Nitrogen or phosphorus limitation in lakes and its impact on phytoplankton biomass and submerged macrophyte cover
- 1k Downloads
We used data on nutrients, chlorophyll a (Chla) and submerged macrophyte cover from up to 817 Danish lakes to elucidate seasonal variations in nitrogen (N) and phosphorus (P) concentrations and to study the impact of N or its role in combination with P. In both deep and shallow lakes, we found marked seasonality in the ratio between total N and total P (TN:TP) and in the inorganic concentrations of nitrogen (DIN), indicating that N more easily becomes a limiting nutrient as summer proceeds. TN:TP reached its lowest values of <7 (by mass) in August in 25% of the shallow lakes. Chla generally related more strongly to TP than to TN, but at high TP concentrations TN explained more of the variability in Chla than TP. Macrophyte cover tended to decrease at increasing TN when TP was between 0.1 and 0.4 mg/l. At macrophyte cover above 20%, Chla was considerably lower compared with lakes with low macrophyte cover. We conclude that P is of key importance for the ecological quality of Danish lakes but that increased N concentrations, particularly in shallow lakes with moderate to high TP, may have significantly adverse effects on lake water quality and ecological status in summer.
KeywordsDanish lakes Nutrients Seasonality Chlorophyll a TN:TP ratio
The project was supported by the EU project MARS (Managing Aquatic ecosystems and water Resources under multiple Stress) funded under the 7th EU Framework Programme and by CLEAR (a Villum Kann Rasmussen Centre of Excellence project). The Danish regional environmental authorities are acknowledged for their careful lake monitoring and data collection. Anne Mette Poulsen and Tinna Christensen are acknowledged for editorial and layout assistance.
- Barko, J. W. & W. F. James, 1998. Effect of Submersed Aquatic Macrophytes on Nutrients Dynamics, Sedimentation and Resuspension. In Jeppesen, E., M. Søndergaard, M. Søndergaard & K. Christoffersen (eds), The Structuring Role of Submerged Macrophytes in Lakes, Ecological Studies 131. Springer, New York: 197–214.CrossRefGoogle Scholar
- Davis, T. W., G. S. Bullerjahn, T. Tuttle, R. M. McKay & S. B. Watson, 2015. Effects of increasing nitrogen and phosphorus concentrations on phytoplankton community growth and toxicity during Planktothrix blooms in Sandusky Bay, Lake Erie. Environmental Science & Technology 49: 7197–7207.CrossRefGoogle Scholar
- Elser, J. J., M. E. S. Bracken, E. E. Cleland, D. S. Gruner, W. S. Harpole, H. Hillebrand, J. T. Ngai, E. W. Seabloom, J. B. Shurin & J. E. Smith, 2007. Global analysis of nitrogen and phosphorus limitation of primary producers in freshwater, marine and terrestrial ecosystems. Ecological Letters 10: 1135–1142.CrossRefGoogle Scholar
- Jeppesen, E., M. Søndergaard, M. Søndergaard & K. Christoffersen (eds), 1998. The Structuring Role of Submerged Macrophytes in Lakes, Ecological Studies 131. Springer, New York.Google Scholar
- Jeppesen, E., B. Kronvang, J. E. Olesen, J. Audet, M. Søndergaard, C. C. Hoffmann, H. E. Andersen, T. L. Lauridsen, L. Liboriussen, S. E. Larsen, M. Beklioglu, M. Meerhoff, A. Özen & K. Özkan, 2011. Climate change effects on nitrogen loading from cultivated catchments in Europe: implications for nitrogen retention, ecological state of lakes and adaptation. Hydrobiologia 663: 1–21.CrossRefGoogle Scholar
- OECD, 1982. Eutrophication of Waters—Monitoring, Assessment and Control. Organisation for Economic Co-operation and Development, Paris: 154.Google Scholar
- Paerl, H. W., 1988. Nuisance phytoplankton blooms in coastal, estuarine, and inland waters. Limnology & Oceanography 33: 823–847.Google Scholar
- Redfield, A. C., 1958. The biological control of chemical factors in the environment. American Scientist 46: 205–221.Google Scholar
- Svendsen, L.M., L. van der Bijl, S. Boutrup & B. Norup, B. eds), 2005. NOVANA. National Monitoring and Assessment Programme for the Aquatic and Terrestrial Environments. Programme Description, part 2. NERI Technical Report No. 537. National Environmental Research Institute, Aarhus, Denmark. 13C89536/0/FR537_www_S_H.pdf.Google Scholar
- Vollenweider, R. A., 1976. Advances in defining critical loading levels for phosphorus in lake eutrophication. Memorie dell’lstituto Italiano di Idrolnologia 33: 53–83.Google Scholar