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Phytoplankton extracellular release and its relation to the seasonal cycle of dissolved organic carbon in a eutrophic lake 1
Author(s) -
Storch Thomas A.,
Saunders George W.
Publication year - 1978
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1978.23.1.0112
Subject(s) - phytoplankton , dissolved organic carbon , environmental chemistry , eutrophication , total organic carbon , organic matter , environmental science , chemistry , extracellular , ecology , nutrient , biology , biochemistry
The concentration of total dissolved organic carbon (TDOC), the daily rates of release of extracellular dissolved organic carbon (DOC) by viable phytoplankton, and the daily rates of assimilation of the phytoplankton extracellular DOC by bacteria were investigated simultaneously from April through October in Frains Lake, Michigan. The concentration of TDOC varied aperiodically. The release of DOC by phytoplankton and its utilization by bacteria fluctuated markedly, but these processes did not play a significant role in causing the seasonal variations of TDOC. Increases in the concentration of TDOC greatly exceeded the amounts accumulated from release by the phytoplankton, even when maximum rates of phytoplankton DOC release were calculated by assuming release exclusively from a large intracellular pool not at isotopic equilibrium. In addition, bacterial utilization of the phytoplankton DOC alone could not account for decreases in TDOC concentration. Therefore, there must be other major sources of dissolved organic matter than that provided by the mechanism of extracellular release by phytoplankton. The littoral flora and the decomposition of dead particulate organic materials are the most likely sources of fluctuations of TDOC in Frains Lake.