Hypoxia and Medicine - Is the "Dead Zone" in the Gulf of Mexico made worse by AGW,or is it a "hoax" or a "natural occurrence"?

Is the "Dead Zone" in the Gulf of Mexico made worse by AGW,or is it a "hoax" or a "natural occurrence"?

There is a "Dead Zone" off the Wash. / Ore. coast also. http://www.kristy/global/story.asp?s=8718376

I think it has to do with agricultural run off but not sure. Here is an article that isn't going to help matters http://news.yahoo.com/s/nm/20080723/us_nm/oil_spill_louisiana_dc
The dead zone is a natural occurrence. It is formed when salt and fresh water mix in large quantities. It is rather large this year due to the midwest flooding in the spring.