The Guardians of the Kelp Restoring an Underwater Forest
Along Norway’s wild northerly coasts, rampant sea urchins are destroying kelp – and entire ecosystems with it. Leading the fightback, a team of volunteer divers is giving the underwater plant a chance to establish a foothold and once again flourish into the nursery of the ocean.
With broad, brown blades reaching up to the surface, kelp is a regular sight in shallow oceans all over the globe. This commonplace plant makes vast, underwater forests that are some of the most dynamic and ecologically productive marine habitats in the world. Towering up through the water column, kelp forests provide vital shelter and food for young cod and other fish, as well as crabs and native sea urchins.
Consequently, when kelp is absent, the effects are profound. When divers from Norway’s northern city of Tromsø realised how degraded the local ecosystem had become, they set up Tarevoktere (Guardians of the kelp) to restore this keystone species.
We spoke to the co-leader of Tarevoktere, Ida Søhol, who told us about their work.
The destruction caused by sea urchins
“We have a huge problem with underwater urchin barrens,” says Ida. “Scientists believe that overfishing of predators back in the 1970s and 1980s led to huge expansions in urchin numbers.”
“Today, we have almost 15,000 kilometres of coastline that are dominated by these urchin barrens, due to a lack of urchin predators.”
– Ida Søhol, co-leader of Tarevoktere
“The loss of predators such as wolffish caused sea urchins to expand their feeding sites so much that they grazed the kelp down,” she continues. “Today, we have almost 15,000 kilometres of coastline that are dominated by these urchin barrens, due to a lack of urchin predators.”
Without the shelter and the habitat that kelp normally provides, it's very hard to re-introduce the species that used to be there. Ida explains that there’s a threshold of having enough kelp so the important predators of the urchins such as crabs and wolffish can return, and then keep the urchins under control.
Effects on the ecosystem of removing kelp
Without the kelp, you don't really have an ecosystem,” explains Ida. “When we dive here, we can tell that the ecosystem is not in balance; there's just no biodiversity.”
“Kelp forests are very productive ecosystems that are a hotspot for marine biodiversity. They serve as the nursery and feeding ground for so many organisms. So, it’s a very important habitat for a considerable number of marine species,” she continues.
The benefits don’t stop there. Kelp s also photosynthetic, meaning it captures energy from sunlight in order to grow, and it functions as a carbon sink. This makes kelp forests very important in the work against the climate crisis. What’s more, it filters seawater and protects the coastline from erosion by damping sea movements near the shore.
Fighting back against the urchins
“We are behaving like the predators, so we either remove the sea urchins or eliminate them so the kelp forests can come back,” says Ida.
“We are behaving like the predators, so we either remove the sea urchins or eliminate them so the kelp forests can come back,” says Ida.”
– Ida Søhol, co-leader of Tarevoktere
“We've tried different methods such as just crushing them where they are with hammers. It sounds very dramatic, but I think it's actually one of the best methods. Then they serve as food to many other species.”
After working in this way for a year, the team could see more species coming back. They believe the nutrients made available by crushing the urchins is speeding up the process of the species reinhabiting the restored kelp area.
Encouraging results so far
The team has already succeeded in restoring a few sites, where they’ve observed a clear shift from a lifeless oceantowards a balanced, healthy ecosystem with different fish species, crabs, and starfish.
“It's wonderful to see how a small intervention has had such a positive impact on the local ecosystem right here,” says Ida.
“It's wonderful to see how a small intervention has had such a positive impact on the local ecosystem right here.”
– Ida Søhol, co-leader of Tarevoktere
“When we use less than a year and we can restore a kelp forest, that's kind of crazy. Then I think it must be possible to fix the problem quickly.”
Support from Hurtigruten Foundation
With a grant of NOK 50,000 (approx. €4,400), the team will continue their valuable marine wildlife restoration work, and maintain their diving equipment.
“Our number one goal is to expand our work as much as we can and invite all of the diving clubs that are interested in joining,” says Ida. “So far, we're about 150 divers, and we’re working on including the diving clubs that are close to us, and then expanding to other parts of northern Norway, to as many as we can find. With a grant like this, we can definitely do that.”
It's also important to the team to reach out to the local community, to students, and to everyone who wants to learn more about Norway’s oceans and coastline. They talk about the issue and the work they do, inviting the scientists with whom they've been collaborating to explain its importance.
As Ida concludes, “This problem affects everyone – not only the people who actually see it. We all need a healthy ocean and a healthy coastline.”
Where can I learn more?
You can read more about the work of Ida and her colleagues on the Tarevoktere website.
If you would like to learn more about travelling to Norway, see Hurtigruten Expeditions’ cruises to Norway.