Razvojne faze u životu akumulacije i procena trofičkog statusa

Abstract

Na osnovu rezultata dugoročnog monitoringa određuju se razvojne faze u životu akumulacije i propisuju mere za sprečavanje degradacije kvaliteta vode u akumulacijama. Iz tih razloga je kontinuiranim monitoringom u periodu od 20 godina, praćen kvalitet vode u akumulaciji Grlište“, koja služi za vodosnabdevanje grada Zaječara (Istočna Srbija). Treba istaći da su rezultati dobijeni ovim monitoringom korišćeni i u svrhu pronalaženja uzroka cijanobakterijskog cvetanja, kao posledice algalne produkcije. Limitirajući faktor algalne produkcije su obično azot i fosfor, međutim, u ovom slučaju, rezultati razlike indeksa trofičnosti izračunatog preko hlorofila a (TSIChl-a) i indeksa trofičnosti izračunatog preko ukupnog fosfora (TSITP), su ukazali da je limitirajući faktor algalne produkcije bila svetlost. Na osnovu koncentracija rastvorenog kiseonika, ukupnog fosfora i hlorofila a (Chl-a) na površini i na dnu, zaključeno je da je akumulacija tokom ispitivanog perioda prošla kroz četiri razvojne faze. Rezultati dugoročnog monitoringa su pokazali da je u prvim godinama nakon formiranja akumulacije trofičnost bila najizraženija (hipereutrofan status), nakon čega je akumulacija imala uglavnom eutrofan status.

On the basis of long-term monitoring results, developmental stages in the life of the reservoir can be determined, and measures for preventing the degradation of water quality in reservoirs can be prescribed. Therefore, by the continuous monitoring during a period of 20 years, the water quality of reservoir "Grlište", which is used for the water supplying town Zaječar (Eastern Serbia), was observed. It should be noted that the obtained results were used also in the purpose of finding a cause of cyanobacteria bloom, as a consequence of algal production. Limiting factors of algal production usually are nitrogen and phosphorus, however, in this study, obtained results of subtraction between trophic state index, calculated through total chlorophyll a (TSIChl-a) and trophic state index, calculated through total phosphorus (TSITP), indicated that limiting factor of algal production was light. On the basis of the concentrations of dissolved oxygen (DO), total phosphorus (TP) and chlorophyll a (Chl-a) in the surface and in the bottom, it was concluded that the reservoir passed through four development phases during the examined period. Results of long-term monitoring showed that in the first years after the formation of the reservoir, the highest trophicity was detected (hypereutrophic status), but later the reservoir mostly maintained eutrophic status.