Ken I understand that your paper is based on theoretical computations and that your simulation is based on a global ocean carbon cycle model.
"Here, using a global ocean carbon cycle model, we performed idealized ocean iron fertilization simulations to place an upper bound on the effect of iron fertilization on atmospheric CO2 and ocean acidification." The abstract starts with a bias against 'commercial interest' citing 'carbon credits' ".. and there is continued commercial interest in using iron fertilization to generate carbon credits. " Natural Iron fertilization, diatoms biomass, oxygen level of atmosphere, fish biomass in oceans, temperature, ocean pH level, etc., have varied in the past. O2 level of atmosphere was as high as 30%, perhaps even 35%. At this point in time what was the - natural iron fertilization ? diatom biomass ? fish biomass ? Ocean pH ? Temperature ? etc. Anthropogenic Carbon emissions are about 9 Billion tons per year. Natural Diatom production is about 23.5 Billion tons of C per year. So a 40% increase in diatoms can consume all the anthropogenic carbon emissions ( all this may not be sequestered ). Human population was 2 Billion 100 years ago when Haber-Bosch process to make ammonia was invented and urea was made using this process. Now 100 million tons per year of urea is used by farmers to feed the 7 billion people. So why can't something similar be done in oceans ? Fish biomass has declined in the oceans. The contrast between massive fertilization of land to feed more people and the decline in fish biomass and reluctance to fertilize oceans needs to be discussed. Given the ratio of N : Fe required by Diatoms, 1 million tons of Fe in oceans may do what 100 million tons of N achieves on land. Regards Bhaskar On Fri, Nov 29, 2013 at 2:33 AM, Ken Caldeira <[email protected] > wrote: > Of course, even under rather extreme assumption, changes in planktonic > productivity can do little to slow the rising tide of ocean acidification. > (see Cao and Caldeira, 2010 for a relevant study) > > The main threat from ocean acidification is not to net primary > productivity, but rather to biodiversity. > > > _______________ > Ken Caldeira > > Carnegie Institution for Science > Dept of Global Ecology > 260 Panama Street, Stanford, CA 94305 USA > +1 650 704 7212 [email protected] > http://dge.stanford.edu/labs/caldeiralab > https://twitter.com/KenCaldeira > > > > On Thu, Nov 28, 2013 at 8:00 AM, M V Bhaskar <[email protected]>wrote: > >> >> >> http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0079890 >> Iron Limitation Modulates Ocean Acidification Effects on Southern Ocean >> Phytoplankton Communities >> >> >> - Clara J. M. Hoppe, >> - Christel S. Hassler, >> >> >> - Christopher D. Payne, >> >> >> - Philippe D. Tortell, >> >> >> - Björn Rost, >> >> >> - Scarlett Trimborn >> >> >> - Published: Nov 20, 2013 >> - DOI: 10.1371/journal.pone.0079890 >> >> >> Abstract >> >> The potential interactive effects of iron (Fe) limitation and Ocean >> Acidification in the Southern Ocean (SO) are largely unknown. Here we >> present results of a long-term incubation experiment investigating the >> combined effects of CO2 and Fe availability on natural phytoplankton >> assemblages from the Weddell Sea, Antarctica. Active Chl *a* fluorescence >> measurements revealed that we successfully cultured phytoplankton under >> both Fe-depleted and Fe-enriched conditions. Fe treatments had significant >> effects on photosynthetic efficiency (Fv/Fm; 0.3 for Fe-depleted and 0.5 >> for Fe-enriched conditions), non-photochemical quenching (NPQ), and >> relative electron transport rates (rETR). pCO2 treatments significantly >> affected NPQ and rETR, but had no effect on Fv/Fm. Under Fe limitation, >> increased pCO2 had no influence on C fixation whereas under Fe >> enrichment, primary production increased with increasing pCO2 levels. >> These CO2-dependent changes in productivity under Fe-enriched conditions >> were accompanied by a pronounced taxonomic shift from weakly to heavily >> silicified diatoms (i.e. from *Pseudo-nitzschia* sp. to *Fragilariopsis* >> sp.). >> Under Fe-depleted conditions, this functional shift was absent and thinly >> silicified species dominated all pCO2 treatments (*Pseudo-nitzschia* sp. >> and*Synedropsis* sp. for low and high pCO2, respectively). Our results >> suggest that Ocean Acidification could increase primary productivity and >> the abundance of heavily silicified, fast sinking diatoms in Fe-enriched >> areas, both potentially leading to a stimulation of the biological pump. >> Over much of the SO, however, Fe limitation could restrict this possible CO >> 2 fertilization effect." >> >> >> regards >> >> Bhaskar >> >> -- >> 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/groups/opt_out. >> > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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