Rod Fujita, director of research and development for EDF’s oceans program, questions the approach of growing kelp for combating climate change. It’s hard to measure how much carbonseaweed sequesters, he notes, because fish and microbes feed on seaweed, then exhale it as carbon dioxide.

Also, they’re not just using sunlight and carbon dioxide, but also extracting other nutrients from the ecosystem and sequestering it with the carbon.

Every nightfall, cranks mounted on a floating platform lower the ring 25 meters below the surface to expose the seaweed to cooler, more nutrient-rich water.

I could see this going wrong in a number of ways. I hope they permit a lot of open research on the initiative so there are several layers of accountability and everyone can learn from it.