His research over four decades addresses comparative ecology and biogeochemistry of estuaries to understand how they respond as ecosystems to climatic-hydrologic variability and human disturbance. His team investigation of San Francisco Bay included studies of primary production, nutrient cycling, algal and zooplankton community dynamics, ecosystem metabolism and food web dynamics, disturbance by introduced species, ecosystem restoration, and past and projected future responses to a changing climate. His career achievements have been recognized with selection as Fellows of the American Geophysical Union (AGU) and Association for the Sciences of Limnology and Oceanography (ASLO), and as recipient of the Woods Hole Oceanographic Institution B.H. Ketchum Award, Delta Science Program Brown-Nichols Achievement Award, ASLO Ruth Patrick Award, Coastal and Estuarine Research Federation Odum Lifetime Achievement Award, and Department of Interior's Distinguished Service Award. He is currently an Adjunct Senior Fellow at the Public Policy Institute of California, a member of the Delta Stewardship Council's Independent Science Board, and editor-in-chief of Limnology and Oceanography Letters.