Diatoms in the thermal mud of Abano Terme, Italy (Maturation period)

Abstract

The beneficial effects of thermal mud mostly depends on the so called maturation process. During this process, thermophilic microrganisms, mainly diatoms, progressively colonize the mud, and are abundant even at a depth of several centimeters. Examination of samples collected at different levels in a maturation tank over two months (24 January-26 March 1997) showed a qualitatively rich diatom microflora (more than 80 taxa although the enviroment was rather selective), in great quantities (cell numbers almost always higher than 10 x 10 6 cells per cm 3 ). The dominant species was Aulacoseira granulata (EHRENBERG) SIMONSEN, a centric diatom with high thermal tolerance and a great vertical distribution. Undoubtedly the type and density of diatoms depends on the maturation period examined, which was limited, but sufficient to get the clay ready for the mudpacks.