Coastal ecosystems, from large estuarine systems to salt marshes, are recognized for their important ecological function and societal value. They provide habitat and nursery grounds for commercially- and recreationally important finfish and shellfish. Marshes absorb energy from storms and protect the land from hurricanes. These important ecosystems are threatened by multiple human stressors as well as natural disturbances. The nation is losing much of its coastal marsh due to development, land subsidence, erosion, and sea level rise. In some areas, invasive species have displaced native species, threatening commercially important biological resources by altering habitat and productivity of the marsh. Reduction of water clarity, through increases in suspended sediments and algal blooms, adversely affects the growth of submerged aquatic vegetation, the nursery grounds for many fish and shellfish. In order to protect against continued degradation and loss of coastal ecosystem services and to plan for their remediation, new indicators are needed that will predict when and where ecosystem degradation and wetland losses will occur.