Shelby Gunnells

Trace metals play a critical role in the global carbon cycle by serving as necessary micronutrients for photosynthesizing marine organisms (called phytoplankton). However, trace metals are often found in extremely low concentrations in the surface ocean and limit the growth of the phytoplankton throughout ~40% of the global surface ocean. As such, understanding the sources and sinks of these metals and the mechanisms and rates that govern their abundance is vitally important as we look to the future of our planet.

I will be investigating the fate of trace metals in two different areas: deep-sea mining ventures and hydrothermal vents. Proposed deep-sea mining of polymetallic nodules will likely produce two plumes of suspended metalliferous sediment in the water column – one right above the seafloor and one at the depth of mining discharge. Samples will be carefully collected and used in experiments to observe the concentrations and chemical transformations of trace metals at these depths to elucidate potential long-term effects to the environment. Hydrothermal vents are known to effuse hot, metal-rich fluids from the ocean floor, but there is uncertainty in what the ultimate flux of metals are to the greater ocean and the mechanism of this process. My research will pinpoint this transition of buoyant to non-buoyant plume using multiple sampling and observational techniques.

Advisor: Dr. Jessica Fitzsimmons