TROPHIC STATUS AND ECOLOGICAL POTENTIAL OF RESERVOIRS IN BULGARIA BASED ON SELECTED PARAMETERS
MONIKA SUBEVA1*, LYUBOMIR KENDEROV2, VESELA EVTIMOVA1
1-Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Blvd., Sofia 1000, Bulgaria
2-Department of General and Applied Hydrobiology, Faculty of Biology, Sofia University “St. Kliment Ohridski”, Sofia, Bulgaria
*Corresponding author: monika.subeva@gmail.com
Keywords: physical and chemical parameters, chlorophyll a, Carlson’s trophic state index, reservoirs, Bulgaria
Abstract: The Water Framework Directive (WFD) aims to achieve good ecological status (potential for heavily modified water bodies) of surface waters. Ecological status is characterised by the quality, structure and functioning of aquatic ecosystems. It is quantified through chemical and ecological parameters, with standard biological quality elements (BQE) for lake ecosystems (natural or artificial) being phytoplankton, macrophytes, phytobenthos, benthic macroinvertebrate and fish communities. The trophic state of reservoirs indicates their biological productivity and is usually assessed from data on phosphorus, chlorophyll a concentrations and Secchi depth. Our aim was to study the physical and chemical parameters of the water column, as well as the primary productivity (quantified as chlorophyll a). Here we present some preliminary results for eight Bulgarian reservoirs: Bebresh, Gorni Dabnik, Telish, Sopot, Sinyata Reka, Konush, Chetiridesette Izvora and Pchelina Reservoirs. Samples were collected from several stations and different horizons in spring and summer 2016.