Holocene pattern of organic carbon accumulation in a small lake in Estonia

A comprehensive study of the sediment profile of L. Viitna Linajärv, a small closed drainage lake located in northern Estonia (59°27´N, 25°01´E), was conducted to assess the impact of water-level changes on the carbon accumulation dynamics in the lake during the Holocene. The variations of the P content, C/N ratio, fossil pigments and diatom communities indicate essential changes in the lake ecosystem history during the Holocene. The results show that on millennial time-scale (103 years) fluctuations of the lake level, concurrent shore erosion and coprecipitation of dissolved organic matter with allochthonous mineral particles were the driving factors in the lake history. Net organic carbon accumulation was ~30 g m–2 yr–1 at the beginning of the Holocene (ca 9000 BP), then decreased to 10 g m–2 yr–1 (5000–2000 BP) and increased in the upper layers (since 1000 BP) up to 60 g m–2 yr–1.