MacArthur Fellows Program

Daniel Sigman

Biogeochemist | Class of 2009

Unraveling the interrelated physical, chemical, geological, and biological forces that have shaped the oceans’ fertility and the Earth’s climate over the past two million years.

Title
Biogeochemist
Affiliation
Princeton University
Location
Princeton, New Jersey
Age
40 at time of award
Area of Focus
Earth Sciences

Daniel Sigman is a biogeochemist who explores the interaction of biomass and climate in shaping the Earth’s geologic history. He is a leader in the use of nitrogen isotopic studies for understanding modern ocean biogeochemistry and for the reconstruction of ocean chemistry history. It has been clear for some years that the varying abundance of stable isotopes of nitrogen and oxygen in oceanic nitrate and in sedimentary deposits reflects changes in the Earth’s nutrients and carbon cycle during previous periods of climatic history. Sigman’s research focuses in large part on determining the role of carbon dioxide sequestration (through death of photosynthetic creatures that drop to the bottom of the ocean). In an important technical advance, he developed an enzymatic method to measure the nitrogen in tiny, unicellular creatures known as diatoms, which are trapped within ocean sediments. By comparing the bioavailable inorganic nitrogen (e.g., in nitrates or ammonium) with organic nitrogen extracted from once living cells, Sigman has been able to construct models of paleoceanographic nitrogen cycling. Using sediments collected from the deep sea floor — both at its surface and deeper core samples — at various water depths and latitudes throughout the world’s oceans, Sigman is carefully reconstructing the quantitative net contribution of ocean biology to the carbon cycle over geological time scales. He and his colleagues are also developing clearer notions of the effects of biomass in present-day carbon cycling. To this end, he has improved the resolution of a method for measuring nitrate flux through sophisticated analysis of the stable oxygen and nitrogen isotopes. Such advances promise to give us an ever-sharper picture of the physical, chemical, geological, and biological forces that have regulated the oceans’ fertility and the Earth’s climate over the past two million years.

Daniel Sigman received a B.S. (1991) from Stanford University and a Ph.D. (1997) from the Massachusetts Institute of Technology/Woods Hole Oceanographic Institution’s Joint Program in Oceanography. In 2009, he was named the Dusenbury Professor of Geological and Geophysical Sciences in the Department of Geosciences at Princeton University, where he was previously a postdoctoral fellow (1998-1999), an assistant professor (2000-2006), and a professor (2006-2009).

Photos for Download

High-resolution photos of MacArthur Fellows are available for download (right click and save), including use by media, in accordance with this copyright policy.


Please credit: John D. & Catherine T. MacArthur Foundation

More Fellows

View All 2009 Fellows

Stay Informed
Sign up for periodic news updates and event invitations.
Check out our social media content in one place, or connect with us on Twitter, Facebook, YouTube, and LinkedIn.