We are investigating soil nematode communities in mofette fields where geogenic CO2 rises from magma chambers through clefts and cracks in the crust upwards to the soil surface. The uppermost soil layers around these gas escapes show small-scale patches where CO2 concentrations are up to 100% and O2 concentrations are accordingly low or even zero. From “mofette species”, i.e species which we find in soils with high CO2 concentrations, we analyse population ecology and adaptations to the temporary or even lasting lack of oxygen.
Since October 2005 we investigate primary succession of soil nematode and tardigrade communities in a post-mining site “Chicken Creek” which was constructed and then left without further amelioration or recultivation. The study was part of the SFB Transregio 38, Structures and processes of the initial ecosystem development in an artificial water catchment of BTU Cottbus, TU München and ETH Zürich. Since 2011 the site is investigated in a long-term monitoring with sampling once a year in early October.
Within the “German Barcode of Life” project (www.bolgermany.de), we – together with the department of animal ecology at the University of Bielefeld – started generating an inventory of nematode species occurring in soil and freshwater sediments in Germany, including their genetic fingerprints. During the GBOL I period, about 600 ribosomal large subunit DNA fragments (D3-D5 region) were amplified and published (BOLD and GenBank) for 79 terrestrial and limnic nematode species sampled at 147 locations across Germany. Since then, inventory and assignment of species-specific barcodes are continuously continued as an important step towards an assessment of soil nematode biodiversity within Germany.
Participation in Departmental projects
Soil animals of Antarctica are surprisingly well studied, e.g. with about 60 papers published on the nematode fauna of all parts of maritime (islands) and continental Antarctica wherever scientists had access to. We are thus able to more or less precisely predict species inventories of locations and based on this knowledge and on board of a tourist ship we investigate the role of human activity in the introduction of foreign species to Antarctica and the spreading of organisms within Antarctica.
Forest of the future
Due to increasing crop losses caused by drought, foresters in some German regions are starting to plant South European oak trees,(Quercus ilex, Q. pubescens and Q. frainetto), which are known to tolerate dryness much better than most of the trees commonly grown in Middle Europe . In cooperation with the Biodiversity and Climate Research Centre BiK-F, we are investigating litter decomposition rate of South European oak species and the involvement of Middle European soil animals in decomposition processes. Analysis of the soil nematode fauna shall further give insight into decomposer food web structure and decomposition pathways.
Predator-prey interaction in the soil food web
With densities of more than one million individuals per square meter, nematodes are the most numerous soil animals. Their activities affect microbial activity, decomposition rates, nutrient cycles and plant growth. Many predators exploit the nematode pool, but little is known about the strength of predator-prey interaction and the regulatory top-down influence on nematode species composition and population growth. To provide deeper insights into the structuring forces of predator-nematode interaction, we investigated feeding rates (functional response), influences (temperature, prey density, body sizes, soil pore sizes) and behavior (optimal foraging, preference changes, prey perception, attack response) in a tardigrade (Paramacrobiotus richtersi) nematode (Acrobeloides nanus) system. The results are used in testing ecological models.