engleski

The evaluation of algal growth potential (AGP) and water toxicity of Lake Sakadaš (Nature Reserve Kopački Rit)

From November 1997 until April 1998, algal growth potential of Chlorella kessleri FOTT et NOV. was investigated in the water of Lake Sakadaš by miniaturized bioassay method. Nitrogen and phosphorous were added to the original water samples in concentration of 0.72 ; 1.44 ; 2.89 gdm-3 KNO3 and 2.25 ; 3.37 ; 6.75 gdm-3 KH2PO4 and the weekly growth increase of Chlorella kessleri was evaluated. For the evaluation of toxicity the original sample was diluted 1:1 with distilled water and through the addition of Na2EDTA. Maximal values of algal biomass were determined after 28 and 35 days of cultivation. According to the AGP results, the original water samples of Lake Sakadaš were meso-eutrophic in December and January, and oligotrophic during the other months of investigation. The saturation of the investigated water layers of Lake Sakadaš with solutions of N ad P stimulated most the growth of the biomass test algae in December 1997 and January 1998. At the beginning of spring, the addition of solutions of N and P did not have a stimulating effect on the growth of Chlorella kessleri. Toxic compounds were present in Lake Sakadaš only during the winter months.

Chlorella kessleri; algal growth potential; miniaturized growth bioassay

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