OIMB's Galloway Takes Readers On Deep Dive

Red sea urchins. Photo by Markus Thompson

Last fall, Aaron Galloway, an assistant professor with the UO’s Oregon Institute of Marine Biology (OIMB), took his first-ever trip in a submersible: Cyclops 1 is a prototype sub developed and operated by OceanGate, of Washington state. Galloway and colleague Alex Lowe, of the Smithsonian Institution, searched for red sea urchins in the inland waters between Washington and British Columbia. Galloway described the experience to Oregon Quarterly.

I love being underwater. I spend as much time as I can in the water. I’m a scuba diver and I’ve done hundreds of dives in the San Juan Islands. But being in a submersible—that was a frontier I’d never explored. I was honestly a bit terrified to get into this little tube and dive to the bottom of the ocean.

When I first got into the sub, it felt really tight—it was like having five people in a little Volkswagen bug. I didn’t sleep well the night before, I was nervous, I was thinking about stuff you shouldn’t think about when you go on a sub dive—what if the power goes out and we’re stuck on the bottom of the ocean? I was reflecting on different parts of my life, as if it might be coming to a close. Is this worth it?

But as we descended, I got really excited and the worries just disappeared. I was in the front, and the whole front of the Cyclops is a window. It’s amazing to sit there with your head in this glass dome and see ocean all around you. By then, it felt like there was plenty of room in the sub. I was in a group of four scientists and the pilot, and this was something we’d wanted to do our whole lives. It was like being a kid at Disneyland.

We wanted to start simple and see how deep we could find red urchins and the drifting algae they usually eat. Urchins are at the base of the food pyramid—they eat algae and kelp, making food available to smaller critters, and they’re also an important food for sea otters in some places, and even people. Urchins have a cool and important role to play in marine ecosystems. Unfortunately, organisms like algae and urchins are often ignored as people tend to focus on splashier vertebrates, like fish or marine mammals.

The deepest red urchin on record was 410 feet. We were scheduled for a two-hour trip, going more than twice as deep, to 950 feet—taller than the tallest skyscraper in Seattle [the Columbia Center rises 937 feet]. No kelp grows at 900 feet, there’s no sunlight. Finding urchins that deep would raise new questions about urchin ecology, because the prevailing view is that these urchins are primarily herbivores.

Aaron Galloway felt anticipation–and a bit nervous–before his first-ever dive in the submersible Cyclops. Photo courtesy Aaron Galloway and OceanGateFood Processors of the Deep

Why do I study urchins? They’re just so weird. They’re like the result of an artist visualizing an alien life form in some ocean anywhere in the universe.

Red urchins can live more than 100 years, and old individuals can be huge—they can be the size of a basketball, they have these three- or four-inch spines radiating off, hundreds of them, very sharp. Next to the spines are little tube-like structures called pedicellariae with three little jaws on the end—they can use these appendages to defend themselves. Urchins don’t have eyes, per se, but do respond to differences in light; they move around by remarkably coordinated locomotion of tube feet. However, in the San Juan Islands, we’ve shown that they don’t move much, presumably because their food usually just comes right to them.

When a piece of kelp drifts by, the urchin spines will catch it—like chopsticks—and the tube feet will glom onto it and pin it down and manipulate it down underneath, to its mouth. The mouth looks like a star—it has five different teeth, they’re like triangles, they come together like a camera aperture with five panels. It’s called an Aristotle’s lantern.

Red urchins are basically shredders; they mostly eat kelp and other algae, pooping it out and making it available to smaller critters like hermit crabs and snails. Urchins are also important food—both for otters and humans. Have you heard of uni? Uni is a sushi ingredient—it’s the gonads of an urchin, five gold or yellow lobes, each about the size of your thumb. The red urchin is one of the main species harvested. It’s a valuable fishery along the Pacific coast.

Unfortunately, when urchin numbers get out of control they can mow through a kelp forest and eat it down to the rock. That’s bad, because kelp creates critical habitat for all kinds of organisms. Sometimes people are so alarmed about urchins taking over that they consider efforts to control or eradicate them. I’m studying this right now. It’s tricky; if you don’t have urchins, you don’t have the food source for the smaller organisms, or the otters, or the fisheries for the uni. It’s pretty complex—in ecology all of these things are connected.

Outside, A Lab the Size of an Ocean

On the creature's underside is "Aristotle's lantern"–a mouth consisting of five teeth. Photo by Rey M Yoshioka, PhD student, OIMBIn my research, I focus on the relationships between algae and creatures like urchins, because I’m fascinated by the fact that algae play an important ecosystem service of synthesizing essential omega-3 fatty acids. The long-chain omega-3 fish oils that are so important to health? Algae create them, not fish! Algae synthesize these molecules which are passed up the food chain from herbivores to predators like fish and mammals. It’s important to know how these fatty acids are transferred from one organism to another because we can’t create these molecules, they come from what we eat.

I try to figure out which foods are critical for these marine creatures by measuring their own fatty acids after we experiment with their diets. For example, we’ve tested the fatty acids of red, purple, and green urchins after feeding them different algal diets—these experiments help us discover what wild urchins are eating in different habitats, including extremely deep water.

When I applied for my position at the UO in 2015, nobody at OIMB was specializing in marine macroecology, so this has become my niche. OIMB is right on the coast, it’s a marine biologist’s dream location. I get to go scuba diving and see really special things right outside our back door. The UO is building me a lab here where we’ll be able to experiment with urchins and other creatures like Dungeness crab and abalone.

On another dive on this trip, we saw a giant Pacific octopus. The thrill of that was enough—“Oh my god, there’s a GPO! GPO!”—and then somebody said, “Hey, there’s a lingcod right in front of it.” I didn’t even see the lingcod at first! The lingcod was in the 20-pound range, it was probably hunting that octopus—I’ve seen lingcod with octopus tentacles hanging out of their mouths. They were basically squaring off, like, who’s going to move?

On our dive to find the deepest red urchin, as we were dropping to the ocean floor, it got really dark and cold. You weren’t allowed to wear shoes in the sub—they don’t want any kind of bacteria in there. The ocean temperature was about 55 degrees, and eventually that room got down close to that temperature. We had these little chemical toe-warmers in our socks.

The craft's front-facing dome offers expansive views of the marine world. Photo courtesy of Aaron Galloway and OceanGateBy the time we were 400 feet down, it was really black. We had these big floodlights on, they were illuminating what we call “marine snow”—it’s the detritus in the water, dead phytoplankton, poop from plankton and fish. It’s like being in a blizzard. Finally we saw the bottom. The first depth I wrote down was 950 feet—Alex and I just kept looking at each other: “Whoa, we’re over 900 feet deep now, that’s just crazy.” Once we were on the sea floor, the water pressure outside was more than 25 times greater than at sea level. But the sub is pressurized—my ears didn’t even pop on the way down.

The previous maximum recorded depth for a red urchin was 410 feet, but we expected we might find them deeper. Six minutes into the dive, at 931 feet, we saw a red urchin. As soon as I saw the tell-tale red spines I grabbed Alex and yelled out—“There it is! Deepest red urchin! Deepest red urchin!” That’s official. That became the deepest red urchin. We’ll update the records.

What does it mean? Here you have red urchins living more than 900 feet deep—we only saw one on that dive since the visibility was so poor, but there are certainly more down there. It must be that there are either nutritional subsidies that feed them in deep water—for example, kelp drifting down to them—or maybe they’re more omnivorous than we’d expected. This expands the environment that is possible for them.

The only downside is, we didn’t get a picture of that deepest urchin. People will say, “I want to see a picture.” Well, I got the coordinates, and the raw data sheet with the notes. We are scientists, after all, and people are going to have to take our word for it, I guess.

—By Aaron Galloway, OIMB aquatic ecologist, as told to Oregon Quarterly

Photos by Markus Thompson (red sea urchins in seascape) and Reyn Yoshioka, PhD student, OIMB (closeup of sea urchin); others courtesy of Aaron Galloway and OceanGate