The tide pools at Drake’s Point teem with life. Snails cling to wave-washed rocks. Nudibranchs—a squishy species of post-shell mollusk—pool about in colorful patterns. Kelp sways gently in the water while sea stars and anemones dot the tidepools with color bursts that look like living confetti. Being here, it’s easy to see how a curious mind would never run out of new interests to research. This is why, perhaps, Dr. Aaron Galloway spends multiple days a week here gazing into these small, underwater worlds.
Galloway, a marine ecologist, has spent 10 years studying kelp forest ecology and sunflower sea star recovery in Coos Bay, Oregon, at the Oregon Institute of Marine Biology (OIMB). His work explores the intricate relationships within kelp forest ecosystems, focusing on potential solutions to counter the devastation caused by the overpopulation of a specific species: purple sea urchins.
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In 1993, purple sea urchins began popping up in the waters of Coos Bay. At first, no one paid attention. But the thing about purple sea urchins is they can rapidly populate an area in a relatively short period. They reproduce annually between January and March, with female urchins being able to release millions of eggs at a time. This explosion of purple sea urchins disrupts the balance of other marine life in areas where the urchins find a foothold. When purple sea urchins overpopulate, they overgraze kelp forests—destroying vital habitats, reducing biodiversity, and destabilizing the marine ecosystem.
In 2013, Coos Bay saw the rapid rise of the purple sea urchin populations—often driven by the decline of natural predators like sea otters or sunflower sea stars. This boom in urchins has led to kelp forests at being overgrazed at unsustainable rates. As purple urchins feed on kelp holdfasts, the structures that anchor kelp to the seafloor, it causes entire forests to detach and disappear. As lush underwater habitats are reduced to "urchin barrens," species like rockfish, abalone, and sea otters lose critical food and shelter, leading to population declines. This loss disrupts the coastal food web and weakens the ecosystem’s ability to absorb carbon and produce oxygen, further endangering marine life in the region.
Galloway’s work is now focusing on potential solutions to counter the devastation caused by the overpopulation of purple sea urchins. One of his most promising areas of study involves the sunflower sea star, a predator whose recovery could hold the key to restoring balance to the kelp forests.
The sunflower sea star is a massive, fast-moving sea star with a soft, spiny body that can reach over three feet in diameter with up to 24 arms. Its colors range from orange and yellow to purple and brown, helping it blend into the diverse seafloor habitats it occupies.
This species is native to the Pacific Northwest, including the waters around Coos Bay. Once abundant along the West Coast, sunflower sea stars suffered catastrophic population declines due to sea star wasting syndrome, a disease that nearly wiped them out between 2013 and 2015. Their absence has contributed to the unchecked explosion of purple sea urchin populations, as they are one of the few natural predators capable of keeping urchins in check.
As researchers work to restore sunflower sea star populations, their recovery could provide a natural solution to the urchin problem. By reintroducing this key predator, scientists hope to control urchin numbers and allow kelp forests to regenerate. However, conservationists must also consider the challenges of reintroducing a species that is still recovering from disease and whether populations can be restored quickly enough to make a meaningful impact.
Once you know what to look for in the waters, a sea of purple appears. At first, it may be subtle—a patch here, a speck there. But then it’s impossible to ignore. Purple sea urchins cover the rocks in the water of Drake’s Point in overwhelming numbers, transforming the tidepools from a vast array of colors to a spiny purple expanse. At OIMB it's common advice that if you lose your balance while walking around the tidepools you shouldn’t fight it. Stepping on sea urchins is seen as a way of helping to combat them.
“Any chance to cull the purple sea urchin is welcome,” Galloway says. “Their populations have exploded so rapidly that researchers simply can’t keep up. Without intervention, they’ll continue to devastate kelp forests, which are essential for the health of countless marine species.”
But amidst the army of purple spins, there it is the sunflower sea star. Aside from being a keystone predator in this kelp forest ecosystem, it also has another edge on the purple sea urchin: similarly rapid population expansion.
Unlike other native and natural predators like sea otters, a single sunflower sea star each can “produce millions of eggs under the right conditions,” Galloway explains.
And while they are the Bay’s best chance at recovery from the urchin invasion, sunflower sea stars are still vulnerable to the sea star wasting disease. Research shows that one factor in its onset is rising ocean temperatures caused by climate change. This warming perpetuates a cycle of kelp decline, increased urchin populations, and the loss of native species.
Despite these challenges, Galloway remains focused on the future. He has identified potential factors that can help to restore kelp forests, like reducing carbon emissions, manually culling urchins, seeding kelp, and aiding in predator recovery. Of these, he explained how predator recovery offers the most promise. In a recent study, Galloway observed that a single sunflower sea star can consume five urchins in seven days.
Within the last month, the Oregon Kelp Alliance (ORKA) received extensive funding from the National Oceanographic and Atmospheric Administration (NOAA) to lead research into predator loss and reintroduction, furthering the efforts to restore balance to the ecosystem. While Galloway’s primary research is on sunflower sea stars, he is also an avid supporter of sea otter reintroduction. He works closely with the Elakha Alliance, an Indigenous nonprofit organization dedicated to reintroducing sea otters and native keystone predators to the Oregon Coast to restore kelp forests and the biodiversity they support.
“The whole ecosystem depends on that species being there to function properly,” says Chanel Hason, a marine biologist and sea otter recovery advocate for the Elahka Alliance.
Galloway hopes that with the combined efforts of Elahka Alliance, ORKA, and OIMB, a collaboration between scientists, governmental agencies, and Indigenous communities will bring Oregon’s underwater forests back to life.
"Kelp forests create this habitat—food, space, and structure—that feeds and protects juvenile rockfish, salmon, and invertebrates.” Galloway explains “Most things benefit from more kelp being around. When we lose that, we lose more than just the kelp; we lose the connections that sustain an entire community. Restoring kelp isn’t just about the environment—it’s about restoring balance for everything that depends on it, including us.”