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An empirical study of nitrogen dynamics in lakes
Author(s) -
Hellström Thomas
Publication year - 1996
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143096x127208
Subject(s) - epilimnion , denitrification , algae , temperate climate , chlorophyll a , nitrogen , nitrogen fixation , zoology , organic matter , environmental science , chemistry , nutrient , ecology , environmental chemistry , biology , botany , eutrophication , hypolimnion , organic chemistry
The parameters determining the annual balances of nitrogen (N) and the concentrations of total N in lakes were analyzed. This was carried out by the use of multiple regression analyses on data from a number of northern temperate lakes with a hydraulic detention time of 0.25 yr or more. The result indicated that the removal of N in a lake, which in most cases is dominated by denitrification, seems to be controlled by organic matter. If no major N fixation is taking place, the concentration of total N in the epilimnion during summer is proportional to the load of N and inversely proportional to the concentration of total P or chlorophyll a . For some lakes N fixation is taking place. The increase in total N due to N fixation was found to be proportional to the concentration of total P reduced by a fraction of the estimated N concentration without any fixation. For most lakes, the effect of N fixation is to balance the N content with the P content, which means that the algal biomass is limited by the P content. A ratio of the total concentrations N/P less than approximately 10 indicates a rate of denitrification exceeding the capacity of N fixation. N is not balanced with P, and the algae is controlled by N.