Structural evolution of two suprabenthic soft-bottom communities of the South Gascogne continental shelf
Sorbe, J.-C. (1989). Structural evolution of two suprabenthic soft-bottom communities of the South Gascogne continental shelf, in: Ros, J.D. (Ed.) Topics in Marine Biology: Proceedings of the 22nd European Marine Biology Symposium, Barcelona, Spain, August 1987. Scientia Marina (Barcelona), 53(2-3): pp. 335-342 In: Ros, J.D. (Ed.) (1989). Topics in marine biology: Proceedings of the 22nd European Marine Biology Symposium, Barcelona, Spain, August 1987. European Marine Biology Symposia, 22. Scientia Marina (Barcelona), 53(2-3). 145-754 pp., more In: European Marine Biology Symposia., more |
| Abstract | A survey of two sites (situated on a E-W bathymetric transect off Arcachon Bay) was carried out from January 1981 to March 1982. Analysis of the motile fauna sampled monthly by means of a quantitative sledge shows the existence of two distinct suprabenthic communities in relation to the depth gradient. The structural evolution of the coastal community (31 m depth; unstable sediments) reflects the severe and fluctuating environmental conditions of this area: dominance of a reduced number of species, low species richness and diversity indices, strong fluctuations of density and biomass values, alternation of log-linear with log-normal demographic profiles, some frequency rank curves with typical features of juvenile assemblages. At a deeper site (91 m depth; muddy sand sediments), the more stable environmental conditions lead to a community structure organized in a different way from that of the coastal one (either in its daytime or night-time aspect): higher values of species richness and diversity indices, most demographic profiles in close conformity to the log-normal modelof abundance distribution, convex shape of all the rank frequency curves. Comments are made about the indirect role of hydrodynamic action on the structure of these suprabenthic communities. |
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