The diatom Didymosphenia geminata: distribution and mass occurrence in the Province of Trento (Northern Italy)

摘要

Didymosphenia geminate (Lyngbye) M. Schmidt is an epilithic and epiphytic diatom known from oligotrophic rivers of many Northern Hemisphere boreal or mountainous regions (ISSG 2005). It often develops in high abundances, visible as muci-laginous mats covering submerged substrata, and is mainly composed of the stalks secreted by the alga. Its presence, both in lakes and streams, in Northern Italy has been recorded since 1880 (BRUN 1880, BONARDI 1888, BELTRAMI et al. 2008). We evaluated the occurrence, distribution and development of D. geminata in the Province of Trento, and conducted a preliminary investigation on the effects of these mucilaginous mats on diatom and macroinvertebrate communities.