In a series of floating seaweed farms off the coast of Bali, Indonesia, a catamaran travels back and forth through lines of dangling red algae. Custom technology on board automatically harvests and replants the seaweed, which quickly grows several feet long. The system is designed to help the tiny seaweed industry scale up—and to capture some of seaweed’s potential to help fight climate change.
“Agriculture on the sea is in its infancy,” says Shrikumar Suryanarayan, cofounder and managing director of Sea6 Energy, the India-based company that designed the “Seacombine,” the tractor-like machine now in use at its Indonesian seaweed farm. The company just announced a new $9 million funding round, led by Aqua-Spark, an investment firm focused on sustainable aquaculture. There’s growing interest in seaweed farming now in part because of seaweed’s ability to absorb carbon: Macroalgae like seaweed can grow as quickly as two feet a day, sucking up CO2 much faster than trees (and unlike forests, seaweed doesn’t face risks from drought or fire). While some projects aim to permanently sequester that carbon by sinking seaweed to the ocean floor, the algae can also be used to make products, from fish feed to human food. Grown at a large scale, seaweed could replace some of the crude oil used to make jet fuel or plastic. But it’s been so expensive to grow that it can’t compete with fossil fuels.
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