A new study says that scientists underestimated the effects global warming is having on dead zones in bodies of water across the world. When fertilizer runoff is introduced into a body of water, it brings added nutrients like nitrogen and phosphorus into the mix. These nutrients sustain microbes and algal blooms, creating dead zones that choke off oxygen availability to marine wildlife. (MORE: Global Warming Might Push Back Fall Foliage Transformations) Scientists have long known that warmer water increases this...