Ocean fertilization refers to the technique of adding iron or other nutrients to ocean areas with low biological productivity (i.e., low
Ocean fertilization schemes seek to increase the amount of available nutrients in the top layer of the ocean to stimulate the growth of phytoplankton. These
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.
Analyses of natural, long-term climate changes (ice age cycles; Sigman and Boyle, 2000) and ship-based in vitro experiments (Martin et al., 1990) suggest that the global ocean uptake of carbon is sensitive to nutrient availability, and that for many (but not all) ocean regions, iron would be particularly effective as the fertilizing nutrient for geoengineering purposes. Whilst initial modelling indicates that global deployment of pipes could significantly alter biologi-cal production and export of carbon, net changes to air–sea 480 Process Safety and Environmental Protection 9 0 ( 2 0 1 2 ) 475–488 Fig. 2 – Processes affecting the sequestration efficiency of large-scale ocean fertilization based on the addition of iron or other limiting nutrients.
Ocean fertilization involves adding nutrients, such as iron, to seawater to promote photosynthesis in the surface ocean. As phytoplankton draw
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
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.