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)

Table 4 (continued) a2-96 a2-98 a3-98 a3-98 a2-99 a3-99 730 106 812 106 930 930 Navicula lenzii Hust. 0.25 1.13 Navicula menisculus Schumann 0.56 Navicula pupula Kütz. 0.36 0.56 Navicula rádiósa Kütz. 0.56 Navicula rhynchocephala Kütz. 0.60 0.72 0.54 0.45 1.23 0.56 Navicula saprophila Lange-Bert. 3.38 3.76 7.69 Navicula subminuscula Manguin 0.56 Navicula tripunctata (0. F. Müller) Bory 0.30 0.25 1.13 Navicula veneta Kütz. 1.49 0.24 1.08 0.45 0.49 5.65 Nitzschia acicularis (Kütz.) W. Smith 0.56 Nitzschia angustata Grun. 5.08 Nitzschia angustatula Lange-Bert. 1.69 Nitzschia dissipata (Kütz.) Grun. 0.99 5.08 Nitzschia frustulum (Kütz.) Grun. 3.57 1.45 1.97 0.45 1.73 Nitzschia fruticosa Hust. 1.23 Nitzschia linearis (Agardh) W. Smith 0.30 1.25 0.45 2.82 Nitzschia palea (Kütz.) W. Smith 0.30 Nitzschia recta Hantzsch 14.48 Nitzschia sinuatawnr. tahellaria (Grun.) Grun. 0.18 Nitzschia small 5.36 3.05 0.25 Nitzschia sp. (spine-like) 0.48 0.18 Rhoicosphaenia abbreviata (Agardh) Lange-Bert. 1.21 Surirella ovális Bréb. 0.90 0.25 face to the bottom of the river. Our results contribute to their statement, as Cocconeis placentula is probably a shadow-adapted species. But we must lay special emphasis on the appearance and growing abundance of Navicula cf. saprophila and Achnanthes hungarica. We have not found them earlier in other parts of the Szigetköz. These two species were also unknown before 1998 in this dead arm at Ásványráró. Achnanthes hungarica was found only in one sample in 1998, Naviculacï. saprophila in two samples in 1998. In 1999 they became abundant, and even dominant taxa of periphyton in this dead arm.