A5040114417- Hydrology and Watershed Management Studies
- Groundwater flow and contamination studies
- Soil and Water Nutrient Dynamics
- Groundwater and Isotope Geochemistry
- Hydrology and Sediment Transport Processes
- Microplastics and Plastic Pollution
- Recycling and Waste Management Techniques
- Fish Ecology and Management Studies
- Smart Materials for Construction
- Hydrological Forecasting Using AI
- Wastewater Treatment and Nitrogen Removal
- Water Quality Monitoring and Analysis
- Freshwater macroinvertebrate diversity and ecology
- Soil and Unsaturated Flow
- Water Quality Monitoring Technologies
- Integrated Circuits and Semiconductor Failure Analysis
- VLSI and Analog Circuit Testing
- Peatlands and Wetlands Ecology
- Urban Stormwater Management Solutions
- Industrial Vision Systems and Defect Detection
- Analytical Chemistry and Sensors
- Water Quality and Pollution Assessment
- Pharmaceutical and Antibiotic Environmental Impacts
- Marine and coastal ecosystems
- Landfill Environmental Impact Studies
Helmholtz Centre for Environmental Research
2016-2025
Bayerisches Landesamt für Umwelt
2023
Karlsruhe University of Education
2023
University of Tübingen
2023
Deutsches Institut für Normung
2023
Colorado State University
2019
Colorado School of Public Health
2019
Fraunhofer Institute for Applied Polymer Research
2019
Politecnico di Milano
2010
Deutsches Biomasseforschungszentrum
2008
A substantial fraction of marine plastic debris originates from land-based sources and rivers potentially act as a major transport pathway for all sizes debris. We analyzed global compilation data on in the water column across wide range river sizes. Plastic loads, both microplastic (particles <5 mm) macroplastic >5 are positively related to mismanaged waste (MMPW) generated catchments. This relationship is nonlinear where large with population-rich catchments delivering disproportionately...
More than 1000 rivers account for most plastic emissions, ranging from small urban drains to large rivers.
Abstract The movement of water, matter, organisms, and energy can be altered substantially at ecohydrological interfaces, the dynamic transition zones that often develop within ecotones or boundaries between adjacent ecosystems. Interdisciplinary research over last two decades has indicated interfaces are “hot spots” ecological, biogeochemical, hydrological processes may provide refuge for biota during extreme events. Ecohydrological have significant impact on global biogeochemical cycles,...
Abstract. Streambed temperatures can be easily, accurately and inexpensively measured at many locations. To characterize patterns of groundwater-stream water interaction with a high spatial resolution, we 140 vertical streambed temperature profiles along 220 m section small man-made stream. Groundwater sufficient depth remains nearly constant while stream vary seasonally diurnally. In summer, groundwater discharge zones are relatively colder than downwelling water. Assuming flow in the...
[1] Exchange of water and solutes across the stream-sediment interface is an important control for biogeochemical transformations in hyporheic zone (HZ). In this paper, we investigate interplay between turbulent stream flow HZ pool-riffle streams under various ambient groundwater conditions. Streambed pressures, derived from a computational fluid dynamics (CFD) model, are assigned at top fluxes bottom model domain represent losing gaining Simulations different Reynolds numbers (Re)...
Wastewater treatment plants (WWTP) are considered to be a point source of microplastic (particles <5 mm) for riverine environments. However, data on effluent concentrations in WWTPs is collected with broad range methods, which impede comparisons across sets. We provide an estimate the annual emissions particles by into ten major river basins Germany. analyze concentration patterns microplastics among different stream orders resulting from spatial organization along network. The local...
Rivers play a major role in the transport of plastic debris from inland sources such as urban areas into marine environment. The present study examined particle concentrations and loads (>500 μm) upstream downstream an subcatchment over 15 months investigated relationship between river water discharge (Q) concentration (C). increases by 0.8 g/1000 m3 or 79 n/1000m3 rural to subcatchment. In subcatchment, C does not increase with increasing Q (p = 0.57), whereas positive exists catchment...
Abstract At the interface between stream water, groundwater, and hyporheic zone (HZ), important biogeochemical processes that play a crucial role in fluvial ecology occur. Solutes infiltrate into HZ can react with each other possibly also upwelling solutes from groundwater. In this study, we systematically evaluate how variations of gaining losing conditions, discharge, pool‐riffle morphology affect aerobic respiration (AR) denitrification (DN) HZ. For purpose, computational fluid dynamics...
Abstract Hyporheic exchange transports solutes into the subsurface where they can undergo biogeochemical transformations, affecting fluvial water quality and ecology. A three‐dimensional numerical model of a natural in‐stream gravel bar (20 m × 6 m) is presented. Multiple steady state streamflow simulated with computational fluid dynamics code that sequentially coupled to reactive transport groundwater via hydraulic head distribution at streambed. Ambient flow considered by scenarios...
Abstract. The spatial distribution of groundwater fluxes through a streambed can be highly variable, most often resulting from heterogeneous aquifer and permeabilities along the flow pathways. Using heat transport model, we defined four scenarios permeability distributions to simulate assess impact subsurface heterogeneity on streambed: (a) homogeneous low-K within aquifer; (b) (c) well connected (d) poorly aquifer. simulation results were compared with base case scenario, in which had same...
Micro-organisms are known to degrade a wide range of toxic substances. How the environment shapes microbial communities in polluted ecosystems and thus influences degradation capabilities is not yet fully understood. In this study, we investigated highly complex environment: capillary fringe subjacent sediments hydrocarbon-contaminated aquifer. Sixty sediment sections were analysed using terminal restriction fragment length polymorphism (T-RFLP) fingerprinting, cloning sequencing bacterial...
Abstract Rivers in climatic zones characterized by dry and wet seasons often experience periodic transitions between losing gaining conditions across the river‐aquifer continuum. Infiltration shifts can stimulate hyporheic microbial biomass growth cycling of riverine carbon nitrogen leading to major exports biogenic CO 2 N rivers. In this study, we develop test a numerical model that simulates biological‐physical feedback zone. We used explore different initial terms dissolved organic...
Abstract Bioclogging in rivers can detrimentally impact aquifer recharge. This is particularly so dry regions, where losing are common, and disconnection between surface water groundwater (leading to the development of an unsaturated zone) occur. Reduction riverbed permeability due biomass growth a time‐variable parameter that often neglected, yet reduction from bioclogging introduce order magnitude changes seepage fluxes over short (i.e., monthly) timescales. To address combined effects on...
Abstract Bed form‐induced hyporheic exchange flux ( q H ) is increasingly viewed as a key process controlling water fluxes and biogeochemical processes in river networks. Despite the fact that streambeds are inherently heterogeneous, majority of bed form flume‐scale studies were done on homogeneous systems. We conducted salt dye tracer experiments to study effects losing gaining flow conditions using laboratory recirculating flume system packed with heterogeneous streambed, equipped drainage...
Abstract We introduce LPMLE3, a new 1‐D approach to quantify vertical water flow components at streambeds using temperature data collected in different depths. LPMLE3 solves the partial differential equation for coupled and heat transport frequency domain. Unlike other approaches it does not assume semi‐infinite halfspace with location of lower boundary condition approaching infinity. Instead, uses local upper conditions. As such, streambed can be divided into finite subdomains bound top...
Abstract Improved understanding of stream solute transport requires meaningful comparison processes across a wide range discharge conditions and spatial scales. At reach scales where tracer tests are commonly used to assess behavior, such is still confounded due the challenge separating dispersive transient storage from influence advective timescale that varies with length. To better resolve interpretation these field‐based observations, we conducted recurrent conservative along 1 km study...
Plastics in rivers and lakes have direct local impact, may also reach the world's oceans. Monitoring river plastic pollution is therefore key to quantify, understand reduce plastics all aquatic ecosystems. The lack of harmonization between ongoing monitoring efforts compromises comparison combination available data. United Nations Environment Programme (UNEP) launched guidelines on freshwater monitoring, provide a starting point for practitioners scientists towards harmonized data...
Abstract The use of temperature‐time series measured in streambed sediments as input to coupled water flow and heat transport models has become standard when quantifying vertical groundwater‐surface exchange fluxes. We develop a novel methodology, called LPML, estimate the parameters for 1‐D by combining local polynomial (LP) signal processing technique with maximum likelihood (ML) estimator. LP method is used frequency response functions (FRFs) their uncertainties between top several...