Seep vs. Spill

One of the facts that is being used by pro-drilling folks to defend BP ( and offshore drilling in general ) is that nearly 1,000,000 gallons of crude oil leak into the Gulf Of Mexico every year from natural seeps in the sea floor. By their reasoning, the Deepwater Horizon spill is just an extension of this natural process.

They are wrong, because they are ignoring the spatial and temporal distribution of the oil.

What do I mean by that?
Back when I was a starving student, I owned a second-hand Mercury Grand Marquis that leaked nearly a quart of oil every two weeks from a bad seal that was prohibitively expensive to fix on my budget. So, I dutifully added oil to the crankcase twice a month. 2 quarts per month. 24 quarts per year. The oil leaking from my car was distributed in small drops on my driveway and on the roads that I traveled and in the parking lots where I parked over the course of the year. I had a small black spot in my driveway, but it wasn't a big deal.
That's an oil seep.

Now, for comparison, let's say that I took the same 24 quarts of oil and poured them out onto my driveway all at once.
That's an oil spill

And there is nothing natural about it.