A5033694176- Groundwater and Isotope Geochemistry
- Hydrology and Watershed Management Studies
- Plant Water Relations and Carbon Dynamics
- Groundwater flow and contamination studies
- Isotope Analysis in Ecology
- Tree-ring climate responses
- Soil and Water Nutrient Dynamics
- Atmospheric and Environmental Gas Dynamics
- Meteorological Phenomena and Simulations
- Climate variability and models
- Oceanographic and Atmospheric Processes
- Geology and Paleoclimatology Research
- Pharmaceutical and Antibiotic Environmental Impacts
- Freshwater macroinvertebrate diversity and ecology
- Nuclear Physics and Applications
- Pesticide and Herbicide Environmental Studies
- Cryospheric studies and observations
- Pesticide Residue Analysis and Safety
- Peatlands and Wetlands Ecology
- Species Distribution and Climate Change
- Soil and Unsaturated Flow
- Polymer-Based Agricultural Enhancements
- Environmental Toxicology and Ecotoxicology
- Hydrocarbon exploration and reservoir analysis
- Plant responses to elevated CO2
University of Freiburg
2015-2025
Abstract The vadose zone plays a crucial role in the water cycle for storing water, providing to vegetation and transporting solutes or degrading contaminants. Earth scientists have long acknowledged importance of zone, numerous methods been developed better understand predict hydrological processes within this ‘critical zone’. For several decades, stable isotopes ( 18 O 2 H) pore used as environmental tracers gain insights into movement other processes. To determine isotopic composition,...
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,...
Abstract Field studies analyzing the stable isotope composition of xylem water are providing important information on ecosystem relations. However, capacity isotopes to characterize functioning plants in their environment has not been fully explored because methodological constraints extent and resolution at which samples could be collected analysed. Here, we introduce an situ method offering potential continuously monitor tree via its vapour phase using a commercial laser‐based analyser...
We developed a method to measure in situ the isotopic composition of liquid water with minimal supervision and, most important, temporal resolution less than minute. For this purpose microporous hydrophobic membrane contactor (Membrana) was combined an isotope laser spectrometer (Picarro). The contactor, originally designed for degassing liquids, used N 2 as carrier gas order transform small fraction vapor. generated vapor then analyzed continuously by Picarro analyzer. To prove membrane's...
Recently, laser-based water stable isotope spectrometers have become popular as they enable previously impossible approaches of environmental observations. Consequently, been subjected to increasingly heterogeneous atmospheric conditions. However, there is still a severe lack data on the impact nonstandardized gas matrices analyzer performances. Against this background, we investigated influence changing proportions N2, O2, and CO2 in carrier measurements typical (Picarro L2120-i). We...
Core Ideas Observed biases were gas matrix effects exclusively caused by biogenic headspace CO 2 . exceeded 30× (δ H) and 65× 18 O) accepted measurement uncertainties. The proposed correction scheme uses data from repeated analyses of soil samples only. Post‐correction quality isotope matches presented method helps to avoid grave misinterpretations water data. isotopic composition H, δ pore is an invaluable tracer for the minimally invasive study subsurface flow transport processes. Here, we...
Abstract. To investigate water movement in environmental systems, stable isotope (2H and 18O) ratios of are commonly used tracers. Analyzing the isotopic or adsorbed to substances like soil plant tissue necessitates extraction equilibration prior analysis. One such method, direct vapor equilibration, is popular due its cost-effectiveness straightforward sample processing. However, analysis requires significant manual labor, thereby limiting number samples that can be analyzed. This...
Seasonal floodplain forests are important ecosystems that attenuate floods and have high biodiversity. However, floodplains threatened by human activities, such as dam building, agricultural water use, climate change. Improving our understanding of the functioning can aid in their protection. Trees southeastern Brazil experience flooding for more than a month per year but also must endure very dry periods where groundwater level is several meters below surface. Species composition depends on...
The contamination of aquifers by polluted recharge from agricultural areas remains a major danger to water resources. But continuous observations are limited due lack adequate monitoring systems.  So far, commercial UV-Vis spectrometers have been used continuously monitor dissolved organic carbon (DOC) and nitrate levels in surface waters treatment facilities. While combined with suction cups measure in-situ the concentration soil water, this solution is costly difficult operate....
Abstract. The direct vapor equilibration laser spectrometry (DVE-LS) method has been developed for obtaining matrix-bound water stable isotope data in soils, the critical zone, and bedrock, deriving therefrom subsurface flow transport processes and, ultimately, characterizing, example, groundwater recharge vulnerability. Recently, DVE-LS increasingly adopted due to its possible high sample throughput, relative simplicity, cost-efficiency. However, this come at cost of a non-unified standard...
Abstract. The water isotopic composition of throughfall is affected by complex diffusive exchange with ambient vapour, evaporative enrichment heavy isotopes, and mixing processes in the tree canopy. All interception occur simultaneously space time, generating a pattern depth composition. This ultimately cascades through entire hydrologic system therefore crucial for isotope studies catchment hydrology, where recharge areas are often forested, while reference meteorological stations generally...
Abstract. Using water-stable isotopes to track plant water uptake or soil processes has become an invaluable tool in ecohydrology and physiological ecology. Recent studies have shown that laser absorption spectroscopy can measure equilibrated vapour well enough support inference of liquid-stable isotope composition water, on-site real-time. However, current situ systems require the presence instrument field. Here we tested, first lab then field, a method for equilibrating, collecting,...
Abstract. For more than two decades, research groups in hydrology, ecology, soil science and biogeochemistry have performed cryogenic water extractions for the analysis of δ2H δ18O water. Recent studies shown that extraction conditions (time, temperature, vacuum) along with physicochemical properties may affect extracted isotope results. Here we present results from first worldwide round robin laboratory intercomparison. We test null hypothesis identical soils, standards, protocols analyses,...
Abstract. To investigate water movement in environmental systems, stable isotopes (2H and 18O) are commonly used tracers. Analyzing the isotopic composition of bonded to substances like soil or plant tissue necessitates its extraction prior analysis. One such method, direct vapor equilibration, is popular due cost-effectiveness straightforward sample processing. However, analysis requires a significant manual labor, thereby limiting number samples that can be analyzed. This limitation...
Abstract Rationale Laser‐based analyzers are widely used in ecohydrology to analyze plant water isotopic compositions (δ 18 O and δ 2 H). The suitability of three different extraction isotope equilibration techniques was compared. We examined whether co‐extracted volatile organic compounds (VOCs) affect laser‐based measurements the instrument's spectral parameters post‐correct for interfering VOCs. Methods Cryogenic vacuum extraction, vapor headspace bags, situ probes were extract liquid or...
Abstract The protection of the globally widespread lentic small water bodies (LSWB) must be based on detailed knowledge about their hydrological connectivity and balance. study aimed to identify quantify balance components as well surface‐groundwater interaction two LSWB in a characteristic lowland region with combination different methods. This includes collection data use bromide stable isotopes ( δ 2 H 18 O) tracers. With help, mixing models were established, daily balances assessed....
Abstract. The isotopic composition of throughfall is affected by complex exchange, enrichment, and mixing processes in the tree canopy. All interception occur simultaneously space time generating a pattern amount composition. This ultimately cascades through entire hydrologic system therefore crucial for studies catchment hydrology where recharge areas are often forested while reference meteorological stations generally open. For quasi real-time observation both gross precipitation we...
Abstract Water is a limiting factor for plant development. Therefore, understanding plant–water relations vital food security and ecosystem conservation. The stable isotopes of water (δ 2 H δ 18 O) are widely used to study ecohydrological processes, such as root uptake. However, obtaining from plants measure their isotopic composition requires extraction techniques that laborious challenging. A method developed soil pore circumvents the water‐vapour equilibrium (WVE) method. In this study,...
Abstract. The stable isotopes of oxygen and hydrogen, 18O 2H, provide information on water flow pathways hydrologic catchment functioning. Here a data set time series precipitation streamflow isotope composition in medium-sized Swiss catchments, CH-IRP, is presented that unique terms its long-term multi-catchment coverage along an alpine to pre-alpine gradient. comprises fortnightly both δ2H δ18O as well deuterium excess from for 23 sites Switzerland, together with summary statistics the...
Abstract. The direct vapor equilibration laser spectrometry (DVE-LS) method has been developed for obtaining matrix-bound water stable isotope data in soils, the critical zone and bedrock, deriving therefrom subsurface flow transport processes and, ultimately, characterising e.g. groundwater recharge vulnerability. Recently, DVE-LS increasingly adopted due to its possible high sample throughput, relative simplicity cost-efficiency. However, this come at cost of a non-unified standard...