Inter-Research
Aquatic Microbial Ecology

ABSTRACT: In this paper we discuss the suitability of the cetyltrimethylammonium bromide (CTAB) precipitation method for the determination of dissolved DNA (dDNA) in lake water. Factors affecting dDNA recovery from the precipitate and further DAPI fluorometric assay were also examined. The proposed method was particularly suitable for routine determination of dDNA concentration in low and moderately eutrophicated freshwater environments. The detection limit of the method varied from 1.5 µg dDNA l^-1 for mesotrophic waters to 2.5 µg dDNA l^-1 for eutrophic lakes. Preliminary observations on the concentration of dDNA in the surface water of 8 southern German lakes showed that dDNA concentrations were generally related to their trophic status and varied between 2.5 and 46.0 µg l^-1 in mesotrophic and from 11.5 to 72 µg l^-1 in eutrophic waters.

KEY WORDS: Dissolved DNA · Lake water · CTAB · DAPI

Published in AME Vol. 11, No. 2 (1996) on August 29
Print ISSN: 0948-3055; Online ISSN: 1616-1564. Copyright © Inter-Research, Oldendorf/Luhe, 1996