Increased nutrient loading and rapid changes in phytoplankton expected with climate change in stratified South European lakes: sensitivity of lakes with different trophic state and catchment properties
We hypothesised that increasing winter affluence and summer temperatures, anticipated in southern Europe with climate change, will deteriorate the ecological status of lakes, especially in those with shorter retention time. We tested these hypotheses analysing weekly phytoplankton and chemistry data collected over 2 years of contrasting weather from two adjacent stratified lakes in North Italy, differing from each other by trophic state and water retention time. Dissolved oxygen concentrations were higher in colder hypolimnia of both lakes in the second year following the cold winter, despite the second summer was warmer and the lakes more strongly stratified. Higher loading during the rainy winter and spring increased nutrient (N, P, Si) concentrations, and a phytoplankton based trophic state index, whilst the N/P ratio decreased in both lakes. The weakened Si limitation in the second year enabled an increase of diatom biovolumes in spring in both lakes. Chlorophyll a concentration increased in the oligo-mesotrophic lake, but dropped markedly in the eutrophic lake where the series of commonly occurring cyanobacteria blooms was interrupted. The projected increase of winter precipitation in southern Europe is likely to increase the nutrient loadings to lakes and contribute to their eutrophication. The impact is proportional to the runoff/in-lake concentration ratio of nutrients rather than to the retention time, and is more pronounced in lakes with lower trophy.
KeywordsClimate change Anoxia Phosphorus release Silicon limitation Change of dominant species Flushing
- Allaby, M., 2007. Encyclopedia of Weather and Climate. Revised Edition. Facts On File, Inc., New York.Google Scholar
- Bouraoui, F., B. Grizzetti, G. Adelsköld, H. Behrendt, I. de Miguel, M. Silgram, S. Gómez, K. Granlund, L. Hoffmann, B. Kronvang, S. Kværnø, A. Lázár, M. Mimikou, G. Passarella, P. Panagos, H. Reisser, B. Schwarzl, C. Siderius, A. S. Sileika, A. A. M. F. R. Smit, R. Sugrue, M. Van Liedekerke & J. Zaloudik, 2009. Basin characteristics and nutrient losses: the EUROHARP catchment network perspective. Journal of Environmental Monitoring 11: 515–525.PubMedCrossRefGoogle Scholar
- Cardille, J., M. T. Coe & J. A. Vano, 2004. Impacts of Climate Variation and Catchment Area on Water Balance and Lake Hydrologic Type in Groundwater-Dominated Systems: A Generic Lake Model. Earth Interactions 8, Paper No. 13: 1–24.Google Scholar
- CEN, 2003. Guidance standard for the routine analysis of phytoplankton abundance and composition. CEN TC 230/WG 2/TG 3/N83, updated 22 June 2006.Google Scholar
- George, D. G. & M. A. Hurley, 2003. Using a continuous function for residence time to quantify the impact of climate change on the dynamics of thermally stratified lakes. Journal of Limnology 62(Supplement 1): 21–26.Google Scholar
- George, G., U. Nickus, M. T. Dokulil & T. Blenckner, 2010. The influence of changes in the atmospheric circulation on the surface temperature of lakes. In George, D. G. (ed.), The Impact of Climate Change on European Lakes, Aquatic Ecology Series 4. Springer, Dordrecht, Heidelberg, London, New York: 293–310.CrossRefGoogle Scholar
- Gerten, D. & R. Adrian, 2002. Effects of climate warming, North Atlantic oscillation, and El Niño-Southern oscillation on thermal conditions and plankton dynamics in Northern Hemispheric lakes. The Scientific World Journal 2: 586–606.Google Scholar
- Gröne, T., 1997. Volatile organic sulfur species in three North Italian lakes: seasonality, possible sources and flux to the atmosphere. Memorie dell’Istituto Italiano di Idrobiologia 56: 77–94.Google Scholar
- Heaney, S. & C. Butterwick, 1985. Comparative mechanisms of algal movements in relation to phytoplankton production. In Rankin, M. A. (ed.), Contributions in Marine Science Supplement, Vol. 27: 114–133.Google Scholar
- Hosper, S. H., 1997. Clearing Lakes: An Ecosystem Approach to the Restoration and Management of Shallow Lakes in the Netherlands. Ph.D. Thesis, Wageningen University, The Netherlands.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
- Mischke, U. & J. Böhmer, 2008. Software PhytoSee Version 3.0 Preliminary English Version of the calculation program for German Phyto-See-Index (PSI) according to Mischke et al. (2008) to assess natural lakes to implement the European Water Framework Directive. Free Internet Download (PhytoSee_Vers3_0_eng.zip), http://igb-berlin.de/abt2/mitarbeiter/mischke.
- Mischke, U., U. Riedmüller, E. Hoehn, I. Schönfelder & B. Nixdorf, 2008. Description of the German system for phytoplankton-based assessment of lakes for implementation of the EU Water Framework Directive (WFD). In Mischke, U. & B. Nixdorf (eds), Brandenburg Technical University of Cottbus, ISBN 978-3-940471-06-2, BTUC-AR 2: 117–146.Google Scholar
- Nickus, U., K. Bishop, M. Erlandsson, C. D. Evans, M. Forsius, H. Laudon, D. M. Livingstone, D. Monteith & H. Thies, 2010. Direct impacts of climate change on freshwater ecosystems. In Kernan, M., R. W. Battarbee & B. Moss (eds), Climate Change Impacts on Freshwater Ecosystems. Wiley-Blackwell, Oxford: 38–64.Google Scholar
- Nilsson, C. & B. M. Renöfält, 2008. Linking flow regime and water quality in rivers: a challenge to adaptive catchment management. Ecology and Society 13: 18–38.Google Scholar
- Nõges, P., T. Nõges, M. Ghiani, B. Paracchini, J. Pinto Grande & F. Sena, (in press). Morphometry and trophic state modify the thermal response of lakes to meteorological forcing. Hydrobiologia.Google Scholar
- OLL, 2005. Qualità delle acque lacustri in Lombardia. Osservatorio dei Laghi Lombardi. Rapporto No. 1. Fondazione Lombardia per l’Ambiente: 354 pp. http://www.flanet.org/101/progetto/osservatorio-dei-laghi-lombardi.
- Pettersson, K., D. G. George, P. Nõges, T. Nõges & T. Blenckner, 2010. The impact of the changing climate on the supply and re-cycling of phosphorus. In George, D. G. (ed.), The Impact of Climate Change on European Lakes, Aquatic Ecology Series 4. Springer, Dordrecht, Heidelberg, London, New York: 121–137.CrossRefGoogle Scholar
- Premazzi, G., A. C. Cardoso, E. Rodari, M. Austoni & G. Chiaudani, 2005. Hypolimnetic withdrawal coupled with oxygenation as lake restoration measures: the successful case of Lake Varese (Italy). Limnetica 24: 123–132.Google Scholar
- Prepas, E. E. & T. Charette, 2003. Worldwide eutrophication of water bodies: causes, concerns, controls. In Sherwood Lollar, B. (ed.), Environmental Geochemistry. Elsevier, Oxford, Amsterdam: 311–331.Google Scholar
- Provincia di Varese, 2009. Sintesi meteorologica 2008. Centro Geofisico Prealpino: 4 pp. http://www.astrogeo.va.it/statistiche/statmet.php.
- Räisänen, J., U. Hansson, A. Ullerstig, R. Döscher, L. P. Graham, C. Jones, H. E. M. Meier, P. Samuelsson & U. Willén, 2004. European climate in the late twenty-first century: regional simulations with two driving global models and two forcing scenarios. Climate Dynamics 22: 13–31.CrossRefGoogle Scholar
- Sommer, U., M. Gliwicz, W. Lampert & A. Duncan, 1986. The PEG-model of seasonal succession of planktonic events in fresh waters. Archiv für Hydrobiologie 106: 433–471.Google Scholar
- Standard Methods, 1992. Standard Methods for the Examination of Water and Wastewater, 18th ed. American Public Health Association, Washington, DC.Google Scholar
- Stefaniak, K., R. Gołdyn & K. Kowalczewska-Madura, 2007. Changes of summer phytoplankton communities in Lake Swarzędzkie in the 2000–2003 period. International Journal of Oceanography and Hydrobiology 36(Supplement 1): 77–85.Google Scholar
- Talling, J. F., 1974. In standing waters. In Vollenweider, R. A. (ed.), A Manual on Methods for Measuring Primary Production in Aquatic Ecosystems. Blackwell Publishing, Oxford: 119–123.Google Scholar
- Thornthwaite, C. W. & J. R. Mather, 1957. Instructions and Tables for Computing Potential Evapotranspiration and the Water Balance. Publications in Climatology 10. C.W. Thornthwaite & Associates, Centerton, NJ.Google Scholar
- Utermöhl, H., 1958. Zur Vervollkommnung der quantitativen Phytoplankton-Methodik. Internationale Vereinigung für theoretische und angewandte Limnologie/Mitteilungen 5: 567–596.Google Scholar
- Visconti, A., M. Manca & R. de Bernardi, 2008. Eutrophication-like response to climate warming: an analysis of Lago Maggiore (N. Italy) zooplankton in contrasting years. Journal of Limnology 67: 87–92.Google Scholar
- Wu, J.-T. & J.-W. Chou, 1998. Dinoflagellate associations in Feitsui Reservoir, Taiwan. Botanical Bulletin of Academia Sinica 39: 137–145.Google Scholar