Potential for enhancement of biodegradation of crude oil in Louisiana saltmarshes using nutrient amendments

Salt marsh ecosystems in Louisiana are at high risk of an oil contamination event while remediation of these systems is mainly limited to intrinsic bi oremediation due to the physical sensitivity of salt marshes. This study in vestigated both the intrinsic and nutrient enhanced rates of crude oil degr adation both in microcosm and core studies. In addition, limiting elements, loading rates and optimum nitrogen forms (NH4+ or NO3-) were determined. S alt marshes have relatively low intrinsic degradation rates (0-3.9% day(-1) ) of the alkane component (C11-C44) but high rates (8-16% day(-1)) of degra dation of the polycyclic aromatic hydrocarbon (PAH) fraction (naphthalene. C1, and C2-Naphthalene and Phenanthrene, C1, and C2-Phenanthrene). Addition s of nitrogen statistically enhanced degradation of many alkanes and total PAHs while naturally present phosphorous was found to be sufficient. Nitrog en was found to be most effective if applied as NH4+ in the range of 100-50 0-N mg kg(-1) of soil producing a pore water range of 100-670-N mg L-1. Cor e studies indicate that similar trends are observed when applying fertilize rs to intact portions of salt marsh.