ISSN:
1573-5117
Schlagwort(e):
Nitrogen fixation
;
nutrient enrichment
;
limnocorral
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Abstract Nitrogen fixation was measured in situ by the 15N tracer technique in the Bay of Quinte, Lake Ontario, and three lake enclosures with different nutrient enrichment. The fixation rates in the Bay were low but detectable during the summer season. The fixation activities were found to be correlated with the presence of nitrogen-fixing blue-green algae and the distribution of the algal species in the water was affected by nitrate enrichment. The study showed that, with the addition of nitrate, species not able to fix atmospheric nitrogen became predominant. However, in the absence of external nitrogen (i.e., nitrate), species able to fix nitrogen became dominant. Phosphorus enrichment alone did result in higher N-fixation rates in the water and, without the addition of phosphorus, the fixation rates are lower and fluctuate throughout the season, presumably dependent on the availability of phosphorus in the water. A comparison between the 15N-isotopic method and the acetylene reduction method is reported and the factors involved in the variations between these two methods are discussed.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00017515
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