Program (SF0170011s08) "Will climate change alter the relative importance of catchment and in-lake processes in the carbon balance of shallow lakes?" (2008- 2013)
Lakes may act as CO2 sources if heterotrophic processes dominate over autotrophic ones due to extensive inflow of dissolved organic carbon (DOC). The larger is the ratio of the catchment area (A) and the lake volume (V), the stronger and quicker is the impact of catchment processes on lake ecosystem. In large shallow Võrtsjärv (270 km2, mean depth 2.8 m, A 3100 km2) the variation of DOC (0.6-22 mg/l) and A/V are larger than in other well-studied large lakes. Natural water level variation and up to 3-fold changing A/V enables a large range of assessment of the impact of catchment processes on the lake ecosystem. Planned basic study addresses the carbon budget of a large shallow lake integrating catchment, lake, and sediment compartments and tests the hypothesis that
1) large shallow lakes are heterotrophic CO2-emitting systems responding nonlinearly to the climate related pressures, and
the CO2 emission from a unit of large lake area exceeds that from a unit of catchment area.
Members of the group: Tiina Nõges (program leader), Peeter Nõges, Lea Tuvikene, Priit Zingel, Ilmar Tõnno, Henn Timm, Ain Järvalt, Teet Krause, Tõnu Feldmann, Helen Agasild, Helen Tammert, Jaana Salujõe, Helen Luup, Anu Kisand, Kersti Kangro, Evi Lill, Alo Laas, Kaire Toming, Ly Soone, Helen Gottlob, A. Tuvikene, S. Vilbaste, P. Pall, K. Piirsoo, M. Viik, J. Melikize, R. Freiberg, I. Zemit, R. Kreitsberg, V. Kisand
Program (SF0170006s08) "Effects of natural and man induced pressures on the ecosystems of large lakes." (2008- 2013)
Combining limnological and paleolimnological methods, novel statistical and management analyses, the project aims at clarifying the co-effect of manmade and natural stressors on large lake ecosystems. A complex and interdisciplinary approach will be used for exploring triggers of change in lake ecosystems, nonlinearity of the processes, abrupt regime changes and bifurcational developments. This project will innovatively test the working hypotheses by comparative analysis of European large lakes using joint models of multivariate structural co-variations. Mathematical models and scenario analysis elaborated in this project offer an outstanding example for international academic and policy use. The results will give fundamental scientific knowledge on the influence and interaction of anthropogenic and natural stressors in large lakes. Thus, project will serve as an important basis for assessing ecological risks and designing sustainable management strategies for these unique ecosystems.
Members of the group: Külli Kangur (program leader), Tõnu Möls, Andu Kangur, Reet Laugaste, Juta Haberman, Ervin Pihu, Helle Mäemets, Peeter Kangur, Tarmo Timm, Henn Timm, Margit Kumari, Evely Mälton, Lilian Freiberg, Marina Haldna, Kadi Palmik, Kätlin Blank, Kati Kangur, Kai Ginter, Olga Buhvestova
Program "Hydrobiological Collections."
Hydrobiological collections include mainly the materials gathered from the Estonian inland and coastal waters in the XX and XXI centuries. During 2005-2008, they were financed by the national program "Humanitarian and natural science collections". In January, 2009 they included the following items: plankton samples in fluid (>12 000 items, among them ~200 collected before the Second World War), herbarium of macrovegetation (ca 4 000), slides of diatoms (>600), zoobenthos (> 8 500 items; among them samples in fluid, dry collection, slides including type specimens of 27 oligochaete species), fishes (>900 otolithes and slides), photos of aquatic fauna (>1 500), photos of water bodies and aquatic habitats (>3 000).
The collections are located in the Estonian University of Life Sciences (EULS): either in the Centre for Limnology (at Lake Võrtsjärv), or in Tartu, Riia 181. The samples of lake plankton, lake macrovegetation, freshwater macroinvertebrates (including separately the molluscs and oligochaetes), fishes, photos of biota and waterbodies are located in the Centre for Limnology. The samples of stream and marine phytoplankton and macrovegetation, diatom slides, and marine macroinvertebrates are located in Tartu. The materials will be consistently complemented, maintained and catalogized. Most of them are already digitally catalogized.
The collections are associated with two current scientific programs of EULS: 1) SF0170011s08 "Will climate change alter the relative importance of catchment and in-lake processes in the carbon balance of shallow lakes?"; and 2) SF0170006s08 "Effects of natural and man-induced pressures on the ecosystems of large lakes". Monitoring and expertise projects also use the vaucher specimens from collections, at the same time complementing them with new items. The collections are currently used by students concerned to hydrobiology. The materials also serve as a source of exposition in the Lake Museum of the Lake Võrtsjärv Study and Experimental Centre.
The catalogues are available on http://www.limnos.ee/index.php?alam=92