Why We Need The Purple Sea Star

In an ongoing series on keystone species, each Nature Links participant has chosen a species that is crucial for the survival of its own ecosystem. The purple sea star does exactly that, and we had the pleasure of learning about it in a class taught by participant Derian Gatewood.

In its habitat along the Pacific coast of the United States, the purple sea star plays a crucial role in maintaining the balance of marine ecosystems by preying on mussels, controlling their population, and preventing them from dominating intertidal communities. This creature’s presence promotes biodiversity and supports the survival of numerous other species giving it significant ecological influence.

In Derian’s excellent class, she taught us that purple sea stars are not always purple (they’re sometimes orange or reddish), they can lose an arm and grow it back and they digest mussels by putting their stomach outside their bodies and into the shell of the unsuspecting mussel. Purple sea stars, while incredibly crucial to the well-being of the Pacific intertidal zone, are suffering from a mysterious sickness called sea star wasting disease. Scientists are unclear on the causes of the disease, but it can lead to the deterioration of sea star bodies in just 3 days.

A slide from Derian’s presentation about how the mysterious “sea star wasting disease” can destroy the purple sea star

In this informative, student-led series, we’ve learned about how coyotes, beavers, bats, spruce budworms, mountain lions, saguaro cactuses, and wolves are indispensable in maintaining a delicate balance of organisms where they live. Here at Nature Links, we believe that we are all teachers, and our participants have so much knowledge to share. Great job to Derian and the other Nature Links participants who shared a fascinating range of knowledge on why we need the survival of keystone species like the purple sea star.