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| Author(s): |
Mauricio Shimabukuro
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto Oceanográfico (IO/DIDC) |
| Defense date: | 2011-04-07 |
| Examining board members: |
Ana Maria Setubal Pires Vanin;
Paulo Cesar de Paiva
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| Advisor: | Ana Maria Setubal Pires Vanin |
| Abstract | |
Composition and distribution of polychaetes were studied in southeastern Brazilian continental shelf adjacent to Santos (ECOSAN Thematic Project). Aiming a spatio-temporal community comprehension, 21 stations were sampled in duplicates during August/2005 and February/2006, with a box-corer (0.09 m2). Polychaete was the dominant macrofauna group, totalizing 16274 individuals and 214 species. The fauna distribution along the depth gradient was related to sediment type, mean grain size and sediment sorting, which partially promoted the existence of three distinct communities: (1) a shallow community, dominated by Apoprionospio dayi, inhabiting very fine and fine well selected sand; (2) a community dominated by Aphelochaeta sp., Levinsenia gracilis and Aricidea (A.) catherinae, inhabiting mixed sediments between 50-84 m depth; (3) and a community dominated by Sigambra grubii, Sternaspis capillata and Leitoscoloplos kerguelensis, inhabiting muddy sediments in a deeper region of the continental shelf. The local hydrodynamic regime and the deep intrusion of the South Atlantic Central Water (SACW) were considered secondary factors in the distribution of polychaetes. High values of richness and diversity were observed throughout the shelf, ranging from 20 to 66, and from 2.37 to 5.45 respectively. The region between 50-84m showed peaks of these community descriptors, probably associated with greater sediment heterogeneity, and the communities overlapping. The functional groups showed a similar distribution to species distribution. Interface-feeders were dominant functional group in coastal region, while motile surface and subsurface deposit feeders with soft proboscis and motile carnivores with jaws were dominant in the region between 50 and 100m. (AU) | |