Aspects of aerobic mineralization during spring in Lake Vechten with special reference to the 14C-labelling technique
Aerobic mineralization, i.e. seston respiration, microbial breakdown of detritus and microbial assimilation-dissimilation of photosynthetically derived D(issolved) O(rganic) C(arbon) was measured in concentrated samples from the pelagic zone of Lake Vechten. The samples were described by cell numbers of dominant algae prior to concentrating by centrifuge with continuous rotor. The concentrated samples were incubated in the laboratory at in situ temperature and a light intensity of 30 W · m-2 for measuring primary production and photosynthetically derived DOC. After filtration the particulate fraction was incubated in unlabelled lake water for measuring respiratory production of DI14C. Portions of the same particulate fraction were sterilized and incubated in unlabelled sample concentrate for measuring microbial breakdown of detritus. The seston respiration amounted to 19–30% loss of the particulate fraction over 15–45 h. Microbial breakdown of detritus amounted to 28–40% loss of the particulate fraction over 24–168 h. In both cases P(articulate) O(rganic) 14C(arbon) was transformed to mainly DI14C. Microbial assimilation-dissimilatioh of photosynthetically derived DOC could not be measured reliably.
Keywordsaerobic mineralization respiration photo-assimilation extracellular release carbon recycling
Unable to display preview. Download preview PDF.
- Blaauboer, M. A. C. I., van Keulen, R. & Cappenberg, Th. E. (in press). Extracellular release of photosynthetic products by freshwater phytoplankton populations, with special reference to the algal species involved. Freshwat. Biol.Google Scholar
- Cappenberg, Th. E., 1976. Methanogenesis in the bottom deposits of a small stratifying lake. In: ( Schlegel, H. G., Pfennig, N., Gottschalk, G., (Eds.). Microbial Production and Utilization of Gases, H2, CH4, CO, E. Goltze-Verlag, Göttingen, pp. 125–134.Google Scholar
- Golterman, H. L., Clymo, R. S. & Ohnstad, M. A. M., 1978. Methods for Physical and Chemical Analysis of Fresh Waters. IBP Handbook No. 8. Blackwell Scientific, Oxford.Google Scholar
- Gulati, R. D., 1977. Vertical changes in the filtering, feeding and assimilation rates of dominant zooplankters in a stratified lake. Verh. int. Verein. Limnol. 20: 950–956.Google Scholar
- Steenbergen, C. L. M. & Korthals, H. J. (in press). Distribution of phototrophic microorganisms in the anaerobic and microaerophilic strata of Lake Vechten. Pigments analysis and role in primary production. Limnol. Oceanogr.Google Scholar
- Utermöhl, U., 1958. Zur Vervollkommnung der quantitativen Phytoplankton methodik. Mitt: int. Verein. Limnol. 9: 1–38.Google Scholar
- Wiebe, W. J. & Smith, D. F., 1977b. 14C-labelling of the compounds excreted by phytoplankton for employment as a realistic tracer in secondary productivity measurements. Microb. Ecol. 4: 1–8.Google Scholar