Bacterial extracellular enzymatic activities in a Tyrrhenian ecosystem (Gulf of Milazzo).

Leucine aminopeptidase, beta-glucosidase and alkaline phosphatase activities were estimated by fluorogenic substrates in a Tyrrhenian ecosystem; two different periods were studied, as indicative of different hydrographic structures (i.e., water column stratification and homogeneity). The measured values of metabolic activities sometimes followed a general decreasing coastal-offshore gradient; during water homogeneity, enhanced leucine aminopeptidase activity rates, heterotrophic and autotrophic biomasses occurred, while during water stratification high levels of metabolic activity were detected.