Dimensions of Complexity of Aquatic Systems
Revealing patterns and dynamics in freshwater systems and biota
Aquatic ecosystems are intrinsically complex because they have a network structure and nonlinear processes often take place at various spatial and temporal scales. Nonlinear reactions can occur, for example, as a result of perturbations that trigger a so-called regime shift, such as prolonged drought. Important determinants of complex aquatic ecosystems are the landscape structure in which the water bodies are located and the connectivity, i.e. the interconnection of the water bodies at different levels: These include the flows of water, energy, information, nutrients and pollutants, and the dispersal of organisms. These processes determine the structure and dynamics of ecosystems and are changed over time by external factors such as land use and climate change.
In the programme area “Dimensions of complexity of aquatic systems”, IGB aims to gain a better understanding of the dynamics and functioning of aquatic systems and the living organisms within them. Its overall goal is to enhance our mechanistic understanding on how freshwater ecosystems function and to study their spatial and temporal scaling. An important focus is on the interfaces and interactions between terrestrial and aquatic habitats, between sediment and the water column, between water and air, and between and within organisms.
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April 2025
WIREs Water. - 12(2025)2, Art. e70018
The Unexploited Treasures of Hydrological Observations Beyond Streamflow for Catchment Modeling
Other hydrological data than streamflow have the potential to improve process consistency in hydrological modeling and consequently for predictions under change. The authors review how storage and flux variables are used for model evaluation and calibration; improving process representation.
April 2025
Biogeochemistry. - 168(2025), Art. 40
Biogenic polyphosphate as relevant regulator of seasonal phosphate storage in surface sediments of stratified eutrophic lakes
Using nuclear magnetic resonance spectroscopy, the authors studied the polyphosphate seasonality in the topmost sediment layer of three stratified lakes with prolonged anoxic periods during summer stratification. Polyphosphate acted as a temporary phosphorus storage, formed at the beginning of the summer stratification under oxic conditions and released time delayed under anoxic conditions.
March 2025
WIREs Water. - 12(2025)2, Art. e70015
Recent Developments and Emerging Challenges in Tracer-Aided Modeling
The authors reviewed recent advances and remaining challenges of tracer-aided modelling which offers insights into internal storages, water sources, flow pathways, mixing processes, and water ages, which cannot be derived from hydrometric data alone. Tracer data have the capability to falsify hydrological models and test hypotheses, and thus increase understanding of hydrological processes.
March 2025
Water Resources Research. - 61(2025)3, Art. e2024WR038779
DREAM(LoAX): Simultaneous Calibration and Diagnosis for Tracer-Aided Ecohydrological Models Under the Equifinality Thesis
The authors developed a new algorithm DREAM(LoAX) as an effective conditioning tool to consider epistemic uncertainty in process-based models. It provides real-time diagnostic information of model failures for identification of uncertainty in data or flaws in model structure, and hence is a learning tool for limitations in current monitoring networks and development of future models.
February 2025
Hydrological Processes. - 39(2025)2, Art. e70084
Electrical Conductivity as a Tracer for Seasonal Reverse Flow and Transport of Trace Organic Contaminants in River Spree
The authors studied if the electrical conductivity can serve as a hydrological tracer to capture the intensity and duration of seasonal reverse flow phases in a specific section of River Spree. Moreover, they studied the effect of upstream transport on chemical water quality, i.e. on trace organic contaminant during these reverse flow phases.
