Patterns of extracellular enzyme activities in littoral sediments of Lake Gooimeer, The Netherlands

The seasonal variation in enzymatic activities against protein and several polysaccharides together with esterase as a measure of general hydrolytic activity was studied in a transect of sediments through the littoral zone of Lake Gooimeer, The Netherlands. Absolute activities showed a linear relation with organic matter content of the sediments. Patterns of activities were different between inside and outside a reed bed. Inside, polysaccharide hydrolyzing activities dominated, whereas protein related activity was relatively more important outside the bed. This pattern of activities was related to the polymeric composition of the dominant sources of organic matter as determined in a previous study, which changed from a macrophyte dominance to an algal or cyanobacterial dominated system going from inside to outside the reed bed. This suggests that patterns of enzyme activities can be used as a new approach to infer available sources of organic matter in natural systems. [KEYWORDS: extracellular enzyme activity; sediment; littoral; organic matter content; organic matter source Deep-sea sediments; fresh-water ecosystems; organic-matter; marine-sediments; microbial-production; amino-acids; carbon; environment; geochemistry; preservation