Water level changes in a large shallow lake as reflected by the plankton:periphyton-ratio of sedimentary diatoms
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Biostratigraphic diatom analyses were carried out on a short sediment core from the large shallow-water Lake Võrtsjärv, Estonia, in order to relate the diatom composition to the instrumental water level record. We dated the sediment core by radiometric methods (210Pb, 137Cs, 241Am) and spheroidal fly-ash particle abundance chronology and evaluated the statistical significance of the relationships between the percentage of planktonic diatoms and the water level continuously monitored since 1871. Before the 1960s, the percentage of planktonic diatoms in the sediment showed quite strong positive relationship to water level. The impact of eutrophication after the 1960s presumably masked the influence of water level changes on the diatom community. In addition, statistical analysis of the upper part of the sediment core (1970—present day) together with measured limnological parameters of the lake showed that water transparency had the strongest influence on diatoms, while temperature, pH and alkalinity had lesser impacts. Our study shows that the planktonic:periphytic diatom ratio in the sediment can be used to track overall trends of the lake-level changes in Lake Võrtsjärv before the onset of cultural eutrophication; however, the results have to be interpreted carefully, taking into consideration other possible limnological factors such as water transparency, nutrients and wind.
KeywordsPaleolimnology Sediment diatoms Water level changes Lake Võrtsjärv Estonia
Funding for this research was provided by the Estonian Ministry of Education (SF0362480s03 and SF0332710s06), by Estonian Science Foundation grants (5738 and 5923), and by the European Union project CLIME (EVK1-CT-2002-00121).
- Alliksaar, T., 2000. Spatial and temporal variability of the distribution of spherical fly-ash particles in sediments in Estonia. Tallinn Pedagogical University, Dissertations on Natural Sciences 4: 1–44.Google Scholar
- Battarbee, R. W., 1986. Diatom analysis. In Berglund, B. E. (ed.), Handbook of Holocene Palaeoecology and Palaeohydrology. John Wiley & Sons, Chichester: 527–570.Google Scholar
- Battarbee, R., V. J. Jones, R. J. Flower, N. G. Cameron, H. Bennion, L. Carvalho & S. Juggins, 2001. Diatoms. In Smol, J. P., H. J. B. Birks & W. M. Last (eds), Tracking Environmental Change Using Lake Sediments, Vol. 3: Terrestrial, Algal, and Siliceous Indicators. Kluwer Academic Publishers, Dordrecht: 155–202.Google Scholar
- Chatfield, C., 1996. The Analysis of Time Series, 5th edn. Chapman & Hall, New York.Google Scholar
- Clarke, G., M. Kernan, A. Marchetto, S. Sorvari & J. Catalan, 2005. Using diatoms to assess geographical patterns of change in high-altitude European lakes from pre-industrial times to the present day. Aquatic Sciences 67: 224–236.Google Scholar
- Glew, J. R., J. P. Smol & W. M. Last, 2001. Sediment core collection and extrusion. In Last, W. M. & J. P. Smol (eds), Tracking Environmental Change Using Lake Sediments, Vol. 1: Basin Analysis, Coring, and Chronological Techniques. Kluwer Academic Publishers, Dordrecht: 73–105.Google Scholar
- Järvet, A., 2004. Hydrology of Lake Võrtsjärv. In Haberman, J., E. Pihu & A. Raukas (eds), Lake Võrtsjärv. Estonian Encyclopaedia Publishers, Tallinn: 105–139.Google Scholar
- Krammer, K. & H. Lange-Bertalot, 1986–1991. Bacillariophyceae. In Ettl, H., G. Gärtner, J. Gerloff, H. Heynig & D. Mollenhauer (eds), Süßwasserflora von Mitteleuropa, Vol. 2(1–4). Gustav Fischer Verlag, Stuttgart.Google Scholar
- Nõges, T., 2004. Reflection of the changes of the North Atlantic Oscillation Index and the Gulf Stream Position Index in the hydrology and phytoplankton of Võrtsjärv, a large, shallow lake in Estonia. Boreal Environment Research 9: 401–407.Google Scholar
- Nõges, P. & T. Nõges, 2006. Indicators and criteria to assess ecological status of the large shallow temperate polymictic lakes Peipsi (Estonia/Russia) and Võrtsjärv (Estonia). Boreal Environment Research 11: 67–80.Google Scholar
- Pork, M. & V. Kõvask, 1973. Vetikad. In Timm, T. (ed.), Võrtsjärv. Valgus, Tallinn: 95–99 (In Estonian with English summary).Google Scholar
- StatSoft, Inc., 2001. STATISTICA (data analysis software system), version 6. http://www.statsoft.com.
- Stoermer, E. F. & J. P. Smol (eds), 1999. The Diatoms: Application for the Environmental and Earth Sciences. University Press, Cambridge.Google Scholar
- ter Braak, C. J. F. & P. Šmilauer, 2002. CANOCO Reference manual and CanoDraw for Windows Users guide: Software for Canonical Community Ordination (version 4.5). Microcomputer Power, Ithaca, New York.Google Scholar
- Vassiljev, J., 1997. Simulating the paleorecord of northern European lakes using a coupled lake catchment model. Lundqua Thesis 41: 1–19.Google Scholar
- Wetzel, R. G., 1983. Limnology. Saunders College Publishing, Philadelphia.Google Scholar
- Wolin, J. A. & H. C. Duthie, 1999. Diatoms as indicators of water level changes in freshwater lakes. In Stoermer, E. F. & J. P. Smol (eds), The Diatoms: Application for the Environmental and Earth Sciences. University Press, Cambridge: 183–202.Google Scholar