Comparison of 16S rRNA genes and 16S rRNA transcripts based on T-RFLP analyses from BAL and NEREIS+BAL.

<p>(<b>A</b>) Percentage of Operational Taxonomic Units (OTUs) specific to the 16S rRNA genes (RNA− DNA+) or the 16S rRNA transcripts (RNA+ DNA−), or common to both (RNA+ DNA+). The stars show significant differences obtained by the Duncan test (p-value<0.05) compared to the day 2 value. (B) Relationships between percentage of OTUs common to 16S rRNA genes and transcripts (RNA+ DNA+) with n-alkanes concentrations.</p

Characteristics of the CTRL_270d, BAL_270d, NEREIS_270d and NEREIS+BAL_270d cDNA libraries.

<p>Characteristics of the CTRL_270d, BAL_270d, NEREIS_270d and NEREIS+BAL_270d cDNA libraries.</p

Relationship between microcosm conditions and bacterial phylotypes (phylum level).

<p>(A) Heatmap with double clustering. The microcosm conditions are clustered at the top and bacterial phylotypes are clustered on the left of the heatmap according to their intensity profile similarity. Black corresponds to a higher abundance and white to an absence of taxa. (B) Relative abundance (%) of phylogenetic groups in 16S rRNA libraries from the four incubation conditions at 270 days.</p

Bacterial community structure changes based on the 16S rRNA gene (A) and transcripts (B) for 270 days for the four conditions.

<p>Hierarchical analysis was performed using all replicates but only the average similarity between replicates is represented. CTRL, white circle; BAL, black circle; NEREIS, white triangle; NEREIS+BAL, black triangle. Clusters were formed under the 69.9% threshold.</p

Microcosms’ box design.

<p>Sediments were maintained in such microcosm boxes and subjected to 12-hour tidal cycles, renewing the seawater with each tidal cycle.</p

Chemical analyses of hydrocarbon content in sediments.

<p>A) Depth distribution of relative TPH content (%) in the BAL and NEREIS+BAL conditions during the 270 days of the experiment. The 100% TPH represents the total TPH per sampling time (addition of all depths). B) Total petroleum hydrocarbons (TPH) content during the 270 days of the experiment for the BAL and NEREIS+BAL conditions in the 0–2 cm layer. C) Concentration (µg/g of dry sediment) of n-alkanes and PAHs (from benzothipohene and its alkylated forms to chrysenes and their alkylated forms) during the 270 days of the experiment for the BAL (left) and NERREIS+BAL (right) conditions. The stars show significant differences obtained by the Duncan test (p-value<0.05) compared to the day 2 value.</p