The application of in-situ burning to a Louisiana coastal marsh following a hydrocarbon product spill: Preliminary assessment of site recovery

The high degree of physical disturbance associated with conventional responses to oil spills in wetlands is driving the search for alternative cleanup methodologies. In March 1995, in southwestern Louisiana, a spill of gas condensate product into a brackish marsh at Rockefeller Wildlife Refuge was removed by in-situ burning. A monitoring program was established to examine the recovery of the marsh sire. three treatments were examined: (1) condensate-impacted and burned, (2) condensate-impacted and unburned, and (3) a reference that was neither exposed to the condensate nor burned. In March, July, and October 1995, vegetation plots were analyzed for biomass and stem density. Permanent quadrats were surveyed in July and October for total and species-specific percent cover. Although vegetation recovery was apparent 7 months after the burn, the burn treatment resulted in significantly lower biomass and stem density compared with both unburned treatments. In addition, burning led to conditions that favored initial recolonization by the sedge Scirpus robustus in a site previously dominated by the grasses Distichilis spicata and Spartina patens. However, biomass and stem density data suggest that D. spicata is regaining dominance. On the basis of these initial results, observations made in 1996 at the study site, and previous research, it is expected that in-situ burning will be successful at this site.