Ref ID : 7226
Demetrio Boltovskoy and Viviana A. Alder; Microzooplankton and tintinnid species-specific assemblage structures: patterns of distribution and year-to-year variations in the Weddell Sea (Antarctica). J.Plankton Research 14(10):1405-1423, 1992
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Silicoflagellates, large heterotrophic dinoflagellates, radiolarians, tintinnids and microcrustaceans were counted in 72 screened (15 um) samples retrieved at 0-150 m from the Weddell Sea in January 1989. Tintinnid species were identified and biomass estimate were carried out for all groups on the basis of measurements of cell dimensions. Dinoflagellates dominated the microheterotrophic community at all stations and depths (65% of overall microzooplanktonic carbon in the 0-150 m interval), followed by the tintinnids (18%), microcrustaceans (16%) and radiolarians (1%). All groups, with the exception of silicoflagellates, peaked noticeably in the vicinity of the southern end of the transect (76-77 degrees S). Relationships between concentrations of chlorophyll a and microzooplanktonic biomass were present, yet not altogether consistent, but both phyto- and microzooplankton seemed to generally respond to regional enhancement associated with the ice edge. Comparison with similar Weddell and Weddell-Scotia data retrieved in February-March 1987 and November 1988-December 1989, respectively, are highly coherent in terms of microplanktonic abundances, their geographic and vertical distribution patterns, and the specific make-up and distribution of tintinnid assemblages. Analyses of the oral diameters of tintinnid morphotypes suggest that latitudinal and vertical distribution of their five dominant taxa (which account for >90% of all individuals) is structured so as to maximize resource partitioning.