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100-635: OIF may refer to: Ocean iron fertilization , the intentional introduction of iron to the upper ocean to stimulate a phytoplankton bloom Office for Intellectual Freedom, a department of the American Library Association Operation Iraqi Freedom , the United States' code-name for the Iraq War from 2003 to 2010 Optical Internetworking Forum ,

200-466: A 2013 study indicates the cost versus benefits of iron fertilization puts it behind carbon capture and storage and carbon taxes. While ocean iron fertilization could represent a potent means to slow global warming, there is a current debate surrounding the efficacy of this strategy and the potential adverse effects of this. The precautionary principle is a proposed guideline regarding environmental conservation. According to an article published in 2021,

300-516: A decline in basic activity level and information usage at 1000 ppm, when compared to 500 ppm. However a review of the literature found that a reliable subset of studies on the phenomenon of carbon dioxide induced cognitive impairment to only show a small effect on high-level decision making (for concentrations below 5000 ppm). Most of the studies were confounded by inadequate study designs, environmental comfort, uncertainties in exposure doses and differing cognitive assessments used. Similarly

400-611: A glass state similar to other members of its elemental family, like silicon dioxide (silica glass) and germanium dioxide . Unlike silica and germania glasses, however, carbonia glass is not stable at normal pressures and reverts to gas when pressure is released. At temperatures and pressures above the critical point, carbon dioxide behaves as a supercritical fluid known as supercritical carbon dioxide . Table of thermal and physical properties of saturated liquid carbon dioxide: Table of thermal and physical properties of carbon dioxide (CO 2 ) at atmospheric pressure: Carbon dioxide

500-400: A global scale. Ocean fertilization occurs naturally when upwellings bring nutrient-rich water to the surface, as occurs when ocean currents meet an ocean bank or a sea mount . This form of fertilization produces the world's largest marine habitats . Fertilization can also occur when weather carries wind blown dust long distances over the ocean, or iron-rich minerals are carried into

600-508: A lack of iron. In 1989 he tested this hypothesis (known as the Iron Hypothesis ) by an experiment using samples of clean water from Antarctica . Iron was added to some of these samples. After several days the phytoplankton in the samples with iron fertilization grew much more than in the untreated samples. This led Martin to speculate that increased iron concentrations in the oceans could partly explain past ice ages. This experiment

700-442: A major component of the carbon-rich deep sea precipitation known as marine snow . Marine snow also includes fish fecal pellets and other organic detritus, and steadily falls thousands of meters below active plankton blooms. Of the carbon-rich biomass generated by plankton blooms, half (or more) is generally consumed by grazing organisms ( zooplankton , krill , small fish, etc.) but 20 to 30% sinks below 200 meters (660 ft) into

800-508: A mass basis, each kilogram of iron can fix 83,000 kg of carbon dioxide. The 2004 EIFEX experiment reported a carbon dioxide to iron export ratio of nearly 3000 to 1. The atomic ratio would be approximately: "3000 C: 58,000 N: 3,600 P: 1 Fe". Therefore, small amounts of iron (measured by mass parts per trillion) in HNLC zones can trigger large phytoplankton blooms on the order of 100,000 kilograms of plankton per kilogram of iron. The size of

900-491: A mature forest will produce as much CO 2 from respiration and decomposition of dead specimens (e.g., fallen branches) as is used in photosynthesis in growing plants. Contrary to the long-standing view that they are carbon neutral, mature forests can continue to accumulate carbon and remain valuable carbon sinks , helping to maintain the carbon balance of Earth's atmosphere. Additionally, and crucially to life on earth, photosynthesis by phytoplankton consumes dissolved CO 2 in

1000-477: A minor effect on mitigating CO2-induced acidification at the surface ocean." Unfortunately, the impact on ocean acidification would likely not change due to the low effects that iron fertilization has on CO 2 levels. Consideration of iron's importance to phytoplankton growth and photosynthesis dates to the 1930s when Dr Thomas John Hart , a British marine biologist based on the RRS ; Discovery II in

1100-477: A molecule touches a surface or touches another molecule, the two bending modes can differ in frequency because the interaction is different for the two modes. Some of the vibrational modes are observed in the infrared (IR) spectrum : the antisymmetric stretching mode at wavenumber 2349 cm (wavelength 4.25 μm) and the degenerate pair of bending modes at 667 cm (wavelength 15.0 μm). The symmetric stretching mode does not create an electric dipole so

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1200-424: A non-profit industry organization founded in 1998 Organisation internationale de la Francophonie , an international organization representing Francophonic and Francophilic countries and regions Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title OIF . If an internal link led you here, you may wish to change the link to point directly to

1300-410: A possible starting point for carbon capture and storage by amine gas treating . Only very strong nucleophiles, like the carbanions provided by Grignard reagents and organolithium compounds react with CO 2 to give carboxylates : In metal carbon dioxide complexes , CO 2 serves as a ligand , which can facilitate the conversion of CO 2 to other chemicals. The reduction of CO 2 to CO

1400-565: A significant amount of carbon into the deep ocean, where it was expected to remain for centuries to millennia. The eddy was chosen because it offered a largely self-contained test system. As of day 24, nutrients, including nitrogen, phosphorus and silicic acid that diatoms use to construct their shells, declined. Dissolved inorganic carbon concentrations were reduced below equilibrium with atmospheric CO 2 . In surface water, particulate organic matter (algal remains) including silica and  chlorophyll increased. After day 24, however,

1500-441: A significant benefit to the marine food chain in addition to sequestering carbon for long periods of time. A 2009 study tested the potential of iron fertilization to reduce both atmospheric CO 2 and ocean acidity using a global ocean carbon model. The study found that, "Our simulations show that ocean iron fertilization, even in the extreme scenario by depleting global surface macronutrient concentration to zero at all time, has

1600-521: A significant effect on the concentration of atmospheric carbon dioxide by altering rates of carbon sequestration. In fact, fertilization is an important process that occurs naturally in the ocean waters. For instance, upwellings of ocean currents can bring nutrient-rich sediments to the surface. Another example is through transfer of iron-rich minerals, dust, and volcanic ash over long distances by rivers, glaciers, or wind. Moreover, it has been suggested that whales can transfer iron-rich ocean dust to

1700-450: A significant role in supplying the world's oceans with iron. Volcanic ash is composed of glass shards, pyrogenic minerals, lithic particles and other forms of ash that release nutrients at different rates depending on structure and the type of reaction caused by contact with water. Increases of biogenic opal in the sediment record are associated with increased iron accumulation over the last million years. In August 2008, an eruption in

1800-399: A small amount of carbon. Ocean iron fertilization is an example of a geoengineering technique that involves intentional introduction of iron-rich deposits into oceans, and is aimed to enhance biological productivity of organisms in ocean waters in order to increase carbon dioxide ( CO 2 ) uptake from the atmosphere, possibly resulting in mitigating its global warming effects . Iron

1900-416: A study on the effects of the concentration of CO 2 in motorcycle helmets has been criticized for having dubious methodology in not noting the self-reports of motorcycle riders and taking measurements using mannequins. Further when normal motorcycle conditions were achieved (such as highway or city speeds) or the visor was raised the concentration of CO 2 declined to safe levels (0.2%). Poor ventilation

2000-570: A surface complex with the Fe (III) metal center of an iron-containing mineral (such as hematite or goethite ). On exposure to solar radiation the complex is converted to an excited energy state in which the ligand, acting as bridge and an electron donor , supplies an electron to Fe(III) producing soluble Fe(II). Consistent with this, studies documented a distinct diel variation in the concentrations of Fe (II) and Fe(III) in which daytime Fe(II) concentrations exceed those of Fe(III). Volcanic ash has

2100-495: A turn over in the plankton masses that are produced. This results in no beneficial effects and actually causes an increase in CO 2 . Finally, a 2010 study showed that iron enrichment stimulates toxic diatom production in high-nitrate, low-chlorophyll areas which, the authors argue, raises "serious concerns over the net benefit and sustainability of large-scale iron fertilizations". Nitrogen released by cetaceans and iron chelate are

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2200-402: A variety of measurements, combining ship-borne and remote sampling, submarine filtration traps, tracking buoy spectroscopy and satellite telemetry . Unpredictable ocean currents can remove experimental iron patches from the pelagic zone, invalidating the experiment. The potential of fertilization to tackle global warming is illustrated by the following figures. If phytoplankton converted all

2300-469: Is Emiliania huxleyi whose calcite scales have formed the basis of many sedimentary rocks such as limestone , where what was previously atmospheric carbon can remain fixed for geological timescales. Plants can grow as much as 50% faster in concentrations of 1,000 ppm CO 2 when compared with ambient conditions, though this assumes no change in climate and no limitation on other nutrients. Elevated CO 2 levels cause increased growth reflected in

2400-425: Is 0.29 W/m of globally averaged negative forcing, offsetting 1/6 of current levels of anthropogenic CO 2 emissions. These benefits have been called into question by research suggesting that fertilization with iron may deplete other essential nutrients in the seawater causing reduced phytoplankton growth elsewhere — in other words, that iron concentrations limit growth more locally than they do on

2500-419: Is 304.128(15) K (30.978(15) °C) at 7.3773(30) MPa (72.808(30) atm). Another form of solid carbon dioxide observed at high pressure is an amorphous glass-like solid. This form of glass, called carbonia , is produced by supercooling heated CO 2 at extreme pressures (40–48  GPa , or about 400,000 atmospheres) in a diamond anvil . This discovery confirmed the theory that carbon dioxide could exist in

2600-453: Is a trace gas in Earth's atmosphere at 421  parts per million (ppm) , or about 0.042% (as of May 2022) having risen from pre-industrial levels of 280 ppm or about 0.028%. Burning fossil fuels is the main cause of these increased CO 2 concentrations, which are the primary cause of climate change . Its concentration in Earth's pre-industrial atmosphere since late in

2700-447: Is a weak acid , because its ionization in water is incomplete. The hydration equilibrium constant of carbonic acid is, at 25 °C: Hence, the majority of the carbon dioxide is not converted into carbonic acid, but remains as CO 2 molecules, not affecting the pH. The relative concentrations of CO 2 , H 2 CO 3 , and the deprotonated forms HCO − 3 ( bicarbonate ) and CO 2− 3 ( carbonate ) depend on

2800-403: Is a limiting nutrient in many ocean waters. They hoped that the iron would fertilize algae, which would bolster the bottom of the marine food chain and sequester carbon as uneaten algae died. The experiment was demolished by a storm, leaving inconclusive results. The maximum possible result from iron fertilization, assuming the most favourable conditions and disregarding practical considerations,

2900-411: Is a trace element in the ocean and its presence is vital for photosynthesis in plants, and in particular phytoplanktons, as it has been shown that iron deficiency can limit ocean productivity and phytoplankton growth. For this reason, the "iron hypothesis" was put forward by Martin in late 1980s where he suggested that changes in iron supply in iron-deficient seawater can bloom plankton growth and have

3000-415: Is an end product of cellular respiration in organisms that obtain energy by breaking down sugars, fats and amino acids with oxygen as part of their metabolism . This includes all plants, algae and animals and aerobic fungi and bacteria. In vertebrates , the carbon dioxide travels in the blood from the body's tissues to the skin (e.g., amphibians ) or the gills (e.g., fish ), from where it dissolves in

3100-533: Is an important iron source. Satellite images and data (such as PODLER, MODIS, MSIR) combined with back-trajectory analyses identified natural sources of iron–containing dust. Iron-bearing dusts erode from soil and are transported by wind. Although most dust sources are situated in the Northern Hemisphere, the largest dust sources are located in northern and southern Africa, North America, central Asia and Australia. Heterogeneous chemical reactions in

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3200-414: Is called sublimation . The symmetry of a carbon dioxide molecule is linear and centrosymmetric at its equilibrium geometry. The length of the carbon–oxygen bond in carbon dioxide is 116.3  pm , noticeably shorter than the roughly 140 pm length of a typical single C–O bond, and shorter than most other C–O multiply bonded functional groups such as carbonyls . Since it is centrosymmetric,

3300-404: Is comparable to benzaldehyde or strongly electrophilic α,β-unsaturated carbonyl compounds . However, unlike electrophiles of similar reactivity, the reactions of nucleophiles with CO 2 are thermodynamically less favored and are often found to be highly reversible. The reversible reaction of carbon dioxide with amines to make carbamates is used in CO 2 scrubbers and has been suggested as

3400-451: Is found in the gas state at room temperature and at normally-encountered concentrations it is odorless. As the source of carbon in the carbon cycle , atmospheric CO 2 is the primary carbon source for life on Earth. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation , acting as a greenhouse gas . Carbon dioxide is soluble in water and is found in groundwater , lakes , ice caps , and seawater . It

3500-522: Is generally consumed by other organisms (small fish, zooplankton , etc.) and substantial part of rest of the deposits that sink beneath plankton blooms may be re-dissolved in the water and gets transferred to the surface where it eventually returns to the atmosphere, thus, nullifying any possible intended effects regarding carbon sequestration. Nevertheless, supporters of the idea of iron fertilization believe that carbon sequestration should be re-defined over much shorter time frames and claim that since

3600-602: Is not observed in IR spectroscopy, but it is detected in Raman spectroscopy at 1388 cm (wavelength 7.20 μm), with a Fermi resonance doublet at 1285 cm . In the gas phase, carbon dioxide molecules undergo significant vibrational motions and do not keep a fixed structure. However, in a Coulomb explosion imaging experiment, an instantaneous image of the molecular structure can be deduced. Such an experiment has been performed for carbon dioxide. The result of this experiment, and

3700-481: Is one of several in which iron fertilization could be conducted—the Galapagos islands area another potentially suitable location. Some species of plankton produce dimethyl sulfide (DMS), a portion of which enters the atmosphere where it is oxidized by hydroxyl radicals (OH), atomic chlorine (Cl) and bromine monoxide (BrO) to form sulfate particles, and potentially increase cloud cover. This may increase

3800-632: Is one of the main causes of excessive CO 2 concentrations in closed spaces, leading to poor indoor air quality . Carbon dioxide differential above outdoor concentrations at steady state conditions (when the occupancy and ventilation system operation are sufficiently long that CO 2 concentration has stabilized) are sometimes used to estimate ventilation rates per person. Higher CO 2 concentrations are associated with occupant health, comfort and performance degradation. ASHRAE Standard 62.1–2007 ventilation rates may result in indoor concentrations up to 2,100 ppm above ambient outdoor conditions. Thus if

3900-410: Is ordinarily a difficult and slow reaction: The redox potential for this reaction near pH 7 is about −0.53 V versus the standard hydrogen electrode . The nickel-containing enzyme carbon monoxide dehydrogenase catalyses this process. Photoautotrophs (i.e. plants and cyanobacteria ) use the energy contained in sunlight to photosynthesize simple sugars from CO 2 absorbed from

4000-405: Is produced as a by-product. Ribulose-1,5-bisphosphate carboxylase oxygenase , commonly abbreviated to RuBisCO, is the enzyme involved in the first major step of carbon fixation, the production of two molecules of 3-phosphoglycerate from CO 2 and ribulose bisphosphate , as shown in the diagram at left. RuBisCO is thought to be the single most abundant protein on Earth. Phototrophs use

4100-510: Is put to commercial use, mostly in the fertilizer industry and in the oil and gas industry for enhanced oil recovery . Other commercial applications include food and beverage production, metal fabrication, cooling, fire suppression and stimulating plant growth in greenhouses. Carbon dioxide cannot be liquefied at atmospheric pressure. Low-temperature carbon dioxide is commercially used in its solid form, commonly known as " dry ice ". The solid-to-gas phase transition occurs at 194.7 Kelvin and

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4200-580: Is relatively inexpensive compared to scrubbing , direct injection and other industrial approaches, and can theoretically sequester for less than €5/ton CO 2 , creating a substantial return. In August, 2010, Russia established a minimum price of €10/ton for offsets to reduce uncertainty for offset providers. Scientists have reported a 6–12% decline in global plankton production since 1980. A full-scale plankton restoration program could regenerate approximately 3–5 billion tons of sequestration capacity worth €50-100 billion in carbon offset value. However,

4300-425: Is released from organic materials when they decay or combust, such as in forest fires. When carbon dioxide dissolves in water, it forms carbonate and mainly bicarbonate ( HCO − 3 ), which causes ocean acidification as atmospheric CO 2 levels increase. Carbon dioxide is 53% more dense than dry air, but is long lived and thoroughly mixes in the atmosphere. About half of excess CO 2 emissions to

4400-623: The CO 2 uptake and that due to the ocean's albedo increase, however the amount of cooling by this particular effect is very uncertain. Beginning with the Kyoto Protocol , several countries and the European Union established carbon offset markets which trade certified emission reduction credits (CERs) and other types of carbon credit instruments. In 2007 CERs sold for approximately €15–20/ton CO 2 . Iron fertilization

4500-509: The Precambrian was regulated by organisms and geological features. Plants , algae and cyanobacteria use energy from sunlight to synthesize carbohydrates from carbon dioxide and water in a process called photosynthesis , which produces oxygen as a waste product. In turn, oxygen is consumed and CO 2 is released as waste by all aerobic organisms when they metabolize organic compounds to produce energy by respiration . CO 2

4600-607: The Sahara desert fertilizes the Atlantic Ocean and the Amazon rainforest . The naturally occurring iron oxide in atmospheric dust reacts with hydrogen chloride from sea spray to produce iron chloride, which degrades methane and other greenhouse gases, brightens clouds and eventually falls with the rain in low concentration across a wide area of the globe. Unlike ship based deployment, no trials have been performed of increasing

4700-521: The South Atlantic . India was also involved. As part of the experiment, the German research vessel Polarstern deposited 6 tons of ferrous sulfate in an area of 300 square kilometers. It was expected that the material would distribute through the upper 15 metres (49 ft) of water and trigger an algal bloom. A significant part of the carbon dioxide dissolved in sea water would then be bound by

4800-608: The Southern Ocean speculated - in "On the phytoplankton of the South-West Atlantic and Bellingshausen Sea, 1929-31" - that great "desolate zones" (areas apparently rich in nutrients, but lacking in phytoplankton activity or other sea life) might be iron-deficient. Hart returned to this issue in a 1942 paper entitled "Phytoplankton periodicity in Antarctic surface waters", but little other scientific discussion

4900-538: The albedo of the planet and so cause cooling—this proposed mechanism is central to the CLAW hypothesis . This is one of the examples used by James Lovelock to illustrate his Gaia hypothesis . During SOFeX, DMS concentrations increased by a factor of four inside the fertilized patch. Widescale iron fertilization of the Southern Ocean could lead to significant sulfur-triggered cooling in addition to that due to

5000-425: The carbonate ion ( CO 2− 3 ): In organisms, carbonic acid production is catalysed by the enzyme known as carbonic anhydrase . In addition to altering its acidity, the presence of carbon dioxide in water also affects its electrical properties. When carbon dioxide dissolves in desalinated water, the electrical conductivity increases significantly from below 1 μS/cm to nearly 30 μS/cm. When heated,

5100-467: The food chain for other marine organisms . There are two ways of performing artificial iron fertilization: ship based direct into the ocean and atmospheric deployment. Trials of ocean fertilization using iron sulphate added directly to the surface water from ships are described in detail in the experiment section below. Iron-rich dust rising into the atmosphere is a primary source of ocean iron fertilization. For example, wind blown dust from

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5200-458: The nitrate and phosphate present in the surface mixed layer across the entire Antarctic circumpolar current into organic carbon , the resulting carbon dioxide deficit could be compensated by uptake from the atmosphere amounting to about 0.8 to 1.4 gigatonnes of carbon per year. This quantity is comparable in magnitude to annual anthropogenic fossil fuels combustion of approximately 6 gigatonnes. The Antarctic circumpolar current region

5300-467: The pH . As shown in a Bjerrum plot , in neutral or slightly alkaline water (pH > 6.5), the bicarbonate form predominates (>50%) becoming the most prevalent (>95%) at the pH of seawater. In very alkaline water (pH > 10.4), the predominant (>50%) form is carbonate. The oceans, being mildly alkaline with typical pH = 8.2–8.5, contain about 120 mg of bicarbonate per liter. Being diprotic , carbonic acid has two acid dissociation constants ,

5400-450: The precautionary principle (PP) is a concept that states, "The PP means that when it is scientifically plausible that human activities may lead to morally unacceptable harm, actions shall be taken to avoid or diminish that harm: uncertainty should not be an excuse to delay action." Based on this principle, and because there is little data quantifying the effects of iron fertilization, it is the responsibility of leaders in this field to avoid

5500-426: The (incorrect) assumption that all dissolved CO 2 is present as carbonic acid, so that Since most of the dissolved CO 2 remains as CO 2 molecules, K a1 (apparent) has a much larger denominator and a much smaller value than the true K a1 . The bicarbonate ion is an amphoteric species that can act as an acid or as a base, depending on pH of the solution. At high pH, it dissociates significantly into

5600-516: The 2012 iron fertilization; many factors contribute to predictive models, and most data from the experiment are considered to be of questionable scientific value. On 15 July 2014, the data gathered during the project were made publicly available under the ODbL license. In 2022, a UK/India research team plans to place iron-coated rice husks in the Arabian Sea , to test whether increasing time at

5700-716: The Aleutian Islands deposited ash in the nutrient-limited Northeast Pacific. This ash and iron deposition resulted in one of the largest phytoplankton blooms observed in the subarctic. Previous instances of biological carbon sequestration triggered major climatic changes, lowering the temperature of the planet, such as the Azolla event . Plankton that generate calcium or silicon carbonate skeletons, such as diatoms , coccolithophores and foraminifera , account for most direct sequestration. When these organisms die their carbonate skeletons sink relatively quickly and form

5800-699: The Australian-based Ocean Nourishment Corporation, planned to engage in fertilization projects. These companies invited green co-sponsors to finance their activities in return for provision of carbon credits to offset investors' CO 2 emissions. LOHAFEX was an experiment initiated by the German Federal Ministry of Research and carried out by the German Alfred Wegener Institute (AWI) in 2009 to study fertilization in

5900-439: The air and water: Carbon dioxide is colorless. At low concentrations, the gas is odorless; however, at sufficiently high concentrations, it has a sharp, acidic odor. At standard temperature and pressure , the density of carbon dioxide is around 1.98 kg/m , about 1.53 times that of air . Carbon dioxide has no liquid state at pressures below 0.51795(10) MPa (5.11177(99) atm ). At a pressure of 1 atm (0.101325 MPa),

6000-443: The atmosphere are absorbed by land and ocean carbon sinks . These sinks can become saturated and are volatile, as decay and wildfires result in the CO 2 being released back into the atmosphere. CO 2 is eventually sequestered (stored for the long term) in rocks and organic deposits like coal , petroleum and natural gas . Nearly all CO2 produced by humans goes into the atmosphere. Less than 1% of CO2 produced annually

6100-658: The atmosphere for at least a period of time. This technique is controversial because there is limited understanding of its complete effects on the marine ecosystem , including side effects and possibly large deviations from expected behavior. Such effects potentially include release of nitrogen oxides , and disruption of the ocean's nutrient balance. Controversy remains over the effectiveness of atmospheric CO 2 sequestration and ecological effects. Since 1990, 13 major large scale experiments have been carried out to evaluate efficiency and possible consequences of iron fertilization in ocean waters. A study in 2017 considered that

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6200-425: The atmosphere modify the speciation of iron in dust and may affect the bioavailability of deposited iron. The soluble form of iron is much higher in aerosols than in soil (~0.5%). Several photo-chemical interactions with dissolved organic acids increase iron solubility in aerosols. Among these, photochemical reduction of oxalate -bound Fe(III) from iron-containing minerals is important. The organic ligand forms

6300-499: The carbon is suspended in the deep ocean it is effectively isolated from the atmosphere for hundreds of years, and thus, carbon can be effectively sequestered. Assuming the ideal conditions, the upper estimates for possible effects of iron fertilization in slowing down global warming is about 0.3W/m of averaged negative forcing which can offset roughly 15–20% of the current anthropogenic CO 2 emissions. However, although this approach could be looked upon as an easy option to lower

6400-428: The colder water strata below the thermocline . Much of this fixed carbon continues into the abyss, but a substantial percentage is redissolved and remineralized. At this depth, however, this carbon is now suspended in deep currents and effectively isolated from the atmosphere for centuries. Evaluation of the biological effects and verification of the amount of carbon actually sequestered by any particular bloom involves

6500-407: The concentration of CO 2 in the atmosphere, ocean iron fertilization is still quite controversial and highly debated due to possible negative consequences on marine ecosystems . Research on this area has suggested that fertilization through deposition of large quantities of iron-rich dust into the ocean floor can significantly disrupt the ocean's nutrient balance and cause major complications in

6600-484: The conclusion of theoretical calculations based on an ab initio potential energy surface of the molecule, is that none of the molecules in the gas phase are ever exactly linear. This counter-intuitive result is trivially due to the fact that the nuclear motion volume element vanishes for linear geometries. This is so for all molecules except diatomic molecules . Carbon dioxide is soluble in water, in which it reversibly forms H 2 CO 3 (carbonic acid), which

6700-806: The condition. There are few studies of the health effects of long-term continuous CO 2 exposure on humans and animals at levels below 1%. Occupational CO 2 exposure limits have been set in the United States at 0.5% (5000 ppm) for an eight-hour period. At this CO 2 concentration, International Space Station crew experienced headaches, lethargy, mental slowness, emotional irritation, and sleep disruption. Studies in animals at 0.5% CO 2 have demonstrated kidney calcification and bone loss after eight weeks of exposure. A study of humans exposed in 2.5 hour sessions demonstrated significant negative effects on cognitive abilities at concentrations as low as 0.1% (1000   ppm) CO 2 likely due to CO 2 induced increases in cerebral blood flow. Another study observed

6800-566: The dispersing effects of wind, it can collect in sheltered/pocketed locations below average ground level, causing animals located therein to be suffocated. Carrion feeders attracted to the carcasses are then also killed. Children have been killed in the same way near the city of Goma by CO 2 emissions from the nearby volcano Mount Nyiragongo . The Swahili term for this phenomenon is mazuku . Adaptation to increased concentrations of CO 2 occurs in humans, including modified breathing and kidney bicarbonate production, in order to balance

6900-541: The effects of blood acidification ( acidosis ). Several studies suggested that 2.0 percent inspired concentrations could be used for closed air spaces (e.g. a submarine ) since the adaptation is physiological and reversible, as deterioration in performance or in normal physical activity does not happen at this level of exposure for five days. Yet, other studies show a decrease in cognitive function even at much lower levels. Also, with ongoing respiratory acidosis , adaptation or compensatory mechanisms will be unable to reverse

7000-451: The emerging bloom and sink to the ocean floor. The Federal Environment Ministry called for the experiment to halt, partly because environmentalists predicted damage to marine plants. Others predicted long-term effects that would not be detectable during short-term observation or that this would encourage large-scale ecosystem manipulation. A 2012 study deposited iron fertilizer in an eddy near Antarctica. The resulting algal bloom sent

7100-410: The first one for the dissociation into the bicarbonate (also called hydrogen carbonate) ion ( HCO − 3 ): This is the true first acid dissociation constant, defined as where the denominator includes only covalently bound H 2 CO 3 and does not include hydrated CO 2 (aq). The much smaller and often-quoted value near 4.16 × 10 (or pK a1 = 6.38) is an apparent value calculated on

7200-469: The gas deposits directly to a solid at temperatures below 194.6855(30) K (−78.4645(30) °C) and the solid sublimes directly to a gas above this temperature. In its solid state, carbon dioxide is commonly called dry ice . Liquid carbon dioxide forms only at pressures above 0.51795(10) MPa (5.11177(99) atm); the triple point of carbon dioxide is 216.592(3) K (−56.558(3) °C) at 0.51795(10) MPa (5.11177(99) atm) (see phase diagram). The critical point

7300-566: The harmful effects of this procedure. This school of thought is one argument against using iron fertilization on a wide scale, at least until more data is available to analyze the repercussions of this. Critics are concerned that fertilization will create harmful algal blooms (HAB) as many toxic algae are often favored when iron is deposited into the marine ecosystem. A 2010 study of iron fertilization in an oceanic high-nitrate, low-chlorophyll environment, however, found that fertilized Pseudo-nitzschia diatom spp., which are generally nontoxic in

7400-601: The harvestable yield of crops, with wheat, rice and soybean all showing increases in yield of 12–14% under elevated CO 2 in FACE experiments. Increased atmospheric CO 2 concentrations result in fewer stomata developing on plants which leads to reduced water usage and increased water-use efficiency . Studies using FACE have shown that CO 2 enrichment leads to decreased concentrations of micronutrients in crop plants. This may have knock-on effects on other parts of ecosystems as herbivores will need to eat more food to gain

7500-498: The intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=OIF&oldid=1084675966 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Iron fertilization Ocean iron fertilization is an example of a geoengineering technique. Iron fertilization attempts to encourage phytoplankton growth , which removes carbon from

7600-476: The iron particles is critical. Particles of 0.5–1 micrometer or less seem to be ideal both in terms of sink rate and bioavailability. Particles this small are easier for cyanobacteria and other phytoplankton to incorporate and the churning of surface waters keeps them in the euphotic or sunlit biologically active depths without sinking for long periods. One way to add small amounts of iron to HNLC zones would be Atmospheric Methane Removal . Atmospheric deposition

7700-496: The islands of Haida Gwaii . The Old Massett Village Council financed the action as a salmon enhancement project with $ 2.5 million in village funds. The concept was that the formerly iron -deficient waters would produce more phytoplankton that would in turn serve as a "pasture" to feed salmon . Then-CEO Russ George hoped to sell carbon offsets to recover the costs. The project was accompanied by charges of unscientific procedures and recklessness. George contended that 100 tons

7800-679: The method is unproven; the sequestering efficiency was low and sometimes no effect was seen and the amount of iron deposits needed to make a small cut in the carbon emissions would be in the million tons per year. However since 2021, interest is renewed in the potential of iron fertilization, among other from a white paper study of NOAA, the US National Oceanographic and Atmospheric Administration, which rated iron fertilization as having "moderate potential for cost, scalability and how long carbon might be stored compared to other marine sequestration ideas" Approximately 25 per cent of

7900-403: The molecule has no electric dipole moment . As a linear triatomic molecule, CO 2 has four vibrational modes as shown in the diagram. In the symmetric and the antisymmetric stretching modes, the atoms move along the axis of the molecule. There are two bending modes, which are degenerate , meaning that they have the same frequency and same energy, because of the symmetry of the molecule. When

8000-553: The natural level of atmospheric iron. Expanding this atmospheric source of iron could complement ship-based deployment. One proposal is to boost the atmospheric iron level with iron salt aerosol . Iron(III) chloride added to the troposphere could increase natural cooling effects including methane removal , cloud brightening and ocean fertilization, helping to prevent or reverse global warming. Martin hypothesized that increasing phytoplankton photosynthesis could slow or even reverse global warming by sequestering CO 2 in

8100-578: The ocean by glaciers , rivers and icebergs. About 70% of the world's surface is covered in oceans. The part of these where light can penetrate is inhabited by algae (and other marine life). In some oceans, algae growth and reproduction is limited by the amount of iron. Iron is a vital micronutrient for phytoplankton growth and photosynthesis that has historically been delivered to the pelagic sea by dust storms from arid lands. This Aeolian dust contains 3–5% iron and its deposition has fallen nearly 25% in recent decades. The Redfield ratio describes

8200-420: The ocean floor where their carbonate skeletons can form a major component of the carbon-rich deep sea precipitation, thousands of meters below plankton blooms, known as marine snow . Nonetheless, based on the definition, carbon is only considered "sequestered" when it is deposited in the ocean floor where it can be retained for millions of years. However, most of the carbon-rich biomass generated from plankton

8300-426: The ocean surface has ample macronutrients, with little plant biomass (as defined by chlorophyll). The production in these high-nutrient low-chlorophyll (HNLC) waters is primarily limited by micronutrients , especially iron. The cost of distributing iron over large ocean areas is large compared with the expected value of carbon credits . Research in the early 2020s suggested that it could only permanently sequester

8400-421: The oceans. Martin's 1988 quip four months later at Woods Hole Oceanographic Institution , "Give me a half a tanker of iron and I will give you an ice age ," drove a decade of research. Carbon dioxide Carbon dioxide is a chemical compound with the chemical formula CO 2 . It is made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It

8500-592: The open ocean, began producing toxic levels of domoic acid . Even short-lived blooms containing such toxins could have detrimental effects on marine food webs. Most species of phytoplankton are harmless or beneficial, given that they constitute the base of the marine food chain. Fertilization increases phytoplankton only in the open oceans (far from shore) where iron deficiency is substantial. Most coastal waters are replete with iron and adding more has no useful effect. Further, it has been shown that there are often higher mineralization rates with iron fertilization, leading to

8600-554: The particulate matter fell to between 100 metres (330 ft) to the ocean floor. Each iron atom converted at least 13,000 carbon atoms into algae. At least half of the organic matter sank below, 1,000 metres (3,300 ft). In July 2012, the Haida Salmon Restoration Corporation dispersed 100 short tons (91 t) of iron sulphate dust into the Pacific Ocean several hundred miles west of

8700-499: The presence of sufficient oxygen, manifesting as dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour. Concentrations of more than 10% may cause convulsions, coma, and death. CO 2 levels of more than 30% act rapidly leading to loss of consciousness in seconds. Because it is heavier than air, in locations where the gas seeps from the ground (due to sub-surface volcanic or geothermal activity) in relatively high concentrations, without

8800-496: The products of their photosynthesis as internal food sources and as raw material for the biosynthesis of more complex organic molecules, such as polysaccharides , nucleic acids , and proteins. These are used for their own growth, and also as the basis of the food chains and webs that feed other organisms, including animals such as ourselves. Some important phototrophs, the coccolithophores synthesise hard calcium carbonate scales. A globally significant species of coccolithophore

8900-445: The relative atomic concentrations of critical nutrients in plankton biomass and is conventionally written "106 C: 16 N: 1 P." This expresses the fact that one atom of phosphorus and 16 of nitrogen are required to " fix " 106 carbon atoms (or 106 molecules of CO 2 ). Research expanded this constant to "106 C: 16 N: 1 P: .001 Fe" signifying that in iron deficient conditions each atom of iron can fix 106,000 atoms of carbon, or on

9000-563: The resulting algal bloom died and sank to the sea floor. Planktos was a US company that abandoned its plans to conduct 6 iron fertilization cruises from 2007 to 2009, each of which would have dissolved up to 100 tons of iron over a 10,000 km area of ocean. Their ship Weatherbird II was refused entry to the port of Las Palmas in the Canary Islands where it was to take on provisions and scientific equipment. In 2007 commercial companies such as Climos and GreenSea Ventures and

9100-420: The same amount of protein. The concentration of secondary metabolites such as phenylpropanoids and flavonoids can also be altered in plants exposed to high concentrations of CO 2 . Plants also emit CO 2 during respiration, and so the majority of plants and algae, which use C3 photosynthesis , are only net absorbers during the day. Though a growing forest will absorb many tons of CO 2 each year,

9200-604: The sea. He died shortly thereafter during preparations for Ironex I, a proof of concept research voyage, which was successfully carried out near the Galapagos Islands in 1993 by his colleagues at Moss Landing Marine Laboratories . Thereafter 12 international ocean studies examined the phenomenon: John Martin , director of the Moss Landing Marine Laboratories , hypothesized that the low levels of phytoplankton in these regions are due to

9300-532: The surface can stimulate a bloom using less iron. The iron will be confined within a plastic bag reaching from the surface several kilometers down to the sea bottom. The Centre for Climate Repair at the University of Cambridge, along with India's Institute of Maritime Studies assessed the impact of iron seeding in another experiment. They spread iron-coated rice husks across an area of the Arabian Sea. Iron

9400-544: The surface, where planktons can take it up to grow. It has been shown that reduction in the number of sperm whales in the Southern Ocean has resulted in a 200,000 tonnes/yr decrease in the atmospheric carbon uptake, possibly due to limited phytoplankton growth. Phytoplankton is photosynthetic : it needs sunlight and nutrients to grow, and takes up carbon dioxide in the process. Plankton can take up and sequester atmospheric carbon through generating calcium or silicon-carbonate skeletons. When these organisms die they sink to

9500-535: The upper ocean and thereby promotes the absorption of CO 2 from the atmosphere. Carbon dioxide content in fresh air (averaged between sea-level and 10 kPa level, i.e., about 30 km (19 mi) altitude) varies between 0.036% (360 ppm) and 0.041% (412 ppm), depending on the location. In humans, exposure to CO 2 at concentrations greater than 5% causes the development of hypercapnia and respiratory acidosis . Concentrations of 7% to 10% (70,000 to 100,000 ppm) may cause suffocation, even in

9600-458: The water begins to gradually lose the conductivity induced by the presence of C O 2 {\displaystyle \mathrm {CO_{2}} } , especially noticeable as temperatures exceed 30 °C. The temperature dependence of the electrical conductivity of fully deionized water without CO 2 saturation is comparably low in relation to these data. CO 2 is a potent electrophile having an electrophilic reactivity that

9700-546: The water, or to the lungs from where it is exhaled. During active photosynthesis, plants can absorb more carbon dioxide from the atmosphere than they release in respiration. Carbon fixation is a biochemical process by which atmospheric carbon dioxide is incorporated by plants, algae and cyanobacteria into energy-rich organic molecules such as glucose , thus creating their own food by photosynthesis. Photosynthesis uses carbon dioxide and water to produce sugars from which other organic compounds can be constructed, and oxygen

9800-551: Was followed by a larger field experiment (IRONEX I) where 445 kg of iron was added to a patch of ocean near the Galápagos Islands . The levels of phytoplankton increased three times in the experimental area. The success of this experiment and others led to proposals to use this technique to remove carbon dioxide from the atmosphere. In 2000 and 2004, iron sulfate was discharged from the EisenEx. 10 to 20 percent of

9900-582: Was negligible compared to what naturally enters the ocean. Some environmentalists called the dumping a "blatant violation" of two international moratoria. George said that the Old Massett Village Council and its lawyers approved the effort and at least seven Canadian agencies were aware of it. According to George, the 2013 salmon runs increased from 50 million to 226 million fish. However, many experts contend that changes in fishery stocks since 2012 cannot necessarily be attributed to

10000-455: Was recorded until the 1980s, when oceanographer John Martin of the Moss Landing Marine Laboratories renewed controversy on the topic with his marine water nutrient analyses. His studies supported Hart's hypothesis. These "desolate" regions came to be called " high-nutrient, low-chlorophyll regions " (HNLC). John Gribbin was the first scientist to publicly suggest that climate change could be reduced by adding large amounts of soluble iron to

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