| Summary: | The scale and magnitude of probable impact of human activities over a decade (1983-1994) on the freshwater lake Priyadarshini, at Schirmacher Oasis, East Antarctica, was assessed through an ecological study conducted over an annual cycle during January 1993 to January 1994. Air temperature ranged from -34.5 degrees C to +8.2 degrees C, water temperature (below frozen layer) from -1.5 degrees to +4.7 degrees C, and pH from 8.10 to 8.77. Dissolved oxygen varied from 8.4 to 12.1 mg l sup(-1) with higher values during winter months (June-July). The biological parameters - phytoplankton, chlorophyll-a and microbenthos - showed a bi-modal pattern of fluctuations with one maxima in austral summer and another in spring (late winter). Fluctuations in the hydrobiological parameters were closely related to meteorological conditions over the area. Biological productivity of the lake was dependent on the availability of ice-free water and increase in atmospheric temperature. An in-depth analysis and comparison of certain lake environmental aspects over a decadal period indicate that the lake environment is in a healthy condition. However, intensive human activities in the catchment area may deteriorate the ecosystem and hence regular monitoring and stringent regulations are needed to maintain its quality.
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