<abstract xmlns="http://www.w3.org/1999/xhtml">

An excess of nitrogen and phosphorus causes an increase in productivity, leading to degradation of a water reservoir. In order to reduce the eutrophication, protective and restoration methods are used. The objective of the paper was to determine the hourly and daily variability in nitrogen and phosphorus compounds in a lake restored by the hypolimnetic withdrawal method. In the epilimnion, the organic form dominates: 97% of Ptot and 75% of Ntot. Hourly variations in the concentration of the investigated compounds indicate that the highest values occurred at night and in the morning, whereas lower measurements were recorded at noon and in the evening. Such a distribution of the concentrations of nutrients during a day is strongly associated with photosynthesis. Along with depth, the proportion of this form decreased in favor of mineral forms. A high content of mineral phosphorus (70%) and ammonium ions (75%) in the hypolimnion results from their release from bottom sediments under anaerobic conditions. As a result of the generated thermocline, they are blocked and accumulated. At the experimental station, the concentration of mineral compounds was at a lower level than at the reference station since their amount was systematically reduced by the outflow of over-fertilized waters from the hypolimnion.
</abstract>

An excess of nitrogen and phosphorus causes an increase in productivity, leading to degradation of a water reservoir. In order to reduce the eutrophication, protective and restoration methods are used. The objective of the paper was to determine the hourly and daily variability in nitrogen and phosphorus compounds in a lake restored by the hypolimnetic withdrawal method. In the epilimnion, the organic form dominates: 97% of Ptot and 75% of Ntot. Hourly variations in the concentration of the investigated compounds indicate that the highest values occurred at night and in the morning, whereas lower measurements were recorded at noon and in the evening. Such a distribution of the concentrations of nutrients during a day is strongly associated with photosynthesis. Along with depth, the proportion of this form decreased in favor of mineral forms. A high content of mineral phosphorus (70%) and ammonium ions (75%) in the hypolimnion results from their release from bottom sediments under anaerobic conditions. As a result of the generated thermocline, they are blocked and accumulated. At the experimental station, the concentration of mineral compounds was at a lower level than at the reference station since their amount was systematically reduced by the outflow of over-fertilized waters from the hypolimnion.

Hourly and daily variability in nitrogen and phosphorus in a lake restored by the hypolimnetic withdrawal method

Department of Water Protection Engineering

Oceanological and Hydrobiological Studies

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

An excess of nitrogen and phosphorus causes an increase in productivity, leading to degradation of a water reservoir. In order to reduce the eutrophication,...

Hourly and daily variability in nitrogen and phosphorus in a lake restored by the hypolimnetic withdrawal method

Published Online: Sep 30, 2015

Page range: 381 - 392

Received: Feb 23, 2015

Accepted: Apr 13, 2015

DOI: https://doi.org/10.1515/ohs-2015-0036

Keywords
nutrients, photosynthesis, primary production, eutrophication, restoration methods

© 2015 Faculty of Oceanography and Geography, University of Gdańsk, Poland

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Hourly and daily variability in nitrogen and phosphorus in a lake restored by the hypolimnetic withdrawal method

Published Online: Sep 30, 2015

Page range: 381 - 392

Received: Feb 23, 2015

Accepted: Apr 13, 2015

DOI: https://doi.org/10.1515/ohs-2015-0036

Keywordsnutrients, photosynthesis, primary production, eutrophication, restoration methods

© 2015 Faculty of Oceanography and Geography, University of Gdańsk, Poland

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
nutrients, photosynthesis, primary production, eutrophication, restoration methods