THE ROLE OF JUNCUS ROEMERIANUS IN CLEANUP OF OIL-POLLUTED SEDIMENTS

ABSTRACT Several locations in the Mississippi Sound of the Central Gulf of Mexico have been sites of accidental and simulated oil spills over the past decade, providing excellent testing grounds for detecting interactions of indigenous marsh vegetation with petroleum pollutants. Spartina alterniflora and Juncus roemerianus, dominant marsh plants of this region, show resilience in the face of acute oil spills, with J. roemerianus decidedly more resilient in chronic exposures. More important, J. roemerianus can remove large amounts of petroleum hydrocarbons from the underlying sediments and from the water column. Collections of Juncus and underlying sediment from five estuarine environments showed levels and distributions of petroleum hydrocarbons in the aerial leaf portions that mirrored those found in the sediment substrate. Up to 9,000 ppm total hydrocarbons were found in J. roemerianus growing in oil-contaminated sediments. In two different studies, salt marsh plots of Juncus roemerianus and Spartina alterniflora were exposed to sediments inoculated with three different crude oils, an alkene, chrysene, and naphthalene, and uptake was monitored with time. Juncus was able to take up hydrocarbons unaltered within 10 days. Spartina showed no evidence of uptake, though it did show relative increases in lipid fractions.