In temperate lagoons on the U.S. East Coast in Virginia, climate forcing has resulted in both rising water temperatures and an increase in the frequency of marine heatwaves. These lagoons host one of the largest seagrass restorations known, with over 40 km² of seagrass meadows restored over the last two decades. Long-term monitoring captured a marine heatwave in 2015 that caused massive seagrass die-off in some regions, resulting in a loss of stored sediment carbon. Continued research has shown that the seagrass meadows were resilient, recovering to pre-disturbance densities within 2-4 years but that carbon stocks lagged behind. A large-scale replicated seagrass removal experiment designed to mimic seagrass loss due to a heatwave has provided a more detailed time series on seagrass recovery and changes in sediment accumulation and carbon stocks. This presentation synthesizes our results and provides guidelines for future restoration efforts to minimize vulnerability of seagrass populations and optimize conditions for carbon stock permanence.

Primary Presenter: Karen McGlathery, University of Virginia (kjm4k@virginia.edu)

Authors:

Carolyn Ewers Lewis, University of Virginia  (ced8p@virginia.edu)

Lillian Aoki, University of Oregon  (laoki@uoregon.edu)

Amelie Berger, University of Virginia  (acb4rk@virginia.edu)

Spencer Tassone, University of Virginia  (sjt7jc@virginia.edu)

Peter Berg, University of Virginia  (pb8n@virginia.edu)

Patricia Wiberg, University of Virginia  (pw3c@virginia.edu)

Michael Pace, University of Virginia  (mlp5fy@virginia.edu)