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Potassium dependence and phytoplankton ecology: an experimental study
Author(s) -
Jaworski G. H. M.,
Talling J. F.,
Heaney S. I.
Publication year - 2003
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1046/j.1365-2427.2003.01051.x
Subject(s) - phytoplankton , macrophyte , diatom , biomass (ecology) , growth rate , zoology , algae , botany , aquatic plant , dry weight , biology , potassium , environmental chemistry , ecology , chemistry , nutrient , geometry , mathematics , organic chemistry
SUMMARY 1. Unialgal cultures of three species common in the freshwater phytoplankton were used to test limitation of specific growth rate and final yield in defined media of low K + concentration (range <0.3–6 μmol L −1 or mmol m −3 ). 2. Growth rate of the diatom Asterionella formosa was independent of K + concentration above 0.7 μmol L −1 . Final yield was dependent on initial concentration when accompanied by K + depletion below this concentration, but not by lesser depletion with more residual K + . Analyses of particulate K in the biomass indicated a mean final cell content of 2.8 μmol K 10 −8 cells, approximately 1.0% of the organic dry weight. 3. Less detailed work with the diatom Diatoma elongatum showed no dependence of growth rate or final yield upon the initial K + concentration in the range 0.8–3.2 μmol L −1 . The phytoflagellate Plagioselmis nannoplanctica suffered net mortality in the lowest concentration tested, 0.8 μmol L −1 . 4. Comparison with the range of K + concentration in natural fresh waters, including a depletion induced by an aquatic macrophyte, suggests that K + is unlikely to limit growth of phytoplankton. Nevertheless, there can be correlation of K + with lake trophy.