Friday 14 July 2023

Pacific kelp forests are dying off at alarming rates, but experts say there's room for optimism

One of the ocean's greatest supporters of life is finding itself hanging on by a thread.

Pacific kelp forests have been depleted by more than 90% in just a few short years., and scientists say their survival is critical.

Kelp forests provide crucial habitats to support marine animals, and humans around the world benefit from healthy kelp because they protect our coastlines from waves, absorb carbon dioxide from the atmosphere and produce oxygen like trees on land.

And a new study published earlier this year revealed that healthy kelp forests contributed more than $500 billion to the world economy.

Needless to say, their survival has a direct impact on our own.

Surfers paddle near dying kelp beneath Scripps Pier on August 7, 2018 in San Diego, California. (Photo by Mario Tama/Getty Images)
Surfers paddle near dying kelp beneath Scripps Pier on August 7, 2018, in San Diego, California. (Photo by Mario Tama/Getty Images)

So why are they dying? Well, the main driver of the massive die-off, like many other problems facing the world's oceans, is global climate change.

Jennie Dean, Vice President of Education and Conservation at the Aquarium of the Pacific in Long Beach, says warming waters is having an adverse effect on Pacific kelp forests, as warm waters are not conducive to kelp growth.

Kelp prefers clear, cold, nutrient-rich water with temperatures ranging between 42–72 degrees. Any higher, and kelp will begin to struggle.

"It slows it down," Dean said in an interview with KTLA. "We saw significant declines in 2013, due to that warming water, but also several other compounding factors."

Other threats to kelp include a loss of predators that existed naturally in the kelp forests, leaving many other species with free rein to dine.

Urchins are among the biggest threats to kelp, Dean says. Urchins like to eat the "holdfast" of kelp, which is a root-like structure that attaches kelp to the seabed. When that part of the kelp is killed, the rest of the organism goes with it.

Sea otters hunt urchins, keeping the kelp-eaters at bay, but sea otters have their own long, traumatic history in California and were at one point nearly hunted to extinction as part of the fur trade. They remain a threatened species and to this day are listed on the endangered species list.

"So as otters were removed, sea urchin populations were able to grow unchecked and therefore they're very effective, essentially grazers, mowing down the kelp," Dean said.

Another compounding factor creating the perfect storm for the razing of Pacific kelp forests is a disease that has laid waste, literally, to one of the ocean's most important predators.

Sea star wasting disease is a little-understood biological phenomenon that has devastated sea star populations across the globe. According to the National Park Service, symptoms of the disease include "abnormally twisted arms, white lesions, deflation of arms and body, arm loss, and body disintegration."

While it's unclear if the disease is caused by bacteria or viruses, it's believed that warm ocean waters make the animals more vulnerable to easily-transmissible and deadly diseases, the NPS says.

Sea stars were another important predator that lived amongst the kelp forests, and their disappearance has disrupted the balance of the underwater ecosystem, Dean says.

These factors, each amplifying and magnifying their impact due to the combined existence of each other, have resulted in massive die-offs of Pacific kelp forests. In Northern California alone, bull kelp populations have decreased by more than 95% in only the last 15 years.

But Dean and other researchers say there is room for optimism.

Kelp is resilient, robust and grows at such a rate that it can bounce back under the right circumstances.

Many organizations are working together to advocate for the critical piece of the ocean ecosystem.

The Aquarium of the Pacific has partnered with the Monterey Bay Aquarium - two of the most prominent and well-respected aquariums in the world - as well as other institutions, to brainstorm and strategize how to protect kelp forests and maintain the balance that allows them to thrive.

Monterey Bay has a renowned otter rehabilitation program that nurses stranded otters and raises orphaned pups and reintroduces them to the wild when they're healthy and mature to survive on their own.

In March, the Aquarium of the Pacific launched a new program that aims to help the bull kelp population in California waters. Similar to a seed bank that protects the biodiversity of the world's plant species, the aquarium is embarking on a project to help facilitate future kelp restoration projects by preserving the important genetic material of bull kelp. The genetic material, or gametophytes, will be stored at the Long Beach aquarium and can be used to grow kelp and "reforest" ecosystems off the coast.

With cooperation from the ocean community and those living on land, kelp forests could become the next great conservation success story, Dean says.

"Our goal is, collectively as Californians, to help reestablish those right conditions," Dean said. "It's being thoughtful about the choices that you're making in your day-to-day life so you can look at your emission footprint and try and reduce it in small ways so that collectively we are reducing it in big ways. It's about doing research to understand how some of these threats can be mitigated, like the sea star wasting disease, and then it's getting active in these habitats and helping with restoration."

To read more about Pacific kelp forests and the Aquarium of the Pacific's new preservation program, click here.



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