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Dark fixation of 14 C: Variations related to biomass and productivity of phytoplankton and bacteria
Author(s) -
Li W. K. W.,
Irwin B. D.,
Dickie P. M.
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.1993.38.3.0483
Subject(s) - phytoplankton , productivity , biomass (ecology) , bacteria , primary productivity , biology , environmental science , fixation (population genetics) , oceanography , botany , ecology , nutrient , geology , economics , biochemistry , gene , macroeconomics , genetics
In various North Atlantic sites, the rate of dark 14 C fixation by microbial plankton was significantly correlated with the rate of light 14 C fixation, with the rate of bacterial [ 3 H]thymidine incorporation, and with chlorophyll biomass. For plankton sampled near the sea surface (<5 m) and at the depth of the maximum light 14 C fixation, the median value for the ratio of dark to light fixation was only 1%. At the depth of the subsurface chlorophyll maximum where less light was available, the median value for this ratio was still quite low at 7%. Our results confirm early claims that generally in the oceans, including oligotrophic regions where plankton biomass is low, dark 14 C fixation is high in relation to light fixation only at depths where photosynthesis is severely limited by light. We infer that direct 14 C fixation by both bacteria and phytoplankton are significant processes that contribute to measured 14 C fixation in opaque bottles during 12 h dawn‐to‐dusk incubations.