Ocean fertilization for the purpose of geoengineering aims to increase CO2 uptake by marine biological processes (the 'biological carbon pump'), in sufficient
Ocean fertilization uses nutrients to enhance photosynthesis by marine phytoplankton, which remove CO₂ and convert it into biomass that can
Scientists plan to seed part of the Pacific Ocean with iron to trigger a surface bloom of phytoplankton that will hopefully suck carbon dioxide out of the air.
Further reading ETC’s Case Study, Ocean Fertilization near Haida Gwaii, http://www.etcgroup.org/content/case-study-ocean-fertilization-near-haida-gwaii Greenpeace, A scientifc critique of oceanic iron fertilization as a climate change mitigation strategy http://www.greenpeace.to/publications/iron_fe rtilisation_critique.pdf CBD, Scientifc Synthesis of the Impacts of Ocean Fertilization on Marine Biodiversity https://www.cbd.int/doc/publications/cbd-ts-45-en.pdf Strong, A. (2009) Ocean fertilization: Science, Policy, and Commerce, in:Oceanography, Vol. 22(3): 236 - 261, https://tos.org/oceanography/article/ocean-fertilization-science-policy-and-commerce; Secretariat of the CBD (2009) Scientifc Synthesis of the Impacts of Ocean Fertilization on Marine Biodiversity, Montreal, Technical Series No. 45, https://www.cbd.int/doc/publications/cbd-ts-45-en.pdf; Abate and Greenlee (2010); GESAMP (2019) High level review of a wide range of proposed marine geoengineering techniques, (Boyd, P.W. and Vivian, C.M.G., eds.), IMO/FAO/UNESCO-IOC/UNIDO/WMO/IAEA/UN/UN Environment/ UNDP/ISA Joint Group of Experts on the Scientifc Aspects of Marine Environmental Protection).
Iron fertilization is a Carbon Dioxide Removal (CDR) technique that would artificially add iron to the ocean’s surface to stimulate growth of phytoplankton. When the plume of dust or ash settles over the ocean’s surface, it triggers massive blooms of phytoplankton that remove substantial amounts of carbon dioxide from the atmosphere. Iron fertilization is a Carbon Dioxide Removal (CDR) technique that would mimic this natural system, artificially adding iron to the ocean’s surface to stimulate growth of phytoplankton. If relatively small amounts of iron can be added to the ocean’s surface to effectively remove large amounts of carbon dioxide from the atmosphere, iron fertilization has the potential to play a pivotal role in reducing additional impacts associated with climate change. Until experiments are done to test these potential outcomes and determine how much carbon can be sequestered in the ocean depths, iron fertilization should not be put to use as a method of slowing climate change. ### Fertilizing the Ocean with Iron.
Scientists have proposed a number of land- and ocean-based CDR techniques. This paper focuses on ocean fertilization, which involves adding iron or other
DEEP-OCEAN STEWARDSHIP INITIATIVE Fig. 1 Elements of the biological pump (Fig. 1 From McClain (2010) American Scientist) Deep Ocean Climate Intervention Impacts Deep Ocean Climate Intervention Impacts Ocean Fertilization Key Points DECEMBER 2021 Policy Brief Page 2 DOSI Scaling and Effectiveness The subarctic Northern Pacific, Eastern Equatorial Pacific and Southern Ocean are high-nutrient, low-chlorophyll regions where iron scarcity limits phytoplankton growth, and thus have been proposed for OIF (Yoon et al., 2018, GESAMP, 2019). The alteration of natural phytoplankton communities may result in changes in the seasonality of particulate organic carbon flux to the deep-sea floor (benthic-pelagic coupling) and in compositions of phytoplankton species in the marine snow, potentially impacting deep-sea benthic communities that rely on food from the ocean surface (Billet et al., 1983; Gooday, 1988; Graf, 1989; Ruhl and Smith, 2004; Nomaki et al., 2021).
The approach leverages a natural process: adding small amounts of iron to iron-poor ocean regions stimulates phytoplankton growth, which absorbs