Carbon-dioxide-removal options are multiplying

In what used to be a fish-processing plant in Akranes, a small port in Iceland, fragments of seaweed rise and fall in glass columns lit by leds. Running Tide, the Maine-based company which runs the facility, is trying to work out how best to get them to sporulate. The company needs spores in abundance to embed in the biodegradable buoys it is developing as a form of CDR. Once the buoys, made in part from biomass, are in the ocean, the spores will grow into deep-green fronds; after a certain amount of weed-growth and buoy-degradation, the whole kit and caboodle will become waterlogged and sink, transporting the carbon the seaweed has sucked up through photosynthesis to the bottom of the ocean.