Chemical gradients across the summer density interface in Lake Michigan
Seasonal temperature-dependent density structure controls movement of nutrients between deep and surface water, which is critical for production of biomass in Lake Michigan. Nutrients are accompanied by non-nutrient dissolved chemicals that can act as indicators of physical mixing processes (e.g., chloride). In turn, the temperature structure may be controlled by the abundance of light-absorbing algae and hence influence seasonal heat budgets and regional climate. In this study, students will precisely measure nutrient and other chemical profiles from summer cruises into central Lake Michigan to coordinate with physical measurements of temperature structure and thermal mixing. Using shipboard methods, water samples will be collected and stabilized. In the lab, students will use wet chemical analyses and chromatography to quantify crucial nutrients and mineral-derived chemicals.