Trophic Status of Blidinje Lake (Bosnia and Herzegovina) Based on the Determination of the Trophic State Index (TSI)

Blidinje lake is an integral part of the Nature Park Blidinje established in 1995. Blidinje lake is largest mountain lake in Bosnia and Herzegovina (B&H) according to the surface and water supplies. Considering the surface, it is surprising to its low depth and large surface changes. Eutrophication is defined as the ‘biological effect of increasing concentrations of plant nutrients in aquatic ecosystems’. Eutrophication results in increased primary production or the production of aquatic plants. It can adversely affect the suitability of the use of water resources for other purposes. Metabolism of shallow lakes is extremely specific such as classical connections; algal biomass with a load of nutrients in shallow lakes can have catastrophic effects. Nutrients that come directly or indirectly into water lead to increase in the amount of algae as well as changes in the composition of phytoplankton, where there is suppression of diatoms and green algae by cyanobacteria. The values of parameters assessing trophic index (Trophic State Index [TSI]) are total phosphorus, chlorophyll a and transparency. This method that generalises numerous data using mathematical equations allows the expression of trophic level. On the basis of earlier studies on physical and chemical parameters of water quality in Blidinje lake, Carlson trophic index was calculated, and based on that assessment, trophic level is given.