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Biological soil crusts are a complex community of photosynthetically active green algae, cyanobacteria, mosses and lichens, heterotrophic fungi, protozoa and bacteria that cover the uppermost millimetres of the soil.

The community of organisms and their excretory products form a micro-ecosystem whose ecological function is particularly important in pioneer colonisation of open soils (e.g. nitrogen fixation by cyanobacteria, primary production, water retention, stabilisation of the topsoil or provision of plant-available nutrients).

Despite their important ecological function, soil crusts are mainly studied only in arid and semi-arid habitats. Therefore, this project aims to elucidate the species composition of temperate crusts and to investigate a possible correlation with land use intensity and soil parameters.

Picture: The photo shows leaf moss in a close-up.
Moss
Picture: The graphic shows a cross-section of the structure of the crust and transition zone floor.
Scheme crust and transitional zone soil

The determination of biodiversity within the soil crust will contribute to the identification of relationships among organisms and their responses to external factors, such as land use intensity.

The functional role of soil crusts in the biogeochemical cycles of C and N will be investigated using mass spectrometric fingerprinting (Py-FIMS, pyrolysis field ionisation mass spectrometry) and XANES (X-ray absorption near edge structure). Various C- and N-containing component classes of crusts and adjacent soil will be characterised and quantified, so that an influence of land use intensity on molecules or component classes can then be statistically determined.

P-fraction analyses of the crust and the adjacent soil will provide information on the ecological function of the soil crust as a mobiliser for mineral P-components of the soil.


1.With increasing land use intensity, the abundance of nitrogen-fixing cyanobacteria decreases and causes a shift in the community of partner organisms (ammonium-oxidising bacteria and archaea).

2. Intensified land use reduces the biochemical diversity of soil organic matter molecules while simultaneously enriching stable, N-containing molecules.

3. Mineral P fractions are transformed into organic fractions by the biological soil crust. An increase in land use intensity increases organic P fractions in the crust.


  • Cultivation of photosynthetically active organisms
  • Light microscopy
  • PCR and 454 sequencing
  • Py-FIMS (Pyrolyse Feldionisation Massenspektrometrie)
  • C-, N-, P – XANES (X-ray Absorption Near Edge Structure)
  • P fractionation
  • 31P-NMR (nuclear magnetic resonance)
Picture: The photograph shows a piece of forest floor in a summery shady forest in the middle of the picture, which has been cleared of wilted leaves. Next to the crust are two female scientists and two male scientists. One of the men is standing in the front right of the picture, holding a document in his left hand. Behind him, one of the women is kneeling and watching the work of the second man, who is kneeling on the ground on the left of the picture and taking a sample of the crust with his right hand. In front of him on the left of the picture is the second woman, who is also watching him.
Crust sampling along a back alley on SEW 30
Picture: The photo shows two free spots in the soil after a crust removal.
Free areas after crust removal
Picture: The photo shows a Petri dish with leaf moss enrichment cultures in it.
Enrichment cultures
Picture: The photo shows a Petri dish with a soil pile in the middle.
Floor

Doc
Beitrag biologischer Bodenkrusten zur Zusammensetzung und Stabilität organischer Bodensubstanz in gemäßigten Wäldern
Baumann K., Eckhardt K.-U., Acksel A., Gros P., Glaser K., Gillespie A. W., Karsten U., Leinweber P. (2021): Contribution of biological soil crusts to soil organic matter composition and stability in temperate forests. Soil Biology and Biochemistry 160: 108315. doi: 10.1016/j.soilbio.2021.108315
More information:  doi.org
Doc
Biologische Bodenkrusten als zentrales Element im biogeochemischen P-Kreislauf während der Pedogenese sandigen Substrats
Baumann K., Siebers M., Kruse J., Eckhardt K.-U., Hu Y., Michalik D., Siebers N., Kar G., Karsten U., Leinweber P. (2019): Biological soil crusts as key player in biogeochemical P cycling during pedogenesis of sandy substrate. Geoderma 338, 145-158. doi: 10.1016/j.geoderma.2018.11.034
More information:  doi.org
Doc
Einfluss der Landnutzung auf die Artenzahl der Algen in Biologischen Bodenkrusten mit Implikationen für Phosphorkreislauf
Glaser K., Baumann K., Leinweber P., Mikhailyuk T., Karsten U. (2018): Algal richness in BSCs in forests under different management intensity with some implications for P cycling. Biogeosciences 15 (13), 4181-4192. doi: 10.5194/bg-15-4181-2018
More information:  doi.org
Doc
Habitat beeinflusst das Vorkommen von Klebsormidium-arten mehr als geographische Distanz
Glaser K., Donner A., Albrecht M., Mikhailyuk T., Karsten U. (2017): Habitat-specific composition of morphotypes with low genetic diversity in the green algal genus Klebsormidium (Streptophyta) isolated from biological soil crusts in Central European grasslands and forests. European Journal of Phycology 52 (2), 188-199. doi: 10.1080/09670262.2016.1235730
More information:  doi.org
Doc
Donner A., Glaser K., Borchhardt N., Karsten U. (2017): Ecophysiological Response on Dehydration and Temperature in Terrestrial Klebsormidium (Streptophyta) Isolated from Biological Soil Crusts in Central European Grasslands and Forests. Microbial Ecology 73 (4), 850–864. doi: 10.1007/s00248-016-0917-3
More information:  doi.org
Doc
Biologische Bodenkrusten in Wäldern gemäßigter Breiten: Ihre Rolle im P-Kreislauf
Baumann K., Glaser K., Mutz J.-E., Karsten U., MacLennan A., Hu Y., Michalik D., Kruse j., Eckhardt K.-U., Schall P., Leinweber P. (2017): Biological soil crusts of temperate forests: Their role in P cycling. Soil Biology and Biochemistry 109, 156–166. doi: 10.1016/j.soilbio.2017.02.011
More information:  doi.org
Doc
Schnellbestimmung von organischen Bodensubstanzen mittels Farbanalyse und Fourier Transform Infrarot Spektroskopie
Baumann K., Schöning I., Schrumpf M., Ellerbrock R. H., Leinweber P. (2016): Rapid assessment of soil organic matter: soil color analysis and Fourier transform infrared spectroscopy. Geoderma 278, 49–57. doi: 10.1016/j.geoderma.2016.05.012
More information:  doi.org
Doc
Effects of biological soil crusts on phosphorus pools in near-surface soil
Einfluss von biologischen Bodenkrusten auf die Phosphor-Pools im oberflächennahen Boden
Mutz J.-E. (2015): Effects of biological soil crusts on phosphorus pools in near-surface soil. Bachelor thesis, University Rostock

Project in other funding periods

Picture: The photo shows a close-up of liverwort.
Crustfunction III (Contributing project)
#Soil biology & Element cycling  #Soil Ecology  #FOX  #2023 – 2026  #2020 – 2023  #Functional diversity […]
Picture: The photo shows a close-up of liverwort.
Crustfunction II (Contributing project)
#Soil biology & Element cycling  #2017 – 2020  #Microbial community […]

Scientific assistants

Prof. Dr. Ulf Karsten
Project manager
Prof. Dr. Ulf Karsten
Universität Rostock
Prof. Dr. Peter Leinweber
Project manager
Prof. Dr. Peter Leinweber
Universität Rostock
Dr. Karen Baumann
Employee
Dr. Karen Baumann
Universität Vechta
Jun.-Prof. Dr. Karin Glaser
Employee
Jun.-Prof. Dr. Karin Glaser
Technische Universität Freiberg
Samira Khanipour Roshan
Alumni
Samira Khanipour Roshan
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