A5081837515- Soil Carbon and Nitrogen Dynamics
- Isotope Analysis in Ecology
- Groundwater and Isotope Geochemistry
- Soil and Water Nutrient Dynamics
- Plant Water Relations and Carbon Dynamics
- Plant responses to elevated CO2
- Peatlands and Wetlands Ecology
- Microbial Community Ecology and Physiology
- Wastewater Treatment and Nitrogen Removal
- Soil and Unsaturated Flow
- Plant nutrient uptake and metabolism
- Crop Yield and Soil Fertility
- Radioactive contamination and transfer
- Microbial Metabolic Engineering and Bioproduction
- Forest ecology and management
- Legume Nitrogen Fixing Symbiosis
- Atmospheric chemistry and aerosols
- Agronomic Practices and Intercropping Systems
- Groundwater flow and contamination studies
- Water Treatment and Disinfection
- Ammonia Synthesis and Nitrogen Reduction
- Bioenergy crop production and management
- Nematode management and characterization studies
- biodegradable polymer synthesis and properties
- Biofuel production and bioconversion
University of Göttingen
2015-2024
University of Koblenz and Landau
2023
Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau
2023
University College Dublin
2003-2005
Universitätsmedizin Göttingen
2003
Federal Institute for Population Research
2002
Institute of Soil Science
2000
Abstract The concept of biomass growth is central to microbial carbon (C) cycling and ecosystem nutrient turnover. Microbial usually assumed grow by cellular replication, despite microorganisms’ capacity increase synthesizing storage compounds. Resource investment in allows microbes decouple their metabolic activity from immediate resource supply, supporting more diverse responses environmental changes. Here we show that C the form triacylglycerides (TAGs) polyhydroxybutyrate (PHB)...
Amino sugars are increasingly used as indicators for the accumulation of microbial residues in soil and plant material. A reverse-phase high-performance liquid chromatography method was improved simultaneous determination muramic acid, mannosamine, glucosamine galactosamine hydrolysates via ortho-phthaldialdehyde (OPA) pre-column derivatisation fluorescence detection. The retention time reduced, separation acid mannosamine optimised by modifying mobile phase. effects excitation wavelength,...
Summary 1. Soil food webs are compartmentalized and comprise major energy channels, such as the plant litter, fungal bacterial channel. However, relative contribution of basal resources to these channels for nutrition higher trophic levels is largely unknown. 2. The study took advantage Swiss Canopy Crane Project, where a mature temperate forest was labelled with 13 C ‐depleted CO 2 . By exchanging leaf litter between ‐enriched area an unlabelled control area, we were able separate carbon...
Abstract. For more than two decades, research groups in hydrology, ecology, soil science, and biogeochemistry have performed cryogenic water extractions (CWEs) for the analysis of δ2H δ18O water. Recent studies shown that extraction conditions (time, temperature, vacuum) along with physicochemical properties may affect extracted isotope composition. Here we present results from first worldwide round robin laboratory intercomparison. We test null hypothesis that, identical soils, standards,...
In recent years, research and applications of the N2O site-specific nitrogen isotope composition have advanced, reflecting awareness contribution to anthropogenic greenhouse effect, leading significant progress in instrument development. Further dissemination isotopomer analysis, however, is hampered by a lack internationally agreed gaseous reference materials an uncertain compatibility different laboratories analytical techniques.In first comparison approach, eleven were each provided with...
RATIONALE A high sensitivity elemental analyzer/isotope ratio mass spectrometer setup was developed to allow analysis of 13 C and 15 N isotopic composition on microgram amounts N, respectively. METHODS Increased a conventional analyzer equipped with low blank autosampler obtained by decreased carrier gas flow 35 mL/min. The diameters the oxidation reduction reactors water trap were reduced 7.8, 7.8 4 mm i.d., respectively, obtain sharp sample peaks in spectrometer. To increase lifetime...
Abstract. The isotopic composition of soil-derived N2O can help differentiate between production pathways and estimate the fraction reduced to N2. Until now, δ18O has been rarely used in interpretation signatures because rather complex oxygen isotope fractionations during by denitrification. latter process involves nitrate reduction mediated through following three enzymes: reductase (NAR), nitrite (NIR) nitric oxide (NOR). Each step removes one atom as water (H2O), which gives rise a...
Abstract The stability and turnover of soil organic matter ( SOM ) are a very important but poorly understood part carbon (C) cycling. Conversion C 3 grassland to the 4 energy crop Miscanthus provides an ideal opportunity quantify medium‐term dynamics without disturbance (e.g., plowing), due natural shift in δ 13 signature C. For first time, we used repeated abundance approach measure loamy Gleyic Cambisol after 9 21 years cultivation. This is longest –C vegetation change study on under...
We tested experimentally if photoautotrophic microorganisms are a carbon source for invertebrates in temperate soils. exposed forest or arable soils to (13)CO2-enriched atmosphere and quantified (13)C assimilation by three common animal groups: earthworms (Oligochaeta), springtails (Hexapoda) slugs (Gastropoda). Endogeic (Allolobophora chlorotica) hemiedaphic (Ceratophysella denticulata) were highly enriched when incubated under light, deriving up 3.0 17.0%, respectively, of their body from...
Abstract Food webs in soil differ fundamentally from those aboveground; they are based on inputs both living plants via root exudates, and detritus, which is a complex mixture of fungi, bacteria, dead plant remains. Trophic relationships difficult to disentangle due the cryptic lifestyle animals inevitable microbial contributions their diet. Compound‐specific isotope analysis amino acids ( AA s) increasingly used explore food webs. The combined use δ 13 C 15 N values promising new approach...
Influence of plant internal nitrogen (N) stocks on carbon (C) and N uptake allocation in 3-year-old beech (Fagus sylvatica L.) was studied two 15N- 13C-labeling experiments. In the first experiment, trees were grown sand received either no nutrition (–N treatment) or 4 mM unlabeled (+N for 1 year. The –N- +N-pretreated then supplied with 15N a 13CO2 atmosphere 24 weeks. second pretreated year weeks remobilization stored monitored. On whole-plant level, new C significantly reduced...
Despite a long history and growing interest in isotopic analyses of N2 O, there is lack isotopically characterized O reference materials (standards) to enable normalization reporting isotope-delta values. Here we report the characterization two pure gas materials, USGS51 USGS52, which are now available for laboratory calibration (https://isotopes.usgs.gov/lab/referencematerials.html).A total 400 sealed borosilicate glass tubes each were prepared from single filling high vacuum line. We...
Abstract Tropical soils often contain less soil organic C (SOC) and microbial biomass (MBC) than temperate and, thus, exhibit lower fertility. The addition of plant residues N fertilizers can improve fertility, which might be reflected by use efficiency (CUE) functional diversity. A 42-day incubation study was carried out, adding leaf litter the C4 finger millet ( Eleusine coracana Gaertn.) inorganic 15 fertilizer. aim to investigate amendment effects on CUE diversity in a tropical Nitisol...
The role of soil decomposer animals in nutrient cycling is commonly seen as indirect, slow and cumulative, through grazing engineering effects on microbes their mineralization activities. Here, we show that nitrogen (N) carbon (C) movement from living to plants herbivores can be extremely rapid. In two complementary experiments under laboratory field conditions, used stable isotope tracers follow transfer earthworms soil, wheat seedlings, aphids. Earthworm-derived 15N 13C was acquired by...
Abstract It has been assumed that high winter N 2 O emissions from soils are the result of increased amounts microbially available organic C liberated during freezing and metabolized subsequent thawing. In a laboratory experiment, we attempted to simulate freeze‐thaw events by adding dissolved (DOC) sieved soil water content (95% water‐filled pore space). full factorial design, CO a) samples provided with DOC extracted frozen b) for 46 days thawed were compared. Additionally, NO $_3^-$ ,...
Beech and pine wood blocks were treated with 1,3-dimethylol-4,5-dihydroxyethylen urea (DMDHEU) to increasing weight percent gains (WPG). The resistance of the specimens against Trametes versicolor Coniophora puteana, determined as mass loss, increased WPG DMDHEU. Metabolic activity fungi in was assessed total esterase (TEA) based on hydrolysis fluorescein diacetate heat or energy production by isothermal micro-calorimetry. Both methods revealed that fungal related loss caused fungi. Still,...