Silica-scaled chrysophytes from North Tyrol (Austria) including a description of Mallomonas tirolensis sp. nov.
Abstrakt
The silica-scaled chrysophyte flora of the eastern Alpine region of North Tyrol was examined by means of transmission electron microscopy. Altogether, 46 taxa of the genera Chrysosphaerella, Mallomonas, Paraphysomonas, Spiniferomonas and Synura were recorded including one species new to science, Mallomonas tirolensis.
The samples were taken from 22 sampling sites that comprised natural lakes, artificial ponds and mires. Moreover, conductivity and pH were measured in situ and major ions and nutrients of water samples were analysed.
The pH of the localities ranged from 5.9 to 8.5 with the majority of the sites being slightly alkaline. The most common species in our study were P vestita agg., C. brevispina, M alpina and M striata that were recorded in more than 50 % of the sites.
On the other hand, several rare species were found, e.g. M guttata and M hexagonis.
Furthermore, the presence of M pseudocoronata in the Alps was confirmed. We recorded this species, which was originally described as endemic to North America, in four waterbodies.
The species composition of the Tyrolean waterbodies was found to be significantly related to pH, dissolved reactive silica content, lake depth, calcium content and altitude. The biogeographical implications of our findings as well as potential effects of human activities on the flora are also discussed.