Nitrogen Fixation on the Tropical Volcano, La Soufriere (Guadeloupe): I. A Survey of Nitrogen Fixation by Blue-Green Algal Microepiphytes and Lichen Endophytes

Biotropica ◽  
1987 ◽  
Vol 19 (3) ◽  
pp. 194 ◽  
Author(s):  
Richard P. Fritz-Sheridan ◽  
Jacques Portecop
Keyword(s):  
Nitrogen Fixation ◽  
Green Algal

Comparison of the Nitrogen-15 Uptake and Acetylene Reduction Methods for Estimating the Rates of Nitrogen Fixation by Freshwater Blue-Green Algae

1980 ◽  
Vol 37 (3) ◽  
pp. 488-493 ◽  
Author(s):  
B. M. Graham ◽  
R. D. Hamilton ◽  
N. E. R. Campbell
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Experimental Lakes Area ◽  
Method Of Calculation ◽  
Blue Green Algae ◽  
Northwestern Ontario ◽  
Green Algal ◽  
Reduction Methods ◽  
Ratio Determination ◽  
Relationship Of

The relationship of acetylene reduction to nitrogen-15 uptake was investigated using blue-green algal populations in three lakes in the Experimental Lakes Area, northwestern Ontario. Nitrogen fixation rates, as estimated with both techniques, were compared and acetylene to nitrogen ratios determined. Lake ratios ranged from 6.3 to 9.1 moles of acetylene reduced per mole of nitrogen fixed varying from sample to sample and also with the method of calculation. Explanations of the discrepancies between theoretical and empirical ratios are discussed; these include hypotheses of excretion of assimilated nitrogen-15 labeled material and interference from nitrogenase-mediated hydrogen production.Key words: acetylene reduction, nitrogen-15 uptake, nitrogen fixation, C2H2/N2 ratio determination

Ecology of deepwater rice-fields in Bangladesh 4. Nitrogen fixation by blue-green algal communities

Hydrobiologia ◽  
1988 ◽  
Vol 169 (1) ◽  
pp. 43-56 ◽  
Author(s):  
J. A. Rother ◽  
Abdul Aziz ◽  
N. Hye Karim ◽  
B. A. Whitton
Keyword(s):  
Nitrogen Fixation ◽  
Rice Fields ◽  
Deepwater Rice ◽  
Algal Communities ◽  
Green Algal

Iron in Eutrophic Clear Lake, California: Its Importance for Algal Nitrogen Fixation and Growth

1983 ◽  
Vol 40 (9) ◽  
pp. 1419-1429 ◽  
Author(s):  
Wayne A. Wurtsbaugh ◽  
A. J. Horne
Keyword(s):  
Nitrogen Fixation ◽  
Large Volume ◽  
Carbon Fixation ◽  
Algal Growth ◽  
Clear Lake ◽  
Blue Green Algae ◽  
Green Algal ◽  
Chlorophyll Production ◽  
Low Nitrogen

Clear Lake, California, is warm, shallow, polymictic, and eutrophic. During 1975, levels of dissolved (< 0.45 μm) iron in all three basins of Clear Lake were always low (15–30 μg∙L−1) and decreased to 2 μg∙L−1 during the major bloom of Aphanizomenon flos-aquae. Nitrogen fixation (acetylene reduction) rates of the blue-green algal populations were stimulated as much as 500% above control levels by iron additions in laboratory and in situ large-volume bioassays. Carbon fixation rates and chlorophyll a levels were also significantly stimulated by iron additions, but usually less rapidly and to a lesser extent than N2 fixation. Additions of nitrate stimulated carbon fixation and chlorophyll production but inhibited increases in nitrogen fixation. Phosphate additions either had no effect or produced a mixture of stimulation or depression of all three variables. The bioassays indicate that the growth of blue-green algae and other algae in Clear Lake is usually directly limited by combined nitrogen and occasionally by iron or phosphorus. Low iron levels aggravate the effects of low nitrogen by limiting nitrogen fixation, thus reducing blue-green algal growth.

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