Robotic Surveyors for Shallow Coastal Environments

mental consequences of a warming global climate. Ocean heating, rising sea level, and increasing coastal storm frequency and intensity are imposing stresses on coastal environments that historically were less frequent and less severe. At the same time, human population within 100 km of the coast is projected to nearly double by mid-century, increasing pressure on a variety of marine services including fisheries and recreation. Shallow water environments are key components of healthy coastal ecosystems as they provide feeding grounds and nurseries for fish and crustaceans and act to buffer the impacts of coastal storms on adjacent land areas. But they are also susceptible to rapid degradation because stresses are distributed within a compressed water volume. To address these challenges, policymakers and natural resource managers increasingly rely on more accurate and timely environmental data. The past two decades of robotic and sensor technology development have resulted in ocean observing systems that can monitor and survey water column properties autonomously at temporal and spatial scales and in environmental conditions that exceed what is possible with traditional human-based operations involving ships and divers (Chai et al., 2020). Most recently, new system concepts are providing more complete environmental descriptions of shallow water environments, including water quality and the shape and composition of the seafloor. In 2017, the US Naval Research Laboratory (NRL) began developing robotic surveying approaches that support remote sensing of shallow coastal environments (Ackleson et al., 2017). The initial approach was to use a modified,