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Estimates of phytoplankton N uptake based on 14 CO 2 incorporation into protein
Author(s) -
DiTullio Giacomo R.,
Laws Edward A.
Publication year - 1983
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.1983.28.1.0177
Subject(s) - phytoplankton , constant (computer programming) , yield (engineering) , amino acid , chemistry , zoology , biology , environmental science , environmental chemistry , biochemistry , ecology , nutrient , thermodynamics , physics , computer science , programming language
The feasibility of estimating phytoplankton N uptake in N‐limited systems by measuring the rate of 14 CO 2 incorporation into protein was studied using laboratory cultures and field populations. The accuracy of the method depends on the fact that the N:C ratio in protein is remarkably constant and that under N limitation a rather constant percentage (85%) of phytoplankton N is incorporated into protein. Results showed that incubations of 5–6 h are required to yield accurate estimates of N uptake due to internal cycling of amino acids before that. Estimates of phytoplankton N:C ratios based on field studies implied a positive correlation between distance from land and degree of N limitation.