LIMNOLOGICAL SURVEY OF THE WARM MONOMICTIC LAKE TRICHONIS (CENTRAL-WESTERN GREECE)

The physical and chemical status of Trichonis - the largest and deepes t natural lake in Greece - is examined over two annual cycles (1985-86 and 1988-89). A correlation between lake nutrient patterns and phytop lankton biomass is attempted. Limnological features are compared with data from other warm and temperate lakes. With regard to its thermal r egime, Trichonis is classified as a warm monomictic lake. The lake's s tratification pattern and annual heat budget resemble those of other t emperate lakes. Trichonis is a carbonate type, low conductivity lake ( 'cIass II, low salinity' warm lake). Nitrogen and phosphorus concentra tions were rather low. The inorganic nitrogen content fluctuated widel y over the two annual cycles examined. On the contrary, phosphorus con centrations showed no significant changes. The limiting factor during 1985-86 was P, while N was limiting during stratification in 1988-89. A weak correlation was found between the plankton community features ( species abundance, biomass, chlorophyll-a) and light penetration. At p resent the eutrophication process from oligotrophy towards mesotrophy has not been essentially accelerated.