Seminars of the Institute of Hydrobiology BC CAS
15.10. Predictive limnology: Using lake models for projecting climate change effects in reservoirs and identifying potential adaptation strategies.
Karsten Rinke (UFZ Magdeburg)
The thermal structure in reservoirs affects the development of aquatic ecosystems, and can be substantially influenced by climate change and management strategies. We use lake models to explore the response of the thermal structure in Germany's largest drinking water reservoir, Rappbode Reservoir, to future climate projections and different water withdrawal strategies. Based on our experience from different lake models we believe that 2D models are better suited for canyon-shaped reservoirs than classical 1D models.
We use projections for representative concentration pathways (RCP) 2.6, 6.0 and 8.5 from an ensemble of 4 different global climate models. Simulation results show substantial changes in stratification dynamics and will turn this dimictic reservoir into a state that we currently only know from comparable water bodies south of the European Alps. Our results also indicate that another withdrawal strategy can be an effective adaptation strategy under strong climate warming (RCP 8.5) to reduce surface warming and avoid hypolimnetic warming.
In a second step, we extended our physical model to include basic aspects of aquatic biogeochemistry and plankton ecology by simulating oxygen and phytoplankton dynamics in this reservoir. We were particularly interested in the dynamics of oxygen and Planktothrix rubescens in the metalimnion of the reservoir and designed also a detailed monitoring program before starting the modelling. While the model was not only able to reproduce the key dynamics of the relevant state variables it also allowed us to identify the major drivers of metalimnetic oxygen dynamics and to generate testable hypotheses for further research. We are currently using this model setting for identifying potential adaptation strategies against rising incidences of Planktothrix mass developments and oxygen minima in the metalimnion.
If not otherwise stated, seminars take place Thursdays at 13:00 h in the Lecture hall IHB institute, Na Sádkách 7 (the "big lecture hall" at the 1-st floor, 008). All seminars are given in English. Contact: Jiří Kaňa, e-mail: firstname.lastname@example.org