Project: Unifying Data and Models through Biogeography
I seek a fundamental understanding of the interdependence between ecological diversity and biogeochemical fluxes in the ocean. In the upper euphotic zone, carbon, nitrogen and phosphorus move rapidly between particulate organic matter, dissolved organic matter and their inorganic forms. Alongside this fast cycle is a slow one. The export of sinking organic particles is balanced by the upwelling of inorganic nutrients from the deep sea. How are these two cycles coupled? Does ecology drive export or does upwelling set the ecology? Any attempt to answer these questions is muddled by the extreme diversity inside each nutrient reservoir. Dissolved organic material contains tens of thousands of unique compounds, and living particulates include tens of thousands of species that interact differently with their chemical environment and one another. I will tackle these general problems in three specific ways. First, I will leverage the database infrastructure we are building to compare satellite, model and in situ data statistically. Second, I will use the DARWIN model infrastructure to explore the relationship between traits and carbon flux to the deep ocean. Third, I will work toward understanding the relationship between fluctuations around an ecosystem’s steady state and the biogeochemical rates that can be extracted from them.
In my work, I combine a broad background in oceanography with a foundation in physics to answer systems-level questions about marine nutrient cycles. I start with simple concepts and equations, and collaborate heavily with both modelers and experimentalists. This approach has led me to advances in understanding the cycling of dissolved organic carbon in the deep ocean, the persistence of the summertime export pulse of carbon in the North Pacific Subtropical Gyre, and the invention of novel methods for the measurement of nitrogen fixation from diel measurements of particulate elemental ratios. I was heavily involved in work connecting the genetic relationship between organisms to their chemical fingerprint, and have worked on utilizing big-data approaches to understand the interactions between the physical and ecological structuring of the surface ocean. I have recently advised a project connecting estimates of primary production and export flux through the moments of their probability distributions.