Finding Life at the Rocky Edge of the Sea
Students in Allison Barner’s course Marine Biology of Coastal Maine get an up-close look at the intertidal zone
At the edge of the sea, the ocean’s constant ebb and flow fills tidepools and creates a unique ecosystem where tiny creatures abound.
The rocky intertidal zone is where Allison Barner, Clare Boothe Luce Assistant Professor of Biology, has focused her teaching and research. This year, she’s teaching a new course, Marine Biology of Coastal Maine, that gives students a firsthand look at the science—and magic—that happens in the liminal space where waves and rockbound shore meet.
Between the high and low tide marks there’s a world filled with small, often slow-moving organisms like sea stars, mussels, and barnacles, seemingly ready for a kid or a scientist to crouch down and watch for minutes or hours. The wonder of the intertidal zone is equaled by its accessibility—there’s no need for specialized training or equipment to get there.
“If I wanted to study what’s happening on the bottom of the ocean, I would need a vessel. I’d need to be a diver. But in the intertidal, all we have to do is wait for the tide to be low, put on our boots, and just tromp down,” Barner said. “It’s a really rare marine and ocean ecosystem that, luckily, every day for some period of time, is exposed to the air and accessible to us as humans. It’s an incredible opportunity.”
The treasures of tidepools
This semester, Barner took her students on an overnight field trip to Allen Island, part of Colby’s Island Campus in Maine’s Muscongus Bay. They followed the schedule set by the tides, pulling on their waterproof boots to head to the shore early in the morning and late at night.
They searched the tidepools for organisms they’d studied in class and collected seaweed to press for the College’s collection of preserved plant specimens. Part of the field trip’s thrill was they didn’t know what they would find, from predatory snails to worms, sea urchins to crabs. There were tunicates, a marine invertebrate animal, and they also spotted juvenile lobsters swimming in a tidepool, which serves as nurseries for many different species.
“We were trying to find new things that we hadn’t seen before,” Barner said.
When she found a large, bright green sea sponge and called the students over to look at it, “they all gasped,” she recalled.
“Most students haven’t spent time in this intertidal area, an ecosystem found on every coastline on the planet. To really get them to make connections between what we’ve talked about in class and saw in the field, that was really fun,” the professor said.
A closer look at marine organisms
When Barner came to Colby five years ago, she discovered students were interested in learning more about the fundamentals of marine biology. They wanted to learn about seaweed and the anatomy of marine organisms to know the answers to questions like, “How do sea stars eat?”
A marine community ecologist with research experience in the interactions between species and the impact of climate change on those interactions, Barner got to work. She developed a broad survey course that gives students a closer look at the taxonomy, biology, and ecology of Maine’s coastal organisms.
The students study the marine organisms living in a saltwater aquarium in the Arey Life Sciences Building, use 3D models of different organisms, and utilize other hands-on learning. The overnight trip to Allen Island and an upcoming trip to the Bigelow Laboratory for Ocean Sciences in East Boothbay are also important components of the course.
“The goal is to see these organisms in their natural context because that is the environment in which they typically evolved,” Barner said. “You can stare at a page as much as you want, or a slide, or a 3D model, but it’s different when you [see it in its environment]. It’s really remarkable just to see these things move.”
Learning how to observe
We live in a fast-paced world that has many competing demands on our attention, from phone message chimes to breaking news alerts, and more. To do the kind of science Barner loves requires nurturing a different kind of skill: how to observe.
This semester, students are learning how to look at organisms they find in nature and figure out how to identify them. It requires slowing down and concentrating on what they see before them.
“It’s a very hard thing to teach and to learn, but learning how to observe nature is really important,” Barner said. “It’s easy to overlook because it basically means you’ve got to just look at something for a long time. One of the things I’m trying to do with this class is to develop those skills of observation. How much do you notice when you look at something for a couple of minutes, for 10 minutes, for 20 minutes? You start to notice more and more and more.”
At first glance, the rocky intertidal zone might look like it’s home to rocks and not much else. But through taking a closer look, a person might spot something moving in the rocks, then a slight tinge of color that could indicate seaweed or barnacles. The intertidal world expands out from there, leading to all kinds of possible discoveries for a patient onlooker.
“It’s hard to get everybody to slow down and focus on something for a really long time, but it’s very rewarding,” Barner said. “To just try to tune other things out and see what you can see in the world around you.”
