Meroplankton distribution in the Central Barents Sea in relation to local oceanographic patterns
Abundance and spatio-temporal distribution of meroplankton (larvae ofinvertebrate benthos) in the Central Barents Sea and their dependence onabiotic factors were investigated. Samples were taken in different depthintervals on a south-north transect in the marginal ice zone in May1997. At several locations sampling was repeated in June 1997. In May,total meroplankton abundances varied between 0.1 ind. m-3 and 32.0 ind.m-3, but mainly fluctuated around 10 ? 15 ind. m-3. They were stronglyaffected by the mass occurrence of single species. At the northern,heavily ice covered stations numbers decreased significantly. Larvae of27 types were found. Polychaetes represented the most diverse group (13larvae), followed by echinoderms (8 types). Larvae of only one bivalvespecies were found (Mya truncata), but with very high abundances (86ind. m-3). Other taxa were represented only by single specimens. InJune, total abundances were similar. The same species were present; butthe distribution patterns were less distinct, diversity values werehigher and most larvae were further developed than in May. Distributionpatterns of the larvae were to a large extent determined by physicalprocesses in the area of the Polar Front, which acted as a distinctbarrier in surface waters. In May, four meroplankton assemblages weredistinguished; each associated with a different water mass. Most of thelarvae have also been found in other investigated Arctic areas andbelong to species with an Atlantic?Boreal-Arctic or Boreal-Arcticdistribution. The relatively high numbers of larval types found in thisstudy indicate that indirect development with pelagic larval stages playa role for benthic recruitment in this Sub-Arctic region. The relevanceof these observations for the so-called Thorson rule is discussed.
ARK > XIII > 2