There was an experiment in 2009 that ended up seeding algae and plankton instead of diatoms, but it didn't sequester carbon as hoped: http://www.awi.de/en/news/

There was an experiment in 2009 that ended up seeding algae and plankton instead of diatoms, but it didn't sequester carbon as hoped: http://www.awi.de/en/news/press_releases/detail/item/lohafex_provides_new_insights_on_plankton_ecology_only_small_amounts_of_atmospheric_carbon_dioxide/?tx_list_pi1%5Bmode%5D=6&cHash=ffd0b4deee http://www.awi.de/en/news/press_releases/detail/item/lohafex... It seems the larger diatoms seeded in the more recent experiment may actually be better at sequestering carbon. We need to be doing more experiments like this so we understand the processes and potential fallout before we get to a point where our survival depends on it succeeding.