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)
Methods. The samples (38) were collected at 2 locations in the big branch system in the Szigetköz called "Ásványráró branch system" between 1992 and 1999 (Table 1, Fig. 2). Each sample has an accession code referring to the place, time and substrate. The first two characters of the code refer to the location (Fig. 2). The 3rd character means the name of the substrate. The stem of macrophyta (n, N = reed, Phragmites aust ralis, g = Typha sp.) were cut off at water level, and about 10 cm below it. The submerged plants (c = Ceratophyllum sp., e = Elodea canadensis, f = branches (carried by the water), j = Najas sp., o - Potamogeton crispas, p = Potamogeton perfoliatus leaf, P = Potamogeton perfoliatus stem, q = Ranunculus circinatus, r = Rorippa sp., s = Solidago gigantea, u = Potamogeton lucens, x = Carex sp., y = Polygonum sp., z = Potamogeton nodosus) were carefully taken off, the leaves cut off, and only the stems were placed into the sampling jars. The 4th and the 5th characters indicate the year and the 6th stands for the month (4 = April, 5 = May, 6 = June, 7 = July, 8 = August, 9 = September, 10 = October), see Table 1. The last 2 characters mean the day of collection. The algal mats were collected in jars (formaldehid solution was used for their preservation) as well as in dried form. Laboratory methods. The coating was washed into water, which later was homogenised. The diatoms were treated with H 2 0 2 , after which the preparata were embedded into Styrax. The first 400 diatoms were counted. Permanent slides are accessible in the Col lectio Algarum of the Department of Botany of the Hungarian Natural History Museum (BP). In the course of the statistical treatment a constancy value was given to each species as follows. First the percentage was calculated on the basis of the function: K = N/S x 100 where N = the number of preparata where the taxon had occurred, and S = the total number of preparata. The constancy of a species was 5 when its K value was between 80-100%, 4 when K was between 60-80%, and so on. Table 1. Codes of the samples. 1992 1995 1996 1997 1998 1999 coatings a2f92626 a2n95823 a2z96730 a2n97108 a2n98106 a2c99812 a2j92626 32P95823 a2n97703 a3n98106 a2e99812 a2n92626 a3c95823 a2n97703 a2g99812 a2r92626 a3n95823 a3n97108 a2n99812 a3q92626 a3x95823 a3p97703 a2n99930 a3s92626 a3y95823 a2o99812 a2u99812 a3e99812 a3n99812 a3n99930 mat of algae a2-96730 a2-98106 a2-99930 33-98812 a3-99930 a3-98106
