Energy Research at the University of Washington

Julian P. Sachs

Energy Research Area: Constructing tropical climate variations for the pre-industrial period from molecular fossils in ocean and lake sediments. The impact of ocean acidification on coral reefs.

Professor
College of the Environment
School of Oceanography

We study the natural variations that occurred in Earth's climate in the pre-industrial age, with a focus on the tropics, the heat engine of the climate system. This provides a baseline against which more recent changes caused by human activities can be assessed. Because satellites, thermometers, rain gauges and and the like did not exist or were not widely used prior to the start of the Industrial Age about 150 years ago we must develop indirect means to reconstruct the climate of that time. We specialize in developing a relatively new class of climate proxies based on the hydrogen and carbon isotope ratios of molecular fossils left behind by microalgae and mangroves. We put much effort into testing and calibrating these new measures of rainfall and salinity by growing phytoplankton cultures and mangrove trees under controlled conditions in our lab so that we can estimate these parameters in the past with precision. A more recent focus of our research is to understand the effect of ocean acidification on coral reefs with continuous measurements of pH, oxygen, temperature and salinity on Tetiaroa, a pristine atoll in French Polynesia.

Collecting sediment cores on Washington Island, Republic of Kiribati, July 2005.  Local helpers abound!  (Prof. Julian Sachs carrying a core)
Collecting sediment cores on Washington Island, Republic of Kiribati, July 2005. Local helpers abound! (Prof. Julian Sachs carrying a core)

Research Images

Coring the sediments of a mangrove swamp for a rainfall reconstruction of the last 2,000 years on Kosrae Island, Federated States of Micronesia.  August 2009  (From L to R: UW graduate student Dan Nelson and Prof. Julian Sachs). Collecting sediment samples from the Chesapeake Bay for historical rainfall reconstructions, May 2006.  (From L to R:  UW postdoc Dr. Valerie Schwab, Prof. Julian Sachs, and UW postdoc Dr. Rienk)

Campus and Other Collaborators/Partners

Record last updated on March 9th 2015 PDT.