May 17, 2011

Four TAMUG scientists receive $400,000 research grant from NASA and USDA

Researchers to study sequestration (storage) of carbon in tidal wetlands along the Texas coast

NASA and the U.S. Department of Agriculture have awarded a three-year, $400,000 carbon cycle science investigation grant to four researchers at Texas A&M University at Galveston.

The TAMUG study’s principal investigator, Dr. Patrick Louchouarn, said, “The focus of this funded research is to examine how land development in wetland areas, other wetland losses and shifts in vegetation affect the long-term storage or sequestration of carbon on the coast of the Gulf of Mexico.” Louchouarn is a professor and department head of Marine Sciences at the university.

According to the U.S. Department of Energy, carbon sequestration— an important ecosystem function in all vegetated habitats that accounts for the storage of carbon in the ground when plants and animals die and decay — is a natural way to reduce the atmospheric buildup of greenhouse gases.

Scientists have determined that excesses of carbon dioxide and other greenhouse gases in the atmosphere are responsible for rising temperatures across the Earth.

The TAMUG scientists emphasize increasing evidence that suggests tidal wetlands play a vital role in regional and global carbon storage.

However, Louchouarn explained, “Carbon storage information is seldom part of the decision-making process that assigns value to these coastal ecosystems. The TAMUG project thus seeks to provide the quantitative data to start incorporating sequestration into the value system of coastal wetlands.”

“Previous research suggests that tidal wetlands store approximately ten percent of worldwide soil carbon pools, but we have much to learn and understand about the mechanisms that control this storage process,” he said.

By combining field research and laboratory studies with analyses from NASA’s remote sensing imagery, we’ll be seeking better understandings about potential changes in carbon sequestration driven by climate change and alterations in the types of wetland vegetation over the past decades” said Louchouarn.

Continuing, he said, “Since large-scale carbon stocks are sequestered in the surface meter of soil in tidal estuarine wetlands, substantial losses of or alternations in these ecosystems have the potential to offset any improvement in preservation of soil organic carbon within managed croplands, even at its highest efficiency.”

Project Co-PIs are Dr. Wesley Highfield, a research scientist at TAMUG’s Center for Texas Beaches and Shores (CTBS); Dr. Anna Armitage, assistant professor of Marine Biology; and Dr. Samuel D. Brody, who is professor of both Marine Sciences (TAMUG) and Landscape Architecture & Urban Planning (TAMU), as well as director of CTBS and holder of TAMUG’s George P. Mitchell ’40 Chair in Sustainable Coasts.

The team’s innovative combination of ecological, biogeochemical and remote sensing approaches will also help them study an intriguing result of climate change in the region, namely encroachment of mangrove trees in salt marsh ecosystems, resulting in the replacement of grasses by woody vegetation in a number of Gulf coast wetlands.

Louchouan explained, “Analyses of a time series of remote sensing images will lead to determinations about past and recent changes in wetland types, sizes and locations. Then, the next step will involve focusing on the extent to which climatic changes and population growth ― as well as development along the coast ― are affecting estuarine wetland ecosystems”.

“We believe our field assessments will further enable us to assess changes in the ability of our coastal wetlands to effectively sequester carbon,” he said.

Ultimately, the TAMUG scientists working on this grant agree that the aim of their integrated research is to characterize the storage of carbon within diverse estuarine wetland ecosystems while they determine the influence development on coastal wetlands and climate-induced shifts may have on pools and carbon exchanges in these systems

After they quantify the carbon sequestration on the Texas coast, the TAMUG researchers will be able to scale up to estimate the carbon storage potential in wetland areas throughout the entire Gulf of Mexico region.

In summary, the specific objectives of this vital TAMUG research are to:

• Quantify carbon sequestration in coastal wetlands with special emphasis on marsh and mangrove plant communities along the Texas coast.

• Identify and measure the shifts in vegetation structure that have occurred in estuarine wetlands over the last decade.

• Identify and measure the loss of naturally occurring estuarine wetlands over the last decade from development along the Gulf of Mexico coast.

• Measure the amount of wetlands carbon sequestration capacity lost due to recent human-induced changes in the landscape.

“Our TAMUG team’s research is an ideal fit for the carbon cycle science investigations within the NASA Earth Science Program because it will improve understanding of the global carbon cycle and quantify changes in carbon storage at the interface between the land and the sea and ‘in response to land use and land cover change and other human activities and natural events,’” Louchouarn said.

“By investigating the interactions between land use and land cover change and the carbon cycle, we believe we will develop applications that directly inform future resource management, policy development and decision-making,” he said.

**TAMUG**