Abstract:
The coastal salt marsh is a strong “blue carbon” sink, which plays an important role in global and regional carbon and nitrogen cycling. We measured greenhouse gas (CO2 and CH4) emissions and carbon sequestration in salt marshes across a nitrogen-loading gradient of four Spartina salt marshes in Waquoit Bay, Massachusetts. The GHG flux measurements were made in situ with a state-of-the-art mobile gas measurement system using the cavity ring down technology. Both vertical (CO2 and CH4) and lateral (dissolved organic and inorganic carbon) fluxes are important in quantifying carbon sequestration in salt marsh and understanding how and why the carbon stock changes over time. Our results facilitate model development to simulate GHG emissions in coastal wetlands and support methodology development to assess carbon credits in preserving and restoring coastal wetlands.