I'm surprised *New Scientist* writer Jeff Hect failed to note my 2008 account of inadvertant iron fertilization by smokestack fallout from ships, which appeared in *Science* online in response to a 2007 ocean fertilization piece by Eli Kintisch: CARBON SEQUESTRATIONShould Oceanographers Pump Iron? - Eli Kintisch
Science 30 November 2007: 1368-1370. - Summary <http://www.sciencemag.org/content/318/5855/1368.summary> 1. <http://www.sciencemag.org/content/318/5855/1368.summary/reply#content-block> Ocean Iron Fertilization - Russell Seitz Cambridge, MA, USA E. Kintisch’s article, "Should oceanographers pump iron?" (News Focus, 30 November 2007, p. 1368) reminds us that controversy surrounds ocean fertilization as a means of offsetting atmospheric carbon dioxide. Biologists are skeptical, because despite the late John Martin’s famous assertion, "Give me a half tanker of iron and I'll give you an ice age" ( *1*), many offshore areas sequester little carbon because their waters are perennially deficient in nitrogen and phosphorus as well. But Martin’s wish for a series of massive experiments may have been realized anyway—before he was born. During the decades before oil became the dominant marine transportation fuel, burning coal to raise steam at sea spewed literally megatons a year of iron, nitrogen, and phosphorous into nutrient-deficient surface waters. Burning coal typically generates ash equal to ~10% of the fuel mass. In modern combustion technology, electrostatic precipitators, bag houses, and scrubbers remove over 95% of particulates. But no effort was made to capture fly ash in early marine propulsion, and about three-fourths was entrained and released with hot flue gases, the rest being incorporated into stack ash, boiler slag, and scoria (*2*). Owing to the low energy density of coal relative to oil, the 50,000,000 ton fleet of coal-burning ships operating in the early 20th century (*3*) consumed many times its displacement in fuel annually. The efficient but ill-fated Titanic consumed 1.5% of its 42,000 tonne displacement daily, and lesser vessels typically combusted their displacement in bunker coal in a matter of months. The scale of marine fuel demand was such that Europe's 1913 export of 213 million tons of bunker coal represented less than half the world total (*4*). Coal ash typically contains from 2.5% to 8.5% iron (*5*). Much occurs as pyrites (FeS2), and sulfate enrichment of ash particles by its oxidation may enhance the bioavailability of fly ash iron. This suggests that early 20th century European maritime activity alone annually released ~0.39 to 2.16 teragrams of iron at sea, with a high and frequently replenished flux of aerosol iron flux along heavily traveled shipping lanes. But what of nitrogen and phosphorus? Before the Haber process revolutionized nitrogen fixation, one of the most important fertilizers was the ammonium sulfate inevitably co-produced with coal tar in gas works and coke ovens. Since ship's coal typically contains 1 to 3% nitrogen, mostly in polycyclics, the pyrolysis yield of water-soluble pyrroles, pyridine and ammonium compounds from combustion at sea, may also have been in the low-teragram range. Unlike metallurgical coal, the ash of that mined to raise steam typically contained on the order of a kilogram of phosphorus per ton. This suggests that the co-deposition of nutrient phosphorus and nitrogen with iron may have at least locally met the N-P-Fe synergy criterion for enhancement of carbon fixation. Given that literal shiploads of fly ash fell at sea for decades, understanding what exactly was combusted along historic shipping lanes may shed light on the risks and benefits of the more modest CO2 sequestration experiments of today, and perhaps add the record of another historic aerosol (*6*) to the list of those already known to impact climate model estimates of 20th century and future radiative forcing. Russell Seitz Cambridge, MA 02138, USA. References 1. J. H. Martin *et al*., *Nature* 371, 123 (1994). 2. *U.S. EPA Radiation Protection* (http://www.EPA.gov/rpdweb00/tenorm/coalandcoalash.html). 3. *Lloyds Register* (http://www.coltoncompany.com/shipping/statistics/wldflt.htm). 4. J. F. Bogardus, *Geographical Review* 20 (4), 642 (1930). 5. S. K. Gupta, T. F. Wall, R. A. Creelman, R. P. Gupta, *Fuel Processing Technology* 56 (issues 1–2), 33 (1998). 6. R. Seitz, *Nature* 323, 116 (1986). ... less <http://www.sciencemag.org/content/318/5855/1368.summary/reply#> Submit response<http://www.sciencemag.org/letters/submit/sci;318/5855/1368?title=Re:Ocean%20Iron%20Fertilization> Published 12 May 2008 On Thursday, February 7, 2013 6:50:19 PM UTC-5, andrewjlockley wrote: > > Posters note : Ships apparently 'geoengineering' with iron as well as > sulfur. Where would we be without them? > > > http://www.newscientist.com/article/mg21729035.100-sooty-ships-may-be-geoengineering-by-accident.html > ? > > Sooty ships may be geoengineering by accident > > 06 February 2013 by Jeff Hecht > > Magazine issue 2903. > > GEOENGINEERING is being tested - albeit inadvertently - in the north > Pacific. Soot from oil-burning ships is dumping about 1000 tonnes of > soluble iron per year across 6 million square kilometres of ocean, new > research has revealed.Fertilising the world's oceans with iron has been > controversially proposed as a way of sucking carbon dioxide out of the > atmosphere to curb global warming. Some geoengineers claim releasing iron > into the sea will stimulate plankton blooms, which absorb carbon, but ocean > processes are complex and difficult to monitor in tests."Experiments > suggest you change the population of algae, causing a shift from > fish-dominated to jellyfish-dominated ecosystems," says Alex Baker of the > University of East Anglia, UK. Such concerns led the UN Convention on > Biological Diversity (CBD) to impose a moratorium on geoengineering > experiments in 2010.The annual ship deposition is much larger, if less > concentrated, than the iron released in field tests carried out before the > moratorium was in place. Yet because ship emissions are not intended to > alter ocean chemistry, they do not violate the moratorium, says Jim Thomas > of the ETC Group, a think tank that consults for the CBD. "If you > intentionally drove oil-burning ships back and forth as a geoengineering > experiment, that would contravene it."The new study, by Akinori Ito of > the Japan Agency for Marine-Earth Science and Technology, is the first to > quantify how shipping deposits iron in parts of the ocean normally > deficient in it. Earlier models had assumed that only 1 to 2 per cent of > the iron contained in aerosols, including shipping emissions, is soluble in > seawater, so the remaining 98 to 99 percent would sink to the bottom > without affecting ocean life. But Ito found that up to 80 per cent of the > iron in shipping soot is soluble (Global Biogeochemical Cycles, > doi.org/kdj). As this soot rapidly falls to the sea surface, it is likely > to be fertilising the oceans.In the high-latitude north Pacific - a region > that is naturally iron-poor and therefore likely to be most affected by > human deposits - ship emissions now account for 70 per cent of soluble iron > from human activity, with the burning of biomass and coal accounting for > the rest. Shipping's share will rise as traffic continues to grow and > regulations restrict coal and biomass emissions.Can we learn anything from > this unintentional experiment? Baker thinks not. "The process isn't > scientifically useful," he says, because the uncontrolled nature of the > iron makes it difficult to draw meaningful comparisons.The depositions are > unlikely to be harmful at current levels, he says, but "given the > uncertainties, I just don't know how much these iron emissions would have > to increase before there was demonstrable harm to an ecosystem, or benefit > in terms of carbon uptake, for that matter". > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to geoengineering+unsubscr...@googlegroups.com. To post to this group, send email to geoengineering@googlegroups.com. Visit this group at http://groups.google.com/group/geoengineering?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
