I understand the limiting factor is iron, which the plankton require. This can be blown in from the Sahara occasionally. The whale faeces float, whales eat at

I understand the limiting factor is iron, which the plankton require. This can be blown in from the Sahara occasionally. The whale faeces float, whales eat at depth but due to the high pressure of the deep ocean they can only defaecate at the surface. If they’re in an eddy and grouped as a pod the nutrients are concentrated in an area the plankton can then use the iron, and the krill which live for six years or so feed on it. The idea being to seed the oceans with simulated whale faeces this should jump start the plankton and ideally the krill giving the whales an opportunity to feed should their numbers expand, a trial in the Arabian ocean is planned to start. Currently iron levels are only sufficient near the coasts, the hope being that all far more of the oceans could start to support life instead of being deserts. This Inside Science podcast has a good bit about it all: https://www.bbc.co.uk/programmes/m00114n7 https://www.bbc.co.uk/programmes/m00114n7 Just thinking about it, this sounds slightly like Dune. The whales being the sand worm of the oceans, reprocessing krill into plankton food which is thought to have a huge effect in sequestering carbon.