Abstract
The response of the planktonic heterotrophic bacterial community to the buildup and breakdown of a semipermanent, crusted, floating cyanobacterial mat, or hyperscum, that covered 1 to 2 ha was studied in a hypertrophic lake (Hartbeespoort Dam, South Africa). The initial response of bacteria in the main basin to the release of dissolved organic carbon (DOC) from the hyperscum 1 km away was an increase in activity per cell from 35 × 10−12 to 153 × 10−12 μg of C cell−1 h−1 for total cell counts, while activity per cell for metabolically active cells increased from 19 × 10−11 to 85 × 10−11 μg of C cell−1 h−1. No major population growth occurred at this stage. Later, with the continuous supply of DOC from the hyperscum, total bacterial numbers increased from 6.6 × 106 to 20 × 106 cells ml−1, while the activity per cell declined. Metabolically active bacteria followed the same trend. Shorter-term DOC increases caused only increases in bacterial activity per cell. The data from Hartbeespoort Dam demonstrate an interesting and little-documented mechanism by which aquatic bacteria respond to increased DOC concentration and which may be universal for aquatic systems.
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- Kogure K., Simidu U., Taga N. A tentative direct microscopic method for counting living marine bacteria. Can J Microbiol. 1979 Mar;25(3):415–420. doi: 10.1139/m79-063. [DOI] [PubMed] [Google Scholar]
- Wright R. T. Measurement and significance of specific activity in the heterotrophic bacteria of natural waters. Appl Environ Microbiol. 1978 Aug;36(2):297–305. doi: 10.1128/aem.36.2.297-305.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]