Phyllaplysia taylori, also known as eelgrass sea hares, are wonders of their ecosystems and way more than “humble, zebra-striped slices of green jello.” These small aquatic slugs stand out thanks to their bright coloring, zippy patterns, and bunny-like tentacles or rhinophores, but they also do a stand-out job of eating the microscopic algae that gathers on the blades of marine seagrass.
Slurping up the algae on the eelgrass lets more sunlight hit the plants so the meadows can keep growing. Seagrass meadows help control erosion and absorb carbon from the atmosphere. Also, they make some sweet digs for all kinds of creatures.
When sea otters were reintroduced to Elkhorn Slough, they started eating the crabs that eat the sea hares. This meant the sea hares could get back to work cleaning the eelgrass of excessive algae, enabling the eelgrass to grow again. Researchers call this a trophic cascade, when a top predator, like a sea otter, has a balancing effect on the ecosystem.
In an eelgrass ecosystem like Elkhorn Slough, where nutrient-polluted waters cause regular extreme algal blooms, the “grazers just become really, really important for controlling that algal overgrowth.” When otters were missing and not eating crabs, the crab population grew and ate too many sea hares, so the eelgrass had less help dealing with the suffocating algae growth.
Read more about the challenges faced by these Pacific coast ecosystems at KQED.
Then watch more videos about sea slugs, otters, and all kinds of crabs, including:
• These stunning sea slugs steal ‘weapons’ from their ingested hydroid prey
• This Jorunna sea slug looks like a tiny, fluffy “sea bunny”
• A crab takes a video camera into its hole
• For sea otters, lounging around is the key to conserving energy