> I was thinking about doing a kickstarter to rent a boat and seed the oceans with iron

Maybe don't though.

- Phytoplankton blooms are often environmentally and economically harmful

- There's no actual guarantee you'll sequester carbon.

    - Consider that the biomass may end up in an anaerobic environment and digested into methane. Now you've converted carbon dioxide into a greenhouse gas 23x more powerful.

    - Iron may well not be the limiting factor in that part of the ocean & you'll just release carbon from your exhaust

    - How much carbon did it take to create this iron?

Edit: That being said, I do think that we should look to the Azolla Event as a model for how significant drawdown can be accomplished in a short timescale - but in controlled environments, not the ocean.