Relationship between soil cellulose decomposition and oil contamination after an oil spill at Swanson Creek, Maryland

In wetlands, oil spills may affect decomposition in soils, which controls organic matter accumulation, the primary contributor to positive elevation change. In this study we examined how oil from a spill affected organic matter decomposition in soils of a brackish intertidal marsh in Maryland. Decomposition was measured using the cellulose (cotton) strip technique. Cellulose decomposition was not affected by concentrations of different oil components (total hydrocarbons, total resolved hydrocarbons, and polycyclic aromatic hydrocarbons). Rather, other abiotic characteristics of the soil had strong effects on decomposition rates, including strong negative effects of soil depth and salinity, and a positive effect of pH. Measures of soil fertility (NH4–N and PO4–P) were not significantly related to cellulose decomposition. Thus, we conclude that decomposition was controlled more by naturally occurring environmental factors rather than by exposure to oil.