Sea otters are warding off the accumulation of acidic carbon dioxide in Alaska’s waters by preying on sea urchins that feed on underwater kelp beds vital to the oceans’ health, according to a study.
Otter-protected kelp beds absorb about 12 times as much carbon dioxide during photosynthesis as thinned-out kelp beds, according to a study published in the September issue of Frontiers in Ecology and the Environment.
Atmospheric carbon dioxide threatens marine environments because the gas, when absorbed into the ocean, increases acidity levels, causing the phenomenon known as “ocean acidification,” according to scientists. So by devouring sea urchins, otters allow the kelp to grow and keep the oceans cleaner.
Urchin-eating sea otters produce a significant savings, according to the study’s authors, who said it would cost between $205 million to $408 million to offset the carbon that sea otters enable kelp beds to absorb, based on prices used in the European Carbon Exchange.
The study relied on data collected over 40 years from sites between British Columbia, Canada, and Alaska’s Aleutian Islands.
Co-author Jim Estes said he hopes the study will help people understand that sea otters have far-reaching benefits.
The Telegraph, 5 September 2012. Article.
Christopher C Wilmers, James A Estes, Matthew Edwards, Kristin L Laidre, and Brenda Konar. 2012. Do trophic cascades affect the storage and flux of atmospheric carbon? An analysis of sea otters and kelp forests. Frontiers in Ecology and the Environment Article (subscription required).
