Effect of crude oil on a Louisiana Spartina alterniflora salt marsh

The effect of Louisiana crude oil on growth of Spartina alterniflora Loisel and selected anaerobic soil processes in a Louisiana salt marsh was investigated. Greenhouse and field studies indicated that S. alterniflora can tolerate a large amount of oil without a short-term decrease in above-ground biomass. Neither the biological reduction of nitrate, manganese, iron and sulphate nor the production of methane and ammonium in stirred reduced sediments were affected by additions of up to 10% oil on a soil-weight basis. Oil placed on the water surface of unstirred sediment caused a release of iron, manganese and ammonium from the sediment to the overlying water due to the absence of oxygen in the water column.