ISSN:
1420-9055
Keywords:
Key words: Proteolytic activity, glycolytic activities, bacteria, organic matter, reservoir.
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract: From February to August 1996, the following parameters were determined in surface water samples from an oligotrophic reservoir: concentrations of dissolved combined amino acids (DCAA), monosaccharides (DFCHO) and polysaccharides (DCCHO); activities of glycolytic and proteolytic enzymes associated with three size fractions (0-0.2 μm, 0.2-2 μm, and 2-100 μm); densities and biomass of free-living and attached bacteria, nanoflagellates, and metazoan zooplankton. The mean concentrations of DCAA, DFCHO and DCCHO were 2.7, 0.5 and 1.4 mg C l-1 respectively. Both βGlcA and αGlcA showed a high substrate affinity. The enzyme activities associated with all size fractions fluctuated throughout the year. Highest activities were generally associated with the 2-100 μm fraction; the mean percentages of leucine-aminopeptidase (LeuA), β-glucosidase (βGlcA), α-glucosidase (αGlcA) and β-N-acetylglucosaminidase (βGlcNAcA) activities were 58%, 62%, 76%, and 59%, respectively. Activities of αGlcA and βGlcNAcA in the 0.2-2 μm fraction were correlated with the abundance of free-living picobacteria (bacteria 〈2 μm). The biomass-specific activity of attached bacteria was 18 to 64 fold higher for attached compared to free-living bacteria. The abundances of autotrophic and mixotrophic nanoflagellates (ANF) were correlated with LeuA (r = 0.59, P 〈 0.05) and the βGlcA (r = 0.64, P 〈 0.05) activities in the 2-100 μm fraction.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s000270050066
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