Original paper

Nitrogen fixation (acetylene reduction) in Lake Hefner, Oklahoma

McFarland, Mel A.; Toetz, Dale W.

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Archiv für Hydrobiologie Volume 114 Number 2 (1988), p. 213 - 230

48 references

published: Dec 14, 1988

DOI: 10.1127/archiv-hydrobiol/114/1988/213

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ArtNo. ESP141011402003, Price: 29.00 €

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Abstract

The rate of nitrogen fixation (NF) was estimated in the euphotic zone of Lake Hefner, Oklahoma, at intervals of 2—3 days between June and September, 1981. NF was positively correlated to heterocyst density, cell numbers of nitrogen fixing algae and nitrate (NO3-) concentrations. Nitrogen fixation was best described by density of nitrogen fixing algae and nitrate concentration in a stepwise multiple linear regression. Apparently, high concentrations of ammonium + ammonia (NH4+) reduced NF to nil during July and early August. A decrease in NH4+ concentration was probably responsible for an increase in the density of Anabaena, spp. during late August and an increase in rates of NF. The seasonal contribution of NF to the N budget was 1268 kgN2 or 1.3 kgN ha-1. However, the percentage contribution was only 1.5 %.

Keywords

euphotic zone • density • Anabaena • seasonal contribution • Lake Hefner • Oklahoma