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to energy sources other than acetate or HL (such as methylamines) , and
sulfate reduction dominates as the significant terminal process (Winfrey
and Ward, submitted). As another major objective of this study we
examined terminal processes of the anaerobic food chain, which should
indicate the activity of the overall food chain, for evidence of
changes due to AMOCO CADIZ oiling. The processes investigated were
those which dominated the food chains, principally sulfate reduction
and acetate metabolism.
Location of Sampling Sites
METHODS
Sites were selected to represent beach, estuary and salt marsh
sediments in the lower intertidal region which were significantly oiled
by AMOCO CADIZ pollutants. Similar sites in areas unoiled or lightly
polluted were selected as controls. Locations are shown in Figure 2.
Observations on the chronology of oil movements were used to determine
the extent of oil impact and times at which oiling first occurred
(Centre National pour 1 'Exploitation des Oceans, 1979; Gundlach and
Hayes, 1978). The oiled beach site was between stations B and C at
AMC-4 (Gundlach and Hayes, 1978). This site was opposite the wreck and
was heavily oiled immediately after the spill. The control beach site
was 100 m east of the west access to the beach at Trez-hir. This beach
faces
oiled
the Bay
estuary
of Brest
site was
and was not reported to have been oiled.
a mudflat at Aber Wrac'h, 200 m south of
The
the
stone wall at
tected in this
EPA-7
area
(Calder,
in medium
et al., 1978).
thickness two
AMOCO CADIZ oil was de-
days after the oil spill.
The control estuary site was a mudflat on the south bank of Aber Ildut
approximately 3 km west of Breles. Oiling at this site was prevented
by two booms extended across the mouth of the Aber. The oiled marsh
site was an intertidal mudflat in lie Grande near AMC-18 (Gundlach and
Hayes, 1978). Thick accumulations of AMOCO CADIZ oil reached this site
by 'the eighth day following
mudflat in the lie Grande
the spill. The control marsh was a natural
marsh, just south of the main intertidal
channel. A barricade at the bridge adjoining east and west marsh areas
prevented oiling at this site.
Sample Collection and Processing
Sediment cores were collected with hand- pushed plexiglass tubes
(60 cm x 37 mm ID), stoppered, and transferred to the lab in an upright
position. Cores for sediment hydrocarbon analysis were kept frozen
until processing. Processing of samples for biological activities was
done at the Centre Oceanologique de Bretagne in Brest or at the Station
Biologique at Roscoff within 8 h after collection. All manipulations
for analysis of biological activity were carried out using strict an-
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