Is a great iron fertilization experiment already underway?

News Release 26-Jun-2019

Is a great iron fertilization experiment already underway?

University of South Florida (USF Innovation)

The RV Knorr was operated by Woods Hole Oceanographic Institution from 1970-2016. It was used on the GEOTRACES expeditions in 2010-2011 during which iron aerosol samples were collected for the study led by the USF College of Marine Science. Credit: University of South Florida

The RV Knorr was operated by Woods Hole Oceanographic Institution from 1970-2016. It was used on the GEOTRACES expeditions in 2010-2011 during which iron aerosol samples were collected for the study led by the USF College of Marine Science. Credit: University of South Florida

ST. PETERSBURG, FL – It’s no secret that massive dust storms in the Saharan Desert occasionally shroud the North Atlantic Ocean with iron, but it turns out these natural blankets aren’t the only things to sneeze at. Iron released by human activities contributes as much as 80 percent of the iron falling on the ocean surface, even in the dusty North Atlantic Ocean, and is likely underestimated worldwide, according to a new study in Nature Communications.

“People don’t even realize it,” said lead author Dr. Tim Conway, Assistant Professor at the USF College of Marine Science, “but we’ve already been doing an iron fertilization experiment of sorts for many decades.”

Burning fossil fuels, biofuels, and forests all release iron, which can be transported as an aerosol over large distances from land into the guts of the North Atlantic and beyond. But human-derived iron aerosols have been nearly impossible to see in the data – until now. The team used the isotope ratios of iron in the atmosphere to ‘fingerprint’ whether the iron came from Saharan desert dust or human sources such as cars, combustion, or fires.

“Despite much research, iron chemistry is still something of a black box in the ocean,” Conway said. Iron, a trace element, is found in exceedingly low amounts in the ocean; one liter of seawater contains 35 grams of salt but only around one billionth of a gram of iron. This makes it very hard to measure. The iron is also hard to sample without risking contamination, especially if working on a rusty ship.

Trying to establish how much atmospheric iron lands on and dissolves in the ocean presents even more challenges, with storms, seasons, and land use all changing how much dust gets blown from the continents. Digesting dust particles in the lab to see how much iron dissolves is also problematic, and has led to estimates of iron that dissolves when it hits the ocean ranging from 0 to 100 percent.

The current study addresses some of these mysteries that remain in iron chemistry, taking our understanding of atmospheric iron supply to the oceans to the next level.

Conway and his colleagues analyzed aerosol samples collected on research cruises to the North Atlantic in 2010 and 2011 on board the R/V Knorr. The cruises were part of GEOTRACES, a global coordinated research program of 35 countries to study trace metals and their isotopes in the ocean.

Samples were taken from an area off West Africa known to collect dust from the Saharan dust storms, and the others were taken off the coasts of New England and Europe where human-derived pollution is expected to be more important. The team then measured iron isotope ratios in the samples in order to determine whether the iron came from a natural or human source.

Iron isotope ratios (56Fe/54Fe) can change in response to chemical reactions, so human-induced processes like burning fossil fuels release iron with a different isotope ‘signature’ than iron derived from natural materials. Saharan dust particles were previously assumed to have a ratio that looked like the average continental crust, and Conway has suggested that when Saharan dust particles hit the ocean, the iron that dissolves interacts with organic molecules that bind the heavier 56Fe.

“We carried out this research to investigate that idea and fully expected to see continental signals or perhaps more heavy isotopes in the samples from all three regions,” said Conway. “What we found was pretty crazy and very light. We weren’t expecting this at all,” Conway said.

The iron in Saharan air was indeed a match for the continental crust, but was much heavier than the samples from North America and Europe, which were loaded with lighter (more 54Fe), human-derived iron – not iron from the Sahara.

“The fact that we found human-derived iron in the dusty North Atlantic shows how effective this tracer is for anthropogenic iron,” Conway said.

Next, they used the iron-isotope tracer work to improve the models used to predict the amount of dust that falls over the global ocean, and were able to show that the iron from human input is much greater than previously thought.

Since the 1990s scientists have proposed the idea of fertilizing the water with iron released from ships to accelerate the growth of phytoplankton. The thinking goes like this:

Iron is a vital micronutrient that phytoplankton need to grow but it’s generally scarce in the ocean. When available via dust storm or other source, the phytoplankton slurp up the carbon dioxide during photosynthesis at the ocean’s surface. When they die and sink to the ocean bottom, they take the carbon with it – effectively acting as a “carbon sink.” So let’s add more iron to decrease the carbon dioxide from climate change, say geoengineering enthusiasts.

This geoengineering exercise is still hotly debated today, and the study by Conway and team add fuel to the fire with an unexpected twist.

“It seems we’ve already been fertilizing the ocean. We just couldn’t quantify it,” Conway said, although scientists have had a hunch about the human iron input since the mid-2000s.

“We’ve completely changed the system,” he said, and routinely add iron to the ocean when cutting down forests or driving cars. Ironically, because of the way iron works it’s therefore possible that these human sources of iron to the ocean may in fact have been acting to mitigate climate change.

“We don’t know the magnitude of it yet but it’s a fair statement,” Conway said.

###

The work was funded by the National Science Foundation and included researchers from Cornell University, Florida State University, the University of Alaska Fairbanks, and the University of Southern California. Additional support was provided by the USF College of Marine Science.

From EurekAlert!

58 thoughts on “Is a great iron fertilization experiment already underway?

  1. Just wondered how you count a dam burst in Brazil at a major iron mining operation (?). Human, natural, and impact

  2. well…I guess we know it all now
    …when they start having to recycle something…as news…that’s been known forever

    He might want to check and see what makes the Amazon rain forest work while he’s at it

  3. “anthropogenic iron” – It’s good we can put the evil man-made iron to work. Are the creature that use this iron to feed and grow then called “anthropogenic plankton”?

  4. Actually, we had a deliberate experiment and the results are known. iron dumping

    There has been speculation since that the bloom was largely responsible for the return of the largest run in almost a century of sockeye salmon to the Fraser River …

      • My wild ass guess is that that iron doesn’t make its way up the water column to where the plankton are. On the other hand, some bacteria dine royally. link

        • also, that iron is found in such low concentrations in sea water because it quickly reacts with other elements (most obviously oxygen) and precipitates out due to its weight.

        • Speaking under correction here as usual (not enough time or money) my understanding is that the mechanism by which iron fertilisation works is not yet understood. My simplistic explanation is that iron reacts with carbon dioxide, the oxygen makes the iron rust and the resultant carbon provides a free meal to algae, who do not have to expend energy in order to obtain it. These in turn provide more food than usual to phytoplankton, whose population expands, and so on up the food chain. I believe the same phenomenon is experienced in terrestrial ecosystems at times. Thus more phytoplankton, more food available to fish and the fish population expand, and the population of predators feeding off fish likely also expands because of increased food availability. Once the effect wears off, there is a sudden and massive contraction of numbers. As to the amount of iron involved in proportion to the total amount of iron in the ocean, I can only hazard a guess that because there is a local concentration, the impact is only seen locally……

          • Iron is extremely important in most creatures metabolism. Due to it’s electronic structure it has more reduction/oxidation reactions available and is highly important in enzymes and other important molecules.

            Iron is highly important in metabolism because is has more reduction/oxidation potentials which organisms use in enzyme reactions, co-catalyst reactions that are very important.

            Iron is at very low levels in the oceans likely because all organisms need it for basic life processes and absorb it. It’s key in chlorophyll which most algae and all green plants use to metabolize CO2 to make sugars and proteins. There would be a lot of very strange animals and plants without iron.

      • Deep currents are slow, I’m guessing it will be a couple hundred years before any of that iron makes it back to the surface.

      • Okay, now I am curious…

        So, a quick and dirty look suggests 75million tons of shipping sunk.

        Assume a 1 for 1 ‘shipping to steel’ ratio.

        Density steel 8000kg/m3, so we have a volume of 9375000m3 of steel sunk.

        If I get my exchange ratio correct, this is 0.009375 km3 of steel. Hold that number.

        Now another quick and dirty search suggests volume of the ocean is 1.3×10^9 km.

        Now if I crunch the numbers correctly I believe the by volume the sunk ship to ocean ratio is 1:13866700000 (or 1 is to 1.39×10^11)
        Now, again if I crunch my numbers correctly, 1 billionth of a gram in 1 litre of sea water works out to a ratio of 1 is to 8×10^12

        So… and running out of fingers and toes here… assuming all ships sunk were 100% steel (assumption) and that all ships then break down completely (assumption) then ships sunk in WW2 are going to/have taken the ocean iron levels from a very very small number to a very very small number that is 80(?) times bigger…

        So… based on my quick and nasty calcs… no real world practical effect?

        • Craig,
          “So, a quick and dirty look suggests 75million tons of shipping sunk.”
          I haven’t seen that number before, but with a typical merchant ship of the 1940s being perhaps about 5,000 gross tons, that equals ‘about 15,000 ships’.
          Very roughly.
          And that looks a pretty reasonable estimate, based on a quick look at the ineffable Wiki-Thingy [that even I can edit].

          One point – the tonnage of the merchant shipping sunk was, generally, measured in gross tons; gross tons are a measure of volume of the whole ship – with 100 cubic feet equal to one gross [register] ton.
          Weight of the ships themselves were – very roughly – about half the number of gross [register] tons in tons weight [of 2240 lbs, except in the US, where 2000 pounds is still used. And the metric tonne of 1000 kilos (about 2204.8 pounds.)].
          Countervailing that, the weight of the cargo could be considered – and some of that will have been steel. Much, too, was food.

          Naval – military – ships are measured in displacement tons – so the whole weight of the ship, including steel, fuel, ammunition, stores, and even the crew and their effects and food.

          All the foregoing indicates that Craig’s ‘quick and nasty calcs’ are a good first estimate.
          Craig, many thanks indeed.

          Auto

    • The most important consideration is the chemical state of the iron. It must be in a reduced state, preferably iron sulfate. Oxidized iron is essentially useless to plants and phytoplankton. The iron fertilization experiment carried out by the Haida primarily used iron sulfate, and resulted in a 400 percent increase in Salmon populations. It’s ironic that pineapple plantations in Hawaii must be routinely fertilized with reduced forms of iron, despite the fact that the soil is extremely rich in oxidized iron.

    • We can restore the oceans, feed hundreds of millions, and control the rise of CO2.

      RussGeorge.net

  5. This is also another example of how microbial life in the oceans has been left out of the models to which the question or concern about climate change revolves. If the iron chemistry issue and measurement is that limited then it can’t be in the current models. It’s the ion wagging the dog.

  6. This suggests a possible answer for why atmospheric carbon dioxide has always grown less than emission rates would indicate. It appears that burning fossil fuels may be in fact, at least partially, self mitigating.

  7. Did they consider iron being intoduced into the air via the use of Dicyclopentadienyliron used (I beleive) extensively in China and Russia as an octane booster.

    Part of a family of organo-metal compounds such as Tetraethyl-lead which was widely used in the west – now mostly replaced by MMT (Methyl Cyclopentadienyl Mananese Tricarbonyl).

  8. Digesting dust particles in the lab to see how much iron dissolves is also problematic, and has led to estimates of iron that dissolves when it hits the ocean ranging from 0 to 100 percent.

    I’ll Guar-on-tee it’s somewhere between those numbers right there

  9. “We’ve completely changed the system,…” Iron connection goes way back, maybe even earlier. About time they measure it. Rounsefell, G. A. and A. Dragovich. 1966. Correlations between oceanographic factors and abundance of the Florida red tide (Gymnodinium breve Davis), 1954-61. Bulletin of Marine Science. 16(3):404-422. Martin, D. F. 1975. The iron index as a guide for predicting red tides. In Proceedings of the Red Tide Conference Florida Marine Research Publication. 8

    This one suggests the Nitrogen-fixer fertilizes the red tide organism from iron stimulation.
    Walsh, J. J. and K. A. Steidinger. 2001. Saharan dust and Florida red tides: the cyanophyte connection. Journal of Geophysical Research. 106(C6):11597-11612.
    Also this–
    Hayes, M. L., et al.,. 2001. How are climate and marine biological outbreaks functionally linked? Hydrobiologia 460:231-220. (…climate regime shift in the 1970’s causing new marine epidemics, algal blooms, and other effects stimulated by increased iron blown from Africa to the western Atlantic…)

    • Just occurred to me, all this talk about tipping points? There have been old, continual, mostly ignored suggestions about micronutrients, trace elements, microecological factors, etc. Take copper, used as hull plating on wooden ships, toxic at high levels, induces larval settlement at low, invertebrate groups co-opted it to use in a respiratory compound like we use iron. DNA ain’t stupid.

    • Just thinking outside the box for a moment. Isn’t there something than can be done with sediment cores that might be able to correlate the abundance of iron with the abundance of plankton, both ancient and more recently? As I recall, the sooty burning of coal became so prolific in Britain around the turn of century that it actually came around the world back at them (the dragon’s tail), or so goes the story.

  10. Really? And the massive quantity of shipping and cargo sunk during both world wars doesn’t count as iron fertilization? An aside to this is that even after our human population explosion, only now are we seeing reduced fish catches, which are attributed to pollution and overfishing. Could it be that the algal blooms arising from this unintended iron fertilisation allowed fish stocks to flourish in large numbers, and the effect is now wearing off? If we continue with intentional iron fertilisation, perhaps there will also be a recovery in fish stocks, who knows…..

  11. “Ironically, because of the way iron works it’s therefore possible that these human sources of iron to the ocean may in fact have been acting to mitigate climate change.”

    So, problem solved. No need to eradicate fossil fuels, just make sure we release enough iron into the oceans to offset them. Crisis averted, panic over, we can all finally move on with our lives. No more of our taxes going to fund climate scientology, and no more Mickey Mann! No doubt Anthony will take this site down as there’s no longer a need for it, so we will probably never speak again.
    So long, and thanks for all the fish food.

    Whaddya mean, it ain’t over?

    • From the ever err, (un) reliable wikipedia —
      From https://en.wikipedia.org/wiki/Ferrocene#Fuel_additives .

      … ferrocene polyglycol copolymers, prepared by effecting a polycondensation reaction between a ferrocene derivative and a substituted dihydroxy alcohol, has especially promising applications as a component of rocket propellants. In particular, these copolymers provide the rocket propellants with heat stability, serving as a propellant binder and controlling the burn rate of the propellant.[56]

      In a similar light, ferrocene also has been found to be effective at reducing the smoke and sulfur trioxide produced when burning coal. The addition by any practical means, impregnating the coal or simply adding ferrocene to the combustion chamber, can significantly cut down the amount of these undesirable byproducts, even with a small amount of the metal cyclopentadienyl compound.[57]

      [My bold]
      So that’s a win-win!!

  12. The University of Otago in New Zealand did a deliberate small scale iron dumping experiment in about 2007 into a northern tongue of the cold southern ocean off the South Island of New Zealand. The resultant plankton bloom could be seen from a satellite.
    They suggested a few oil tanker loads of iron sand (with a simple treatment) could reduce atmospheric carbon dioxide significantly.
    They decided to take it no further as they had no certainty that it would not go too far. Geoengineering was recognised as a very risky business.
    I have no references. My information was from a cousin who was on the ship sampling ph levels of the sea water.

  13. About 7 or more years ago there was an unauthorized First Nations iron-seeding experiment that drew the ire of the United Nations.

    During the experiment, the salmon corporation dumped 100 tonnes of an iron-rich dirt-like material over about one-square kilometre about 300 kilometres west of the Haida Gwaii islands.”

    CBC News report:
    http://tinyurl.com/y539muvl

  14. Lightning has caused forest fires for millions of years already. Probably much bigger ones than we have today. So finding this human iron imprint from tree smoke might be more difficult than people who grew up watching Bambi might think.

  15. So how much warmer would the Medaeval Warming have been if we weren’t speading iron since the Iron Age and causing cooling?

  16. Also mitigating “climate change”: CO2. Plants and phytoplankton love the stuff, so they grow more. More plants = more carbon sequestration. Funny how that works.

    • Throwing iron into the equation and it’s obvious that we need more fossil fuel powered vehicles.

  17. Abstract
    “The aims of this work are to provide a detailed physicochemical assessment of atmospheric particles collected in the vicinity of three iron and steelmaking plants and to indicate the importance of chemical characterisation of the particles, in addition to the assessment of the particle size and concentrations. In this study, atmospheric sampling sites were selected downstream of three iron and steel processing operations in Australia and one background site in an urban area with little industrial activity. The collected particles were analysed for a range of particle size mass concentrations and detailed chemical analysis of the trace metals Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn in the corresponding particle size ranges was carried out. The PM2.5 fractions in the PM10 particles at all sampling sites ranged from 35 to 62% indicating fine particles made a significant contribution to this size fraction at these sampling sites. Similarly, PM1 to the total PM10 at all sites varied from 20 to 46% and contributed significantly to the PM10 mass loading. When compared to the background sampling site, all detected metals in the particles collected near the iron and steelmaking operations had 3.4-14 times higher concentrations of PM10, PM2.5 and PM1. Iron (Fe) was found to be the dominant metal in the particles collected in vicinity of the iron and steel processing industries contributing up to 12% of the total particle mass loading. This study suggests that the metal composition of PM10, PM2.5 and PM1 varies significantly between sites and the associated metal exposure value is considerably higher in the vicinity of iron and steel processing industries than in the urban area for the same particle concentration level.”
    https://researchers.mq.edu.au/en/publications/characterisation-of-trace-metals-in-atmospheric-particles-in-the-

    6.6.1 Carbon Steels
    “Steelmaking practice for the production of carbon steels traditionally starts from pig iron produced from the blast furnace. The high carbon in the iron, in the region of 3–4%, is the result of the liquid iron percolating down through the coke in the furnace stack. (A similar situation exists in the cupola furnace used in the melting of cast iron used by iron foundries.) Oxygen is added to oxidise the carbon down to levels more normally in the range of a few tenths of a percent. The bonus from the burning of the carbon is the huge and valuable increase of temperature that is needed to keep steels molten. Oxygen to initiate the CO reaction is added in various forms, traditionally as shovelfuls of granular FeO thrown onto the slag, but in modern steelmaking practice by spectacular jets of supersonic oxygen. The stage of the process in which the CO is evolved as millions of bubbles is so vigorous that it is aptly called a ‘carbon boil’.”
    https://www.sciencedirect.com/topics/engineering/steelmaking

    Common Uses for Slag
    Slag’s ain’t Slag’s
    “SLAG is a broad term covering all non metallic co products resulting from the separation of a metal from its ore, Its chemistry and morphology depends on the metal being produced and the solidification process used. Slags can be broadly categorized as ferrous (iron/steel) and non-ferrous (copper, lead/zinc) depending on the industry from which they come. Non ferrous slags make up only 12% of the total annual production Described below are the main types and uses of slag commercially available in Ferrous Slag products”
    http://www.nationalslag.org/common-uses-slag

  18. Really? First damned sentence,”that massive dust storms in the Saharan Desert occasionally shroud the North Atlantic”, after this nothing they say has any legitimacy. Go to AccuWeather, Hurricane Center, Atlantic Basin, and watch how dust storms come off the west African coast. How far is that from the North Atlantic?

    • Very occasionally, high pressure weather systems from the Sahara end up over the British Isles, dumping copious amounts of dust on car windscreens, windows, solar panels etc. So it’s possible that the author is correct.

    • Dust coming off the Sahara?
      Happens every year.
      Toggle the Year button of this WorldView image of the ocean west of Mauritania
      2016 Jun 19

  19. During the billions of years of the Ears existence rivers must have washed
    vast quantities of material into the seas and oceans. Iron would be a part of
    that material.

    As we are still here, I assume that this is normal and life continues as before.

    MJE VK5ELL

    • The Gulf of Mexico has an annual “dead zone” largely due to depleted oxygen from the minerals and nitrates washed in from the Mississippi River.

      The fertilization would need to be much more dispersed over open oceans.

  20. The biochemical activity of iron is also often difficult to accurately quantify in living systems. For example: many research papers will use iron chelators such as EDTA in the beleif that it will sequester iron and remove its confounding effects. Other researchers find that EDTA actually increases the effects of iron by making previously insoluble iron precipitates more soluble and bio-available.

    If we wait long enough, someone will probably eventually report that increased levels of carbon dioxide also effectively increases the amount of iron available to the oceans’ photosynthetic systems.

  21. Of all the Geo-engineering crazy schemes that have been proposed over the years, fertilizing the open oceans with iron, nitrate, and phosphate, especially the Southern Ocean, to pull CO2 out of the atmosphere is the pnly one that makes sense to me.
    1. It’s easy to stop if an unforeseen problem(s) appears.
    2. Its relatively inexpensive, converting old tanker ships to ore/mineral slurry release would be easy. You could even righ them with masts and sails to allow them to use the wind on disperasal legs to reduce fossil fuel use.
    3. It spreads carbon sequestration over vast areas, and the minimal seasonal variation of the Southern Ocean atmosphere pCO2 would allow good ‘signal’ monitoring with reduced seasonal “noise,” as happens in the NH.
    4. It would elevate primary productivity to enhance the entire food chain through all 4 trophic levels.
    5. Australia being in the SH would be a good “local’ source of limitless low grade iron and mineral dusts (red soils).
    6. Cold-water pelagic stocks would likely explode, allowing greatly increased quota-based fishery harvesting to reduce land-based agriculture pressure for livestock-protein feeding on dwindling soil qualities. that could greatly increase humans consumption of fish proteins and reduce demand for beef and pork.

    • I suggest you’re not familiar with the “Terraton Initiative”.

      Everything I know about it is positive. Even if surplus CO2 in the atmosphere has zero negative effects, the world’s cropland soil is carbon deficient. Moving massive amounts of carbon into the soil is something farmers want to do for their own purposes.

      The only negative one could argue is it reduces the CO2 fertilizer effect, but I doubt it ever gets adopted on enough land to truly do that. It would take a few billion acres just to move CO2 emissions to met zero.

      • “Surplus CO2” ???
        That’s a new one.

        Carbon in the soil? Carbon in the soil itself does nothing for plants.
        When was the last time you saw a bag of carbon fertilizer at the garden center?
        (Please say never)

        Manure fertilizers are rich in nitrate, sulfur, and phosphate. The manure releases this as bacteria-fungi consume the manure, releasing CO2 and the nutrients for plants to absorb by their roots. Land plants absorb gaseous CO2 via stomata for sugar conversion in what is biochemically called a dark reaction. The light energy reactions use photon energy to break water and create reducing equivalents used in the dark reactions.

  22. Everybody agrees that fishing was terrific in the years after WW2. The usual explanation is that there was less fishing during the war giving fish stocks an opportunity to grow, but I have often wondered if the many millions of tons of iron dumped in the ocean didn’t help too. Not only several thousand ships with cargo, all over the world in both shallow and deep water and even on beaches, but also literally millions of shells, mines, bombs, torpedoes, sonobuoys, flares, depth charges etc, and most of them blown into small pieces which greatly speeds up oxidation.

  23. “Iron is a vital micronutrient that phytoplankton need to grow but it’s generally scarce in the ocean.”
    ____________________________________________________

    Iron isn’t and won’t be a “nutrient” to any living thing whatsover.

    But iron is an oxygen carrier needed by living things for internal combustion AND internal transporting oxygen to where it’s needed / from where it’s destructive.

  24. “The current study addresses some of these mysteries that” “climate scientists” like to spread before our very eyes.

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