Two researchers from the University of California, Santa Cruz have suggested that sea otters could play a significant role in the fight against global warming. The duo notes that a healthy population of otters would lead to a reduction in sea urchins—which the otters feed on—and thus allow kelp forests to prosper. Kelp is often consumed by sea urchins, but if enabled to grow to maturity the plant could absorb as much as 12 times the amount of CO2 from the atmosphere than it does at its current rates of growth.
The team’s theory was written by UC Santa Cruz professors Chris Wilmers and James Estes and published in Frontiers in Ecology and the Environment. In it, Wilmers, who is an assistant professor of environmental studies, said: “It is significant because it shows that animals can have a big influence on the carbon cycle.” The Santa Cruz team looked at 40 years of data on otters and kelp bloom from Vancouver Island to the western edge of Alaska’s Aleutian Islands and discovered that otters “undoubtedly have a strong influence” on the cycle of CO2 storage.
They discovered that by comparing kelp density with otters and kelp density without otters,that sea otters had “a positive indirect effect on kelp biomass by preying on sea urchins, a kelp grazer.” With a large sea otter population, it was discovered that sea urchins hid in crevices and ate kelp scraps, instead of feasting voraciously on living kelp.
Like seagrass, kelp is particularly efficient at sequestering CO2 from the atmosphere through photosynthesis. The team said that since the beginning of the industrial revolution, CO2 levels in the atmosphere have risen by more than 40% causing global temperatures to rise.
While otters will not be able to solve all of the planet’s global warming woes, Wilmers and Estes argue that “the restoration and protection of otters is an example how managing animal populations can affect ecosystems abilities to sequester carbon”.
“Right now, all the climate change models and proposed methods of sequestering carbon ignore animals,” Wilmers said. “But animals the world over, working in different ways to influence the carbon cycle, might actually have a large impact.
“If ecologists can get a better handle on what these impacts are, there might be opportunities for win-win conservation scenarios, whereby animal species are protected or enhanced, and carbon gets sequestered,” he added
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