B. Papp szerk.: Studia Botanica Hungarica 32. 2001 (Budapest, 2001)

Buczkó, Krisztina; Rajczy, Miklós: Changes of attached diatoms in a dead arm of the Danube between 1992-1999 at Ásványráró (Szigetköz section)

10% 8% 4 6% 4% 4 2% 0% H 4 fN<NfNioooooo^-Hmr^ cd cd j-i cQcScdcjcjcQcocjccj TO Fig. 8. Changes of relative abundance of Navicula veneta between 1992 and 1999. The samples collected in 1999 are black. abundance of this small diatom usually was higher than 50% between 1992 and 1998. In 1999 its contribution became less than 30%. Parallel with the decrease of Achnanthes minutissima, the relative abundance of A. hungarica has increased (Fig. 9). 30% 24% 18% 12% 6% 0% Fig. 9. Changes of relative abundance of Achnanthes hungarica between 1992 and 1999. The samples collected in 1999 are black.