Biodiversity and microbial function
Soil microorganisms, their community structure and function, determine major biogeochemical cycles. We use molecular and biochemical tools to reveal the underlying processes. Our particular interest lies in the reaction of microbes to natural and anthropogenic changes in our environment. We also test the possible application of soil amendments such as biochar, zeolithe and compost for improving soil fertility and carbon sequestration and hence strive at promoting sustainable agricultural production systems.
Greenhouse gases and climate change
To combat climate change it is essential to unravel the underlying mechanisms of soil-atmosphere exchange of trace gases - in managed as well as natural ecosystems. We are especially interested in the feedbacks between changing environmental conditions, land management and the microbial production and consumption of climate-active trace gases (CO2, CH4, N2O, NOx, NH3). In our research, we integrate laboratory experiments, manipulative field studies, long-term ecological observations and mathematical modelling in order to reach conclusions across time and scales.
Stable isotope research
We are using stable isotopes of carbon, nitrogen, sulphur, hydrogen and oxygen, to elucidate global cycles. We are particularly interested in how forest and agricultural soils store carbon and how those stocks react to pollutants and fertiliser inputs. Using isotope tracing and fractionation models we track pollutants into the atmosphere and waterways. Moreover, we investigate how crops and soils react to extreme events of intense rainfall or drought, and work out which inputs or measures, lead to increased systemic resilience in face of climate change. Using the natural global patterns of multiple elemental isotopic signatures, we determine the geographical origin of what we eat and insect pests; ensuring food security and authenticity.
Soil formation and soil functions
This research focus deals with factors and processes of soil formation and examines the impact of soil development and management on ecological soil functions. A major recent research effort is the investigation of soils of the Galápagos archipelago and their development over geological time scales, in different climatic zones and under agricultural land use.
Molecular modeling of the behavior of contaminants in the environment
This research focus investigates the molecular interactions of contaminants with reactive soil surfaces. Reactive surfaces are modeled at the atomic and molecular level and their interaction with agrochemicals and other contaminants is investigated using computational chemistry. For this, very precise and computationally demanding quantum chemical methods are used, as well as classical molecular mechanics (force-field) methods for the investigation of larger systems, as is necessary for soil science questions.
Nutrients and pollutants in the soil-plant-system
The decline of fossil resources for fertilizer production requires alternative technologies for nutrient recycling from by-products and waste materials. We contribute to the development of recycled fertilizers using novel technologies such as hydrothermal carbonization (HTC) and more effective (e.g. infinite-sink-based) fertiliser and soil tests to assess the nutrient availability of the products. We also work on the calibration of novel soil and fertiliser tests for a more precise assessment of nutrient requirements thus contributing towards a more sustainable agriculture. Furthermore, we investigate the fate and management of metals and metalloids in soils and in the rhizosphere and develop approaches for plant-based remediation (phytoremediation) as well as the potential of using metal-accumulating plants for metal recovery (phytomining).
Root exudates driving rhizosphere processes
This interdisciplinary research focuses on unraveling plant- microbe - soil interactions driven by root exudation, including:
- Development and application of innovative sampling techniques to collect root exudates from soil grown plants and analysis by metabolomic fingerprinting
- Investigating fate and function of root exudates, including exudate-driven mobilisation of nutrients, microbial decomposition dynamics, and microbial community composition
- Linking root exudation patterns with soil biogeochemical processes and plant molecular mechanisms
Chemical imaging and biogeochemical hotspots
We develop and apply novel sampling and analytical techniques for 2-D imaging of rhizosphere and soil processes at the microscale. We are particularly interested in unravelling features and processes in biogeochemical hotspots such as around pant roots, fertilizer or biochar granules, or pollutant-releasing particles. We aim at combining / integrating various imaging techniques including:
- 2-D sampling of available nutrients or pollutants using Diffusive Gradient in Thinfilms (DGT) applied to hotspots, and subsequent Laser Ablation ICP-MS imaging.
- Planar optodes for imaging controls of nutrient and pollutant solubility such as pH and oxygen (indication of redox potential)
- Zymography for imaging enzyme activities.