Changes in growth, internode-distance and nutrient concentrations of the seagrass Halophila ovalis with exposure to sediment sulphide

Between November 2005 and December the short-term effects of sulphide on the growth, nutrition and morphology of the seagrass Halophila ovalis were investigated in situ in the Swan River Estuary. Sediments within a H. ovalis meadow were enriched with Na2S equivalent to 0, 1.1 and 4.2 g m-2. The hypothesis tested was that sediment sulphide enrichment would have a negative effect on growth of H. ovalis. Biomass, internode-distance and growth rate (mg apex-1 day-1) were determined, and plant material analysed for soluble carbohydrate, carbon, nitrogen and phosphorus.