~ for immediate release

 news release  June 28, 2007

DRI and collaborators to embark on four-year, $900,000 EPA mercury study
Obrist leads study of how global change may affect atmospheric mercury pollution

Dr. Daniel Obrist

Reno, Nev.—As the world has taken more notice of the effects of global climate change in recent years, much attention has been paid to plant and soil carbon and their effect on carbon dioxide —an important greenhouse gas —in the atmosphere.  But what of the tremendous amounts of mercury that co-exist with carbon in soils and plants?  Mercury tightly associates with carbon and has been a substance of concern by the U.S. Environmental Protection Agency— 45 states have posted fish advisories for mercury in recent years, for instance— but no one has linked how changes in plant biomass and soil carbon pools will affect the mercury sequestered, or stored, in these pools until now.  DRI's Dr. Daniel Obrist, and his colleagues Dr. Yiqi Luo of the University of Oklahoma-Norman, Dr. Dale Johnson of the University of Nevada, Reno (UNR), and Dr. Steve Lindberg, Emeritus Fellow of Oak Ridge National Laboratories and adjunct professor at UNR, have received $900,000 from the U.S. EPA as part of its Science to Achieve Results (STAR) program, to conduct a four-year study to assess how global change, such as climate and land use changes, during the next 100 years is likely to affect mercury cycling processes.

Examples of carbon pools are forest biomass, wood products and organic matter in soils.  It is known that losses of terrestrial carbon in the last 150 years, by deforestation for example, have been contributing about 25 percent to the increase in atmospheric carbon dioxide, with the other 75% from combustion of fossil fuels.  Terrestrial carbon pools, however, also play an important role in deposition, uptake, storage and emission of atmospheric mercury.  Because biomass and soil carbon pools are highly sensitive to climate and land use changes, these may have serious consequences for the fate of an estimated 300,000 to 600,000 tons of mercury within carbon pools.

"We are concerned about the fate of mercury sequestered in carbon pools when these pools may likely shrink in the future as a consequence of global change," Obrist said.  "Does mercury emit back to the atmosphere and add to atmospheric pollution?  Or could protecting and building up carbon pools mitigate future mercury pollution because they securely store mercury in the soil?"

STUDY APPROACH AND EXPECTED RESULTS: Obrist and his team will focus their study on 9 sites across the United States, beginning in the West and including forested sites where Drs. Dale Johnson and Steve Lindberg previously measured carbon inventories.  They aim to collect the first systematic database on mercury pools and fluxes associated with terrestrial carbon pools.  This systematic quantification of mercury levels in major ecosystems will provide a comprehensive database on mercury pools, plant mercury uptake, sequestration and mercury turnover associated with terrestrial carbon pools in the U.S.  Their study will involve laboratory and field studies to clarify the fate of sequestered mercury in carbon pools when these changes occur, specifically to evaluate how much mercury may emit back to the atmosphere.  The study also includes a strong modeling component, lead by Dr. Luo, where mercury data are incorporated into state-of-the-art global carbon models which will enable predictions of how changes in carbon dynamics affect the atmospheric mercury burden during the next 100 years. 

ABOUT DRI: A nonprofit, statewide division of the Nevada System of Higher Education, or NSHE, DRI pursues a full-time program of basic and applied environmental research on a local, national, and international scale.  More than 500 full- and part-time scientists, technicians, and support staff conduct more than 300 research projects at DRI annually.  DRI generates $50 million in total revenue consisting predominately of competitively won research contracts and grants. The State of Nevada provides critical funding in support of DRI's administration, operations, and maintenance through the NSHE education budget.  While DRI’s portion of the NSHE budget is approximately one percent, the institute leverages these funds to enhance its competitiveness.