Bob is an Earth systems scientist, ecosystem biologist, and biogeochemist. He has worked extensively on environmental issues related to human-induced changes in the sulfur, nitrogen, phosphorus, and carbon cycles, the impacts of global climate change, and interaction of energy systems and the environment. He is the Founding Editor of the journal "Biogeochemistry" and was Editor-in-Chief for 21 years, from 1983 to 2004. Previously, he co-chaired the International SCOPE Nitrogen Project (1992-2002), chaired the National Academy of Sciences Committee on Causes and Management of Coastal Eutrophication (1998-2000), coordinated the nutrient responses chapter for the Millennium Ecosystem Assessment (2002-2005), chaired the International SCOPE Biofuels Project (2007-2010), and served as President of the Coastal & Estuarine Research Federation (2007-2009), In 2011, Time Magazine named Bob as one of 50 "People who Matter" for his research on the greenhouse gas footprint of shale gas.