Such pipes could be 100 to 200 metres long, 10 metres in diameter and with a one-way flap valve at the lower end in order to pump water upwards powered by by wave movement. The water pumped up this way could fertilize algae in the surface waters and stimulate them to bloom. More specifically, pumping up water through such pipes would result in an increased presence in the surface waters of the salp, a tiny tube-like species that excretes carbon in its solid faecal pellets. This carbon would subsequently descend to the ocean floor. The hope is that this could store carbon away for millennia on the ocean floor.
An additional effect would be that the algae produced an abundance of dimethyl sulphide (DMS), a chemical that acts as the precursor of nuclei that form sunlight-reflecting clouds. As more clouds would form above the ocean, more sunlight would be reflected away from the Earth's surface, resulting in relative cooling of the ocean underneath.
US company Atmocean has in fact already started trials with this type of technology, using pipes that bring cold water to the surface from a depth of 200m.
References:
- Mixing the oceans proposed to reduce global warming
- Ocean pipes could help the Earth to cure itself
- Lovelock urges ocean climate fix
