| Two greenhouse experiments using Spartina alterniflora (smooth cordgrass) transplants in closed containers were conducted to examine the effect of weathered No. 2 fuel oil on above and below-ground plant tissue, and the influence of surviving plants on oil biodegradation (i.e. phytoremedation potential). In the first experiment, plant growth was significantly depressed at 1/3 aerial exposure and at 34.2 g/kg of oil in sediment (range tested: 2 to 137 g/kg). At the lowest oil concentrations, where plant densities were high and mortality was limited, significant biodegradation of alkanes and PAH's was observed. In the second experiment, two concentrations (1.7 and 17 g/kg) in combination with and without above-ground plant exposure to oil were utilized. Plant mortality was much more severe, occurring at 1.7 g/kg due to plant condition (low vigour). As live plant densities were low, their presence in the salt marsh microcosms did not enhance biodegradation rates of residual oil within the sediment. |
