I can't access the paper, but I'd be a little concerned about differential degradation of the OC and IC in the traps in making this interp. Is the OC/IC constant with depth of trap? Anyway, it is important to keep track of export IC. As (more) CO2 is drawn down in surface water by phytos, pH, [CO3--], and CaCO3 saturation state will all rise, stimulating bio CaCO3 (and CO2) production(?)
Greg >________________________________ > From: Andrew Lockley <[email protected]> >To: geoengineering <[email protected]> >Sent: Sunday, January 11, 2015 2:58 AM >Subject: [geo] Carbonate counter pump stimulated by natural iron fertilization >in the Polar Frontal Zone : Nature Geoscience > > > >Poster's note : paper link below with abstract. NB plain English article >previously posted on list >-http://www.the-scientist.com/?articles.view/articleNo/41564/title/Complexities-of-Carbon-Lowering/ >http://www.nature.com/ngeo/journal/v7/n12/full/ngeo2285.html >Carbonate counter pump stimulated by natural iron fertilization in the Polar >Frontal Zone >Ian Salter, Ralf Schiebel, Patrizia Ziveri, Aurore Movellan, Richard Lampitt & >George A. Wolff >Nature Geoscience 7, 885–889 (2014) >doi:10.1038/ngeo2285 >Published online 10 November 2014 >The production of organic carbon in the ocean’s surface and its subsequent >downward export transfers carbon dioxide to the deep ocean. This CO2 drawdown >is countered by the biological precipitation of carbonate, followed by sinking >of particulate inorganic carbon, which is a source of carbon dioxide to the >surface ocean, and hence the atmosphere over 100–1,000 year timescales. The >net transfer of CO2 to the deep ocean is therefore dependent on the relative >amount of organic and inorganic carbon in sinking particles. In the Southern >Ocean, iron fertilization has been shown to increase the export of organic >carbon, but it is unclear to what degree this effect is compensated by the >export of inorganic carbon. Here we assess the composition of sinking >particles collected from sediment traps located in the Polar Frontal Zone of >the Southern Ocean. We find that in high-nutrient, low-chlorophyll regions >that are characterized by naturally high iron concentrations, fluxes of both organic and inorganic carbon are higher than in regions with no iron fertilization. However, the excess flux of inorganic carbon is greater than that of organic carbon. We estimate that the production and flux of carbonate in naturally iron-fertilized waters reduces the overall amount of CO2 transferred to the deep ocean by 6–32%, compared to 1–4% at the non-fertilized site. We suggest that an increased export of organic carbon, stimulated by iron availability in the glacial sub-Antarctic oceans, may have been accompanied by a strengthened carbonate counter pump. -- >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 [email protected]. >To post to this group, send email to [email protected]. >Visit this group at http://groups.google.com/group/geoengineering. >For more options, visit https://groups.google.com/d/optout. > > > -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
