Grant (ETF8511) "Ciliate and metazooplankton trophic link in shallow and turbid eutrophic lake." (2010- 2013)
Grant holder: Helen Agasild
Planktonic ciliates as potential prey for larger zooplankton form an important linkage between the microbial and classical food webs in aquatic systems. In shallow eutrophic and turbid Lake Võrtsjärv the microbial loop prevails over the classical one and planktonic ciliates are the dominant grazers both on bacterial- and primary productions. Ciliate community in Lake Võrtsjärv is extremely rich and usually its biomass exceeds that of metazooplankton. Previous research has given assumption that the ciliate-metazooplankton link might be very important in functioning of the food webs in that lake. The following goals are addressed in the project 1. To quantify the trophic link between ciliates and metazooplankton in shallow eutrophic and turbid lake. 2. To find out the key factors that regulate the link between ciliates and metazooplankton. 3. To evaluate the relative importance of ciliate – metazooplankton trophic link to food web functioning in shallow eutrophic and turbid lake.
Grant team: Helen Agasild, Rene Freiberg, Kati Lind, Ilmar Tõnno, Jaana Salujõe, Priit Zingel
Grant (ETF JD109) "Is Lake Võrtsjärv a sink or source of atmospheric greenhouse gases?" (2008- 2010)
Grant holder: Eva- Ingrid Rõõm
Planned study is aimed for measuring the direct efflux of CO2 and CH4 from lake surface to the atmosphere by the method of the floating chambers on the lake Võrtsjärv. For the moment GHG (greenhouse gas) emission of the ice-free period is estimated during the year 2009. Concidering the nature of a big and shallow lake, periodical observations were made at 28 subpoints in open water area and littoral zone. Supportive meteorological and physicochemical information was collected at the same subpoints. Considerable variations during the season and measuring points in both GHG emission and supportive data refers to importance of water and sediments temperature, pH, water oxygen content and light conditions for the intensity of GHG efflux.
The results are concidered to be the object of wide international interest since any data of GHG emission in similar lakes in Estonia or at the same latitude on our continent have not been published. Similar measurements on Nordic Countries are mainly made for lakes with granite bedrock and therefore do not reflect the nature of Estonian lakes GHG emission.
Grant team: Eva- Ingrid Rõõm, Tiina Nõges
Grant (ETF7643) "Creation and theoretical reasoning of the generalized synthetic database for water and biota of Estonian freshwater waterbodies." (2008-2011)
Grant holder: Tõnu Möls
Measurements of chemistry and biota in Estonian freshwater water bodies started mainly in 1950. The related dataset of hundreds of thousands of records is rather fragmentary but presents interest as a valuable source of information about past and current changes and pressures in the water ecosystem. Unfortunately, a direct use of raw data for drawing scientific conclusions is complicated because of the problems arising in scaling and time-space synchronization of different irregular datasets. It is also difficult to merge Estonian data with the data of other countries for joint studies. In 2004 T. Möls et al. introduced the Synthetic Database (SD1.0) for Lake Peipsi, which replaces the fragmentary dataset with a regular database composed of mathematically predicted values and supplied with a user-friendly interface that helps generate graphs and tables for tracking changes of water chemical and plankton variables in the time and space. Distributed on a CD, it has inspired several papers and was used in international projects. Presently the SD1.0 is under extension to a joint synthetic database of Estonian lakes and rivers and also of some European freshwater water bodies (Lake IJsselmeer in The Netherlands, for example). The new updated release of SD will offer additional possibilities for water data analysis and is based on a more rich set of advanced mathematical methods. A detailed handbook will be composed to give a clear insight into the background math and help to work with the SD.
Grant team: Tõnu Möls, Henn Timm, Peeter Kangur, Andu Kangur, Külli Kangur, Marina Haldna, Kätlin Blank, Olga Buhvestova, Kai Ginter, Kadi Palmik, Lilian Freiberg, Margit Kumari
Grant (ETF7600) "Is Lake Võrtsjärv an autotrophic or heterotrophic system? The role of autochthonous and allochthonous organic matter in the budget of a large shallow lake." (2008- 2011)
Grant holder: Tiina Nõges
In the frame of the grant is planned: research of the sources of organic matter (OM) in large shallow lake as well in inflowing rivers; investigate the spatial and temporal variability of OM and the influence of OM to the pH, oxygen contents and light conditions of the lake water; calculate the budget of OM, N and P, their retentions and relations between the budgets of the different substances; find out the long-term changes of the budget and retentions of substances and its relations to the weather conditions and the climate changes. Based on the budget of OM the estimations of the emission of CO2 for Lake Võrtsjärv will be given.
Grant team in 2008: Tiina Nõges, Anu Kisand, Alo Laas, Margus Pihlak, Kaire Toming, Piret Kruusimägi, M. Viik, Anu Reinart
"Organic matter and photosynthetic pigments in sediments of lakes Peipsi and Võrtsjärv as markers to follow ecosystem changes in large shallow lakes." (2006- 2009)
Grant holder- Ilmar Tõnno
The research is aimed to analyse ecosystem changes of two Estonian large shallow eutrophic lakes (L. Peipsi and L. Võrtsjärv) based on the information stored in sediments. Investigation of dissolved organic matter and photosynthetic pigments from L. Peipsi and L. Võrtsjärv sediments is expected to give new knowledge to understand eutrophication processes of shallow eutrophic lakes. Few studies have been done on paleolimnological aspects of large shallow lakes. Therefore, the proposed investigation will add important information for using sediment investigations for estimation of long-term ecological changes of such lakes, as well as for modelling and predicting future scenarios.
Scientific team: Ilmar Tõnno, Anu Kisand, René Freiberg, Aina Leeben and Anna-Liisa Kirsi.
Geologist from Institute of Geology, Tallinn University of Technology are involved to the project.
"Relations of fish community with the ecosystem as a whole and possibilities for collaborative management of the fish resources in Lake Peipsi." (2006- 2009)
Grant holder: Peeter Kangur
The project innovatively combines methods of fish biology studies and novel sociological approaches in identifying deficiencies in sustainable management of fish resources and at the same time management strategies for sustaining the well-being of the fishing dependent communities. Large shallow Lake Peipsi has been a water body rich in fish production. However, during 20th century the total commercial catch in the lake has declined. Socio-economic changes brought along with the collapse of the Soviet Union caused drastic increase in pressure on fish resources of L. Peipsi forming potential risk to the ecosystem structure and functioning as well as to local livelihood. Furthermore, valuable fish resources of the lake are under the threat of anthropogenic eutrophication and are strongly influenced also by large natural fluctuations of water level and temperature. The number of professional fishermen and fishing power in L. Peipsi do not correspond to the recent state of fish stocks. The influence of the interactions of these factors on fish community is investigated insufficiently. Moreover the share of poaching, unregistered catches, influence of extensive winter angling is unknown; therefore, the proper assessment of fish stocks is hindered. As local fishing dependent community inhabiting L. Peipsi basin is vulnerable to any fisheries management regulations, next to technocratic and scientific views dominating today, local needs and perspectives on development need to be taken into account in management decisions. Though, the state of fish stock, its management’s implications on local well-being and disparities in understanding the possibilities for mitigating fisheries management problems among different stakeholders have not been addressed jointly in previous studies concerning L. Peipsi. Therefore, the planned study will innovatively approach fisheries management problems integrating social and environmental research efforts in clarifying on how the state of the fish community is affected by the interactions of environmental and anthropogenic pressures, and to assess the impact of fisheries’ management strategies on livelihoods of local people and their motivation for participating in fish resources management.
Fishing pressure of wintertime angling on target species will be assessed based on the participatory observations among anglers on L. Peipsi. In semi-structured interviews with the representatives of fishing dependent community, regulators and experts the possible disparities in understanding environmental and socio-economic risks of fishing related activities and their access to management decisions will be identified. Transboundary citizens’ jury will provide a novel basis for evening the knowledge gaps of different interest groups.
Planned interdisciplinary research project endeavours developing integrated and coherent knowledge on L. Peipsi fisheries status and effects on environmental pressures and socio-economic implications, and legitimate fisheries management affected by local knowledge on its design. The project will provide scientific support for national implementation of the Water Framework Directive and European Common Fisheries Policy as well as can be exploited in protecting Estonian interests in preventing fish stock degradation and ensuring stability of the vulnerable ecosystem of transboundary L. Peipsi.
"Short-term changes in the communities of macrophytes and algae in rivers." (2006- 2009)
Grant holder: Sirje Vilbaste
The aim of this project is to investigate seasonal and annual changes in the communities of macrophytes and algae in Estonian rivers. It is difficult to find out the causes of alternations of species when the knowledge of short-term changes is lacking. The species diversity, quantity, and distribution of the flora in running waters are simultaneously influenced by a complex of ecological factors: light conditions (canopy on the banks and light attenuation by water), character of the river-bed, content of nutrients in water and in bottom sediments, flow regime, fluctuation of water level, current velocity, duration of the ice cover, ice drift, floods, water temperature, etc. At the same time, as the whole vegetation (macrophytes and microphytes) is characterized by a wide geographical distribution area and a wide ecological amplitude, there are only a few data on the autecology of species. Moreover, relevant data provided by different authors are often contradictory.
The principle investigators are: Sirje Vilbaste, Aive Kõrs, Peeter Pall, Kai Piirsoo, Arvo Tuvikene, Malle Viik.