Boxplots of TPH concentrations in (a) Inlet and (b) Marsh surface and subsurface sediments.

<p>Each box represents the concentration range of 50% of the observations. Lines within the boxes represent the median values, open squares are the averages, and the whisker lines connect to outliers.</p

Study site.

<p>(A) Map of Point Aux Pins peninsula. Study site indicated by box in inset. (B) Sediment samples collected ∼25 m from shore outside the marsh stands (designated “Inlet”) and 2–4 m from shore within the marsh stands (designated “Marsh”).</p

Non-metric multi-dimensional scaling (nMDS) ordination of the bacterial community in salt marsh sediments.

<p>Resemblance matrix generated using Bray Curtis similarity and based on the relative abundance of taxa identified by PhyloChip analysis.</p

Hydrocarbon degradation genes in Marsh sediments.

<p>Average abundances of hydrocarbon degradation genes in Marsh sediments compared between June and July. Significant changes indicated by *for p<0.05 and **for p<0.01.</p

GCMS analysis of MC252 oil and oil-contaminated sediment.

<p>(A) GCMS chromatogram of 10 ppm Macondo oil (MC252); (B) concentrations of <i>n</i>-alkanes in tar balls and sediment from July Marsh samples as determined by GCMS.</p

Point Aux Pins salt marsh inlet water column physical and chemical parameters.

<p>Dissolved oxygen concentrations reported relative to 100% air saturation.</p

Functional gene distribution in Inlet and Marsh sediments.

<p>Gene relative abundance determined by GeoChip for samples compared between June and July 2010. Categories with significant changes indicated by *for p<0.05.</p

Relative abundance (%) of families of <i>Proteobacteria</i> known to contain hydrocarbon-degrading species.

<p>Relative abundance (%) of families of <i>Proteobacteria</i> known to contain hydrocarbon-degrading species.</p

Total petroleum hydrocarbons (TPH) detected in one or replicate samples.

*<p>BD indicates total petroleum hydrocarbons were below limit of detection.</p

Relative abundance (%) of families of <i>Actinobacteria</i>, <i>Bacteroidetes</i>, and <i>Firmicutes</i> known to contain hydrocarbon-degrading species.

<p>Relative abundance (%) of families of <i>Actinobacteria</i>, <i>Bacteroidetes</i>, and <i>Firmicutes</i> known to contain hydrocarbon-degrading species.</p