Distribution and origin of dissolved DNA in lakes of different trophic states

Abstract

Concentrations and origin of dissolved DNA (dDNA) were studied in 14 lakes in the Mazurian Lake District (Northern Poland) and 7 lakes in Southern Germany during the summer stratification period. dDNA concentration varied markedly (from 0.5 to 70 μ l-1) in the studied lakes. We suggest that this dissolved organic matter fraction can be potentially one of the most important P and N sources for planktonic microorganisms. Laboratory experiments and field observations suggested that eukaryotic microorganisms (algae) are the most important sources of dDNA in lake water, whereas bacteria mainly decompose the dDNA pool.