Water Flow and Sediment Texture as Co-Varying Submersed Aquatic Vegetation (SAV) Habitat Requirements

Abstract

This study examined the importance of water flow and sediment texture as co-varying habitat parameters of submerged aquatic vegetation (SAV) in the Chesapeake Bay. An outdoor mesocosm experiment was conducted to test the response of SAV (Zostera marina and Ruppia maritima) to combinations of water flows and sediment grain sizes characterized by sediment deposition, bedload transport and erosion. Water flow, sediment and SAV characteristics were also determined at vegetated and adjacent unvegetated areas at 11 study sites and sediment motion conditions assessed. Greater SAV biomass was developed by Z. marina and R. maritima experiencing sediment motion than sediment deposition. Although habitat parameter thresholds in situ were site-specific, overall SAV presence was limited to moderate ranges of both water flow and sediment grain size. All SAV habitat observed was characterized by sediment bedload transport. Consideration of both water flow and sediment habitat requirements will improve SAV restoration success.