Scientists Explore Connections Between Climate, Land Use and Dead Zones

Zong-Liang Yang,
Zong-Liang Yang

Researchers at The University of Texas at Austin and colleagues will use a three-year, $1.5 million grant from NASA to develop computer models to study how changes in climate and land use affect watersheds and coastal ecosystems, seeking to improve understanding of the Texas coast, including dead zones that form in the Gulf of Mexico.

“We’ll be able to try different ‘what if’ experiments and find out what happens when you change variables like irrigation, fertilizer use, urbanization and dams, ” said Zong-Liang Yang, a professor in the university’s Jackson School of Geosciences and the project’s principal investigator.

Yang believes the research will help policy makers, farmers and individuals gauge the impact of their actions on coastal ecosystems.

“The goal is sustainable development,” Yang said.

One of the greatest threats to coastal estuaries and bays is eutrophication, a process in which excessive nutrients such as nitrogen cause harmful algal blooms that remove oxygen from the water and kill fish and shellfish, creating a dead zone. Research suggests excessive use of fertilizers in agriculture is a major cause of dead zones. Less certain is how climate change and the shifting of water through dams, diversions and withdrawals affect the delivery of nutrients to the coast.

“Most people don’t think about how what they do in one place affects other places far away,” said Yang. “But a healthy coast is important for tourism, fisheries and the entire state’s economy.”

In the first phase of the project, scientists will integrate a series of models — dealing with regional and global climate, weather, land surface, river flow, chemistry and ecosystems — into a unified model framework to study the impacts of land use change and climate change.

“We think as the world warms, we’ll experience more intense rainstorms,” said Yang. “We’ll use our model to study how that might affect the formation of dead zones.”

Although the models will initially focus on the contiguous U.S. and surrounding oceans, especially the Gulf of Mexico, the researchers are developing them with the flexibility to be applied to other parts of the world that experience widespread and severe dead zones, such as southeast Asia.

The models will run on the supercomputers of the Texas Advanced Computing Center at The University of Texas at Austin, among the fastest in the world.

In addition to Yang, the team includes six co-investigators: David Maidment and James McClelland at The University of Texas at Austin; Paul Montagna and Hae-Cheol Kim at Texas A&M University at Corpus Christi; Hongjie Xie at The University of Texas at San Antonio; and Wei Min Hao at the U.S. Forest Service. The team also includes five collaborators: Nicole Smith-Downey at The University of Texas at Austin; Christine Wiedinmyer at the National Center for Atmospheric Research; Guo-Yue Niu at Biosphere 2 Inc., University of Arizona; Jianhong Xue at Virginia Institute of Marine Sciences; and Gregory E. Schwarz at the U.S. Geological Survey.

For more information, contact: Marc Airhart, Geology Foundation, Jackson School of Geosciences, 512 471 2241.