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Effect of nitrogen source and growth rate on phytoplankton‐mediated changes in alkalinity 1
Author(s) -
Goldman Joel C.,
Brewer Peter G.
Publication year - 1980
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.1980.25.2.0352
Subject(s) - alkalinity , excretion , chemistry , nitrogen , urea , phytoplankton , glycolic acid , environmental chemistry , nutrient , inorganic chemistry , biochemistry , zoology , biology , lactic acid , organic chemistry , bacteria , genetics
Continuous cultures of the marine chrysophyte Dunaliella tertiolecta were grown on four nitrogen sources: NO 3 NO 2 − , NH 4 +, and urea. Alkalinity changes were consistent with a simple stoichiometric model in which OH production is balanced by NO 3 − and NO 2 − uptake, H + production is balanced by NH 4 + uptake and no change occurs when the uncharged species urea is assimilated. Neither the influent N concentration nor the growth rate had any effect on the 1:1 stoichiometry between N uptake and alkalinity change. These results preclude the possibility of excretion of an organic acid (e.g. glycolic acid) stronger than carbonic acid. However, excretion of a weak organic acid or a salt of a strong organic acid cannot be ruled out. In general, the results are consistent with the notion that excretion of glycolic acid by healthy marine phytoplankton cells is minimal.