Capturing carbon with algae: London-based startup Brilliant Planet is aiming to build giant algae ponds in Morocco’s desert to capture and sequester tons of carbon dioxide, Bloomberg reports. The process — which could potentially remove 3 bn metric tons of carbon annually — has drawn interest from investors who would have shunned the project a decade ago.

How does it work? Algae converts carbon dioxide into biomass and oxygen using photosynthesis — but it does that at a faster rate than trees because it grows faster and covers a larger surface area, QZ writes.

And what does Brilliant Planet do exactly? The startup takes algae from the sea and “feeds” it with nutrient-rich ocean water, making the algae grow faster. After the algae grows enough to fill 16 ponds — filled with 3 mn gallons of water each — large-scale photosynthesis and carbon capturing takes place. The blooms are harvested, dried in the sun and buried under the ground to be stored.

Beyond Morocco: Brilliant Planet has identified almost 300k sq miles of flat desert lands near windy coasts globally for their algae pools — which, combined, have the potential to remove 3 bn metric tons of carbon from the atmosphere each year. In 2021, emissions rose at 36.3 bn tons annually, their highest ever level, according to the International Energy Authority (IEA).

Investors have shown interest: The company, which was founded in 2013 and has a patent that goes back over a decade, faltered in its first attempts to draw investors. But earlier this year, the company received USD 26.7 mn from Union Square Ventures and Toyota Ventures, among other unnamed investors. The company’s model is much cheaper than direct-air capture, according to Union Square Ventures’ Mona Alsubaei. Because the company dries the algae naturally — rather than using industrial dryers — its founders claim that its emissions are almost “negligible.”

Other ocean-based carbon-removal technologies are being tested: As it becomes clear that emissions-reduction is not sufficient to limit warming, interest in carbon-removal — particularly ocean-based methods — is growing, the Financial Times reports. One method that is being explored in Alaska and New England is ocean fertilization, which entails adding iron to the oceans to stimulate marine life growth and remove carbon dioxide from the atmosphere.