Enzymatic potential for decomposition of detrital biopolymers in sediments from Kiel Bay
Reichardt, W. (1986). Enzymatic potential for decomposition of detrital biopolymers in sediments from Kiel Bay, in: Muus, K. (Ed.) Proceedings of the 20th European Marine Biology Symposium: Nutrient Cycling. Processes in Marine Sediments, Hirtshals, Denmark, 9-13 September 1985. Ophelia: International Journal of Marine Biology, 26: pp. 369-384 In: Muus, K. (Ed.) (1986). Proceedings of the 20th European Marine Biology Symposium: Nutrient Cycling. Processes in Marine Sediments, Hirtshals, Denmark, 9-13 September 1985. European Marine Biology Symposia, 20. Ophelia: International Journal of Marine Biology, 26. ISBN 87-981066-4-3. 477 pp., more In: European Marine Biology Symposia., more |
| Abstract | Enzymatic activities involved in the solubilization of particulate organic matter (POM) were determined in the surface samples from coastal sediments of Kiel Bay (Baltic Sea). For this purpose dye release assays were developed and standardized to measure the enzymatic conversion of dye-labelled particulate protein, cellulose, chitin, agar, and algal cell walls to soluble fragments. On the average, about half of the total POM-solubilizing activities were proteolytic. These were reduced when oxygen availability or Eh became limiting. Seasonal and spatial distribution patterns showed opposite trends for protein- and polysaccharide-solubilizing enzymes (most clearly for cellulase). Among the polysaccharases investigated, agarase activities were consistently predominant. During periods of intensive advection of macroalgae in winter they reached even the level of proteolytic activities. Intermediate levels of activity were noted for stained cell walls as a mixed natural substrate. Seasonal changes of the enzyme activities during winter and spring were dominated by the impact of a settling phytoplankton bloom at 18 m water depth, whereas samples from the maximal depth (28 m) with similar ATP levels showed extremely low activities. Concluding from the temporal patterns, the half-lives of the enzymes were a few weeks or less. During the main sedimentarion event, agar- and cellulose-solubilizing enzymes peaked earlier than the proteolytic enzymes. Time-lags between the maxima of ATP-related and volume-based protease activities suggested particularly strong regulatory impacts on the proteases. The analytical potential of dye-release assays to elucidate rate-controlling factors and kinetic details of POM degradation in marine sediments is discussed. |
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