The study of physicochemical and biological parameters can assess the trend of a lake’s trophic state. A trophic state index (TSI) was used to assess eutrophication of LakeAmvrakia. Total phosphorus and chlorophyll c...The study of physicochemical and biological parameters can assess the trend of a lake’s trophic state. A trophic state index (TSI) was used to assess eutrophication of LakeAmvrakia. Total phosphorus and chlorophyll concentrations that recorded were generally at the same level with those recorded in previous years, a fact which indicates that lake’s trophic state did not change. But in the past ten years, agricultural uses have been modified by almost 25% of the catchment area, because of the major reduction of tobacco cultivation. One year of monthly monitoring, in nine sampling stations can report this result. Even if the catchment is small and the agricultural areas are the 47% of the basin, the water quality of the lake did not change. The trophic state is stable probably because the lake is deep monomictic, and seasonally anoxic. For this reason internal phosphorus contribution is very important in the deep hypolimnion.展开更多
The trophic state of a freshwater ecosystem reflects its environmental quality. This is why several trophic indicators have been developed for such water bodies based on chemical, physical and biological parameters. A...The trophic state of a freshwater ecosystem reflects its environmental quality. This is why several trophic indicators have been developed for such water bodies based on chemical, physical and biological parameters. Apart from that, there are several biotic elements which can be used in accessing the environmental condition of a freshwater ecosystem. Zooplankton organisms are important elements of the structure and function of lakes and are considered useful indicators of alterations in their trophic dynamics and ecological state related to changes in nutrient loading and climate. In accordance to the above, the present study is an attempt to assess the trophic condition of the largest lake in Greece (Lake Trichonis) through the investigation of the physicochemical elements, along with the biotic indications provided by a three-year study of the lake’s zooplankton. The present results, compared with previous studies conducted between 15 and 25 years before, showed that there was an increase in the maximum values of the concentrations of chlorophyll-α and nutrients, while there was a decrease in water transparency. The implementation of Carslon’s trophic state index (TSI) revealed that Lake Trichonis still remains an oligo-to mesotrophic ecosystem as it was in the past. However, although the zooplankton investigation showed several features that are common in oligotrophic lakes, there are certain eutrophic characteristics of the zooplankton community (e.g. abundance variation pattern, indicator species, seasonal succession of cladocerans) pointing out a different state of the ecosystem in comparison to the past. In conclusion, the use of a biotic element like zooplankton revealed that Lake Trichonis is experiencing a transitional condition towards the eutrophic state and points out the necessity for constant inspection and monitoring of this ecosystem.展开更多
文摘The study of physicochemical and biological parameters can assess the trend of a lake’s trophic state. A trophic state index (TSI) was used to assess eutrophication of LakeAmvrakia. Total phosphorus and chlorophyll concentrations that recorded were generally at the same level with those recorded in previous years, a fact which indicates that lake’s trophic state did not change. But in the past ten years, agricultural uses have been modified by almost 25% of the catchment area, because of the major reduction of tobacco cultivation. One year of monthly monitoring, in nine sampling stations can report this result. Even if the catchment is small and the agricultural areas are the 47% of the basin, the water quality of the lake did not change. The trophic state is stable probably because the lake is deep monomictic, and seasonally anoxic. For this reason internal phosphorus contribution is very important in the deep hypolimnion.
文摘The trophic state of a freshwater ecosystem reflects its environmental quality. This is why several trophic indicators have been developed for such water bodies based on chemical, physical and biological parameters. Apart from that, there are several biotic elements which can be used in accessing the environmental condition of a freshwater ecosystem. Zooplankton organisms are important elements of the structure and function of lakes and are considered useful indicators of alterations in their trophic dynamics and ecological state related to changes in nutrient loading and climate. In accordance to the above, the present study is an attempt to assess the trophic condition of the largest lake in Greece (Lake Trichonis) through the investigation of the physicochemical elements, along with the biotic indications provided by a three-year study of the lake’s zooplankton. The present results, compared with previous studies conducted between 15 and 25 years before, showed that there was an increase in the maximum values of the concentrations of chlorophyll-α and nutrients, while there was a decrease in water transparency. The implementation of Carslon’s trophic state index (TSI) revealed that Lake Trichonis still remains an oligo-to mesotrophic ecosystem as it was in the past. However, although the zooplankton investigation showed several features that are common in oligotrophic lakes, there are certain eutrophic characteristics of the zooplankton community (e.g. abundance variation pattern, indicator species, seasonal succession of cladocerans) pointing out a different state of the ecosystem in comparison to the past. In conclusion, the use of a biotic element like zooplankton revealed that Lake Trichonis is experiencing a transitional condition towards the eutrophic state and points out the necessity for constant inspection and monitoring of this ecosystem.
