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Allometric scaling of compartmental fluxes of phosphorus in freshwater algae
Author(s) -
Wen Yuan Hua,
Vézina Alain,
Peters Robert Henry
Publication year - 1997
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.1997.42.1.0045
Subject(s) - algae , excretion , allometry , chemistry , zoology , phosphorus , flux (metallurgy) , environmental chemistry , botany , biophysics , biology , biochemistry , ecology , organic chemistry
The time courses of uptake, distribution, and excretion of radioactive PO, were determined for 11 species of freshwater algae. Uptake of PO 4 by algae was rapid, reaching a steady‐state asymptote within an hour and maintaining that maximum for at least 10 h. Uptake could be described as a biphasic exponential function. The rate constants for uptake decreased with cell volume raised to a power of ∼‒0.25, whereas the uptake rates per cell increased with cell size to a power of ∼0.75, suggesting that small cells were much more efficient at sequestering PO 4 . Excretion of PO 4 by algae was fast during the first 10–20 min; thereafter, there was a slower prolonged loss of PO 4 for the remaining period. A two‐compartment model could be convincingly fitted directly to the excretion time‐course data. Both rate constants and flux rates of PO 4 excretion and intercompartmental exchanges showed a similar size‐dependency to those of PO 4 uptake. The net uptake of PO 4 by algae increased proportionately to cell volume raised to a normalized power of 0.75. The allometric compartment model yielded estimates for net PO 4 uptake rates one order of magnitude higher than those determined by means of the Michaelis‐Menten model.