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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Ocean fertilization | 4/4 | https://en.wikipedia.org/wiki/Ocean_fertilization | reference | science, encyclopedia | 2026-05-05T07:35:53.616567+00:00 | kb-cron |
==== Impact on fisheries ==== Adding urea to the ocean can cause phytoplankton blooms that serve as a food source for zooplankton and in turn feed for fish. This may increase fish catches. However, if cyanobacteria and dinoflagellates dominate phytoplankton assemblages that are considered poor quality food for fish then the increase in fish quantity may not be large. Some evidence links iron fertilization from volcanic eruptions to increased fisheries production. Other nutrients would be metabolized along with the added nutrient(s), reducing their presence in fertilized waters. Krill populations have declined dramatically since whaling began. Sperm whales transport iron from the deep ocean to the surface during prey consumption and defecation. Sperm whales have been shown to increase the levels of primary production and carbon export to the deep ocean by depositing iron-rich faeces into surface waters of the Southern Ocean. The faeces causes phytoplankton to grow and take up carbon. The phytoplankton nourish krill. Reducing the abundance of sperm whales in the Southern Ocean, whaling resulted in an extra 2 million tonnes of carbon remaining in the atmosphere each year.
==== Ecosystem disruption ==== Many locations, such as the Tubbataha Reef in the Sulu Sea, support high marine biodiversity. Nitrogen or other nutrient loading in coral reef areas can lead to community shifts towards algal overgrowth of corals and ecosystem disruption, implying that fertilization must be restricted to areas in which vulnerable populations are not put at risk. As the phytoplankton descend the water column, they decay, consuming oxygen and producing greenhouse gases methane and nitrous oxide. Plankton-rich surface waters could warm the surface layer, affecting circulation patterns.
==== Cloud formation ==== Many phytoplankton species release dimethyl sulfide (DMS), which escapes into the atmosphere where it forms sulfate aerosols and encourages cloud formation, which could reduce warming. However, substantial increases in DMS could reduce global rainfall, according to global climate model simulations, while halving temperature increases as of 2100.
== Reactions == In 2007 Working Group III of the United Nations Intergovernmental Panel on Climate Change examined ocean fertilization methods in its fourth assessment report and noted that the field-study estimates of the amount of carbon removed per ton of iron was probably over-estimated and that potential adverse effects had not been fully studied. In June 2007 the London Dumping Convention issued a statement of concern noting 'the potential for large scale ocean iron fertilization to have negative impacts on the marine environment and human health', but did not define 'large scale'. It is believed that the definition would include operations. In 2008, the London Convention/London Protocol noted in resolution LC-LP.1 that knowledge on the effectiveness and potential environmental impacts of ocean fertilization was insufficient to justify activities other than research. This non-binding resolution stated that fertilization, other than research, "should be considered as contrary to the aims of the Convention and Protocol and do not currently qualify for any exemption from the definition of dumping". In May 2008, at the Convention on Biological Diversity, 191 nations called for a ban on ocean fertilization until scientists better understand the implications. In August 2018, Germany banned the sale of ocean seeding as carbon sequestration system while the matter was under discussion at EU and EASAC levels.
== International law == International law presents some dilemmas for ocean fertilization. The United Nations Framework Convention on Climate Change (UNFCCC 1992) has accepted mitigation actions.
=== Law of the sea === According to United Nations Convention on the Law of the Sea (LOSC 1982), all states are obliged to take all measures necessary to prevent, reduce and control pollution of the marine environment, to prohibit the transfer of damage or hazards from one area to another and to prohibit the transformation of one type pollution to another. How this relates to fertilization is undetermined.
== Solar radiation management ==
Fertilization may create sulfate aerosols that reflect sunlight, modifying the Earth's albedo, creating a cooling effect that reduces some of the effects of climate change. Enhancing the natural sulfur cycle in the Southern Ocean by fertilizing with iron in order to enhance dimethyl sulfide production and cloud reflectivity may achieve this.
== See also == Carbon dioxide sink Climate engineering Effects of climate change on oceans Iron fertilization Planetary engineering Soil fertilization
== References ==
== External links == Williamson, Phillip; Wallace, Douglas W. R.; Law, Cliff S.; Boyd, Philip W.; Collos, Yves; Croot, Peter; Denman, Ken; Riebesell, Ulf; Takeda, Shigenobu (1 November 2012). "Ocean fertilization for geoengineering: A review of effectiveness, environmental impacts and emerging governance". Process Safety and Environmental Protection. 90 (6): 475–488. Bibcode:2012PSEP...90..475W. doi:10.1016/j.psep.2012.10.007. ISSN 0957-5820. Dean, Jennie (2009). "Iron Fertilization: A Scientific Review with International Policy Recommendations" (PDF). Retrieved 4 June 2017. "Ocean fertilization" (PDF). geoengineeringmonitor.org. January 2021.