Quantitative development and structure of zoobenthos in channels on the left margin of the Selenga River delta

Abstract

Abstract. There are only a few studies on zoobenthos in the delta of the Selenga River located at the junction of Lake Baikal and its largest tributary. The present work provides the results of research on zoobenthos in the southern (left) Selenga delta channels in 2002. Baikal amphipods and bivalves are widespread up to the upper delta. The direction and velocity of the water flow in the delta induced change of a river zoobenthos complex for a limnophilous one. Baikal amphipods are responsible for high quantitative indicators of zoobenthos in the southern channels of the delta. Low parameters of quantitative development of zoobenthos were registered during summertime. Organic matter from the catchment area of the Selenga River provides trophic resources for zoobenthos. Amphipods, bivalves and oligochaetes are involved in the transformations of suspended, sedimented and buried fractions of allochthonous matter. The authors obtained evidence on maintenance of the principal properties of the delta ecosystem as an ecotone at the time of research.