Phylogenetic analyses of 35 strains including 25 previously published sequences and 10 which have been newly sequenced, representing two species of Euglena, five species of Phacus and three species of Astasia, were carried out using the SSU rDNA. Parsimony, distance and maximum-likelihood inferred phylogenies support (1) monophyly of the euglenoids, (2) kinetoplastids as the sister group, (3) the phagotrophic Petalomonas cantuscygni Cann et Pennick anchoring the base of the euglenoid lineage, (4) evolution of phototrophy within the euglenoids from a single event, (5) multiple origins of osmotrophic euglenoids and (6) polyphyly of the genera Euglena Ehrenberg and Phacus Dujardin. Analyses also indicate that Lepocinclis Perty, Trachelomonas Ehrenberg and Astasia Dujardin are polyphyletic. In addition, the results suggest that neither the Euglenales nor the Eutreptiales form a monophyletic lineage, thus questioning currently available classifications. Concerning the phagotrophic mode of nutrition, the data suggest that the feeding apparatus arose multiple times.

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In the 2 nd order mountain brook "Oberer Seebach" (Austria), diatoms and cyanoprokaryotes dominate the microphytobenthos, with the diatoms forming the richest species group.Comparative investigations of different habitats clearly show seasonal variations in algal species composition and biomass throughout the year. Pool habitats hold a higher number of taxa than riffle sites. In addition, phytobiomass is two-to nearly fourfold higher in pools. Based on investigations of the chlorophyll-a vertical profiles within the coarse gravel sediments, the light discontinuity layer was determined to be situated at 7-10 cm sediment depth. Vertical distribution showed a maximum of taxa a few centimeters below the sediment surface. The same diatom taxa were found throughout all sampling dates, sediment depths and sampling sites.The results of exposed perforated metal tubes clearly indicate that the occurrence of phytobenthos in aphotic zones is primarily controlled by saltatory movements of the upper sediment layers driven by discharge.

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