Species Diversity and Structural Features of the Macrobenthos in Coastal Lagoon Ecosystems, Kandalaksha Bay, White Sea

With Kandalaksha Bay of the White Sea taken as an example, the present study is devoted to its coastal lagoon ecosystems, which are known to differ in their species diversity and structural features, including the macrobenthos. The features of the species composition, spatial structure, and diversity of macrobenthic sublittoral communities in four coastal lagoon ecosystems of the White Sea were studied and analyzed. In the sublittoral of the study lagoons, 39 species of zoobenthos and four species of sea weeds and algae (Zostera marina, Cladophora sericea, Ruppia maritima, and Salicornia pojarkovae) were found. The lowest indices of species diversity and biomass of macrobenthos were revealed in lagoons significantly fenced off and remote from the sea, where littoral eurytopic small species of the zoobenthos (Macoma balthica, Peringia ulvae, Tubificoides benedii, Littorina littorea, Mytilus edulis, and Chironomus salinarius) were mainly found to dominate. In the lagoons in which the connection to the sea was stronger, less euryhaline sublittoral invertebrate species prevailed with higher indices of the species diversity and total biomass of the macrobenthos community (Nereimyra punctata, Terebellides stroemi, Caprella linearis, Asterias rubens, and Molgula griffithsii). Most of the lagoon ecosystems we examined, with the exception of the one most open to the sea, were characterized by low values of ABC indices and a disturbed structure of the macrobenthos community with the predominance of mainly small species of detritophages, this being associated with the negative effects of siltation, carbon loading, and salinity (especially in spring or during the times of heavy rain).