Diatom flora and environmental factors in some fresh water ponds of East Ongul Island

Abstract

Diatom flora and chemical factors of water in sixteen ponds of East Ongul Island, which are 10-100 meters in diameter and less than 2 meters in depth, were investigated from January 7 to 21, 1974. The obtained results are as follows; pH value - 6.7-7.2, chlor ion concentration - 49.0-860 ppm, chemical oxygen demand - 2.34-8.71 ppm and biological oxygen demand - 0.4-4.2 ppm. Twenty-three taxa of diatoms were identified including newly found three taxa, Navicula abiculata, Navicula seminulum v. hustedtii and Gomphonema olivaceum v. tenellum. The Navicula muticopsis, the Stauroneis anceps and the Pinnularia braunii association were distinguished. It was of interest to note that the Nav. muticopsis association was distributed in the eastern and the southern coastal area of the Island, which seemed to be influenced by seaborn salts.