A5022509884- Aquatic Ecosystems and Phytoplankton Dynamics
- Soil and Water Nutrient Dynamics
- Marine and coastal ecosystems
- Fish Ecology and Management Studies
- Hydrology and Watershed Management Studies
- Freshwater macroinvertebrate diversity and ecology
- Water Quality and Pollution Assessment
- Isotope Analysis in Ecology
- Biocrusts and Microbial Ecology
- Diffusion and Search Dynamics
- Aquatic Ecosystems and Biodiversity
- Surface Roughness and Optical Measurements
- Ecology and Vegetation Dynamics Studies
- Sustainability and Ecological Systems Analysis
- Real-time simulation and control systems
- Algal biology and biofuel production
- Earth Systems and Cosmic Evolution
- Coastal wetland ecosystem dynamics
- Water Resources and Management
- Environmental Toxicology and Ecotoxicology
- Control Systems and Identification
- Marine and coastal plant biology
- Marine Biology and Ecology Research
Helmholtz Centre for Environmental Research
2013-2020
Rosenheim Technical University of Applied Sciences
2019-2020
Umeå University
2013-2014
Ludwig-Maximilians-Universität München
2006-2010
We independently manipulated mixing intensity (strong artificial vs. background turbulence) and water‐column depth (2 m, 4 8 12 m) in order to explore their separate combined effects a field enclosure experiment. To accentuate the vertical light gradient, enclosures had black walls, resulting euphotic of only 3.7 m. All were placed well‐mixed water bath equalize temperature across treatments. Phytoplankton responded an initial phosphorus pulse with transient increase biomass, which was...
In shallow aquatic systems, benthic and pelagic primary producers typically compete for light nutrients along opposing vertical supply axes: algae shade the habitat; conversely, intercept nutrient flux from sediment to habitat. We present a general framework analyzing such spatially asymmetric resource competition across habitat boundaries using mechanistic, dynamical model. visualize mechanisms determining outcome of these cross‐habitat interactions zero‐net‐growth isoclines, points,...
Abstract. Excessive amounts of nutrients and dissolved organic matter in freshwater bodies affect aquatic ecosystems. In this study, the spatial temporal variability nitrate (NO3−), carbon (DOC) soluble reactive phosphorus (SRP) was analyzed Selke (Germany) river continuum from three headwaters draining 1–3 km2 catchments to two downstream reaches representing spatially integrated signals 184–456 catchments. Three headwater were selected as archetypes main landscape units (land use ×...
Abstract Understanding and explaining the structure of communities in response to environmental gradients is a central goal ecology. Trait‐based approaches are promising but yet rarely applied understand community dynamics changing conditions. Here, we investigate seasonal succession patterns functional traits phytoplankton how nutrient reductions (oligotrophication) alter these patterns. We used data from 40 years observation Rappbode Reservoir (Germany), which underwent strong shift...
Meeting ecological and water quality standards in lotic ecosystems is often failed due to multiple stressors. However, disentangling stressor effects identifying relevant stressor-effect-relationships complex environmental settings remain major challenges. By combining state-of-the-art methods from ecotoxicology aquatic ecosystem analysis, we aimed here disentangle the of chemical non-chemical stressors along a longitudinal land use gradient third-order river Germany. We distinguished...
Abstract To counteract the severe consequences of eutrophication on water quality and ecosystem health, nutrient inputs have been reduced in many lakes reservoirs during last decades. Contrary to expectations, some phytoplankton biomass did not decrease response oligotrophication (nutrient reduction). The underlying mechanisms preventing a these are subject ongoing discussion. We used hitherto unpublished long‐term data set ranging from 1961 until 2016 German drinking reservoir (Rappbode...
We employed the well-established Horton-Strahler, hierarchical, stream-order (ω) scheme to investigate scaling of nutrient loads (P and N) from ~845 wastewater treatment plants (WWTPs) distributed along river network in urbanized Weser River, largest national basin Germany (~46K km2; ~8.4 million population). estimated hydrologic water quality impacts at reach- basin-scales, two steady discharge conditions (median flow, QR50; low-flow, QR90). Of five WWTPs class-sizes (1 ≤ k 5), ~68% small...
Most phytoplankters face opposing vertical gradients in light versus nutrient supplies but have limited capacities for habitat choice. We therefore explored a dynamical model of negatively buoyant algae inhabiting one-dimensional water column to ask how depth and turbulence constrain total (areal) phytoplankton biomass. show that the population persistence boundaries depth-turbulence space are set by sinking losses limitation nutrients most limiting biomass columns neither too shallow or...
Phytoplankton–grazer dynamics are often characterized by long transients relative to the length of growing season. Using a phytoplankton–grazer model parameterized for Daphnia pulex with either flexible or fixed algal carbon : nutrient stoichiometry, we explored how and light supply (the latter varying depth mixed water column) affect transient system starting from low densities. The goes through an initial oscillation across nearly entire light–nutrient space. With (but not fixed) duration...
In riverine ecosystems primary production is principally possible in two habitats: the benthic layer by sessile algae and surface water planktonic being transported downstream. The relevance of these habitats generally changes along rivers' continuum. However, analyses interaction their controlling factors are, so far, very rare. We use a simplified advection-diffusion model system combined with ecological process kinetics to analyse nutrients idealised streams rivers at regional large...
Ecological theory predicts that the relative importance of benthic to planktonic primary production usually changes along rivers' continuum from a predomination algae in lower stream orders at higher orders. Underlying mechanisms driving interaction between these habitats, its controlling factors and consequences for riverine ecosystems are, however, only partly understood. We present mechanistic analysis governing ecological processes using simplified, numerical model examine how abiotic...
Summary Humic lakes with a high external supply of DOC and low input nutrients can often support biomass metazoan zooplankton. In such lakes, autotrophic algae compete bacteria for inorganic nutrients, but mixotrophic growth. Consequently, planktonic communities are dominated by flagellates, while obligate phytoplankton occurs in numbers extended periods. To test the importance flagellates as food resources grazers and, turn, feedback effects on basal food‐web interactions, we conducted...
Abstract. Excessive amounts of nutrients and dissolved organic matter in freshwater bodies affect aquatic ecosystems. In this study, the spatial temporal variability nitrate (NO3), carbon (DOC) soluble reactive phosphorus (SRP) was analyzed Selke (Germany) river continuum from headwaters draining 1–3 km2 catchments to downstream reaches representing spatially integrated signals 184–456 catchments. Three headwater were selected as archetypes main landscape units (land use x lithology) present...