As a biological oceanographer, his principal interest has been in the role marine microalgae play in modulating the cycling of carbon and nitrogen, with particular emphasis on the scales of temporal and spatial variability of biological productivity in polar oceans. This knowledge is essential to understanding how anthropogenic and atmospheric forcing controls the biogenic flux of carbon dioxide into the oceans, and ultimately, to the sediments. His research is highly interdisciplinary and incorporates three fundamental approaches, (1) satellite remote sensing, (2) ecophysiological modeling, and (3) laboratory and field studies. By combining these techniques, it is possible to address many complex aspects of ocean biogeochemistry at spatial and temporal scales that would not be possible using a single approach.