- Programme area:Dimensions of Complexity of Aquatic Systems
Improved understanding of vegetation dynamics and wetland ecohydrology via monthly UAV-based classification
The authors conducted monthly UAV flights for 2 years in a riparian wetland in Germany. Such multi-flight-based classification outperformed single-flight-based ones, providing a picture of vegetation community evolution. Apart from contributing to an evidence base for wetland management, such multi-flight UAV vegetation mapping could provide fundamental insights into their landscape ecohydrology.
Attenuation of trace organic compounds along hyporheic flow paths in a lowland sandbed stream
As the hyporheic zone of rivers can be very heterogeneous already at cm-scales, the authors developed an experimental setup to preset short and shallow hyporheic flow paths in the field and to sample pore water. In this experimental setup, the authors were able to study the attenuation of 18 different trace organic compounds wherein the majority were attenuated within the short oxic sections.
Synoptic water isotope surveys to understand the hydrology of large intensively managed catchments
Using seasonal, large scale synoptic sampling of stable water isotopes and tritium along the Spree allowed to assess water cycling, storage and losses. The Spree is heavily regulated and drought-sensitive due to high evapotranspiration losses. Such insights are important to adjust water management strategies.
Quantifying changes and trends of NO3 concentrations and concentration-discharge relationships in a complex, heavily managed, drought-sensitive river system
Long-term stream nitrate nitrogen concentrations and concentration-discharge were investigated along the Spree revealing significant heterogeneity in both variables. The upstream parts and winter seasons showed the most serious pollution. Concentrations and relationships are also likely to respond strongly to future droughts, leading to challenges for future land and water management.
Particle-associated organic contaminant and cytotoxicity transport in a river during storm events
This study investigated the mobilisation and transport of particle-associated organic contaminants and their cytotoxicity in a river during storm events. Cytotoxicity determined in cell-based bioassays correlated linearly with total suspended solids concentration in a river, demonstrating that particle-associated contaminant mixtures can strongly affect river water quality during rain events.
Moving Bedforms Control CO2 Production and Distribution in Sandy River Sediments
The study investigated the impact of streamwater flow velocities and the resulting bedform migration on the CO2 production in streambeds. State-of-the-art 2-dimensional imaging techniques reveal the CO2 distribution in the streambed, an increasing CO2 production in the upper sediment and a decreasing hydrological exchange with deeper sediment layers, with increasing flow velocities.
Oxygen depletion and sediment respiration in ice-covered arctic lakes
The study investigated the oxygen budget of 4 arctic lakes using high-frequency data. Incubation experiments measured sediment metabolism. Volume-averaged oxygen depletion in situ was independent of water temperature and duration of ice-cover. Modeling under ice-oxygen dynamics requires consideration of optical properties, biological and transport processes modifying oxygen.
Tracer-aided ecohydrological modelling across climate, landcover, and topographical gradients in the tropics
This study applied a tracer-aided ecohydrology model in a data-scarce tropical catchment, using the output of climate models to estimate spatio-temporal dynamics of how water is partitioned, stored and transported at larger spatial scales. This provided a basis for projecting future climate and vegetation changes and the impact on regional hydrological and biogeochemical cycles.
Integrated ecohydrological hydrometric and stable water isotope data of a drought-sensitive mixed land use lowland catchment
The authors provide open access to a unique ecohydrological and water stable isotope data set from different landscape compartments monitored during the extreme drought of 2018 at multiple spatial scales from lowland headwaters, which are often understudied despite them providing important ecosystem services.This data set allows to differentiate “blue” and “green” water fluxes.
Multispecies collective waving behaviour in fish
Groups composed of more than one species offer a unique opportunity to look into the evolution of both mechanistic and functional aspects of collective behavior. The study presents data on mixed-species fish shoals that perform collective dives. The dampening effect of less responsive gambusia on molly diving behavior can have strong evolutionary consequences on the overall collective behavior.