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Paul A Tyler - One of the best experts on this subject based on the ideXlab platform.
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depth related distribution and abundance of seastars echinodermata asteroidea in the porcupine seabight and porcupine Abyssal plain n e atlantic
Deep Sea Research Part I: Oceanographic Research Papers, 2002Co-Authors: Kerry L Howell, D S M Billett, Paul A TylerAbstract:The depth-related distribution of seastar (Echinodermata: Asteroidea) species between 150 and 4950 m in the Porcupine Seabight and Porcupine Abyssal Plain is described. 47 species of asteroid were identified from ~14,000 individuals collected. The bathymetric range of each species is recorded. What are considered quantitative data, from an acoustically monitored epibenthic sledge and supplementary data from otter trawls, are used to display the relative abundance of individuals within their bathymetric range. Asteroid species are found to have very narrow centres of distribution in which they are abundant, despite much wider total adult depth ranges. Centres of distribution may be skewed. This might result from competition for resources or be related to the occurrence of favourable habitats at particular depths. The bathymetric distributions of the juveniles of some species extend outside the adult depth ranges. There is a distinct pattern of zonation with two major regions of faunal change and six distinct Zones. An upper slope Zone ranges from 150 to ~700 m depth, an upper bathyal Zone between 700 and 1100 m, a mid-bathyal Zone from 1100 to1700 m and a lower bathyal Zone between 1700 and 2500 m. Below 2500 m the lower continental slope and continental rise have a characteristic asteroid fauna. The Abyssal Zone starts at about 2800 m. Regions of major faunal change are identified at the boundaries of both upper and mid-bathyal Zones and at the transition of bathyal to Abyssal fauna. Diversity is greatest at ~1800 m, decreasing with depth to ~2600 m before increasing again to high levels at ~4700 m.
Celia Olabarria - One of the best experts on this subject based on the ideXlab platform.
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patterns of bathymetric zonation of bivalves in the porcupine seabight and adjacent Abyssal plain ne atlantic
Deep Sea Research Part I: Oceanographic Research Papers, 2005Co-Authors: Celia OlabarriaAbstract:Although the organization patterns of fauna in the deep sea have been broadly documented, most studies have focused on the megafauna. Bivalves represent about 10% of the deep-sea macrobenthic fauna, being the third taxon in abundance after polychaetes and peracarid crustaceans. This study, based on a large data set, examined the bathymetric distribution, patterns of zonation and diversity–depth trends of bivalves from the Porcupine Seabight and adjacent Abyssal Plain (NE Atlantic). A total of 131,334 individuals belonging to 76 species were collected between 500 and 4866 m. Most of the species showed broad depth ranges with some ranges extending over more than 3000 m. Furthermore, many species overlapped in their depth distributions. Patterns of zonation were not very strong and faunal change was gradual. Nevertheless, four bathymetric discontinuities, more or less clearly delimited, occurred at about 750, 1900, 2900 and 4100 m. These boundaries indicated five faunistic Zones: (1) a Zone above 750 m marking the change from shelf species to bathyal species; (2) a Zone from 750 to 1900 m that corresponds to the upper and mid-bathyal Zones taken together; (3) a lower bathyal Zone from 1900 to 2900 m; (4) a transition Zone from 2900 to 4100 m where the bathyal fauna meets and overlaps with the Abyssal fauna and (5) a truly Abyssal Zone from approximately 4100–4900 m (the lower depth limit of this study), characterized by the presence of Abyssal species with restricted depth ranges and a few specimens of some bathyal species with very broad distributions. The 4100 m boundary marked the lower limit of distribution of many bathyal species. There was a pattern of increasing diversity downslope from 500 to 1600 m, followed by a decrease to minimum values at about 2700 m. This drop in diversity was followed by an increase up to maximum values at 4100 m and then again, a fall to 4900 m (the lower depth limit in this study)
Angela Mead - One of the best experts on this subject based on the ideXlab platform.
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marine biodiversity in south africa an evaluation of current states of knowledge
PLOS ONE, 2010Co-Authors: C L Griffiths, Tamara B Robinson, Louise Lange, Angela MeadAbstract:Continental South Africa has a coastline of some 3,650 km and an Exclusive Economic Zone (EEZ) of just over 1 million km2. Waters in the EEZ extend to a depth of 5,700 m, with more than 65% deeper than 2,000 m. Despite its status as a developing nation, South Africa has a relatively strong history of marine taxonomic research and maintains comprehensive and well-curated museum collections totaling over 291,000 records. Over 3 million locality records from more than 23,000 species have been lodged in the regional AfrOBIS (African Ocean Biogeographic Information System) data center (which stores data from a wider African region). A large number of regional guides to the marine fauna and flora are also available and are listed. The currently recorded marine biota of South Africa numbers at least 12,914 species, although many taxa, particularly those of small body size, remain poorly documented. The coastal Zone is relatively well sampled with some 2,500 samples of benthic invertebrate communities have been taken by grab, dredge, or trawl. Almost none of these samples, however, were collected after 1980, and over 99% of existing samples are from depths shallower than 1,000 m—indeed 83% are from less than 100 m. The Abyssal Zone thus remains almost completely unexplored. South Africa has a fairly large industrial fishing industry, of which the largest fisheries are the pelagic (pilchard and anchovy) and demersal (hake) sectors, both focused on the west and south coasts. The east coast has fewer, smaller commercial fisheries, but a high coastal population density, resulting in intense exploitation of inshore resources by recreational and subsistence fishers, and this has resulted in the overexploitation of many coastal fish and invertebrate stocks. South Africa has a small aquaculture industry rearing mussels, oysters, prawns, and abalone—the latter two in land-based facilities. Compared with many other developing countries, South Africa has a well-conserved coastline, 23% of which is under formal protection, however deeper waters are almost entirely excluded from conservation areas. Marine pollution is confined mainly to the densely populated KwaZulu-Natal coast and the urban centers of Cape Town and Port Elizabeth. Over 120 introduced or cryptogenic marine species have been recorded, but most of these are confined to the few harbors and sheltered sites along the coast.
Alan J. Jamieson - One of the best experts on this subject based on the ideXlab platform.
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bait attending fishes of the Abyssal Zone and hadal boundary community structure functional groups and species distribution in the kermadec new hebrides and mariana trenches
Deep Sea Research Part I: Oceanographic Research Papers, 2017Co-Authors: Thomas D. Linley, Mackenzie E Gerringer, Toyonobu Fujii, Peter Mcmillan, Jeffrey C. Drazen, Malcolm R. Clark, Andrew L Stewart, Alan J. JamiesonAbstract:Abstract Baited landers were deployed at 83 stations at four locations in the west Pacific Ocean from bathyal to hadal depths: The Kermadec Trench, the New Hebrides Trench, the adjoining South Fiji Basin and the Mariana Trench. Forty-seven putative fish species were observed. Distinct fish faunal groups were identified based on maximum numbers and percentage of observations. Both analyses broadly agreed on the community structure: A bathyal group at The absence of the Abyssal group from the New Hebrides Trench and South Fiji Basin was due to the absence of macrourids ( Coryphaenoides spp.), which defined the group. The macrourids may be energetically limited in these areas. In their absence the species of the AHTZ group appear released of competition with the macrourids and are found far shallower at these sites. The fish groups had distinct feeding strategies while attending the bait: The bathyal and Abyssal groups were almost exclusively necrophagous, the AHTZ group comprised predatory and generalist feeders, while the hadal snailfishes were exclusively predators. With increasing depth, predation was found to increase while scavenging decreased. The data suggest scavenging fish fauna do not extend deeper than the hadal boundary.
Kerry L Howell - One of the best experts on this subject based on the ideXlab platform.
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depth related distribution and abundance of seastars echinodermata asteroidea in the porcupine seabight and porcupine Abyssal plain n e atlantic
Deep Sea Research Part I: Oceanographic Research Papers, 2002Co-Authors: Kerry L Howell, D S M Billett, Paul A TylerAbstract:The depth-related distribution of seastar (Echinodermata: Asteroidea) species between 150 and 4950 m in the Porcupine Seabight and Porcupine Abyssal Plain is described. 47 species of asteroid were identified from ~14,000 individuals collected. The bathymetric range of each species is recorded. What are considered quantitative data, from an acoustically monitored epibenthic sledge and supplementary data from otter trawls, are used to display the relative abundance of individuals within their bathymetric range. Asteroid species are found to have very narrow centres of distribution in which they are abundant, despite much wider total adult depth ranges. Centres of distribution may be skewed. This might result from competition for resources or be related to the occurrence of favourable habitats at particular depths. The bathymetric distributions of the juveniles of some species extend outside the adult depth ranges. There is a distinct pattern of zonation with two major regions of faunal change and six distinct Zones. An upper slope Zone ranges from 150 to ~700 m depth, an upper bathyal Zone between 700 and 1100 m, a mid-bathyal Zone from 1100 to1700 m and a lower bathyal Zone between 1700 and 2500 m. Below 2500 m the lower continental slope and continental rise have a characteristic asteroid fauna. The Abyssal Zone starts at about 2800 m. Regions of major faunal change are identified at the boundaries of both upper and mid-bathyal Zones and at the transition of bathyal to Abyssal fauna. Diversity is greatest at ~1800 m, decreasing with depth to ~2600 m before increasing again to high levels at ~4700 m.
