EGU24-15209, updated on 09 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Soil microbial communities in Danish lowlands are shaped by soil pH 

Anne-Cathrine Danielsen1,2, Charles Pesch1, Cecilie Hermansen1,2, Caitlin Margaret Singleton3, Thomas Bygh Nymann Jensen3, Yu Yang3, Per Halkjær Nielsen3, Mogens Humlekrog Greve1,2, Peter Lystbæk Weber1, Emmanuel Arthur1,2, Sebastian Gutierrez1,2, Per Møldrup4, Signe Normand2, and Lis Wollesen de Jonge1,2
Anne-Cathrine Danielsen et al.
  • 1Section of Soil Physics and Hydropedology, Department of Agroecology, Aarhus University, Blichers Allé 20, 8830 Tjele, Denmark
  • 2SustainScapes - Center for Sustainable Landscapes under Global Change, Department of Biology, Aarhus University, Nordre Ringgade 1, 8000 Aarhus C, Denmark
  • 3Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Frederik Bajers Vej 7H, Aalborg, DK 9220, Denmark
  • 4Division of Civil and Environmental Engineering, Department of the Built Environment, Aalborg University, Thomas Manns Vej 23, Aalborg, DK 9220, Denmark

Agricultural activity on drained lowlands is a common practice in Denmark and there are suggestions to rewet some of them for climate mitigation purposes. Rewetting those lowlands might result in a change in microbial community composition. This study investigates the current prokaryotic diversity and community composition in soil samples from cultivated lowlands to provide the baseline for monitoring changes after rewetting. Furthermore, variations in soil properties between sites are examined, and the properties driving differences in prokaryotic diversity and community composition are identified. In total, 116 samples were collected from field sites across Denmark that were categorized as one of four different land-use types: Crop, Grass, Fallow, and Other. Soil properties were selected to cover chemical (soil water repellency, pH, electrical conductivity), hydrological (depth to ground-water table, soil water content at field capacity (-100 hPa)), nutrient-related (total nitrogen, organic carbon, carbon-to-nitrogen-ratio, fractions of pyrolizable and residual organic matter), and structural (total porosity, pore size distribution index) functions of the soil. Soil samples exhibited significant variations in their chemical and physical properties, including pH ranging from 2.02 to 7.55, organic carbon ranging from 3 g 100g-1 to 50 g 100g-1, soil water repellency ranging from 71.27 mN m-1 (hydrophilic) to 33.85 mN m-1 (very strongly hydrophobic), and total porosity ranging from 51% to 95%. Soil samples clustered according to soil class (mineral, organo-mineral, organic, highly organic) but not according to land-use type (crop, grass, fallow, other). Prokaryotic alpha diversity, measured as Shannon’s diversity index (H), ranged from 4.16 to 5.89 across samples and could best be predicted by pH, followed by total porosity, fraction of pyrolizable carbon, and pore size distribution index. The pH alone explained 36% of the variation in H between samples. Hierarchical clustering identified three prokaryotic clusters highly correlated with pH. A weak correlation was found between differences in community composition (beta diversity) and geographic distance (r = 0.15, p < 0.001). However, pH was also the main driver of beta diversity, explaining 11% of the variation. At the same time, models including additional variables only had marginally better explanatory power. In conclusion, pH was the predominant driver of prokaryotic alpha and beta diversity across land-use types in lowland soils.

How to cite: Danielsen, A.-C., Pesch, C., Hermansen, C., Singleton, C. M., Bygh Nymann Jensen, T., Yang, Y., Halkjær Nielsen, P., Humlekrog Greve, M., Lystbæk Weber, P., Arthur, E., Gutierrez, S., Møldrup, P., Normand, S., and Wollesen de Jonge, L.: Soil microbial communities in Danish lowlands are shaped by soil pH , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15209,, 2024.