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A research on the exxon valdez oil spill

An oiled murre passes the darkened shoreline near Prince William Sound, Alaska, less than a month after the March 1989 spill.

  • Researchers recently gathered in the town's library to talk about herring;
  • The culprits are from a class called polycyclic aromatic hydrocarbon, or PAHs.

At the time, it was the single biggest spill in U. In a series of stories, NPR is examining the lasting social and economic impacts of the disaster, as well as the policy, regulation and scientific research that came out of it. Twenty-five years of research following the Exxon Valdez disaster has led to some startling conclusions about the persistent effects of spilled oil.

When the tanker leaked millions of gallons of the Alaskan coast, scientists predicted major environmental damage, but they expected those effects to be short lived. Instead, they've stretched out for many years. What researchers learned as they puzzled through the reasons for the delayed recovery fundamentally changed the way scientists view oil spills. One of their most surprising discoveries was that long-lasting components of oil thought to be benign turned out to cause chronic damage to fish hearts when fish were exposed to tiny concentrations of the compounds as embryos.

Cordova, Alaska, was the fishing village closest to the spill. Since then it's become a hub for scientists. Researchers recently gathered in the town's library to talk about herring.

  • Shortly after the spill, ships tried using booms floating barricades that constrain oil to gather the oil;
  • They tried to burn it and use skimmers to remove it, and finally utilized dispersants to break it down;
  • Previous article in issue;
  • Even after these cascading discoveries, still no one knew how the oil was damaging the animals over the long term;
  • Through years of research, scientists discovered another unexpected effect, this time related to fish eggs;
  • Inquiries into sociocultural and psychosocial impacts of the EVOS were guided by theories and concepts emerging from studies of numerous technological disaster events.

It was the herring that tipped off scientists that oil's effects were far more complicated than they had imagined. Herring were spawning at the time of the spill. None of those herring eggs survived, but a year later the herring population seemed to bounce back.

Why The Exxon Valdez Spill Was A Eureka Moment For Science

Twenty five years after the oil spill, Cordova, Alaska, has become a hub for scientists. When things were back on track, you walked away," Rice says. And all of a sudden they crash to the bottom of the floor, and then we're scrambling trying to figure out why. Scientists had traditionally believed that oil basically had to cover an animal or embryo to hurt it.

Exxon Valdez Oil Spill: Causes, Effects & Clean-up

But the evidence they saw in Alaska suggested it didn't take much oil to do a lot of damage. And that damage could manifest in different ways.

  • And that damage could manifest in different ways;
  • An oiled murre passes the darkened shoreline near Prince William Sound, Alaska, less than a month after the March 1989 spill;
  • Previous article in issue;
  • Further, the loss of the herring fishery has had adverse economic and sociocultural effects on Cordova that may persist;
  • Findings document acute and chronic psychosocial stress within the community and identify involvement in litigation, resource loss, and perceptions of recreancy as significant contributors to high levels of stress;
  • Let's take a look at why:

For example, oil under rocks and in sediments contaminated clams that sea otters ate. It didn't kill the otters outright: Wildlife biologist Dan Esler of the U. Geological Survey says it shortened otters' lives and suppressed the population for 20 years. Through years of research, scientists discovered another unexpected effect, this time related to fish eggs. The clue came from pink salmon, which weren't doing well even years after the spill.

To figure out why, Rice's team exposed pink salmon embryos to tiny amounts of oil. But we were doing it for a really long time," Rice says.

Another eureka came when they figured out which components of oil were toxic to fish. The culprits are from a class called polycyclic aromatic hydrocarbon, or PAHs.

Before the Exxon Valdez spill, they weren't known to be toxic to aquatic life. But after the spill, scientists discovered these compounds persist long after other parts of oil evaporate.

Even after these cascading discoveries, still no one knew how the oil was damaging the animals over the long term. One possibility was an impact on fish hearts: The heart is one of the first things that develop in a fish embryo. A different team of NOAA scientists spent many years experimenting with fish in its laboratory.

Researchers tried one novel experiment with fish to prove that small concentrations of PAHs were responsible for severely harming fish that looked outwardly normal.