Vegetative response of Sagittaria lancifolia to burning of applied crude oil

Field studies were conducted to evaluate Sagittaria lancifolia sensitivity to in-situ burning of applied crude oil. Twenty-four plots were constructed (2.4 x 2.4 x 0.6 m) in a fresh marsh and experimental treatments were: 1) control (no oiling and/or burning); 2) oiling (natural remediation); and 3) oiling plus burning. South Louisiana Crude was applied at 2 L m(-2), with a garden sprayer, on Sagittaria lancifolia stems and leaves of the oiling a nd oiling/burning treatment plots. Two marsh burns were conducted, one in A ugust (Site A) and a second on separate plots the following April (Site B) to compare seasonal effects of oiling and burning. Burning was initiated th ree days after oil application when the marsh was flooded to a 15-25 cm dep th and winds were calm. Live stem count, plant height growth and carbon fix ation were measured up to 9 times over 52 weeks after the first burn (Augus t) and 6 times over 19 weeks after the second in-situ burn (April). Abovegr ound biomass was measured at the conclusion of each study. Oil application and oil burning had short term effects on Sagittaria lancifolia vegetation. Five to six weeks after each burn, measured Sagittaria lancifolia vegetati ve parameters in control, oiled and oiled/burned plots were not significant ly different. Only biomass clipped 20 weeks after the April burn showed sig nificant treatment differences. Under our experimental conditions, data sug gests leaving oil to degrade and the marsh to recover naturally may be an o ption to consider. Plant recovery in oiled/burned plots was as rapid as oil ed plant recovery. This suggests burning may be a viable remediation method if a rapid response is needed to remove oil and control oil migration to s ensitive areas.