Oil Spill!

Last week, on Tuesday, November 20, 2002, the oil tanker Prestige broke in half off the shore of Spain, spilling an estimated 2.9 million gallons of crude oil into the North Atlantic Ocean. Although emergency response teams are doing what they can to capture the plume spreading out in the sea, much of the oil has already blackened over some 250 miles of Spain's northwestern coastline - inducing about 600 people to help clean up the shores and aid the affected wildlife.

Meanwhile, officials believe the split tanker lies on the ocean floor still holding nearly 17 million gallons of its crude cargo, and local residents are already worrying about the long-term effects of the disaster. Such a coastline clean-up project typically takes up to six months, but the environmental impact of the spill will be monitored for five or more years.

The volume of oil on board the Prestige is twice that of the Exxon Valdez, infamous for the 1989 spill in Alaska after it ran aground. Fortunately, the conditions in the case of the Prestige may make it more favorable for containing the spill, plus scientists and marine officials have learned a lot from the Alaska spill and others since. However, such single-hulled tankers, which are more prone to these accidents than the modern double-hulled ships, won't be legally banned worldwide until the year 2015.

So how exactly do these environmental disasters get cleaned up? What kind of damage do oil spills cause? You'll find the answers to those questions in this week's lesson, with an introduction to oil spill pollution and cleanup, a focus on the Exxon Valdez incident, and a tour of some research studies evaluating the long-term effects on wildlife.

Cleaning Up a Mess

Start your lesson in the United Kingdom at the University of South Hampton site on Water Pollution, created by some of their engineering students. Read through the introduction and click on Oil spills. From there you can read the brief summaries of the Exxon Valdez and Braer oil tanker spills, as well as the release of oil into the water and air during the Gulf War. How did geographic, weather and other conditions influence the severity of each slick's impacts on the environment?

Next, read about the types of measures used to prevent oil slicks from happening. What are the two main methods and why were they implemented? Unfortunately, as last week's incident shows, these measures aren't foolproof. So also check out the various techniques used to cleanup oil spill accidents. What's the difference between Natural Dispersion, Collection, and Chemical Dispersion? In thinking about the oil tanker and military incidents outlined at this site, along with the recent Prestige disaster, which techniques were or could have been used and why?

Also check out the many other sources of oil pollution. You'll see from the pie chart that tanker accidents account for about 12 percent of the annual oil pollution, while runoff from urban areas accounts for 37 percent. When you look around your own community, can you find evidence of oil pollution? Do you see any cars leaking motor oil, for example? How many prevention measures can you think of that could help reduce oil pollution from urban areas? How can these local sites get cleaned up?

From Sea to Oily Sea

Wherever oil is being drawn out of the ground or transported across the landscape, there's always the looming danger that a spill will severely harm the environment. Such disasters can contaminate drinking water, kill wildlife, and undermine local economies that depend on fishing and tourism.

The 1989 Exxon Valdez oil spill was one of those cases, releasing about 11 million gallons into the Gulf of Alaska. But since that incident, the U.S. government has spent a lot of time and money studying the slick's immediate and long-term effects on Alaska and its marine ecosystems.

Visit the official Exxon Valdez Oil Spill website, and start at the Oil Spill Facts section. Read the Q and A page first, to understand how poor judgment - similar to the Prestige case - led to the accident. You'll also read about how clean-up agents experimented with different methods to learn what worked well and what didn't. In what ways did the oil harm wildlife species? Which ones could they help some and which not at all?

Go check out the Spill Map to see how the slick spread over the next couple of months and browse the Spill Photos gallery. Also, read the outline of the Trustee Council's Restoration Plan, the Lingering Oil page, and the Spill Prevention and Response page.

How was settlement money divvied up among the different needs? What did people learn about the short and long-term impacts of the oil spill? How well can current technologies clean-up such messes? How much must be left to natural processes and how long might it take to reach pre-spill health? In what ways does the local climate and other ecological conditions influence the rate oil can degrade?

Wildlife's Recovery

Even with people's help, wildlife can feel the brunt of oil pollution for years to come. While humans can get fresh drinking water and food from outside sources, plants and animals in their native habitats must rely on what they find where they live.

Read through the Status of Injured Resources page, which lists 30 different animals that were affected by the Exxon Valdez spill. Here you'll see the species names in groups based on their recovery status. Click on any of the resource names, such as Cormorants, Sea Otter, or Intertidal Communities - to go to a fact page. What exactly was the nature of the injury and how did it relate to how the animal lives? What is their recovery status and why? What are some of the limits on how well scientists can estimate population numbers? How are these factors similar or different between species?

Birds and mammals are one thing, but what about the fish? Your next stop is at the Alaska Fisheries Science Center's Exxon Valdez Oil Spill Research site. Check out the Fish Species and Oil section, and read the summary of oil's effects on salmon and herring eggs. You can also read about studies on some Other Species. Jump to each project's individual section for a more in-depth explanation of how the study was conducted, and hit the View Poster link to see a large image that summarizes the findings.

So what was so important about each of the projects? What species rely upon the health of another species for survival? How do you think these research projects contributed to understanding Alaska's marine and intertidal habitats? What kinds of questions have yet to be answered about oil's impacts on the environment? What more might we learn from further research to improve prevention and clean-up strategies?

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