Submerged aquatic vegetation (SAV) provide numerous ecosystem services including enhanced biodiversity, erosion control and sediment stabilization, nutrient cycling, improved water quality, and organic carbon sequestration. Rapid environmental changes and increased coastal development have resulted in significant SAV losses globally. Currituck Sound, the northernmost estuary in North Carolina, was once known for extensive SAV beds serving as a refuge and food source to an abundance of fish and waterfowl that attracted anglers and hunters from all over the country. However, declines in water quality as a result of rapid population growth and development have led to massive declines in SAV habitats that have been devastating to the local ecology. This study investigated changes in historical and current SAV distribution and evaluated how these changes have been influenced by water depth, light availability, and bed-sediment composition.The past and present relationship between water depth and SAV cover was examined in several ways: (1) historical SAV cover maps, (2) hydroacoustic surveys, (3) quadrat transect surveys, (4) modeling using light attenuation data, and (5) comparisons with historical ground surveys. In Currituck Sound, SAV is not present beyond a water depth of 1.8 m and are preferentially located at depths shallower than 1.0 m. The median light attenuation for the combined 2016 and 2017 growing seasons was 1.99 m-1. The calculated minimum water-column light requirement was 2.8% and water-column light requirement for peak growth was ≥13.7%. Sediments were dominated by sand (average weight percent >90%) and had very low organic content (average percent loss on ignition ~1.0%). While some spatial and temporal variations in sediment composition were identified, no statistical relationships between SAV cover and sediment characteristics were observed. Light availability with water depth proved to be the dominant factor limiting SAV growth and distribution in Currituck Sound. Therefore, the light and depth thresholds identified in this study are key to developing a sound management and mitigation plan.
