Boenigk, Jens; Jost, Steffen Oliver; Stoeck, Thorsten; Garstecki, Tobias:
Differential thermal adaptation of clonal strains of a protist morphospecies originating from different climatic zones
In: Environmental Microbiology, Jg. 9 (2007), Heft 3, S. 593 - 602
2007Artikel/Aufsatz in Zeitschrift
BiologieFakultät für Biologie » Biodiversität
Damit verbunden: 1 Publikation(en)
Titel:
Differential thermal adaptation of clonal strains of a protist morphospecies originating from different climatic zones
Autor*in:
Boenigk, JensUDE
GND
122715500
LSF ID
52338
ORCID
0000-0001-8858-8889ORCID iD
Sonstiges
der Hochschule zugeordnete*r Autor*in
;
Jost, Steffen OliverUDE
LSF ID
52552
Sonstiges
der Hochschule zugeordnete*r Autor*in
;
Stoeck, Thorsten;Garstecki, Tobias
Erscheinungsjahr:
2007

Abstract:

Eco-physiological variation and local adaptation are key issues in microbial ecology. Here, we investigated the thermal adaptation of 19 strains of the same Spumella morphospecies (Chrysophyceae, Heterokonta). In order to test for local adaptation and the existence of specific ecotypes we analysed growth rates of these strains, which originated from different climate regions. We applied temperature-adaptation as an eco-physiological marker and analysed growth rates of the different Spumella strains at temperatures between 0°C and 35°C. The temperatures allowing for maximal growth of strains from temperate and warm climatic zones ranged between 19.9°C and 33.4°C. Phylogenetically, most of these ‘warm’-adapted strains fall into two different previously defined 18S rDNA Spumella clusters, one of them consisting of mostly soil organisms and the other one being a freshwater cluster. As a rule, the ‘warm’-adapted strains of the soil cluster grew slower than the ‘warm’-adapted isolates within the freshwater cluster. This difference most probably reflect different strategies, i.e. the formation of cysts at the expense of lower growth rates in soil organisms. In contrast, as expected, all isolates from Antarctica were cold-adapted and grew already around melting point of freshwater. Surprisingly, optimum temperature for these strains was between 11.8°C and 17.7°C and maximum temperature tolerated was between 14.6°C and 23.5°C. Our data indicate that despite the relatively high optimal temperature of most Antarctic strains, they may have a relative advantage below 5–10°C only. Based on the thermal adaptation of the flagellate strains the Antarctic strains were clearly separated from the other investigated strains. This may indicate a limited dispersal of flagellates to and from Antarctica. Even if the latter assumption needs support from more data, we argue that the high levels of eco-physiological and molecular microdiversity indicate that the current species concepts do not sufficiently reflect protist eco-physiological differentiation.