Külli Kangur

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Fish play a key role in the trophic dynamics of lakes. With climate warming, complex changes in fish assemblage structure may be expected owing to direct effects of temperature and indirect effects operating through eutrophication, water level changes, stratification and salinisation. We reviewed published and new long-term (10–100 years) fish data series(More)
The stomach contents of eel, bream and ruffe were examined in order to detect the diet overlap and possible food competition between these benthophagous fishes in the eutrophic Lake Võrtsjärv. The frequency of occurrence, mean number and mean restored weight of food items per individual were used for the description of their diet. Overlap in diet of bream(More)
In the 1990s, the nutrient load from the catchment area, carried into the large shallow eutrophic Lake Peipsi (area 3555 km2), diminished in comparison with the 1980s. The aim of the investigation was to analyse statistically biotic response to alterations in nutrient level in the lake following the reduction in external loading. In-lake changes of the(More)
Lakes in Europe have a bipolar distribution by latitude with higher lake densities in the north (58–65° N) and south (38–48° N). By area, 95% of the large lakes (>100 km2) are located at altitudes lower than 100 m above sea level (ASL) and only 1% lie higher than 1,000 m ASL. Physically large lakes exhibit several similarities to seas and oceans in their(More)
Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains(More)
Using sediment traps, we aimed to elucidate the temporal and spatial variations in sediment fluxes in large and shallow Lake Peipsi, over the May to October 2011 period, and analyze the factors behind those variations. The effects of weather factors (mean and maximum wind velocity, water level and water temperature) on sediment resuspension and the(More)
Over the last 3-4 decades, Lake Peipsi water (sampling site A, middle part of the lake, and site B, northern part) has experienced a statistically significant increase of bicarbonate, pH, chemical oxygen demand, nitrate (and nitrite in site B), due to combination of climate change and eutrophication. By photochemical modelling, we predicted a statistically(More)
Ruffe is one of the most numerous fishes in Estonian large Lakes Peipsi (area 3555 km2, mean depth 7.1 m) and Võrtsjärv (270 km2, 2.8 m). Owing to its small size ruffe has little value for commercial or recreational fisheries today. However, due to their high abundance, ruffe play an important role in the food webs of both lakes. The aim of the(More)
Pikeperch is a major predator in the pelagic zone of eutrophic waters, such as the large north-temperate lowland lakes Võrtsjärv (Estonia) and Peipsi (Estonia/Russia). The size and structure of the pikeperch population is strongly influenced by their success at the juvenile stage. Therefore, we investigated the diet and prey selection of pikeperch fry(More)
Limnological monitoring data and palaeorecords from large shallow Lake Pskov were used to study the long-term dynamic pattern of the lake ecosystem and to identify the start of its degradation. Lake Pskov is the southern part of Lake Peipsi s.l., the largest transboundary lake in Europe. The limnological monitoring data collected in the years 1956–2005 show(More)