Intra-specific genetic diversity and ecophysiological performance of the aeroterrestrial green alga Klebsormidium (Klebsormidiophyceae, Streptophyta) in biological soil crusts along a gradient of land-use intensity

 

 

Scientific investigators:

Prof. Dr. Ulf Karsten

(University Rostock)

Goals

Aeroterrestrial filamentous green algae of the widely distributed, cosmopolitan genus Klebsormidium (Klebsormidiophyceae, Streptophyta) are typical components of biological soil crusts. These communities form water-stable aggregates that have important ecological roles in primary production, nitrogen fixation, water retention and stabilization of soils. Recent data indicate, for example, that 40% of global nitrogen fixation are realized by biological soil crusts. In the project the genetic diversity and physiological plasticity in members of Klebsormidium will be evaluated under different land-use intensities, as provided by the Biodiversity Exploratories. The data will indicate whether and how changes in land-use intensity influence population structure and ecological performance of Klebsormidium in soil crusts.

Bild SOILCRUST
soil crust (photo Ulf Karsten)

Hypotheses

H1: Klebsormidium species are a major group of aeroterrestrial green algae in soil crusts of different landscapes, and hence are ecologically relevant for ecosystem structure and function.
H2: The intra-specific genetic diversity of Klebsormidium in soil crusts is strongly affected by gradients of land use intensity.
H3: The intra-specific genetic diversity of Klebsormidium is reflected in ecophysiological response patterns resulting in wide physiological plasticity and flexibility of the respective population.

Methods

Isolation of Klebsormidium strains from soil crusts along gradients of land-use intensity as provided by Biodiversity Exploratories, and establishment of unialgal cultures. Molecular identification of all strains. Evaluation of intra-specific genetic diversity using microsatellites. Ecophysiological characterisation of selected Klebsormidium genotypes of the same species using growth and photosynthesis measurements under defined environmental conditions.