Department of Earth and Planetary Sciences
327 Olin Hall
Johns Hopkins University
3400 N. Charles Street
Baltimore, MD 21218
gnanades at jhu.edu
About me Teaching Research Publications Science Olympiad
Our planet is shaped by the interaction of living things with their physical environment. My interests center on understanding these interactions. Since I trained as an oceanographer, my primary expertise is in how the ocean circulates and influences marine life, climate, and atmospheric chemistry. I got my Ph.D. from the MIT/Woods Hole Joint Program in Physical Oceanography and spent over fifteen years in Princeton at Princeton University and NOAA’s Geophysical Fluid Dynamics Laboratory working to develop computer models of how the planet works. In January 2011 I joined the Department of Earth and Planetary Sciences at Johns Hopkins University.
Introduction to Global Environmental Change and Sustainability: 270.103
Oceans and Atmospheres: 270.108 (changing to 200 level, Spring 2014)
Introduction to Oceanography: 270.325
Ocean biogeochemical cycles: 270.323
Climate variability: Physics and proxies
Advanced Atmospheric Dynamics
How does ocean circulation affect climate, ecosystems and atmospheric composition?
I’ve worked on how the large scale overturning of the ocean is driven by winds and mixing, and how changes in this overturning affect how much carbon dioxide is held in the ocean versus the atmosphere. While at GFDL, I helped lead the development of the ocean component of the global climate model. I’m currently interested in the role of deep mixing in setting the overturning. With Chris Little and Dan Goldberg at GFDL I helped develop the first fully coupled ocean-ice shelf-ice stream models. Key problems I'm currently interested in are
What sets the intensity of hypoxia in the ocean? Almost 10% of the ocean is hypoxic (with concentrations of oxygen less than 2 ml/l) but only 1% progresses all the way to suboxia (0.2 ml/l). Models have trouble representing this. Why?
How do we expect Southern Ocean circulation and ecosystems to respond to climate change? In particular, how will changes in stratification differ from changes in winds?
How do ocean ecosystems affect ocean circulation and climate?
The presence of living organisms in the ocean allows it to hold more carbon than it otherwise would, drawing carbon out of the atmosphere and cooling the planet. But not all biology is equal in this respect. With Irina Marinov, I’ve worked to understand the differing role of biology in the Southern Ocean vs. the low latitudes. With John Dunne and Eric Galbraith, I’ve worked to look at how different size classes of plankton behave differently. With Jorge Sarmiento and Irina Marinov, I’ve looked at the impacts of iron fertilization as a means of offsetting human emissions. Recently, in collaboration with Whit Anderson, Colm Sweeney, Kerry Emanuel and Gabe Vecchi, I’ve also looked at how changes in ocean color can affect the circulation of the ocean, the strength of El Nino, and even the distribution of hurricanes.
Click here for a list of publications with links.
Click at right for my profile at Researcher ID with citations.
I’ve been very involved in Science Olympiad, the nation’s largest team science competition. Click here for more information.