Coastal Wetland Blue Carbon

Science Center Objects

The Coastal Wetland Blue Carbon research described below is conducted and managed under the USGS Applied Landscape Ecology and Remote Sensing project and partners.

Blue Carbon Accounting

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Tidal marsh aboveground carbon density maps of six study regions, based on the final biomass model and plant percent carbon content data (Byrd et al. 2018, ISPRS). Moving from top, left to right: San Francisco Bay, CA, Cape Cod, MA, Everglades, FL, Nisqually NWR, WA, Chesapeake Bay, MD, Terrebonne and St. Mary Parishes, LA. (Credit: Kristin Byrd, USGS. Public domain.)

We have developed the first remote sensing model of tidal marsh aboveground carbon (C) stocks for the conterminous United States (CONUS). This model was created using the first national-scale dataset of aboveground tidal marsh biomass and species composition and aboveground plant C content from six CONUS regions: Cape Cod, MA, Chesapeake Bay, MD, Everglades, FL, Mississippi Delta, LA, San Francisco Bay, CA, and Puget Sound, WA. Through data synthesis, modeling and uncertainty analysis we provide a repeatable remote sensing method that will enable aboveground tidal marsh C stocks to be included in the Coastal Wetlands section of the U.S. EPA Greenhouse Gas Inventory. Information on C stocks will also help to verify emission reductions for coastal wetland restoration and conservation projects included in the voluntary C markets such as the Verified Carbon Standard (VCS). With the increased availability of free post-processed Landsat satellite data, we provide a tractable means of modeling tidal marsh aboveground biomass and C at the global extent as well. This project was funded by the NASA Carbon Monitoring System (Lead PI Lisamarie Windham-Myers), the USGS Land Change Science Program and the USGS LandCarbon Program.

Nisqually River Delta Historical Vegetation Change

As part of a larger project to assess multiple benefits of coastal wetland restoration, we quantified historical vegetation change within the Nisqually River watershed relevant to carbon storage, wildlife habitat, and wetland sustainability, and identified watershed-scale human and hydrodynamic drivers of these changes. To achieve this, we produced time-series classifications of habitat, photosynthetic pathway functional types and species in the Nisqually River Delta for the years 1957, 1980, and 2015. While there was a 188 ha increase in emergent marsh wetland within the Nisqually River Delta between 1957 and 2015 as a result of restoration efforts, there was a 83 ha loss of marsh that occurred in areas near the Nisqually River mouth due to erosion and shifting river channels. This work is part of a larger project to assess multiple benefits of coastal wetland restoration titled, From Food Webs to Marshes (Lead PI Isa Woo). This project is funded by the USGS LandCarbon Program.

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A habitat map of the Billy Frank Jr. Nisqually National Wildlife Refuge 2015 habitat classification (Credit: Laurel Ballanti, USGS. Public domain.)