Szekessy Vilmos (szerk.): A Magyar Természettudományi Múzeum évkönyve 55. (Budapest 1963)

Halász-Halmi, M.: Microphyto-sociology of the acrothermal springs at Harkány and at Budapest - Mt. Gellért

ANNALES HISTORICO-NATURALES MUSEI NATION ALIS HUNG AR ICI Tomus 55. PARS BOTANICA 1963. Mierophyto-Soeiology of the Aerothermal Springs at Harkány and at Budapest — Mt. Gellért By MARTHS. HALÁSZ-HALMI, Budapest The present microsociological study follows in general the principles of the Zürich — Montpellier school for plant-sociology, as far as they are appliable in the microscopic world and the special conditions of thermal microvegetations. The aerothermal federations (alliances) and other microsociological results submitted at the end of the present essay were arrived at by applying the methods of my own system for microphyto-sociological research. The full description of this system was published by the Hungarian Academy of Sciences under the title: Grundriss einer Methode zur soziologischen Erforschung der Algenrasen von Thermalquellen (Acta Biologica, 1949. 1, p. 177—230). In accordance with this system, the area of 1 mm

2 was applied as „Minimi-Areal" during the investigations, and a scale of 5 degrees above the sporadic appearance was used to denote the covering percentage of each species present in the „Minimi-Areal", degree 5 denoting the highest percentage: 60—100%; degree 4 meaning 30— 60%; degree 3 meaning 8—30%; degree 2 meaning 2—8% and degree 1 denoting 0,2—2%, while the sign + marks sporadic appearances. I. Mierosociology of the Algal Vegetation in the Aerothermal Spring Group at Harkány In Hungary, Harkány ranks among the foremost aerothermal springs. It is situated near the Southern border of the country, 27 km South of Pécs, the leading city of the Transdanubian part of Hungary. The chemical composition of this hot spring group of great medicinal value shows a mainly sulphureous character (THAN 1869; EMSZT 1927). The temperature of the spring waters is 62—62,6 centigrades all the year round, and constant since nearly a hundred years ago. The hydrogen-ion concentration (pn) of the waters fluctuates between 6,8—6,9, and the water-output amounts to 3,682 hectoliters per 24 hours at Spring I, and to 3,123 hectoliters at Spring II. A full description of the Harkány hot springs, their chemical composition, together with the detailed plant systematical analysis of their microvegetation, was published by the author in 1961. Between the years 1947—53, the present writer conducted microphyto-sociological investigations at the Harkány spring group. Six biotops were selected for research work on the principle that only such surveying areas should be investigated where the thermal spring waters are free of pollution, are not mingling with foreign waters, and are exposed only to the occasional aerial influences. The six biotops are these: the basins of the two spring-wells, the three cooling basins cf the thermal waters, and the wooden wall flanking the frame of the mud-holding basin constantly moistened by thermal vapours. 11 Természettudományi Múzeum Évkönyvt