“The sea, the great unifier, is man’s only hope. Now, as never before, the old phrase has a literal meaning: we are all in the same boat.” – Jacques Yves Cousteau

On a sunny Saturday morning, I drive about 30 minutes north of my home in Santa Barbara to an area called Refugio Beach. Aptly named after the word “refuge” in Spanish, the waters off the shore are pockmarked with texture where swaths of kelp and sea creatures lurk just below the surface. 

Swimming past the shore break to the peaceful waters beyond, my goggles reveal an expansive ecosystem supported by this underwater forest. Rooted in the seafloor far below, each tendril of kelp stretches up towards the sunny surface above. Sheepshead and perch, native fish, dart between the leaves which sway, seemingly in slow motion, with the gentle current. 

Kelp forests are astonishing, especially to viewers who have only seen seaweed in it’s beached form. My experience with these beautiful plants is not unlike the one Charles Darwin details in The Voyage of the Beagle: 

“The number of living creatures of all Orders, whose existence intimately depends on the kelp, is wonderful. A great volume might be written, describing the inhabitants of one of these beds of sea-weed.”

First things first, what is the difference between seaweed and kelp? Seaweed is a broad term for all ocean plants, while kelp is a specific species of seaweed that grows in large groupings close to shorelines. 

Kelp forests provide a vital ecosystem for marine animals including thousands of fish, invertebrates, and marine mammals. These towering, leafy plants can grow up to 18 inches per day and much like their land-based counterparts, they play a key role in carbon capture. 

Planting on the seafloor offers even more carbon sequestering capabilities than planting trees on land because kelp that sinks to the seafloor can hold carbon there for centuries. One study found that growing and sinking microalgae in a small proportion of federal waters off California’s coast could completely offset emissions from the state’s entire agriculture industry.

An aquaculture startup, Running Tide, is using those carbon-sucking seaweed powers to sequester carbon off the coast of Maine while raising sustainable shellfish. 

Founder Marty Odlin comes from a long line of east coast fishermen and has seen how climate change is impacting our seas first-hand. The company operates by sending out microfarms into open ocean currents. The currents carry the kelp to optimal locations in terms of salinity, temperature, and nutrient levels before the company sinks the plants to the seafloor. The process uses biodegradable buoys to transport the kelp offshore. 

In addition to their carbon capture capabilities, kelp forests also help cushion storm surges, so their preservation is important for reducing the impact of climate-driven storms. 

Unfortunately, kelp forests around the world are declining. In areas like Tasmania and California, forests have declined 90 percent. In response, researchers from the University of Tasmania are engaging in kelp planting to help restore populations and also experimenting with lab-raised, climate-resilient “super-kelp” that is heartier than species found in nature. 

In southern California, scientists are painstakingly clearing forests of purple sea urchins which have devoured nearly three quarters of Santa Monica Bay’s kelp. Researchers are also exploring the reintroduction of otters to promote kelp health.

 In the United Kingdom, a plan known as “Help Our Kelp” aims to restore a 70-square-mile tract of historic kelp forest along the country’s southern Sussex Coast. 

Human technology is also helping boost kelp growth. Researchers from the University of Southern California have come up with a novel contraption to get the best of both the nutrient-rich deep sea and the sun-drenched shallow sea. This machine is called the kelp elevator, and it raises the kelp up to the sunny surface during the daytime and lowers it to depths of around 260 ft (80 m) at night, allowing the kelp to soak up vital nutrients like nitrate and phosphate.

With the kelp elevator, which is made of fiberglass tubes and stainless steel cables, scientists were able to grow kelp off the coast of California much faster over the course of 100 days. In fact, the scientists produced four times the biomass of regular kelp using the kelp elevator.

Kelp elevators help boost growth, but a main factor that nourishes kelp is ocean upwelling, the natural water cycle which brings cool, nutrient-dense water from the ocean’s depths up to the surface. Global warming has slowed natural currents and reduced ocean upwelling in many areas, creating a thick layer of hot water near the surface and disrupting natural ecosystems. 

The Climate Foundation, led by Dr. Brian von Herzen, is working on restoring ocean upwelling using renewable energy in the form of wave-driven pumps. In one Hawaiian experiment with these pumps, after 57 hours after deployment, the system sparked plankton growth and attracted various species of fish. Two weeks later, a 17-foot long whale shark was still circling the area feeding on  plankton that had started blooming. These “marine permaculture” projects are instrumental for restoring kelp populations which in turn rejuvenate entire habitats. 

So what is all this kelp being used for? In addition to capturing carbon, kelp is also a valuable natural resource. Those same elevator-building scientists have come up with a formula for biofuel which uses kelp as a base, rather than resource intensive soy or corn. 

Like corn, kelp can be used to produce ethanol, which is then blended into gasoline. Even better, it can be used to produce bio-crude. This entirely organic materials-based oil is created using hydrothermal liquefaction, a process that relies on temperature and pressure to turn kelp into the oil. 

It’s not just our cars we can feed with kelp. More and more brands are using kelp as a plant-based ingredient for more sustainable snacks. Startup Akua has launched a new line of burgers made from kelp. Unlike other plant-based options, kelp takes no water, soil, or fertilizers to produce and, as we mentioned earlier, its farming actually serves as a major carbon sink. 100 percent of Akua’s kelp is sourced from US-based ocean farmers, like women-owned kelp farms off the coast of Maine, supporting the creation of hundreds of new jobs near coastal areas. 

Eating kelp and using it as a carbon capture system get interwoven in kelp farming, but there’s another avenue where these concepts coexist. A growing body of research has identified the powerful effects of feeding cows seaweed to reduce their methane emissions. 

About 70 percent of agricultural methane comes from enteric fermentation, chemical reactions that occur in the stomachs of cows and other grazing animals as they digest plants. A newly published study from the University of California, Davis confirmed what other studies had theorized that feeding cows seaweed, like kelp, can successfully reduce both methane emissions and feed cost without sacrificing meat quality.

In their research, the scientists found that supplementing cattle diets with just 10 ounces of seaweed a day reduced methane emissions by 67 percent. They also found that the seaweed could be frozen for up to three years without sacrificing nutritional and emissions reduction benefits, making it as convenient as traditionally-stored feed. 

One drawback noticed in the study was that milk-cows fed the seaweed supplement did see reduced milk production, which would disincentivize dairy farmers from adopting the feed. On the other hand, steers who were fed the amended diet converted feed to body weight up to 20 percent more efficiently than conventionally-fed steers, which would greatly reduce input costs for cattle farmers to the tune of $40,320 to $87,320 per year. 

One company putting money behind this concept is Swedish startup Volta Greentech. It has set up a factory to begin the commercial production of Asparagopsis taxiformis, a type of red seaweed. The company is conducting tests to optimize land-based growth of this sea plant and pumping CO2 into the production facility, which the seaweed will capture, enabling it to grow faster.

Algae, a seaweed subgroup, can even be used to produce eco-friendly plastic alternatives. One company experimenting with this is Loliware. They are manufacturing seaweed-based flexible films, pulps and other alternatives to single-use plastic. Algix, a company that is creating an algae-blended material it calls Bloom, which can be used for the soles of shoes is another bioplastic leader. At the moment, Algix works with an impressive list of brands including Native Shoes, Toms, Adidas, and Merrell.

Seaweed is the ocean’s natural support system, but it’s also a valuable and largely-untapped resource for humans. This sustainable source of plant nutrients can not only make our snacks greener (literally), reduce methane emissions from cattle, and help replace fuel, but it also serves as a carbon sink and supports marine ecosystems throughout the farming process. Imagine if land-based agricultural farming created natural habitats and supported native species, rather than hindering them? This is the potential of kelp and seaweed cultivation. It’s a solution that lends a ‘kelping’ hand to both humans and the planet!

Want to hear more about seaweed? Check out our Optimist Daily Update interview with Jason Lewis and Tammie Stevens.