Open AccessDiurnal Variation in N2 Fixation and Photosynthesis by Aquatic Blue-Green Algae
Author(s) -
Richard B. Peterson,
Eugene E. Friberg,
R. H. Burris
Publication year - 1977
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.59.1.74
Subject(s) - photosynthesis , algae , biology , light intensity , carbon fixation , population , diurnal temperature variation , botany , sunrise , green algae , photorespiration , atmospheric sciences , geology , physics , demography , sociology , optics
Rates of (14)CO(2) fixation, O(2) evolution, and N(2) fixation (acetylene reduction) by natural populations of blue-green algae recovered from Lake Mendota were measured at frequent intervals between sunrise and sunset. Photosynthesis and N(2) fixation were depressed during midday when light intensity was greatest. As the light intensity rose, most of the algal population migrated to deeper, light-limited waters where radiation damage would be diminished. As the relative rate of N(2) fixation compared to CO(2) fixation increases with depth, it is suggested that the algae maintain balanced growth by migrating vertically via buoyancy regulation. High concentrations of dissolved O(2) in lake water may inhibit N(2) fixation by enhancing photorespiration. Several factors such as photosynthetic rate, light intensity, dissolved O(2), species composition, and vertical and horizontal migration all affect observed rates of in situ N(2) fixation.