Description
West Falmouth Harbor, Massachusetts, has undergone decades of nutrient enrichment, primarily from a wastewater treatment facility, leading to eutrophication and loss of seagrass meadows. Although nutrient inputs have declined in recent years, seagrass recovery remains incomplete. The inner basin, Snug Harbor, has experienced complete loss of eelgrass (Zostera marina), but meadows exist in the Middle Harbor and Outer Harbor. This study assessed biomass and morphological traits of Z. marina shoots from Middle and Outer Harbor to evaluate differences in varying environmental conditions. Samples were collected by divers, analyzed for below-ground biomass, rhizome diameter, root length, and node density as well as above ground leaf length, width, leaves per shoot, and productivity. Results show that eelgrass from Middle Harbor exhibit significantly greater belowground biomass and rhizome diameter in comparison to plants from Outer Harbor. While the above ground leaf length and width have a significant difference. These patterns are consistent with environmental gradients in the harbor, where sediment texture, porewater chemistry, and possibly legacy nutrient exposure vary spatially. Lower below-ground biomass in the Outer Harbor may indicate reduced anchorage potential, increasing vulnerability to uprooting during storm events and other physical disturbances. Morphological plasticity in eelgrass below-ground structures may influence resilience to sediment erosion and disturbance. Recognizing site-specific differences in rhizome morphology provides important context for understanding seagrass persistence in eutrophic systems and identifying suitable conditions for restoration. The observed trait gradient suggests that even within recovering estuaries, legacy impacts and subtle environmental variation continue to shape seagrass form and function.