His research aims to understand the interactions between climate and ecosystems. He combines numerical models of varying complexity with diverse types of biological and physical data to discover how climate produces spatial patterns and temporal variability in ecosystems, and thus influences their basic functioning. Most of his work has focused on biogeochemical cycles in the ocean, with a particular emphasis on the mechanisms that regulate the cycles of oxygen and nutrients over a range of time scales, from years to millennia. He has received an Investigator Award from the Gordon and Betty Moore Foundation, and is a Fellow of the Kavli Frontiers of Science.