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SOME PHOTOSYNTHETIC CHARACTERISTICS OF A NATURALLY OCCURRING POPULATION OF OSCILLATORIA AGARDHII GOMONT 1, 2
Author(s) -
Baker A. L.,
Brook A. J.,
Klemer A. R.
Publication year - 1969
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.1969.14.3.0327
Subject(s) - noon , light intensity , population , photosynthesis , oscillatoria , moonlight , intensity (physics) , algae , biology , environmental science , atmospheric sciences , botany , ecology , geology , physics , cyanobacteria , demography , genetics , sociology , bacteria , optics , quantum mechanics
A natural metalimnetic population of the filamentous blue‐green Oscillatoria agardhii showed diurnal variation in net production of oxygen. The population was incubated during a series of 2‐hr periods during daylight hours on 7 August 1967, while suspended at several depths in Lake Itasca, Minnesota (47° N lat, 95° W long). The net rate of oxygen production varied with light intensity, reaching light saturation at near 10% of the maximum insolation (the incident intensity, I 0 , at solar noon). Productivity curves for depths corresponding to 100, 60, 30, 17, 11, 6, and 4% I ° were obtained. High rates of production occurred during twilight at the surface, but near solar noon at the 6 and 4% levels. The variation, over the range of depths investigated, of oxygen per unit volume represents the shape of a photosynthesis‐depth profile for a homogeneously distributed population. The highest production is at 30% I 0 . The rate‐light intensity curve for the Oscillatoria population is similar in shape to that for certain cultures of marine algae, using the 14 C technique. Distribution of points on the rate‐light intensity curve suggests that light quality, as well as intensity, is important, and that the filtering effect of lake water enhances subsurface oxygen production even at relatively high light intensities (80% of the solar noon I 0 value).