Sea Otters Aren’t Just Cute – They’re Great for Seagrass Meadows

Written by on August 27, 2013 in Marine Life, Seals, Sea Lions & Sea Otters

Daily Summary

Carbon-sequestering ocean plants may cope with climate changes over the long run
A year-long experiment on coccolithophores(tiny, single-celled algae that play a vital role in the ocean’s carbon cycle) suggests that they may be able to grow their calcified shells even as the ocean gets more acidic. The researchers raised one strain of coccolithophore (Emiliania huxleyi) for over 700 generations under high temperature and acidified conditions and found that the organisms had no trouble building strong shells.

Another study on ocean acidification has more worrying results: Ocean Acidification, More Than Just Corals at Risk.

Risso's dolphins.

Risso’s dolphins. The scars you can see here are most likely from encounters with the dolphin’s favorite prey, squid. Photo credit: BBM Explorer via photopin cc.

Mysterious Dolphin Makes Its Home in Welsh Waters
A new study from Whale and Dolphin Conservation (WDC) has found that a rarely seen dolphin species now lives off the Welsh coast. The study found individuals from a population of Risso’s dolphins living and breeding in remote waters off Bardsey Island in north Wales. Risso’s dolphins are seen so rarely partly because they can dive to 300 meters and remain under for up to 30 minutes. The WDC study also provides the first population estimate for the dolphins.

Sea otters promote recovery of seagrass beds
A study of the decline and recovery of seagrass beds in a California estuary reveals that sea otters were a crucial factor in the recovery. Seagrass meadows, like the one in Elkhorn Slough (on California’s central coast), are threatened by nutrient pollution–excessive nutrient runoff can increase the growth of algae on seagrass leaves, which prevents the leaves from getting enough sunlight. Despite this problem, the seagrass beds in Elkhorn Slough have grown thanks to sea otters. Sea otters eat “enormous amounts” of crabs, which feed on sea slugs, which feed on algae. With fewer crabs preying on them, sea slugs become more abundant and eat much more algae, keeping the seagrass leaves clean.

Sea otters off the central coast of California.

Sea otters off the central coast of California. Photo credit: sarowen via photopin cc.

Copyright © 2013 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .


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  1. rhyne says:

    How are the crab populations doing after being under so much pressure from those cute little sea otters? They have quite the reputation for decimating eco-systems with those hungry little appetites too. At least the seagrass is doing well though.

  2. Emily says:

    As far as I know, the crabs are not under too much pressure. I just sent an email to the lead author of the paper to find out for sure. I’ll let you know what he says!

  3. Emily says:

    Lead author of the paper Brent Hughes was kind enough to answer right away: “The short answer is no, there are plenty of crabs (especially the ones we were studying) to resupply the marine environment with new recruits every year. In Elkhorn Slough we see a fresh arrival of crabs every year from outside sources (a process called recruitment).”

    So there’s one less thing to worry about 🙂