Hidrológiai Közlöny, 2014 (94. évfolyam)
2014 / 5-6. különszám - LV. Hidrobiológus Napok előadásai
49 Effects of extremely dry weather on the individual number of Achnanthidium minutissimum and Achnanthidium eutrophylum in the River Sebes-Körös at Körösszakái Kókai Zs., Török P., Bácsi T-Krasznai E., B-Béres V. Abstract: The summer and autumn was extremely dry in the year of 2012 in Hungary, therefore the water discharge and water level of rivers decreased significantly in comparison with previous years. The main aim of this study was to investigate, how affect the extremely dry weather and the inherent water discharge decrease and nutrient enrichment the dynamics of Achnanthidium minutissimum and Achnanthidium eutrophilum in the river of Sebes-Körös at Körösszakái. The exact identification of this two Achnanthidium species is important, because they are indicator species of waters with different ecological status. Our results show, that the individual number of A. minutissimum correlated positively with water discharge and negatively with nitrate concentration, while opposite tendencies were observed in the case of A. eutrophylum. The results highlight that the diatom assemblage of a river with stable good ecological status could react remarkably sensitively to decreasing water discharge and the concomitant nutrient enrichment caused by extreme weather circumstances. Keywords: species composition of periphyton, guild, extremely dry weather, river Sebes-Körös
