Twenty-five years later, nature is still suffering from the Exxon Valdez oil spill

Although a quarter of a century has gone by now since the infamous Exxon Valdez oil spill, scientist have found since then that these spills can have very long-term and unexpected impacts on nature. This has not only increased our knowledge of the exact effects of these spills, but it's also showing us that companies need to be held responsible for longer, and giving more evidence that moving past fossil fuels really is for the best.

At just after midnight on March 24, 1989, the oil tanker Exxon Valdez was delivering over 200 million litres of crude oil from Alaska to California when it ran aground on the Bligh Reef. Official estimates at the time put the total amount of crude spilled into the waters of Prince William Sound at around 40 million litres (11 million gallons), although more current (and independent) estimates put it at nearly three times that amount (over 120 million litres). It took 21 years for another oil spill in U.S. waters — specifically from BP's Deepwater Horizon, in the Gulf of Mexico — to surpass it in volume, and even now, 25 years later, the Exxon Valdez spill is still causing harm to the local wildlife and ecosystem.

At the time of the spill, it was assumed that it was direct contact with the oil that caused harm to species. According to scientists who recently spoke with NPR, over the past 25 years of research and studies, including new work done after the Deepwater Horizon spill, we know a lot more about this, and just how little oil it takes to damage the wildlife.

Through a series of studies, the researchers narrowed the problem down to the effect the oil was having on the heart. Studying this in fish, they found that the heart was developing differently for fish exposed to the oil than for unexposed fish. However, it wasn't until after the Deepwater Horizon spill that researchers discovered exactly what caused this problem and how.

The damage was occurring due to one particular component of the oil, called polycyclic aromatic hydrocarbons (PAHs). Although some of the oil components, called aromatic hydrocarbons, evaporate fairly soon after they're exposed in the environment, these PAHs stay around for a lot longer. Studies over the past few years found that they act by blocking electrical signals in the fishes' hearts. This prevents the heart from beating properly, and even very small amounts of these PAHs can have an effect, over the long term, if fish embryos are exposed to them.

[ More Geekquinox: Weird Science Weekly: ‘Chicken from Hell’ dino terrorized Cretaceous era Dakotas ]

It's taken 25 years, but all of this has changed how we view these spills, and it should alter the way we respond to them — both legally and environmentally, and in how we plan our future.

We need to take a much longer view of the effects of oil spills, in the oceans and on land, in order to discover any more unexpected impacts that they have, not only on the environment, but potentially our health as well. Companies need to be held responsible for these long-term effects as well. A bigger issue, though, is our continued dependence on oil. The list of spills that have already happened is a very long one, and with this new perspective on their long-term effects, the toll these have already taken on the environment could be quite high. As long as we continue to use oil — and use more of it all the time — spills will continue to happen, only adding to the problem. It will take years for us to completely ween civilization off its oil dependency, but the time to start is now, so that we can leave this 'phase' of our development behind as soon as possible.

Geek out with the latest in science and weather.
Follow @ygeekquinox on Twitter!