National Geographic : 2011 Apr
The sea star on the left was raised in normal water in Kiel, Germany; the one on the right, initially identical, was raised in conditions that could occur in the Baltic Sea by 2100. Ocean acidification is amplified in some coastal waters by pollution from the land, which fertilizes blooms of microbes that take oxygen out of the water and put in more CO . The photographs are to scale. The sea star on the right weighs only a fifth as much as its peer.