Research
Overview
Our research aims to develop a process-level and predictive understanding of the ocean’s “biological pump”, which sequesters carbon in deep ocean waters and regulates the atmospheric concentration of carbon dioxide (CO2). Two factors determine the amount of carbon stored in the ocean: (i) The pump “strength”, defined as the rate of organic carbon production by phytoplankton in sunlit surface waters, and its export to depth as sinking particles. This rate is limited by the availability of scarce macronutrients and even scarcer trace metal micronutrients. (ii) The pump “efficiency”, defined as the timescale of carbon sequestration in the ocean interior. This timescale is governed by the depth of organic particle remineralization to CO2, and pathways of ocean circulation that return it to surface waters.
Our research integrates ocean models and large datasets to understand the strength and efficiency of the biological pump and predict their sensitivity to global environmental change. Recently our research has also expanded to explore the cycling of methane – another important greenhouse gas – in the global ocean and freshwater environments.