Sebastian Diehl

My research and teaching use mathematical modeling as a tool for describing and understanding the dynamics of aquatic ecosystems. My administrative responsibilities include being final examiner for the PhD education at my department, chair of the advisory council of Umeå Marince Science Centre (UMSC), and member of the steering group of the Integrated Science Lab (IceLab).

I am interested in how environmental factors and the presence/absence of certain organisms drive and constrain consumer-resource interactions and the resulting ecosystem dynamics. The studied environmental factors include nutrient and light supply, turbulent mixing, and water temperature in lakes, as well as physical transport processes and disturbances in streams. Study organisms include planktonic and benthic algae, bacteria, protists, planktonic microinvertebrates, benthic macroinvertebrates, fish, and water birds.

Dynamic systems behave often in unexpected ways. Where possible, I therefore translate assumptions into mathematical models from which I derive expectations. Assumptions and predictions of these models are then tested and refined in an iterative process involving field and laboratory experiments and, to a lesser extent, comparative field studies.

Much of my research is performed in the project "Climate induced regime shifts in northern lake ecosystems" ("Changing Lakes") in which a large group of researchers studies how increased water temperature and increased terrestrial inputs of nutrients and organic carbon (humic matter) affect primary and fish production and exchange of greenhouse gases with the atmosphere. One goal of the project is the development of a mathematical ecosystem model that can predict future fish production and greenhouse gas exchange in different types of northern lakes.

I hold an undergraduate degree in biology from the University of Göttingen (Germany) and a PhD in animal ecology from Umeå University (1994). I did postdoctoral studies at the University of California at Santa Barabara (1994-1996) and was professor of aquatic ecology at Ludwig-Maximilians-Universität in Munich (1996-2009) before I moved back to Umeå.