Ecological observations on Skeletonema potamos (Weber) Hasle in the River Danube, near Budapest (1991?92, daily investigations)

The small, chain-forming centric diatom Skeletonema potamos (Weber) Hasle is one of the most important species of phytoplankton in the River Danube in Hungary. In low water periods from May to October, its abundance is high, contributing 10–20% of total biomass (its fresh weight is 3–6 mg 1−1). The first data about its occurrence in Hungary, in the southern Danube stretch, were published by Schmidt & Voros (1981). The presence of S. potamos was noted in Danube samples taken at the end of fifties near Budapest (Kiss, 1986). This species became abundant in the Hungarian stretch of River Danube at the end of sixties simultaneously with eutrophication.