TY  - JOUR
A1  - Weisse, Thomas
A1  - Berendonk, Thomas U.
A1  - Kamjunke, Norbert
A1  - Moser, Michael
A1  - Scheffel, U.
A1  - Stadler, P.
A1  - Weithoff, Guntram
T1  - Significant habitat effects influence protist fitness  evidence for local adaptation from acidic mining lakes
JF  - Ecosphere : the magazine of the International Ecology University
N2  - It is currently controversially discussed if the same freshwater microorganisms occur worldwide wherever their required habitats are realized, i.e., without any adaptation to local conditions below the species level. We performed laboratory experiments with flagellates and ciliates from three acidic mining lakes (AML, pH similar to 2.7) to investigate if similar habitats may affect similar organisms differently. Such man-made lakes provide suitable ecosystem models to test for the significance of strong habitat selection. To this end, we analyzed the growth response of three protist taxa (three strains of the phytoflagellate Chlamydomonas acidophila, two isolates of the phytoflagellate Ochromonas and two species of the ciliate genus Oxytricha) by exposing them to lake water of their origin and from the two other AML in a cross-factorial design. Population growth rates were measured as a proxy for their fitness. Results revealed significant effects of strain, lake (= habitat), and strain X habitat interaction. In the environmentally most adverse AML, all three protist taxa were locally adapted. In conclusion, our study demonstrates that (1) the same habitat may affect strains of the same species differently and that (2) similar habitats may harbor ecophysiologically different strains or species. These results contradict the 'everything is everywhere' paradigm.
KW  - allopatric speciation
KW  - Chlamydomonas acidophila
KW  - ciliates
KW  - everything is everywhere
KW  - flagellates
KW  - freshwater microbes
KW  - habitat-species interaction
KW  - local adaptation
KW  - Ochromonas spp.
KW  - Oxytricha spp.
Y1  - 2011
U6  - https://doi.org/10.1890/ES11-00157.1
SN  - 2150-8925
VL  - 2
IS  - 12
PB  - Wiley
CY  - Washington
ER  - 
TY  - JOUR
A1  - Weisse, Thomas
A1  - Moser, Michael
A1  - Scheffel, Ulrike
A1  - Stadler, Peter
A1  - Berendonk, Thomas U.
A1  - Weithoff, Guntram
A1  - Berger, Helmut
T1  - Systematics and species-specific response to pH of Oxytricha acidotolerans sp nov and Urosomoida sp (Ciliophora, Hypotricha) from acid mining lakes
JF  - European journal of protistology
N2  - We investigated the morphology, phylogeny of the 18S rDNA, and pH response of Oxytricha acidotolerans sp. nov. and Urosomoida sp. (Ciliophora, Hypotricha) isolated from two chemically similar acid mining lakes (pH similar to 2.6) located at Langau, Austria, and in Lusatia, Germany. Oxytricha acidotolerans sp. nov. from Langau has 18 frontal-ventral-transverse cirri but a very indistinct kinety 3 fragmentation so that the assignment to Oxytricha is uncertain. The somewhat smaller species from Lusatia has a highly variable cirral pattern and the dorsal kineties arranged in the Urosomoida pattern and is, therefore, preliminary designated as Urosomoida sp. The pH response was measured as ciliate growth rates in laboratory experiments at pH ranging from 2.5 to 7.0. Our hypothesis was that the shape of the pH reaction norm would not differ between these closely related (3% difference in their SSU rDNA) species. Results revealed a broad pH niche for O. acidotolerans, with growth rates peaking at moderately acidic conditions (pH 5.2). Cyst formation was positively and linearly related to pH. Urosomoida sp. was more sensitive to pH and did not survive at circumneutral pH. Accordingly, we reject our hypothesis that similar habitats would harbour ciliate species with virtually identical pH reaction norm.
KW  - Acid mining lakes
KW  - Growth rates
KW  - pH response
KW  - Oxytricha
KW  - SSU rDNA
KW  - Urosomoida
Y1  - 2013
U6  - https://doi.org/10.1016/j.ejop.2012.08.001
SN  - 0932-4739
VL  - 49
IS  - 2
SP  - 255
EP  - 271
PB  - Elsevier
CY  - Jena
ER  -