Field studies were conducted to investigate the effects of two levels of water velocity (exposure) on seagrass standing crop (biomass) and consequently community productivity. These results were then related to laboratory studies examining the physiological effects of water velocity fluctuations on seagrasses. These effects were light and water velocity on the photosynthetic rates of seagrasses and epiphytes. In addition, laboratory studies were designed to investigate the influence the role of leaf and epiphyte morphology on flow over the surface of seagrass leaves, and the rescaling of turbulence to a level which enhances nutrient uptake by the plants.