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Influence Of Zooplankton Grazing On Free Dissolved Enzymes In The Sea, Alexander B. Bochdansky, Staša Puškarić, Gerhard J. Herndl

OES Faculty Publications

In the Northern Adriatic Sea, extracellular enzymatic activity was measured during a Lagrangian study following a drifting buoy for 40 h. Dissolved free enzymatic activity represented 20 to 70% of total activity depending on the type of enzyme. alpha- and beta-glucosidases exhibited a significantly higher free activity than proteolytic enzymes. In subsequent laboratory experiments we investigated the effect of zooplankton on the free enzyme pool. The 4-step approach included: (1) determination of the enzymatic activities in copepods (mainly Acartia clausi); (2) enzymatic activity in fecal pellets; (3) short- and long-term grazing experiments; and (4) degradability of free glucosidase in seawater. …