Two UC Santa Cruz researchers have discovered that besides being adorable, a large number of sea otters can help reverse one of the main sources of global warming by assisting in the spread of sea kelp beds.
UCSC professors James Estes and Chris Wilmers performed a study on otters, releasing their findings in a paper now available in the online journal Ecological Society of America. The study suggests that large groups of sea otters can keep the population of sea urchins from growing out of control, which will help underwater kelp forests that would normally be a favorite food of the urchins. Without urchins munching on the kelp constantly, the field grows and can absorb up to 12 times as much carbon dioxide from the atmosphere. Kelp is particularly effective at metabolizing carbon dioxide via photosynthesis, removing it from the atmosphere and slowing down global warming.
The two scientists and their co-authors compiled, correlated and analyzed 40 years of data on the population levels of the sea otters and the spread of the kelp in an area near the Aleutian Islands, finding that the otters “undoubtedly have a strong influence” on the levels of kelp spread and by extension, the levels of carbon dioxide in the atmosphere. With rafts of sea otters “preying on sea urchins, a kelp grazer,” the urchins take refuge in crevices and snack on scraps of kelp, allowing the kelp to spread. Without a large number of otters hunting the urchins, the kelp is razed by large numbers of hungry urchins.
Wilmers and Estes note that a spreading number of sea otters will not solve all global warming problems, but it is undeniable that helping the creation of larger kelp fields by protecting and restoring the otter population will “have a larger impact” on global warming than current proposed strategies of removing carbon dioxide from the atmosphere that ignore the actions and possible results of animals like the sea otter.