Megafaunal communities along a depth gradient on the tropical Brazilian continental margin.

Autor: Costa, Paulo Alberto Silva da, Mincarone, Michael Maia, Braga, Adriana da Costa, Martins, Agnaldo Silva, Lavrado, Helena Passeri, Haimovici, Manuel, Falcão, Ana Paula da Costa
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Zdroj: Marine Biology Research; Dec2015, Vol. 11 Issue 10, p1053-1064, 12p
Abstrakt: The species composition, abundance and diversity patterns of the epibenthic megafauna and fish community from the tropical Brazilian continental margin were analysed based on 42 bottom trawls from the Campos Basin continental shelf and slope. Trawls were collected aboard R/VGyreduring autumn 2008 from depths of 13 to 2030 m. Overall, 452 species belonging to five main taxa were identified: teleosts (Actinopterygii) were represented by 196 species, crustaceans by 113 species and echinoderms by 108 species. These three groups contributed 92% to the 452 taxa. Several species (289) were recorded only once or twice, and the species accumulation curves showed no signs of being close to reaching asymptotic values. A tendency of increasing diversity and richness with depth was observed. Analysis of the trawls showed the existence of megafaunal assemblages significantly associated with depth and water mass. The shelf group (13–100 m) had subgroups associated with Coastal Water (CW) and South Atlantic Central Water (SACW). The upper-slope group (376–501 m) was found exclusively under the influence of SACW. The mid- and lower-slope group (978–2030 m) had two subgroups associated with the presence of Antarctic Intermediate Water and North Atlantic Deep Water. The 39 typifying species contributed 90% to the global similarity. Teleosts and squids greatly contributed to the within-group similarity over the shelf, while decapods, echinoids and galatheids contributed to the upper-slope assemblage. Deep-sea isopods and decapods mostly contributed to the mid- and lower-slope assemblages. [ABSTRACT FROM PUBLISHER]
Databáze: Complementary Index
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