Chemical Fluxes at Interfaces
(Q. Liao and H. Bootsma)
In aquatic ecosystems, critical carbon and nutrient fluxes occur at sediment-water and air-0water interfaces. These fluxes can be strongly controlled by physical mixing processes at these interfaces. However, measuring these physical processes in situ is difficult, and often relies on indirect methods. We are using an in situ Particle Image Velocimetry (PIV) system to quantify small- to meso-scale hydrodynamic processes at the sediment-water and air-water interfaces in Lake Michigan. These measurement are being combined with measurements of plankton profiles and chemical gradients to address fundamental biological and biogeochemical questions, such as: 1) What is the in situ plankton consumption rate by dreissenid mussels? 2) What is the fate of nutrients excreted by dreissenids? 3) How do wind and waves influence surface turbulence, and how does this in turn influence lake-atmosphere CO2 flux?