Turbulence and Small-Scale Processes

Turbulence is critical for the distribution of heat, salt, and dissolved substances (including oxygen, nutrients, and pollutants) in marine environments and in lakes. It determines the rate at which these quantities are mixed, it controls their exchange with the atmosphere and the sediments, and it sets the environment for the interactions between microorganisms and chemical constituents at the smallest scales. Dynamically, turbulence directly or indirectly affects ocean currents, and forms a crucial link of the marine energy budget. Understanding the role of turbulence is therefore essential for understanding how marine systems work.

We investigate turbulence and its effect in the ocean, in shelf and inland seas, in lakes, and, in particular, in the Baltic Sea, which we consider as an ideal natural laboratory for the examination of small-scale processes of more general relevance. Using field experiments and idealized numerical process studies, our main goal is to identify the relevant small-scale processes (e.g., internal waves, shear-instabilities, etc.) that trigger turbulence, understand the mechanisms involved, and quantify their overall relevance.

We collaborate with colleagues from other disciplines to investigate the impact of turbulent motions on small-scale microbiological and biogeochemical processes. The understanding of small-scale processes gained from these studies forms the base for the work of other groups focusing on system analysis and the development of accurate numerical models.