Impact Algae Blooms on the Coastal Zone of the Curonian Lagoon of the Baltic Sea

Abstract

Lagoon ecosystem of the freshwater Curonian Lagoon belongs to hypertrophic water bodies, and its coastal zone is of fishery and recreational importance. Long-term monthly data (2014–2015) on chlorophyll and hydrochemical parameters were analyzed. The seasonal dynamics of chlorophyll a (phytoplankton abundance) in the whole Russian water area of the Curonian Lagoon and the influence on hydrochemical and microbiological indicators in the coastal zone near the Curonian Spit National Park (UNESCO World Heritage Site) were considered. During the period of intensive development of Cyanobacteria (“hyperblooming” of water), their acute accumulation in Russian water areas, estimated by chlorophyll, is determined by the wind regime, which causes the local accumulation in separate areas. Algae accumulation in the coastal zone (including the Curonian Spit National Park) in summer and autumn can form harmful hydrochemical and microbiological conditions, corresponding to hypertrophic and hypersaprobic levels, multiple excess of MPC (by BOD5 and ammonia nitrogen, anaerobic zone).