Environmental Engineering Reference
In-Depth Information
Coral larvae were damaged by the oil, and even more so by
the dispersants. Scientists also found that dispersants enabled
the oil to penetrate more deeply into sand on the seabed,
where low oxygen levels would slow down its degradation.
Severe injury was seen in some deep sea corals. The presence
of recently damaged and dead corals beneath the known path
of a plume from the well is strong evidence that the oil dam-
aged deepwater ecosystems. It is too early to assess the over-
all impacts of this disaster, but a committee of the National
Academy of Sciences (NAS) recommended an ecosystem
services-based evaluation. The people who live and work in
the Gulf region depend on ecosystems for services such as
food and fuel, flood and storm protection, and tourism and
recreation. Damage to natural resources from the oil spill
could impair these services, leading to social and economic
impacts that may not be apparent from an assessment of envi-
ronmental damage alone. The NAS committee introduced
an ecosystem services approach that requires understand-
ing environmental impacts from a disruption, the resulting
decrease in goods and services, and the cost of those losses to
individual communities and society at large. They illustrated
how this approach might be applied to coastal wetlands, fish-
eries, marine mammals, and the deep sea—each of which pro-
vide key ecosystem services in the Gulf.
What happens when oil reaches shorelines?
When spilled oil reaches a rocky shoreline, lighter components
of the oil evaporate, leaving behind the heavier components
and turning the oil into tar, which will erode away due to
wave action, and biological communities will return rather
quickly. In marshes, however, oil can sink below the surface
and remain for many years. Oil accumulated in marsh sedi-
ments undergoes some microbial breakdown, but the process
is very slow, and marshes have the slowest rates of recovery
from oil spills. Marshes and sediments in Prince William
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