- Topic:Water and matter cycles
Transformation of organic micropollutants along hyporheic flow in bedforms of river-simulating flumes
In recirculating flumes, the authors investigated the degradation of micropollutants from treated wastewater along specific subsurface flow paths in triangular bedforms. Shallow subsurface flow fields and small-scale heterogeneity of the microbial community are major controlling factors for the transformation of micropollutants in river sediments.
Co-evolution of xylem water and soil water stable isotopic composition in a northern mixed forest biome
The authors investigated the co-evolution of plant xylem water and soil water stable isotopic compositions in a northern mixed forest, Canada. They showed that differences in timing and intensity of water use between deciduous and coniferous trees may account for inter-specific variations in xylem water isotopic composition providing insight into how they may respond to hydroclimatic change.
How daily groundwater table drawdown affects the diel rhythm of hyporheic exchange
With a physically based model that couples flow and heat transport in hyporheic zones, the study provides insights into hyporheic responses to daily groundwater withdrawal and river temperature fluctuations. These interactions have impacts on temporal variability of hyporheic exchange, mean residence times and denitrification potential. Improved pumping schemes can restore ecosystem functions.
Effects of the largest lake of the Tibetan Plateau on the regional climate
The authors used a coupled lake-atmosphere model to investigate the effect of the largest lake of China, the Qinghai, on the weather and climate conditions of the Tibetan Plateau. They found that the lake alters wind conditions and increases precipitation over the arid areas of the earth’s “third pole” Tibet but the effect is irregularly distributed spatially and temporally over the seasons.
Simultaneous attenuation of trace organics and change in organic matter composition in the hyporheic zone of urban streams
Wastewater still contains high amounts of trace organic compounds and organic matter after the wastewater treatment plant. These compounds are usually discharged to rivers with the treated water. The study shows that in the hyporheic zone of the river, i.e. the river sediment, degradation of trace organic compounds takes place simultaneously with a change in the composition of organic matter.
Stable isotopes of water reveal differences in plant – soil water relationships across northern environments
The authors compared stable isotopes of water in the plant stem (xylem) and in the soil over a complete growing season at five northern experimental sites to understand where plants get their water from and what the temporal dynamics are of such root water uptake. This paper was a main finding of an ERC Grant.
Density effects at a concordant bed natural river confluence
Confluences are locations of complex hydrodynamic conditions within river systems. The effects on hydrodynamics and mixing of temperature‐induced density differences between incoming flows were investigated at a small‐size concordant bed confluence.
Advective lateral transport of streamwise momentum governs mixing at small river confluences
Mixing within confluences is highly variable.This study relates patterns and amounts of mixing to three‐dimensional flow structure at three small confluences. The study indicates that generalization of mixing at confluences remains challenging but that advective lateral fluxes of streamwise momentum related to secondary currents or primary flow greatly enhance mixing at confluences.
Geochemical signatures of lignite mining products in sediments downstream a fluvial-lacustrine system
The authors have investigated whether and to what extent mining products from the Lusatian mining are deposited in the sediments of the River Spree: their signature in the river bed reaches 90 kilometres.
Geochemical focusing and sequestration of manganese during eutrophication of Lake Stechlin (NE Germany)
Eutrophication of Lake Stechlin leads to changes in the sediment by an intensification of internal matter cycles. The reductive dissolution of Mn in shallow areas and the precipitation result in the fixation of Mn as rhodochrosite in the sediment below 56 m depth. Geochemical Mn focusing indicates oxygen-free conditions in deep water and can be used to reconstruct former environmental conditions.