathymetric distributions now extend from the coast of Argentina to the northeastern coast of Brazil (state of Bahia) and from deep (1.097 m) to shallow (14-20 m) waters, respectively.

Brittle stars from Southern Ocean (Echinodermata: Ophiuroidea)

The present biogeographic study on the ophiuroid fauna from the Southern Ocean (SO) contains an updated checklist, based on a compilation of all the published information provided for the Antarctic and sub-Antarctic regions as well as the information available in SCAR-MarBIN database. Faunal composition and geographical and bathymetric distribution are included. So far, 219 species have been recorded, of which 126 are endemic to the SO, 76 are exclusive to Antarctic waters, and 30 are exclusive to sub-Antarctic waters. This study corroborated the circumpolar and eurybathic character of the ophiuroid fauna of the SO, but some differences are discussed when considering shelf and deep-sea fauna in the whole SO, or in the Antarctic and sub-Antarctic regions separately. The biogeographic affinities of 17 areas considered in the SO are revised, based on a presence/absence datamatrix of the 219 species. This similarity analysis shows three main groups, two of them including sub-Antarctic areas and one for Antarctic areas. The faunal movement patterns between the main geographical connections have been based on historical site records of each species. These movements have a level of faunal exchange that exceeds that of other Antarctic benthic groups. Such movements are mainly from Antarctic and sub-Antarctic regions to the subtropical waters of South America, and from New Zealand and southern Australian waters to sub-Antarctic areas. In this context, the origin of the ophiuroid Antarctic fauna is discussed.

Habitat selection and population spreading of the horned octopus Eledone cirrhosa (Lamarck, 1798) in Galician waters (NW Atlantic)

Distribution and abundance of Eledone cirrhosa, a benthic octopus inhabiting the NE Atlantic and Mediterranean Sea, were studied in north-western Iberian waters. Capture data collected during two series of surveys, carried out during summer–autumn in Galician waters (NE Atlantic Ocean), were analyzed. “Galicia” series (G1, G2 and G3) extended along the Galician continental shelf from Ribadeo Ría to Miño Estuary in 1974, 1975 and 1976, and “Cigala” series (C 06, C 07 and C 08) were recorded from Finisterre Cape to Miño Estuary in 2006, 2007 and 2008. Data from a total of 276 trawls, ranging from 50 to 500m, and corresponding environmental parameters were transferred to a Geographic Information System (GIS), providing a platform for a spatial–temporal analysis. Bathymetric distribution, variations in abundance, biomass and average body size of the octopus Eledone cirrhosa were analyzed through depth strata and seasons. Higher abundances were obtained in the intermediate strata and in autumn, most likely due to new recruits. Largest sizes of E. cirrhosa were collected in summer and average weight increased with depth throughout the sampling period. These variations of biomass and abundance suggest the existence of segregation by size and agree with the landings pattern of the trawlers fishery, in which E. cirrhosa is not a target species. No significant differences were found between G1 and G2 surveys or between C ones, performed at the same dates, suggesting that the polled data of surveys are useful tools for representing phenological stages of the species. Collected data and developed models illustrate a migratory behaviour during the reproductive period. Among the eight environmental variables considered, only the latitude remained significant in all developed models, suggesting an effect of photoperiod over the species distribution.

Ocean acidification and climate change: advances in ecology and evolution

Atmospheric CO2 concentration [CO2] has increased from a pre-industrial level of approximately 280 ppm to approximately 385 ppm, with further increases (700–1000 ppm) anticipated by the end of the twenty-first century [[1][1]]. Over the past three decades, changes in [CO2] have increased global

The formation of the Lycodinae fauna (Perciformes: Zoarcidae) of the Sea of Japan

The subfamily Lycodinae is represented in the Sea of Japan by two genera (Lycodes and Petroschmidtia) and seven species (Lycodes japonicus, L. nakamurae, L. raridens, L. tanakae, L. teraoi, L. yamatoi, and Petroschmidtia toyamensis), which are widely distributed on the shelf and upper continental slope. Based on the geographic and bathymetric distribution of eelpouts of the Sea of Japan and adjacent waters, two groups of closely related species with different types of distribution ranges were distinguished. The first group includes pairs of species that live primarily on the continental slope and are completely isolated in the Sea of Japan or in the Sea of Okhotsk. The second group is comprised of upper interzonal species of the Sea of Japan that are found on the continental slope and shelf, as well as in the southern Sea of Okhotsk from Terpeniya Bay to the southern Kuril Islands. Their related species in the Sea of Okhotsk are mostly found to the north of the Terpeniya Bay. The study of the eelpout distribution and the data on the geological history and paleoclimate of the Far East show that the Lycodinae fauna of the Sea of Japan was formed from North Pacific eelpout-like fishes during the isolation of the sea in the late Pliocene-early Pleistocene, which was concomitant with the general cooling of the Earth’s climate. During the Pleistocene interglacials, the eelpout migrations were unidirectional, from the Sea of Japan to the southern Sea of Okhotsk. The reconstruction of the formation of the Sea of Japan Lycodinae fauna suggests that the related taxa from the Sea of Japan and the Sea of Okhotsk are separate species, while the northern and southern forms of species from the Sea of Japan (Lycodes yamatoi and L. teraoi) are no more than subspecies.

Reproductive biology and recruitment of the deep-sea fish community from the NW Mediterranean continental margin

Temporal patterns in deep-sea fish reproduction are presently unknown for the majority of deep continental margins. A series of seasonal trawling surveys between depths of 300 to 1750m in the Blanes submarine canyon and its adjacent open slope (NW Mediterranean) were conducted. The bathymetric size distributions and reproductive cycles of the most abundant species along the NW Mediterranean margin were analyzed to assess the occurrence of (i) temporal patterns in reproduction (i.e., spawning season) along a bathymetric gradient and (ii) preferential depth strata for recruitment. The fish assemblages were grouped in relation to their bathymetric distribution: upper slope, middle slope and lower slope species. Middle-slope species (i.e., 800–1350m) showed short (i.e., highly seasonal) reproductive activity compared to the upper (300–800m) and lower (1350–1750m) ones. Our results, together with those previously published for megabenthic crustacean decapods in the area, suggest a cross-phyla depth-related trend of seasonality in reproduction. In the middle and lower slope species, the reproductive activity reached a maximum in the autumn–winter months and decreased in the spring. The observed seasonal spawning patterns appear to be ultimately correlated with changes in the downward transport of organic particles and with seasonal changes in the physicochemical characteristics of the surrounding water masses. The distribution of juveniles was associated with the bathymetric stratum where intermediate nepheloid layers interact with the continental margins, indicating that this stratum acts as a deep-sea fish nursery area.

Nystiellidae (Gastropoda: Epitonioidea) Collected During the REVIZEE Program/Northeast Brazil with Descriptions of New Species and a Checklist of the Family from the Atlantic Coast of South America

Four nystiellids belonging to the genera Eccliseogyra Dall, 1892, Opaliopsis Thiele, 1928 and Papuliscala de Boury, 1911 were collected on the continental slope off Brazil during the development of the REVIZEE Program (2000–2001). Of these Opaliopsis atlantis (Clench and Turner, 1952) was the only species known previously. Three nystiellids unknown to science, belonging to the genera Eccliseogyra and Papuliscala, are presented herein based on shell morphology. Eccliseogyra maracatu sp. nov. and Papuliscala nordestina sp. nov. are described for northeastern Brazil. Only one specimen of Eccliseogyra sp. with damaged shell was found. A formal epithet for this specimen will be delayed until additional material is collected. A checklist of species of Nystiellidae Clench and Turner, 1952 known for the Atlantic coast of South America, as well as their geographic and bathymetric distribution based on data from the literature, is presented.

First record of Monobrachium parasitum Mereschkowsky, 1877 (Cnidaria: Hydrozoa) from Brazil, in the tropical southwestern Atlantic, and its implication for bipolarity concepts

Project HABITATS was recently initiated in the Campos Basin (20.5–24° S), state of Rio de Janeiro, to assess biological impacts of petroleum exploration and exploitation on the continental shelf and slope of Brazil. Among species discovered in benthic samples from the area is the hydroid Monobrachium parasitum Mereschkowsky, 1877, occurring in an epibiotic association with the pelecypod mollusc Mendicula ferruginosa (Forbes, 1844): this is the first report of an association between the two species. Monobrachium parasitum has always been reported from cold waters, and is generally considered bipolar. This report records the occurrence of M. parasitum at lower latitudes, where they have seldom been collected: it is also the first account of this species from South America and the southwestern Atlantic. Moreover, the bathymetric distribution of M. parasitum is extended to a depth of 998 m. No previous records exist of hydroids from the Brazilian continental slope.

A taxonomic guide to the brittle-stars (Echinodermata, Ophiuroidea) from the State of Paraíba continental shelf, Northeastern Brazil

We provide the first annotated checklist of ophiuroids from the continental shelf of the State of Paraíba, northeastern Brazil. Identification keys and taxonomic diagnoses for 23 species, belonging to 14 genera and 8 families, are provided. The material is deposited in the Invertebrate Collection Paulo Young, at the Federal University of Paraíba. Ophiopsila hartmeyeri represents the first record for the northeastern region of Brazil, while Ophiolepis impressa, Ophiolepis paucispina, Amphiura stimpsoni, Amphiodia riisei, Ophiactis quinqueradia, Ophiocoma wendtii and Ophionereis olivaceae are new records for the State of Paraíba. The number of species known for the state was increased from 16 to 23, representing approximately 17% of the species known for Brazil and 54% of the species known for northeastern Brazil. The recorded fauna has a large geographical and bathymetrical distribution.

Morphology and biology of Laetmonice producta producta Grube (Polychaeta: Aphroditidae) in the Bellingshausen Sea and Antarctic Peninsula (Southern Ocean, Antarctica)

The present paper reports on some morphological and biological features of the scale-worm Laetmonice producta producta Grube, 1877 (Polychaeta: Aphroditidae) in the northwestern sector of Antarctica. A total of 114 specimens were collected during the 2003 and 2006 cruises of the BENTART project on the shelf and upper slope of the Antarctic Peninsula and the Bellingshausen Sea. Specimens were collected using an Agassiz trawl at 22 stations covering a depth ranging from 115 to 1431 m. Bathymetric distribution, abundance and sizes, diet, presence of endosymbionts and epibionts, and some observations related to parapodial structure and chaetal types are discussed in relation to taxonomy and environmental characteristics and compared to previous data.

Bathymetrical distribution and size structure of cold-water coral populations in the Cap de Creus and Lacaze-Duthiers canyons (northwestern Mediterranean)

Abstract. Submarine canyons are known as one of the seafloor morphological features where living cold-water coral (CWC) communities develop in the Mediterranean Sea. We investigated the CWC community of the two westernmost submarine canyons of the Gulf of Lions canyon system: the Cap de Creus Canyon (CCC) and Lacaze-Duthiers Canyon (LDC). Coral associations have been studied through video material recorded by means of a manned submersible and a remotely operated vehicle. Video transects have been conducted and analyzed in order to obtain information on (1) coral bathymetric distribution and density patterns, (2) size structure of coral populations, and (3) coral colony position with respect to the substrate. Madrepora oculata was the most abundant CWC in both canyons, while Lophelia pertusa and Dendrophyllia cornigera mostly occurred as isolated colonies or in small patches. An important exception was detected in a vertical cliff in LDC where a large L. pertusa framework was documented. This is the first record of such an extended L. pertusa framework in the Mediterranean Sea. In both canyons coral populations were dominated by medium and large colonies, but the frequent presence of small-sized colonies also indicate active recruitment. The predominant coral orientation (90° and 135°) is probably driven by the current regime as well as by the sediment load transported by the current flows. In general, no clear differences were observed in the abundance and in the size structure of the CWC populations between CCC and LDC, despite large differences in particulate matter between canyons.

New records of Antarctic and Sub-Antarctic sea anemones (Cnidaria, Anthozoa, Actiniaria and Corallimorpharia) from the Weddell Sea, Antarctic Peninsula, and Scotia Arc

Herein we provide new records for 22 Antarctic species of sea anemone sensu lato (Anthozoa: Actiniaria and Corallimorpharia) from the Weddell Sea, Antarctic Peninsula, and the Scotia Sea. We provided short descriptions, images of the external morphology of preserved specimens (but also of living specimens in most cases), cnida data, and distribution maps for each studied species. New records are presented for nine species in the Weddell Sea and the geographic or bathymetric distributions for 19 of the 22 studied species are extended.

New records of Antarctic and Sub-Antarctic sea anemones (Cnidaria, Anthozoa, Actiniaria and Corallimorpharia) from the Weddell Sea, Antarctic Peninsula, and Scotia Arc.

Herein we provide new records for 22 Antarctic species of sea anemone sensu lato (Anthozoa: Actiniaria and Corallimorpharia) from the Weddell Sea, Antarctic Peninsula, and the Scotia Sea. We provided short descriptions, images of the external morphology of preserved specimens (but also of living specimens in most cases), cnida data, and distribution maps for each studied species. New records are presented for nine species in the Weddell Sea and the geographic or bathymetric distributions for 19 of the 22 studied species are extended.

Sharing the slope: depth partitioning of agariciid corals and associated Symbiodinium across shallow and mesophotic habitats (2-60 m) on a Caribbean reef

BackgroundScleractinian corals and their algal endosymbionts (genus Symbiodinium) exhibit distinct bathymetric distributions on coral reefs. Yet, few studies have assessed the evolutionary context of these ecological distributions by exploring the genetic diversity of closely related coral species and their associated Symbiodinium over large depth ranges. Here we assess the distribution and genetic diversity of five agariciid coral species (Agaricia humilis, A. agaricites, A. lamarcki, A. grahamae, and Helioseris cucullata) and their algal endosymbionts (Symbiodinium) across a large depth gradient (2-60 m) covering shallow to mesophotic depths on a Caribbean reef.ResultsThe five agariciid species exhibited distinct depth distributions, and dominant Symbiodinium associations were found to be species-specific, with each of the agariciid species harbouring a distinct ITS2-DGGE profile (except for a shared profile between A. lamarcki and A. grahamae). Only A. lamarcki harboured different Symbiodinium types across its depth distribution (i.e. exhibited symbiont zonation). Phylogenetic analysis (atp6) of the coral hosts demonstrated a division of the Agaricia genus into two major lineages that correspond to their bathymetric distribution (“shallow”: A. humilis / A. agaricites and “deep”: A. lamarcki / A. grahamae), highlighting the role of depth-related factors in the diversification of these congeneric agariciid species. The divergence between “shallow” and “deep” host species was reflected in the relatedness of the associated Symbiodinium (with A. lamarcki and A. grahamae sharing an identical Symbiodinium profile, and A. humilis and A. agaricites harbouring a related ITS2 sequence in their Symbiodinium profiles), corroborating the notion that brooding corals and their Symbiodinium are engaged in coevolutionary processes.ConclusionsOur findings support the hypothesis that the depth-related environmental gradient on reefs has played an important role in the diversification of the genus Agaricia and their associated Symbiodinium, resulting in a genetic segregation between coral host-symbiont communities at shallow and mesophotic depths.

Latitudinal and bathymetric distribution patterns of ophiuroids (Echinodermata: Ophiuroidea) on scallop fishing grounds at the shelf-break frontal system, south-western Atlantic

Ophiuroidea represents the dominant invertebrate group in Patagonian scallop fishery by-catch in the south-western Atlantic. This study presents information that brings forward the spatial patterns and abundance of the most abundant species in the benthic community associated with this fishery at the shelf-break front in the Argentine Sea, between 37° and 44°S during the period 2002–2005. Ophiactis asperula, Ophiacantha vivipara, Ophiura (Ophiuroglypha) lymani and Gorgonocephalus chilensis show a latitudinal and bathymetric distribution pattern, explained by their natural distributional ranges and feeding habits. Our results indicate that the abundance and distribution of these species are not related to scallop fishing activities.

Distribution and relative abundance of main species of grenadiers (Macrouridae, Gadiformes) from the African Atlantic Coast

This study describes the geographic and bathymetric distribution patterns of abundance of the main macrourid species found in Atlantic African waters. A series of demersal trawl surveys, carried out in waters off Morocco, Western Sahara, Mauritania, Guinea Bissau, Gabon, Angola, and Namibia provided the catch data analysed. The survey area was between latitudes 35°56′N and 29°39.50′S and the sampled depths from 20 to 2000 m on the continental shelf and the slope. We collected 50 macrourid species belonging to 15 genera. The most abundant species was Nezumia micronychodon, with 91980 specimens caught, followed by Nezumia duodecim, Trachyrincus scabrus, and Hymenocephalus italicus with 31461, 28411, and 25349 specimens, respectively. The bathymetrical distribution ranges are extended for 21 species of grenadiers.