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A model of river benthic algal photosynthesis in response to rapid changes in light 1
Author(s) -
Gallegos Charles L.,
Ilornberger George M.,
Kelly Mahlon G.
Publication year - 1977
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.1977.22.2.0226
Subject(s) - photosynthesis , productivity , environmental science , benthic zone , oxygen , atmospheric sciences , radiation , ecology , biology , chemistry , botany , physics , organic chemistry , quantum mechanics , economics , macroeconomics
A linear relationship has been found between light and community productivity in a river, but the correlation is reduced when radiation varies rapidly due to the passage of cumulus clouds. To investigate the relationship during periods of patchy cloudiness we developed a method of calculating short term variations in oxygen exchange based on oxygen measurements taken at very frequent intervals. The method has a high degree of resolution when used with data recorded at 1‐min intervals and the results indicate that large fluctuations in oxygen exchange on time scales of about 5 min can be discerned. Cross‐spectral analysis of the productivity data and measured radiation indicated that a linear lead model for algal photosynthesis in rivers is appropriate. This model has the property that the change in net oxygen productivity per unit change in light is enhanced during periods of rapidly varying radiation relative to periods of slowly varying light.