Composition, distribution, and seasonal dynamics of vegetation in the estuaries of the Olga Bay (central Primorye)

Abstract

Twenty-one species of water plants are found in the Avvakumovka River estuary and fourteen species - in the Olga River estuary in 3 surveys conducted in May, July, and September of 2012. Zostera marina dominates in the external estuary of both rivers in any season, whereas Potamogeton spp. and Ruppia maritima are the most abundant in some local areas of the Avvakumovka external estuary and Zostera japonica - in some local shallow areas of the Olga external estuary (where it forms perennial settlements). Chaetomorpha linum is the subdominant species in the Olga external estuary. In the Avvakumovka internal estuary, Cladophora glomerata and Z. marina are the dominants in May, Z. marina - in July, and Z. marina and Potamogeton spp. - in September, but any bottom vegetation is absent in the Olga internal estuary. From May to September of 2012, the summary biomass of water vegetation in both estuaries increased in 5 times: from 0.3 to 1.5 thousand tons.