Environmental Engineering Reference
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in Falmouth, Massachusetts in the late 1960s lasted for over
a decade, according to a team of scientists from the nearby
Woods Hole Oceanographic Institute led by Howard Sanders,
a distinguished benthic ecologist who had been studying
the area. It is rare that a spill occurs right in an area that has
been intensively studied and was well understood prior to
the spill, so their information was particularly useful, though
hotly contested by the oil companies. Fiddler crabs were par-
ticularly sensitive and were still affected seven years after the
spill. The oil affected their burrow construction—the burrows
did not go straight down, but leveled off to a horizontal plane,
perhaps avoiding the oil below. While this was not a problem
during the summer, when winter came the crabs were not
deep enough to be below the freezing zone, so they froze to
death. Benthic communities took about a decade to return to
normal. Over thirty years later, the site of the spill was studied
by another generation of Woods Hole scientists, led by Jennifer
Culbertson, who found that there was still substantial unde-
graded oil residue several inches below the marsh surface,
and fiddler crab burrows in oiled areas were shorter in length
often turned horizontally below 10 cm, sometimes even turn-
ing upward. They found that crabs exposed to the oil avoided
burrowing into oiled layers, had slower escape responses,
reduced feeding rates, and lower population density. Marsh
grass in areas that had some oil remaining grew less densely
than in clean areas, and the loss of marsh grass (especially
roots) made the sediments more likely to erode away. Ribbed
mussels were still experiencing effects of the remaining oil. In
an experiment, mussels were transplanted from a control site
into the oiled site for short-term exposure, and others that had
been exposed to the oil were transplanted from the oiled site to
the control site. Both the short- and long-term exposure trans-
plants had slower growth, shorter shell lengths, and decreased
filtration rates compared to control mussels.
After the Exxon Valdez spill the subsurface oil persisted, and
chronic exposures continued to affect organisms for over a
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