PSU Critical Zone Observatory to study soil formation, water flow

University Park, Pa. -- Shale Hills in central Pennsylvania is already a busy area in Penn State’s managed forest lands, but now a five-year $4.2 million National Science Foundation Grant will make it even busier as scientists study how soils form from bedrock and how soil formation affects water movement and groundwater flow to streams.

"Shale Hills was the site of an NSF study in the 1970s that lasted about 10 years," says Christopher J. Duffy, professor of civil engineering. "In the 1990s, NSF and NASA funded me to revisit the old data, digitize it and build a physical hydrology model of the watershed."

Currently, Henry Lin, associate professor of hydropedology/soil hydrology, has 100 soil moisture monitoring sites in the area. Susan L. Brantley, professor of geosciences and a co-principal investigator on the Shale Hills Critical Zone Observatory, has already begun geochemistry studies on the nature of shale weathering in this area under the Center for Environmental Kinetics Analysis, a joint NSF/ Department of Energy-funded center.

Now, with the NSF Critical Zone Observatory Grant, Shale Hills becomes one of three such observatories in the U.S. looking for a fundamental understanding of water movement in the region between the top of the forest canopy and the base of unweathered rock. The other research locations funded by NSF are the University of California, Merced in the Sierra Nevada Mountains and the University of Colorado, Boulder, in the Front Range of the Rocky Mountains. The three universities and their partners will collaborate in all phases of the project. These observatories are part of the NSF-sponsored Critical Zone Environmental Network.

"There is so much already known about the Shale Hills area in geochemistry, hydrology and soils that there is a great database available," says Duffy.

Besides the Shale Hills site, six satellite sites located along a climatic gradient in the mid-Atlantic region will be used to test the models developed at Shale Hills, and to provide regional data on weathering rates as a function of climate changes. Colgate University will operate the northernmost site in the southern tier of New York. Washington and Lee University in Virginia will have the site located south of Penn State, and the University of Tennessee and Baylor University will cooperatively study sites in eastern Tennessee. Alabama A & M University will manage a site in northern Alabama. The University of Puerto Rico-Mayaguez will operate the southernmost site in the north south transect in Puerto Rico. Juniata College will investigate a site in the same climate regime as Penn State, but with metal- and organics-rich soils.

"The experiments at the six satellite sites will be less extensive than at Shale Hills, but is integral to understanding shale weathering and hydrology in a broader context," says Duffy.

Overseas, the University of Sheffield has already received a grant from the U.K.'s Natural Environment Research Council for the Weathering Science Center to work with the Universities of Leeds and Bristol in partnership with Penn State to look at how natural and human activities affected weathering. WSC is part of the Weathering System Science Center, an international organization of 50 universities looking at weathering, which is part of NSF's CZEN. The Worldwide Universities Network facilitates the collaborations in the WSC and WSSC.

"We do not have a lot of tropical sites in the U.S. or Europe," says Brantley who is also head of Penn State's Earth and Environmental Systems Institute and director of the NSF Center for Environmental Kinetics Analysis. "Hopefully, places like China and Africa can get funding for similar projects around the world."