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Seagrass scenarios driven with satellite derived bio-optical inputs across Tangier Sound
Citation:
Demaree, D., B. Schaeffer, W. Salls, J. Johnston, R. Zimmerman, AND V. Hill. Seagrass scenarios driven with satellite derived bio-optical inputs across Tangier Sound. 2023 International Ocean Colour Science Meeting, St Petersburg, FL, November 14 - 17, 2023.
Impact/Purpose:
Around the globe sea grass meadows are in decline but has increased in the Chesapeake Bay due to restoration efforts. For this project seagrass area was modeled using satellite data and the program Grass Light in the Tangier Sound in Chesapeake Bay. The Tangier Sound was chosen as a test case for this work because the EPA is currently working with the community of Crisfield and with a nearby university on restoring the area and on the potential costs and benefits of ecological restoration. This project is also part of a larger project to scale up the work from this project to model seagrass at the national level.
Description:
Seagrass meadows provide a habitat for marine organisms as well as environmental services, including shoreline stabilization, carbon sequestration, and improved productivity. Historically the seagrass in Chesapeake Bay decreased due to human impacts on the bay ecosystem, but since the 1980’s seagrass extent has increased as a variety of projects increase the ecosystem health. Seagrass is used as a measure of bay restoration, however, in 2022 sea grass extent was only at 59% of the Chesapeake Bay Program’s 2025 restoration goal. Sea grass extent fluctuates yearly, driven by anthropogenic and climatic factors, such as water temperature and light availability. The goal of this project is to map the potential extent of seagrass in Tangier Sound, a sub estuary in the eastern part of Chesapeake Bay. The bio-optical model Grass Light was used to model the sea grass leaf area index combined with a digital elevation model to predict the distribution and density of seagrass. Model inputs included a matrix of climate and water quality target scenarios. Satellite derived sea surface temperature, turbidity, colored dissolved organic carbon, and chlorophyll-a concentrations were applied as baseline conditions. Model results reveal that seagrass has the potential to cover 178 km2 (16%) of Tangier Sound (1130 km2) with expansion and contraction given various climate and water quality combinations.
