Ecology of amorphous aggregations (marine snow) in the northern Adriatic Sea. III. Zooplankton interactions with marine snow

The metazoan species composition in small stringer-shaped aggregates of marine snow from the N Adriatic Sea (<2 cm) was distinctly different from the zooplankton community determined in ambient water. Larval stages dominated the marine snow associated community, with polychaete larvae being most important in terms of biomass. Occasionally polychaete larvae exceeded bacterial biomass and metabolism in marine snow. Together with juvenile turbellarians, they were enriched in marine snow by factors >600 compared to the surrounding water. Polychaete larvae utilize marine snow as a transport vehicle and as a food source as directly observed. During summer, the only copepods found significantly enriched in marine snow were harpacticoids and Temora stylifera, whereas the dominant mesozooplankton species in ambient water were Acartia clausi and Penilia avirostris (neither associated with marine snow). The major fraction of the free-living filter-feeding herbivorous zooplankton is apparently unable to utilize phytoplankton when embedded in the mucoid matrix. (See also 93L/11216) -from Authors