Salt marsh redox potential at sites with runnel remediation in SE Massachusetts, 2020-2022

Natural disturbances, sea level rise, and historic human impacts to salt marshes have increased impounded water on marsh surfaces, resulting in vegetation loss and the associated loss of important ecosystem services such as carbon storage. Runnels are a climate adaptation technique designed to restore salt marsh habitat by reestablishing a tidal connection between impounded water and a nearby drainage feature. While runnels can drain impounded water and promote revegetation, the unintended effects of altering redox conditions remain unknown. Draining sediment and increasing redox potential could stimulate decomposition. We measured redox potential in two marshes in SE Massachusetts (Little Bay in Fairhaven, and Ocean View Farm in Dartmouth) prior to runnel restoration, and two years post restoration. We measured redox potential using three spatial distinctions: in the center of the panne, landward of the panne, and seaward of the panne. This was done every 2-3 weeks over a growing season.