Efficiency of nutrient management in controlling eutrophication of running waters in the Middle Danube Basin
Nutrient emission dropped significantly during the last two decades in the Danube Basin. To assess the effect of reduced nutrient loads on the trophic status of running waters, this regional study analyzed the relationships between nutrients (P and N) and suspended chlorophyll (Chl) using long-term monitoring data in Hungary. Including the upstream catchments of trans-boundary rivers, the study covered an approximate area of 400,000 km2, equivalent to the half of the entire Danube catchment. Decadal median Chl was unrelated to P and N concentrations in the whole data set and weakly related to total P (TP) at natural-moderately polluted (N-MP) sites, which were distinguished from highly polluted (HP) sites by using cutoff values for chloride, chemical oxygen demand and TP. At both the N-MP sites and most of the HP sites, Chl increased with channel length. This indicated that water residence time was a more important determinant of Chl than nutrients. Nutrient concentrations showed a significant downward trend in time at half of our sites. With a nearly equal frequency, a parallel trend might or might not occur in Chl. The apparent efficiency of nutrient management was expressed as the quotient of the slopes of linear trends in Chl and nutrients. At sites within 150 km from source, this efficiency was marginal. In larger rivers, efficiency improved steeply. The highest efficiency was observed in the downstream reach of the Danube (upstream length >1,300 km) where P availability might frequently limit algal growth. The results suggest that eutrophication management in rivers should be based on Chl response functions, rather than universal nutrient criteria. Four Chl response classes were identified based on the observed longitudinal P and Chl gradients.
KeywordsSestonic chlorophyll River size Water residence time Nutrient management efficiency Chlorophyll response functions Water Framework Directive
This study was financially supported by the National Science Foundation (OTKA) Grant No. 63340. We are grateful to Dr. Adrienne Clement for providing the data and the maps to construct Fig. 1. Two anonymous referees helped us to improve a previous version of this paper.
- Csathó, P. & L. Radimszky, 2011. Towards sustainable agricultural NP turnover in the EU 27 countries: a review. In Tóth, G. & T. Németh (eds), Land Quality and Land Use Information in the European Union. JRC-IES, Ispra: 69–86.Google Scholar
- Csathó, P., I. Sisák, L. Radimszky, S. Lushaj, H. Spiegel, M. T. Nikolova, N. Nikolov, P. Čermák, J. Klir, A. Astover, A. Karklins, S. Lazauskas, J. Kopiński, C. Hera, E. Dumitru, M. Manojlovic, D. Bogdanović, S. Torma, M. Leskošek & A. Khristenko, 2007. Agriculture as a source of phosphorus causing eutrophication in Central and Eastern Europe. Soil Use and Management Supplement 23: 36–56.CrossRefGoogle Scholar
- Dokulil, M. 2006. Assessment of potamoplankton and primary productivity in the river Danube: A review. In Proceedings 36th International Conference of IAD. Austrian Committee Danube Research/IAD, Vienna. ISBN 13: 978-3-9500723-2-7, 1-5.Google Scholar
- Erős, T., D. Schmera & R. S. Shick, 2011. Network thinking in riverscape conservation—a graph-based approach. Biological Conservation 144: 181–192.Google Scholar
- Hansen, E. & M. Christ, 2001. EPA’s Nutrient Criteria Recommendations and Their Application in Nutrient Ecoregion XI. http://www.wvrivers.org/wvrcpermitassistance/WVRCPermitAnalysisProgram_files/NutrientCommentsEcoregionXI.pdf
- Honti, M., V. Istvánovics & Z. Kozma, 2008. Assessing phytoplankton growth in River Tisza (Hungary). Verhandlungen der internationle Vereinigung für throretische und angewandte Limnologie 30: 87–89.Google Scholar
- ICPDR, 2005. The Danube River Basin District. Part A—basin-wide overview. http://www.icpdr.org/icpdr-pages/reports.htm
- Kiss, K. T., 1994. Trophic level and eutrophication of the River Danube in Hungary. Verhandlungen der internationle Vereinigung für throretische und angewandte Limnologie 25: 1688–1691.Google Scholar
- Leopold, L. B., M. G. Wolman & J. P. Miller, 1964. Fluvial Processes in Geomorphology. WH Freeman and Company, San Francisco.Google Scholar
- Reynolds, C. S., 1992. Eutrophication and the management of planktonic algae: what Vollenweider couldn’t tell us. In Sutcliffe, D. W. & J. G. Jones (eds), Eutrophication: Research and Application to Water Supply. FBA, Ambleside: 4–29.Google Scholar
- Reynolds, C. S. & J.-P. Descy, 1996. The production, biomass, and structure of phytoplankton in large rivers. Archiv für Hydrobiologie, Supplementband Large Rivers 113: 161–187.Google Scholar
- Royer, T. V., M. B. David, L. E. Gentry, C. A. Mitchell, K. M. Starks, T. I. Heatherly & M. R. Whiles, 2008. Assessment of chlorophyll-a as a criterion for establishing nutrient standards in the streams and rivers of Illinois. Journal of Environmental Quality 37: 437–447.PubMedCrossRefGoogle Scholar
- Salminen, R., M. J. Batista, M. Bidovec, A. Demetriades, B. De Vivo, W. De Vos, M. Duris, A. Gilucis, V. Gregorauskiene, J. Halamic, P. Heitzmann, A. Lima, G. Jordan, G. Klaver, P. Klein, J. Lis, J. Locutura, K. Marsina, A. Mazreku, P. J. O’Connor, S. Å. Olsson, R.-T. Ottesen, V. Petersell, J. A. Plant, S. Reeder, I. Salpeteur, H. Sandström, U. Siewers, A. Steenfelt & T. Tarvainen, 2005. Geochemical Atlas of Europe. Part 1—Background Information, Methodology, and Maps. Association of the Geological Surveys of the European Union/Geological Survey of Finland, www.gtk.fi/publ/foregsatlas/.
- Sas, H., 1989. Lake Restoration by Reduction of Nutrient Loading Expectations, Experiences, Extrapolation. Academic Verlag, St Augustin.Google Scholar
- Schreiber, H., H. Behrendt, L. T. Constantinescu, I. Cvitanic, D. Drumea, D. Jabucar, S. Juran, B. Pataki, S. Snishko & M. Zessner, 2005. Nutrient emissions from diffuse and point sources into the River Danube and its main tributaries for the period of 1998–2000—results and problems. Water Science and Technology 51: 283–290.PubMedGoogle Scholar
- Somlyódy, L. & P. Shanahan, 1998. Municipal Wastewater Treatment in Central and Eastern Europe. Present Situation and Cost-Effective Development Strategies. World Bank, Washington.Google Scholar
- Uherkovich, G., 1971. A Tisza Lebegô Paránynövényei (in Hungarian). Szolnok Megyei Múzeum Adattár, Szolnok, HungaryGoogle Scholar
- Verasztó, C., K. T. Kiss, C. Sipkay, L. Gimesi, C. Vadai-Fülöp, D. Türei & L. Hufnagel, 2010. Long-term dynamic patterns and diversity of phytoplankton communities in a large eutrophic river (the case of River Danube, Hungary). Applied Ecology and Environmental Research 8: 329–349.Google Scholar
- Vollenweider, R. A. & J. J. Kerekes, 1982. Background and Summary Results of the OECD Cooperative Programme on Eutrophication. OECD, Paris.Google Scholar
- Vörös, L., K. V. Balogh, S. Herodek & K. T. Kiss, 2000. Underwater light conditions, phytoplankton photosynthesis and bacterioplankton production in the Hungarian section of the River Danube. Archiv für Hydrobiologie, Supplement band Large Rivers 11: 511–532.Google Scholar