geoengineering explained: the benefits and challenges of ocean fertilization

Ocean fertilization is an untested carbon dioxide sequestration (CDR) technique that involves dissolving nitrates or iron into the water which will encourage an increase in carbon uptake by phytoplankton. After the plankton blooms, it dies and then sinks to the ocean floor where the carbon will be stored as sedimentary rock.

see also:

Question: What is geoengineering?

Albedo Enhancement
Space Reflectors
Stratospheric Aerosols

Afforestation
Ambient Air Capture
Biochar
Bioenergy Capture and Sequestration
Ocean Fertilization
Enhanced Weathering
Ocean Alkalinity Enhancement

sources:
The Editors of Encyclopædia Britannica. (2014). Ocean Fertilization. Retrieved from Britannica.com: http://www.britannica.com/EBchecked/topic/1563580/ocean-fertilization
LePage, M. (2012, September 20). The pros and cons of geoengineering. Retrieved from www.newscientist.com