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Stimulation of the microbial food web in an oligotrophic, slightly acidified lake
Author(s) -
Bell Russell T.,
Vrede Katarina,
Stensdotter-Blomberg Ulrika,
Blomqvist Peter
Publication year - 1993
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.1993.38.7.1532
Subject(s) - bacterioplankton , nutrient , microbial food web , dissolved organic carbon , liter , environmental chemistry , microbial loop , nitrate , bacterial growth , food web , biomass (ecology) , chemistry , zoology , biology , ecology , phytoplankton , bacteria , ecosystem , genetics , endocrinology
We investigated the relative importance of inorganic nutrients vs. organic C in controlling bacterial production in a clear‐water, slightly acidified lake. We added dissolved organic C (DOC) as glucose (0.5 mg C liter −1 ) with and without inorganic nutrients (10 µ g P liter −1 and 100 µg nitrate‐N liter −1 ) to 350‐liter enclosures. The treatment with DOC and nutrients in combination stimulated bacterial production (thymidine incorporation) steadily (from 1 to 9 pmol liter −1 h −1 ) throughout the 3‐week period. Glucose added alone and N+P added alone (at 2 × lake concn) had little effect on bacterial production. The enhancement of bacterial production by glucose with N+P in turn resulted in an increase in chrysophyte biomass, mainly the mixotroph Dinobryon. The enhancement of bacterial production was transferred up to protozoans (ciliates + heliozoans). These results indicate that bacterioplankton are potentially a link for C in this system and that there is a sensitive balance between bacterial limitation by DOC and inorganic nutrients in this oligotrophic lake.