Sunday, 30 January 2011

1969 Oil Spill Still Harms Nature

Long Term Oil Spill Effects on Salt Marshes - DM Smith
Long Term Oil Spill Effects on Salt Marshes - DM Smith
Nearly 40 years after the tanker spill, residual oil under the sediment is still damaging the health of a salt marsh, impacting crabs and sea grass beds.
In 1969 a barge ran aground in Buzzard’s Bay off Cape Cod, spilling 200,000 gallons of oil. Today, nearly four decades later, a study has shown that the oil from the Wild Harbor spill is still affecting the salt marsh and its wildlife.

Effects of Oil Spills on Wildlife and the Environment.

The general public became aware of the damage oil spills can cause when the Exxon Valdez tanker accident spilled an estimated 11 million gallons of oil in 1989. A great deal has been learned since then about long term damage from oil spills. Chronic oiling has been shown to affect seabirds along every coast of the world.
After the Exxon Valdez oil spill, efforts were made to try several different, and often controversial, cleaning methods including hot water washing some beaches. Ongoing studies which were funded until 2005 measured the recovery of each type of beach treatment. In 2005 they found still found oil just below the surface, especially in areas that are sheltered.

Abnormal Fiddler Crab Burrowing Behavior After Oil Spill

These studies mirrored the findings at Wild Harbor, a salt marsh on Cape Cod,which is also protected from the most intense wave action. But the work done at Wild Harbor, Falmouth, Massachusetts gives a much more dramatic picture of just how long term the impacts of oil spills on entire ecosystems are, and why prevention is key to protecting those fragile environments.
40 years after the spill Wild Harbor's marshland sea grass beds and fiddler crabs are still suffering from exposure to oil pollution. When plaster casts were made of fiddler crab burrows, it showed that the crabs in Wild Harbor dug short, twisted burrows as compared to the long straight down burrows of fiddler crabs in nearby Great Sippewissett marsh, which has no residual oil.
Fiddler crab burrowing activity aerates the sediment, which in turn enhances sea grass beds. Sea grass beds provide the stability that prevents erosion of the marshes, in addition to serving as critical habitat for a multitude of birds, fish and invertebrates.

Feeding Patterns and Population Growth Altered by Oil Spill

Beyond the abnormal burrowing behvior, fiddler crabs exposed to oil pollution left from the Wild Harbor oil spill have also been affected in their feeding patterns, escape response and overall population growth. And these effects are still evident after nearly 40 years, reinforcing the concerns raised by findings on chronic oiling in birds.
Oil spill cleanup is difficult at best and any cleaning effort can affect entire ecosystems for at least 15 years, as evidenced by the Exxon Valdez follow-up studies. These studies point up the immense level of damage done long term by oil spills. And unfortunately, oil spills will continue to occur, which means that preventing oil from coming ashore is going to be most important for protecting sensitive habitat from long term damage.