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Supplementary Figure S1. Cumulative 14CO2 recovered from incubations with 14C-labelled substrates (circles), and the respective removal of
these hydrocarbons in incubations with the corresponding unlabelled substrates as measured by HPLC (naphthalene and phenanthrene) or GCMS (n-hexadecane) (squares). (a) phenanthrene; (b) naphthalene; (c) n-hexadecane. The endpoint for these SIP incubations was determined to be
5 days. Each data point is the mean of results from triplicate flasks ± standard deviations. Filled symbols represent live cultures (non-acid
treated); open symbols represent acid-inhibited controls. Some error bars are smaller than the symbol.
Supplementary Figure S2. Distribution of the ‘heavy’ and ‘light’ DNA in separated SIP fractions. The top of each panel shows the DGGE
profiles of bacterial PCR products from separated (a) [13C]-phenanthrene fractions aligned to equivalent [12C]-phenanthrene fractions, (b) [13C]naphthalene fractions aligned to equivalent [12C]-naphthalene fractions, and (c) [13C]-hexadecane fractions aligned to equivalent [12C]hexadecane fractions, with decreasing densities from left to right. The position of unlabelled E. coli DNA, which was used as an internal control
in all three isopycnic centrifugations, is shown on the right. The distribution of qPCR-quantified 16S rRNA gene sequences is shown below the
DGGE image for (a) Colwellia () and Cycloclasticus (), (b) Alteromonas () and Cycloclasticus (), and (c) Marinobacter () and
Alcanivorax () in fractions from [13C]-phenanthrene incubations, [13C]-naphthalene incubations and [13C]-hexadecane incubations,
respectively. The distribution of qPCR-quantified 16S rRNA gene sequences for E. coli is also shown (▼) in fractions for each of the three 13C
incubations. For the 13C-incubation with phenanthrene (Supplementary Figure S2a), fractions 5-10 were combined (shaded area); for the 13Cincubation with naphthalene (Supplementary Figure S2b), fractions 9-12 were combined (shaded area); and for the 13C-incubation with n-
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hexadecane (Supplementary Figure S2c), fractions 6-9 were combined (shaded area). Gene copies in a fraction are presented as a percentage of
the total genes quantified in the displayed range of fractions. Data points are aligned with equivalent fractions of the DGGE images.
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