The Seaweed Diet • Vivienne Hay
(Technology Lead, Blue Ocean Barns || CA USA)
“People are getting really excited about the ocean and its potential role in combating climate change. The most common approach is growing large-scale macroalgae that absorb carbon dioxide from the atmosphere (fun fact, seaweed is a kind of algae). Our approach is different, though. We grow a special type of red seaweed, called Asparagopsis taxiformis (AT). AT contains an active ingredient that prevents cows from burping out methane — an 80% reduction! Methane is one of the most powerful greenhouse gases (thirty to ninety times as powerful as carbon dioxide) and the biggest contributor to greenhouse gas emissions apart from carbon dioxide.
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The tricky thing is that it’s not sustainable to extract AT from the ocean. We need to grow it ourselves, but nobody has ever done this at scale before! As an engineer, my role is to design the system — the right size and shape, water filtration, lighting, a harvest system, and a feedback monitoring system — all to make sure we can grow the seaweed. Imagine a solar farm, but instead of harvesting sunlight to produce electricity, we harvest sunlight to grow the seaweed that combats climate change.
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Seaweed exhibits exponential growth and can replicate quickly. But it’s also extremely finicky! At this point we’ve had hundreds of trials. It’s a case of honing in on the right growing conditions — temperature, light levels, etc. Like with typical farming, where you might have locusts come through and destroy the stock, we have faced similar problems — something comes through and destroys the seaweed. We’ve needed to figure out the right protocols, growing conditions, and photobioreactor design to prevent this, ensuring both biosecurity and optimal growth.
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Before this, I worked for eight years on land-based agriculture, mostly in the Northeast. Since I moved to California, though, my focus has shifted to the ocean. It became a very personal thing to me — I am a certified scuba diver and a surfer, I love ocean swimming, and now I get to work with seaweed — so it all comes together!”
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