The relation between the type of antenna pigments of dominant cyanobacteria and the ambient stratification condition in reservoirs.

We found from field observation data in two reservoirs that the hydraulic state affect the type of antenna pigments of dominant cyanobacteria. To clarify the processes of this phenomenon, we analyzed theoretically the effects of hydraulic states on phytoplankton community based on characteristics of absorption by antennna pigments and underwater light regime. By theoretical analysis we found that phycocyanin-rich cyanobacteria (PC-type) favor shallow stable stratification based on the relationship between the absorption characteristics of antenna pigment and red light penetrative ooptical condition. Furthermore, this hypothesis can also explain the growth condition of bloom forming cyanobacteria. This stratification condition can be estimated as the critical buoyancy frequency(N²cr). This hypothesis is verified using field data.Article信州大学山地水環境教育研究センター研究報告 2: 97-103(2004)departmental bulletin pape

Climate Change Demands Adaptive Management of Urban Lakes: Model-Based Assessment of Management Scenarios for Lake Tegel (Berlin, Germany)

Lakes are known to be strongly affected by climate change as a result of their sensitivity to atmospheric forcing. The combined response of urban lakes to climatic changes and to urbanization of the catchment may be further altered by water quality management measures. We studied Lake Tegel in Berlin, Germany as a representative urban lake profoundly influenced by intense water management measures and a resulting complex hydrodynamic situation: Lake Tegel is fed by nutrient-rich river discharges and effluents from a phosphorus elimination plant (PEP). We estimated changes in water temperatures, the Wedderburn number, and the buoyancy frequency, as well as concentrations of dissolved oxygen and phosphate under climate change using a one-dimensional vertical hydrodynamic model coupled to a water quality model. Further, we investigated how four management scenarios with varying discharges of the PEP could affect the lake system. In all simulations, water temperatures increased and summer stratification extended. The modeling results demonstrated that the water management system buffers the high nutrient supply from the river inflow and can effectively mitigate negative effects of climate change on Lake Tegel, thus highlighting its importance for the lake ecosystem.DFG, 248198858, GRK 2032: Grenzzonen in urbanen Wassersysteme

Effects of the Ambient Stratification Condition in Eutrophicated Reservoirs on the Type of Antenna Pigments of Dominant Cyanobacteria

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv