If the crude comes ashore in great amounts the wetland, oyster flats, generally their entire interlocking ecosystems is destroyed. Estimates of time until recovery start at twenty years.

Exxon Valdez went aground in Prince William Sound in 1989 and parts of the area are still polluted. The black sheets of goop are gone but turning over a rock often produces visible oil and considerable amounts remain trapped in the gravel, sand and sediment of the area. So over twenty years may not be enough.

The good news is that Alaska is cold and biological processes run a bit slower in the cold and oil at those temperatures is thick and viscous. Florida and the gulf are much warmer so the thought is that biological activity is more aggressive and the oil will be easier to break down because it is less viscous.

One thing I haven't seen as a comparison between the two sites is that oil is not native to Prince William Sound so there was no great population of oil eating bacteria. The gulf has natural oil seeps that drain a few thousand gallons (WAG at 100 barrels) of oil into the gulf every year. This means that the populations of oil eating bacteria are naturally higher. Every gallon of seawater on the gulf is seeded with bacteria that love oil. Exposed to oil these bacteria eat, get fat, and double their population at an exponential rate.

That isn't a total solution, and it certainly doesn't mean we can kick back and do nothing, the gulf is screwed but that might offer a glimmer of hope that the majority of the area will clean itself more rapidly than what we saw in Alaska.

On the other hand, estimates of how fast the oil is leaking and how long it will take to staunch the flow mean that the spill in the gulf is likely to involve more oil than what we saw in Alaska. If they have to spend ninety days, longer if the weather doesn't cooperate, drilling a relief well the amounts could be huge. Pessimists are talking about waves of oil washing out of the gulf, engulfing the keys, and heading up the east coast. The sad part is that given the facts there is no easy to spot flaw in their logic that says that it can't get that bad.

On the bright side, given a few thousand years, nature can clean up most anything.

I have to point out that when that well was being designed someone asked how many layers of blow-out protection they would install. The cautious people in the room wanted more to protect the crews and lower the chances of a big spill. The accountants wanted fewer of those expensive devices installed, to save money. I wish they had installed at least one more.

Blow-out preventers are indeed expensive but how expensive are they in terms of the total cost of this situation?