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Research to Examine Role of Salt Marshes in Sequestering Greenhouse Gases

Rita Oliveira Monteiro

Tim Savas, a research assistant working with Jim Tang, measures CO2 fluxes from a salt marsh.

Assistant Scientist Jim Tang of the Ecosystems Center will be a principal investigator on a $1.3 million grant from the National Oceanic and Atmospheric Administration/Nationa l Estuarine Research Reserve System Science Collaborative . Along with partners from the United States Geological Survey (USGS) Woods Hole Science Center, the University of Rhode Island, Florida International University and several other non-profit organizations, the project will examine carbon and nitrogen cycles in salt marshes and their impacts on climate change.

The grant will be coordinated by Alison Leschen from the Waquoit Bay National Estuarine Research Reserve (WBNERR) and fieldwork will be conducted there. Other principal investigators are Kevin Kroeger from USGS and Serena Moseman-Valtierra from University of Rhode Island.

During the three-year project, scientists will quantify how much greenhouse gas is stored and emitted from coastal wetlands, and how the presence of nitrogen changes this balance. Greenhouse gases (GHG), such as carbon dioxide, contribute to global warming by trapping heat in the atmosphere. While it is well known that forests store large amounts of carbon, thus reducing global warming, there is new focus on equivalent stores of so-called “Blue Carbon” in coastal ecosystems such as mangroves, seagrasses, and salt marshes. Preliminary work by the researchers involved in the grant has shown that when nitrogen is present, as it is in most coastal areas due to septic sytems, fertilizer runoff, and atmospheric deposition, salt marshes actually become “sources” of GHG, rather than “sinks.” This is because the nitrogen causes nitrous oxide and methane, much more potent GHGs than carbon dioxide, to be emitted. If this is true, it would add to the incentive for reducing the amount of nitrogen flowing into these areas.

A large focus of the project is to link scientists with “end-users,” who will apply the science to better manage the coast. Non-profit organizations, such as Restore America’s Estuaries (RAE), a consortium of a number of community-based restoraion organizations, will play an essential role in “translating” the science into products that will be used by the coastal management community. The Manomet Center for Conservation Sciences in Plymouth will conduct an economic analysis of the effect that nitrogen has on the “value”of a salt marsh for storing GHGs. A user-friendly model will be developed by a modeler from Florida International University that will enable towns to evaluate this potential.

Jim Tang will be responsible for taking advantage of recently developed laser-based technology to develop a cutting-edge system to measure greenhouse gas emissions from salt marshes directly in the field, which has not been conducted before. This novel system will dramatically improve the accuracy and frequency of greenhouse gas measurement.

"I am very excited to be part of this incredibly talented team that include scientists, modelers, and ecosystem managers," said Dr. Tang. "This grant provides an unprecedented opportunity to translate cutting-edge research on carbon and nitrogen cycles into policy making and management with local, national, and even global applications.”