Rosenstiel School of Marine and Atmospheric Science
Abstract
The influence of seagrass morphology on water flow was studied by measuring water velocity profiles through natural seagrass meadows. An array of eight solid-state electronic current meters was used to obtain profiles through meadows of Amphibolis griffithii (Cymodoceaceae), a seagrass which possesses a profusely-branched erect stem with terminal leaf clusters, and two strap-like seagrasses, Posidonia australis and P. sinuosa (Posidoniaceae). Significant differences were observed in the shapes of velocity profiles of the different seagrass species; in particular, a region of high water velocity was observed beneath the leafy canopy of Amphibolis, but not in the Posidonia canopy. There is a strong correlation between the water velocity profile of Amphibolis plants and the distribution of leaf biomass, highlighting the influence of the 'stem-and-leaf cluster' morphology on the velocity profile. The unusual velocity profile of Amphibolis has implications for the ecology of these ecosystems, and sediment stability in particular. The solid-state electronic current meters used in this study were found to be an effective and inexpensive means of measuring water velocity profiles in seagrass canopies
