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and methanolic (f~) fractions
for oil samples Below. Each
by silica gel chromatography as described
solvent fraction was concentrated by rotary
evaporation to 4 ml and radioactivity of a
was., .determined in AquasoL.as described above.
portion of the
Using these
extract
methods
[1- C] -hexadecane and [1- C] -heptaderene standards were recovered in
the f 1 fraction, whereas [1(4, 5, 8)- C] -naphthalene
was recovered in
the fl fraction. CO was transferred from the extracted sediment
after acidification ana distillation to a C0„ absorbant trap (Carbosorb,
Packard). This trap was combined with Aquasol and radioactivity
determined as described above.
Gas Measurements
Gas subsamples (0.2 to 1.0 ml) were removed from the headspace of
incubation vials using a helium flushed 1 ml glass syringe (Glaspak)
fitted with a Mininert pressure-lock syringe valve (Supelco) . CH,
and C0„ were measured by gas chromatography- gas proportional counting
using the method of Nelson and Zeikus (1974) as modified by Ward
and Olson (1980). This method ensured the specific detection of these
gaseous metabolites. All numerical results were based on amounts
clearly above detection limits, and quantifiable by integration using a
Spectra-Physics Minigrator. C0„ values were corrected for CO^ solubility
and bicarbonate equilibrium as described by Stainton "t 1973) .
Methane concentrations were quantified on a Varian 3700 flame ionization
gas chromotograph as described by Ward and Olson (1980). All
values for gas analyses are reported on a per vial basis.
Chemical Analysis of Oils
Similar methods were used for the analysis of sediment hydrocar-
bons (ERCO) or oils (MSU) although the specific details differed.
Sediment hydrocarbon samples were solvent extracted and fractionated
according to an analytical scheme patterned after that of Brown et al
(1980). Hydrocarbons were separated from methanol-dried samples by
high-energy shaking with methylene chloride:methanol (9:1), fractionated
into saturate, aromatic/unsaturate and methanolic fractions by
alumina/silica gel column chromatography, and analysed by gas chromatography,
mass spectrometry and/or mass f ragmentography as described by
Boehm, et al (1981).
AMOCO CADIZ mousse, fresh or evaporated crude oil, and extracts
C-hydrocarbon experiments (see above) were analyzed as follows.
from ll+
Each sample (a 25 (Jl aliquot of each oil sample diluted in 0.5 ml of
hexane, or extracts described above) was loaded onto a glass column (1
cm ID x 20 cm long) packed with 40-140 mesh silica gel (Baker Chemical
Co.). Saturate components (f,) were removed from the column by eluting
with 200 ml of hexane. The aromatic fraction (f ) was then eluted with
200 ml of a solution of hexane and methylene chloride (70/30 V/V)
. The
methanolic fraction (f ) was then eluted with 150 ml of methanol. Each
fraction was concentrated to 3-4 ml by flash evaporation and further
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