Eelgrass (Zostera marina) forms extensive meadows in low intertidal and shallow subtidal areas of estuaries and embayments along the Northwest Atlantic coast. Ranked among the most productive plant communities on the planet, eelgrass beds are noted for contributing valuable ecosystem functions and services to the coastal zone. Worldwide declines have been linked to water quality degradation and direct physical disturbance; more recently, losses in some coastal areas have been attributed to extremely high summer temperatures. USGS collaborated with National Park Service - Northeast Coastal and Barrier Network to develop a long term eelgrass monitoring protocol within the NPS Vital Signs Monitoring program, for the purpose of providing data to inform NPS resource management decisions. At Cape Cod National Seashore, annual eelgrass monitoring occurs at the lowest summertime tides, which often coincide with daybreak. In this photograph, a researcher ventures into a shallow eelgrass bed at dawn to begin sampling.