The urchin on the right grown in seawater

The urchin on the right, grown in seawater under today's air conditions (400 ppm), is healthy and has normal spines. The urchin on the left, grown under very high CO 2 conditions (2, 850 ppm), is substantially damaged by the more acidic conditions. Weighing the urchins confirmed that they were actually dissolving in the more acidic high CO 2 conditions. (Micrograph below by Justin Ries, WHOI, and photo by Tom Kelindinst, WHOI)

In a surprising result, the lobster on the right, grown under a very high level of CO 2 (2, 850 ppm, or 10 times pre-industrial levels) grew a larger, heavier shell than the lobster on the left, grown under today's CO 2 level (400 ppm). (Photo courtesy of Justin Ries, University of North Carolina)

Blue crabs (Callinectes sapidus) grown for two months under today's CO 2 levels of 400 ppm (left) and under very high CO 2 levels of 2, 850 (right). This species showed an unexpected response to CO 2 level—the crab grown under the highest level (representing ten times the level of CO 2 in the pre-industrial atmosphere) grew a heavier, larger shell. (Photos courtesy of Justin Ries, University of North Carolina)

On the left, a conch from seawater under today's CO 2 levels (400 parts per million, or ppm) has a normal shell, with normal bumpy protuberances. The conch on the right, reared under very high CO 2 conditions (2, 850 ppm), has a shell that has begun to deteriorate, its protuberances dissolved away in the more acidic seawater. (Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)