Planktonic particle dynamics

Our research focuses on plankton ecology and the biogeochemistry of biogenic particles. We integrate these topics into their dynamic oceanographic context, with emphasis on assessing the scales of their impact from micro-scale nutrient fluxes within particles to mesoscale patterns of plankton and particle distributions in the open ocean. We are particularly interested in understanding how microbial drivers influence transformations of nitrogen and oxygen in particles and how these particle-specific chemical transformations may alter inventories of carbon and nutrients, and their recycling rates. Also, we work closely with geochemists and physical oceanographers to further develop insights on how physical mechanisms affect material connectivity in the ocean.

We examine planktonic and particle processes by utilizing several approaches including measurements of primary productivity, bacterial production, nitrogen assimilation rates, and nitrogen fixation rates. Most importantly, we examine these rate processes on particles, both individually and in bulk, thereby targeting particle-specific contributions. In the field, we measure particle size distributions with the Underwater Vision Profiler (UVP), and combined with measurements from sediment trap collections, assess vertical fluxes. Together, these measurements allow us to constrain the spatial and temporal structure of particles, and the rates at which different components of the carbon and nitrogen cycles are exploited.