Grist: Every year, millions of tons of nitrogen and phosphorus fertilizers wash down the Mississippi River and out into the Gulf of Mexico. There, instead of fertilizing corn, they fertilize the growth of algae, which blooms extravagantly and, in turn, creates a massive boom in microorganisms. There are so many aquatic microorganisms reproducing, eating algae and respiring at once, that they literally use up all the oxygen in the water. Anything else that needs to breathe oxygen - all the other marine life...