A between-river comparison of extracellular-enzyme activity.

摘要: River-water extracellular-enzyme activity in the lowland Rivers Ouse and Derwent, northeast England, had much common. In both rivers, mean enzyme activities over 15 months differed following order: leucine aminopeptidase > phosphatase β-D-glucosidase β-D-galactosi-idase β-D-xylosidase. None of five enzymes assayed significant between-river difference activity, there was correlation β-D-glucosidase, phosphatase, leucine-aminopeptidase activity. The common regimes were probably more due to similarity planktonic microbiota than similar physico-chemical conditions. potential for glucose uptake by bacterioplankton closely followed magnitude periodicity. uptake, however, less activity; hence rate release did not limit uptake. There an appreciable highly variable proportion free (<0.2 μm) river water; ranges 10–30%, 53% apparently 104%, 22–98%. These necessarily originate from may explain fairly loose coupling between whole-water microbial variables. Marked downstream increase along about 104 km River found on only one three sampling days; single site used regular reasonably representative most river.