Changes in the General Characteristics of Micro-,Meio-,and Macrobenthos along the Salinity Gradientin the White Sea Estuary

摘要

The changes in the general integral characteristics (density,biomass,and diversity) of micro-,meio-,and macrobenthos along the salinity gradient (from 0 to 20%c) in the Chernaya River estuary (Kandalaksha Bay,White Sea) are considered.The diversity of the organisms of these three size groups in the estuarine and marine communities was shown to be similar to that in the sea and is maintained due to the complementary character of the taxonomic groups,which have different resistance to salinity.The trophic structure of the micro- and meiobenthos is not related to the salinity changes and depends on the sediment type.In contrast,the trophic structure of macrobenthos depends on the hydrodynamic features of the selected estuary and on the amount of organic matter.The changes in the biomass of the neighbouring size blocks of zoobenthos along the salinity gradient occur in the opposite direction (the biomass of microzoobenthos and macrobenthos decreases with the salinity decrease,whereas that of meiobenthos increases).Moreover,a similar complementary character of the distribution pattern was demonstrated for the neighbouring size groups within the micro-,meio- and mac-robenthic communities,which allows one to consider this tendency as a general rule for all the levels of the benthic community organization.Mechanisms of the given complementarity are discussed.