When the Exxon Valdez ran aground in 1989, spilling almost 11 million gallons of crude oil into Prince William Sound, the catastrophe kicked off one of the largest marine science efforts ever undertaken.

Scientists have spent the last eleven years trying to measure and understand the consequences of the spill, which spread oil over about 2,400 kilometres of coastline. Teams of researchers have collected reams of data on everything from fish eggs to seaweed, also looking for ways to help species injured by the oil.

In all about $285 million in U.S. dollars has been spent on hundreds of studies and restoration efforts, and it's not over yet. Plans are now being made to monitor ecosystems in the Gulf of Alaska for another century.

All of this research has led to huge advances in our understanding of how ecosystems are affected by one-time disasters. But it has also underlined the fact that science does not always operate in a vacuum, particularly when major lawsuits and large sums of money are involved.

Not all of the researchers were paid out of the same pot of money. Some scientists were working for a trustee council set up by the Alaskan and U.S. governments, while others were working for the Exxon Corporation. The different teams came up with very different conclusions on how the oil has affected species and ecosystems in the Gulf of Alaska.

"How you frame the question and interpret the results can make a really big difference," said Jennifer Ruesink, an assistant professor in the Department of Zoology at the University of Washington.

Ruesink is a co-author of a paper that reviewed the research conducted by the trustee council scientists, the Exxon scientists, as well as a study conducted by the National Oceanic and Atmospheric Administration on the use of hazardous materials in the cleanup process. She talked about the review in a Yukon Science Institute public lecture last Sunday.

Scientists working for the trustee council were paid out of the $900 million settlement that the Exxon Corporation paid in 1991. Exxon began hiring its own scientists after a class action lawsuit was also launched against the oil company.

For species after species, the trustee council scientists and the Exxon research teams came up with different conclusions. With sea otters,and common murres, for example, the trustee scientists found that densities had declined at oiled sites while the Exxon scientists found that densities were the same before and after the spill.

Alaskans are very concerned about the oil's affect on pink salmon since many people depend upon this species for their livelihood. The trustee scientists found that salmon egg mortality was higher after the spill while Exxon scientists found that egg mortalities were about the same before and after the spill.

These sorts of differences were reported in again and again. In general the Exxon scientists found that the oil caused fewer impacts, and that species recovered faster, than did the trustee council scientists.

It is a small wonder that when the case finally went to court in 1994, jurors did not know who they should believe. In the words of one juror, "You get a guy with four PhDs saying that no fish were hurt. Then you get another guy with four PhDs saying yeah, a lot of fish were hurt... They just kind of delete each other out."

The jury decided in favour of the citizens, awarding them $5 billion in punitive damages, but the decision is being appealed. In the meantime public concern over what is happening in the Gulf of Alaska remains intense, and that interest can present a challenge for scientists continuing to work there.

About 70,000 people live in the area directly affected by the oil spill, and many of them depend upon its resources for their livelihoods. They want to know when -- and if -- Prince William Sound will return to the condition that it was in before the spill.

With time, the Gulf Ecosystem Monitoring (GEM) project should help to answer their questions. The trustee council is funding this long-term monitoring program to track recovery in the Gulf of Alaska for the next century. It gives scientists an opportunity to better understand how ecosystems recover from catastrophes such as oil spills, and why populations of different species in the Gulf began fluctuating long before the oil spill.

Ruesink is on a National Research Council committee that will evaluate the GEM plan as it is put together. The GEM mandate includes ensuring that the public gets the information that it wants, which can present a challenge for scientists continuing to work in the Gulf.

Surveys have found that members of the public usually have very specific questions, such as "Will I get sick if I eat this clam?" Scientists on the other hand, are intrigued by something called the Pacific Decadal Oscillation (PDO).

This very complex theory holds that during Aleutian low pressure systems, ocean currents flow north, causing more upwelling, and higher productivity in ocean systems. During high-pressure systems, the reverse holds true. Many forces come into play, and it can take a decade even figure out whether a shift has happened.

But the PDO could explain why ocean species seem to go through such dramatic cycles, and this understanding could make it easier to answer the public's more specific questions.

And after all the research, and eleven years of effort, how is the Gulf of Alaska faring? That is a complex question with no cut and dried answers, but Ruesink says that she is impressed by how much the area has already recovered. "It is really remarkable to me that people had predicted disaster there for decades, and things came back quite amazingly rapidly," she says.

Jennifer Ruesink can be contacted at ruesink@u.washington.edu. Information on research in the Gulf of Alaska and the different efforts of the Trustee Council can be found at www.oilspill.alaska.us.