Seaweeds create marine habitats the same way trees do on land, producing food, places for whales to forage, and a significant amount of the oxygen we breathe. [downloaded from https://medium.com/ubcscience/seaweed-school-c597a6cf882f\

Floopy, floppy seaweeds have developed a following of sorts amongst scientists. Some study it from a botany and ocean sciences perspective and others from a materials perspective. A July 27, 2026 University of British Columbia (UBC) news release (also received via email) describes a special programme for children on Hornby Island (a Gulf Island found between the British Columbia mainland and Vancouver Island), Note: The wellness community has also discovered seaweeds,

Burying underwear in soil isn’t a typical science lesson. But for students on Hornby Island, it’s one way they can learn how seaweed supports local ecosystems.

The activity and others like it are part of Seaweed School, a unique partnership between UBC and Hornby Island that’s training the next generation of coastal scientists while helping local students stay in their home community for an extra year of school.

We sat down with Dr. Bridgette Clarkston (BC), school co-creator and an associate professor of teaching in UBC’s Department of Botany, and Seaweed School alumna Ava Zielinski (AZ), to discuss how the school is helping students care for the coast they call home.

Why should we care about seaweed?

BC: Seaweeds are the forests of our oceans, primary producers of ecosystems providing oxygen, food, carbon sequestration and more. But with climate change, we’re seeing drastic declines in some key species. So it’s important to get children—our future leaders and environmental guardians—hooked on protecting seaweeds from an early age.

We used to have much more extensive kelp forests in the inner Salish Sea, but most of the big canopy-forming kelps have perished over the last few decades, likely due to rising temperatures. The Hornby community wants to know how they can care for seaweeds in this time of climate change and ecological instability.

How did Seaweed School come to life?

BC: Hornby Island doesn’t have a high school. Starting in eighth grade, students face a two-hour, two-ferry commute to the nearest one in Courtenay, and some families end up moving away. I was approached by Heather Royal-Brant, a teacher at Hornby Island Community School, as part of an initiative by the school and the Hornby Island Natural History Centre to help Grade 8 students stay on the island for an extra year. Together, we co-created Seaweed School.

How is Seaweed School training the next generation of coastal scientists?

BC: Students are learning how to identify, study and monitor the seaweeds around Hornby Island. In the first year, they were assigned “seaweed buddies,” a seaweed species to learn about throughout the year. Along with UBC biology undergraduates, I taught middle school students how to collect and scientifically label specimens. These are now housed in the Beaty Biodiversity Museum with the students listed as the official collectors.

This year, Grade 7, 8 and 9 students are testing the power of seaweed compost, burying cotton underwear in soil treated with either seaweed tea (a fermented mix of seaweeds) or seaweed mulch straight from the sea, or in a control plot with no compost. The whole school voted on which treatment would decompose underwear the fastest. The seaweed tea won.

AZ: My “seaweed buddy” was Turkish towel (Chondracanthus exasperatus). I also learned about photosynthesis, how to press seaweed and how to identify some of the common species around Hornby.

My favourite fun fact is that most seaweeds around Hornby are edible and some have really good health benefits. If I’m down on the beach, I’ll snack on some.

My favourite lesson was when we did fieldwork with the UBC students. It got me thinking that I might want to go to university and share my seaweed knowledge with other students in the future.

What’s next for Seaweed School?

BC: Over the summer, the Seaweed School team will monitor vegetables planted in the “dirty underwear” plots to see which one yields the most produce.

We’re also running the Big Seaweed Search Hornby Island, a community-led seaweed monitoring program for the public. Every month, residents will identify different seaweed species using information cards the students created. This will run until the end of this year.

I would love to work with other communities and other schools. Working on this project has taught me the importance of having relationships with the land and reciprocity, so I would want build a relationship with a community and tailor the offering to their needs.

This research is funded by the Marine Environmental Observation, Prediction and Response Network.

Geoff Gilliard’s May 4, 2026 article (found on Medium) about Seaweed School provides additional detail,

On a gloriously sunny day 11 schoolchildren scamper barefoot across a beach on Hornby Island searching for seaweed. Who knew school could be so much fun?

Dr. Bridgette Clarkston did.

…

Seaweeds are a subset of algae. The many thousands of species worldwide are classified into three branches of the seaweed family tree of life — red, brown and green. Seaweeds photosynthesize and are foundational to coastal marine ecosystems, but the three branches evolved independently. Red and green seaweeds are grouped together with land plants like mosses and vascular plants — brown seaweeds are related to microscopic algae called diatoms.

“We’re very lucky in this part of the world because there’s an overlap where two iconic kelp species live — bull kelp, Nereocystis luetkeana and giant kelp, Macrocystis tenuifolia,” says Dr. Clarkston, who specializes in seaweed biodiversity. “Think of these two ‘canopy-forming’ kelp as the redwoods or Douglas-fir trees of the underwater forest, reaching from the seafloor to the water’s surface, creating a three-dimensional underwater habitat.”

Coastal B.C. is a diversity hot spot hosting over 600 species of seaweeds. But climate change is driving drastic declines. Summer sea surface temperatures of the inner Salish Sea are hitting 20 or 21 degrees Celsius. That’s about six degrees too hot for some kelp to grow.

“We’re seeing declines in some kelp species in British Columbia for a number of reasons. In some areas, in particular the inner Salish Sea between Vancouver Island and the mainland, warming waters may be one of the biggest drivers of this loss,” Dr. Clarkston says. “Bull kelp used to be quite abundant in the waters near Hornby Island and my hometown of Comox. Now they’re gone.”

…

Alongside Western science and traditional ecological knowledge, community involvement makes up the third strand of Seaweed School’s “braided lens” approach.

Seaweed fertilizer does what common farming practices no longer do — help rebuild and regenerate soil through enhancing its microbiological activity and adding essential nutrients. It’s a common method used at Hornby Island’s community garden where clinical herbalist and Seaweed School collaborator Angela Willard guided the students through a project called Dirty Undies.

“The dirty underwear test is a way to gauge the microbiological activity of your soil, and demonstrate the connection between the health of soil and seaweed,” explains Ms. Willard. “You bury 100 per cent cotton underwear in your garden and the faster the underwear rots, the healthier the soil — because it’s biodegrading the cotton. Usually the underwear is buried for a 60 day window. We chose to do 90 days because we took into account the winter months are cooler, so the microbial activity is a little bit slower.”

Late last winter, three plots were set aside in the Hornby Island community garden to run the Dirty Undies test. On the first plot only leaf mulch was applied — the control treatment. On a second plot, large amounts of seaweed were stacked in piles on the soil in the traditional way. The third plot was dosed with seaweed tea, concocted by adding seaweed to a water base and letting it “steep”. As the mixture ferments, seaweed nutrients are extracted and enhanced in the tea.

The goal of Dirty Undies is to see which pair of underwear buried in the three plots breaks down fastest. Seaweed tea requires much less seaweed than mulch. If the tea plot wins out over the other two, it could reduce the amount of biomass removed by gardeners from Hornby Island beaches, allowing the seaweed to remain and replenish the habitats.

At the end of the experiment, there was a bit of cotton left in the control treatment, and a tiny bit left in the stacked seaweed treatment. No cotton remained in the seaweed tea treated undies.

“Everyone in our school wrote down which test plot they thought would decompose undies the fastest and why,” says Ms. Royal [Heather Royal-Brant, teacher at Hornby Island Community School]. “It created natural enthusiasm in the community garden to engage with the scientific method. It’s one of the ripple effects Seaweed School has — now we’re rippling into the community gardeners.”

…

There’s still more interesting detail in Gilliard’s May 4, 2026 article.

Hornby Island is nestled in the northern end of the Salish Sea between Vancouver Island and the mainland. Just over 1,200 people live on the 30 square kilometre island. [downloaded from https://medium.com/ubcscience/seaweed-school-c597a6cf882f]