Homepage - www.protozoology.com
Abstract 47

How to cite the abstract:
Weisse T., Moser M., Scheffel U., Stadler P., Berendonk T., Weithoff G., Berger H. (2012). Morphology, phylogenetic relationships, and pH response of two as yet undescribed Oxytricha species (Ciliophora, Hypotricha) - 31th Annual Meeting of the German Society of Protozoology, March 1-3, 2012, Wuppertal. Abstract on p. 110 of Abstract booklet. Poster (7 MB, PDF). Supported by the Austrian Science Fund; Project P-23425-B17.

Morphology, phylogenetic relationships, and pH response of two as yet undescribed Oxytricha species (Ciliophora, Hypotricha)

Thomas Weissea, Michael Mosera, Ulrike Scheffela, Peter Stadlera, Thomas Berendonkb, Guntram Weithoffc, Helmut Bergerd

Institute for Limnology of the Austrian Academy of Sciences, 5310 Mondsee, Austria; b Technical University Dresden, Institute for Hydrobiology, 01062 Dresden, Germany; c Department of Ecology and Ecosystem Modelling, University of Potsdam, 14469 Potsdam, Germany; d Consulting Engineering Office for Ecology, Radetzkystrasse 10, 5020 Salzburg, Austria

We investigated the morphology, phylogeny, and pH response of two undescribed Oxytricha species isolated from two acid mining lakes (pH ~2.6) located in Lusatia (Germany) and Langau (Austria). The Langau species, tentatively named Oxytricha acidotolerans by Weisse et al. (2011, Ecosphere), is about 60-80 × 25-40 µm in life, has an ordinary 18-cirri pattern, about 24 adoral membranelles, 3 µm long dorsal bristles, three caudal cirri, two macronuclear nodules, two micronuclei, and six dorsal kineties. The species from Lusatia is highly variable in the main characters (body size, shape, infraciliature, nuclear apparatus) making a useable description almost impossible. Both species differ by 3% in their SSU rDNA and occur in a cluster containing, inter alia, other oxytrichids like Onychodromopsis flexilis, Cyrtohymena citrina, and Paraurostyla weissei. However, Oxytricha granulifera, the type species of Oxytricha, is distinctly separated, demonstrating the immature taxonomy of this group. Our ecological hypothesis was that the shape of the pH reaction norm would not differ between our closely related species. Ciliate growth rates measured in the laboratory were calculated from changes in cell numbers vs. time. Results revealed a broad pH niche for O. acidotolerans, with positive growth rates over the entire pH range investigated, peaking at moderately acidic conditions (pH 5.2). Cyst formation was positively and linearly related to pH. Oxytricha sp. from Lusatia was more sensitive to pH and did not survive at circum-neutral pH. Our experimental results characterize O. acidotolerans as an acidotolerant species, while Oxytricha sp. is acidophilic. We reject our hypothesis that similar habitats would harbour ciliate species with virtually identical pH reaction norm. Supported by the Austrian Science Fund (FWF) Projects P20118-B17 (TW) and P23415-B17 (HB).

Homepage www.protozoology.com
Publication list of Helmut Berger
Publisher Helmut Berger
Main publication to this topic
Adobe to get the free Adobe Acrobat Reader

Keywords: Hypotrichia, Ciliophora, ph, acid, limnology, Austria, Germany, Europe, ecology, adaptation, spirotricha


Dr Helmut BERGER
Consulting Engineering Office for Ecology - Technisches Büro für Ökologie
Radetzkystrasse 10, 5020 Salzburg, Austria, Europe
Phone +43-(0)662-432538; Fax +43-(0)662-443139; email office@protozoology.com; http://www.protozoology.com