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Nitrogen-fixing anabaena: physiological adaptations instrumental in maintaining surface blooms
Science (New York, N.Y.)
|May 11, 1979
Summary
Blue-green algae Anabaena spp. dominate lakes by adapting to changing light and oxygen. They optimize carbon dioxide and nitrogen fixation, and alter pigments to survive bloom conditions.
Area of Science:
- Environmental Microbiology
- Aquatic Ecology
- Phycology
Background:
- Blue-green algae, specifically Anabaena spp., are known to dominate surface lake waters.
- These nuisance blooms occur amidst significant diurnal fluctuations in light intensity and oxygen saturation.
Purpose of the Study:
- To investigate the adaptive mechanisms employed by Anabaena spp. to dominate surface lake environments.
- To understand how Anabaena spp. cope with environmental stressors like oxygen toxicity during algal blooms.
Main Methods:
- Laboratory studies and in situ observations were conducted.
- Analysis focused on the physiological and biochemical responses of Anabaena spp. to varying light and oxygen conditions.
Main Results:
- Anabaena spp. exhibit sequential optimization of carbon dioxide and nitrogen fixation to manage oxygen toxicity.
- Pigment alteration is another key mechanism allowing adaptation to fluctuating light intensities.
- These adaptations enable efficient use of radiant energy and reduce competition for photoreductant.
Conclusions:
- Anabaena spp. possess sophisticated adaptive strategies for survival and dominance in surface lake waters.
- The ability to optimize key metabolic processes and alter pigment composition is crucial for overcoming environmental challenges during blooms.
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