They may be microscopic, but some of the sea's smallest animals happen to be some of the world's great buffers against climate change - and they're fighting a losing battle.
Whether they have 11 pairs of legs or sport fins and scales, ocean animals play a crucial role in absorbing and storing carbon, according to a new report by the International Union for Conservation of Nature. Animals such as fish, krill and types of plankton are like roving pockets of carbon. They consume carbon, store it in their bodies and move it by swimming, floating or being eaten. By keeping carbon out of the atmosphere, they can slow the pace of climate change.
Though some of these creatures are tiny, the carbon they suck down is significant. Plankton are like a "biological pump," wrote the IUCN, responsible for sending 150 tons of carbon to the depths of the sea every year (equivalent to the carbon captured by a rainforest the size of the U.K.); krill consume 22.8 million tons of carbon.
Warmer seas don't just mean less ice for polar bears. They also threaten krills' survival. Their eggs hatch only when raised within a narrow band of temperatures, and a 2013 report found that as much as 20 percent of krills' Antarctic habitat is at risk of becoming too hot for the krill to handle.