With all due respect to Martin, I'm very sceptical the iron fueled marine biology was a major player in G-I air CO2 fluctuations, but at $32/reprint, can anyone freely supply me with the evidence? Thanks, Greg ________________________________________ From: geoengineering@googlegroups.com [geoengineering@googlegroups.com] On Behalf Of Andrew Lockley [andrew.lock...@gmail.com] Sent: Monday, August 08, 2011 7:20 PM To: geoengineering Subject: [geo] Important paper on potential CDR / SRM interactions
Hi Please see below abstract of http://www.nature.com/nature/journal/vaop/ncurrent/full/nature10310.html, which suggests reduced precip and increased Aeolian dust as the main amplification mechanism for the Milankovitch cycle. If correct, this relationship suggests that there could be a potentially powerful carbon cycle amplification of SRM. This results from changes to precip in the hydro cycle causing desiccation, and subsequent increases in the Fe-containing aelion dust fluxes to the Southern Ocean. This ultimately may lead to a flux of CO2 from atmosphere as NPP increases and drives a subsequent increased flux of marine snow. A Southern Ocean dust–climate coupling over the past four million years · Alfredo Martínez-Garcia, et al Nature (2011) doi:10.1038/nature10310 Dust has the potential to modify global climate by influencing the radiative balance of the atmosphere and by supplying iron and other essential limiting micronutrients to the ocean1, 2. Indeed, dust supply to the Southern Ocean increases during ice ages, and ‘iron fertilization’ of the subantarctic zone may have contributed up to 40 parts per million by volume (p.p.m.v.) of the decrease (80–100 p.p.m.v.) in atmospheric carbon dioxide observed during late Pleistocene glacial cycles3, 4, 5, 6, 7. So far, however, the magnitude of Southern Ocean dust deposition in earlier times and its role in the development and evolution of Pleistocene glacial cycles have remained unclear. Here we report a high-resolution record of dust and iron supply to the Southern Ocean over the past four million years, derived from the analysis of marine sediments from ODP Site 1090, located in the Atlantic sector of the subantarctic zone. The close correspondence of our dust and iron deposition records with Antarctic ice core reconstructions of dust flux covering the past 800,000 years (refs 8, 9) indicates that both of these archives record large-scale deposition changes that should apply to most of the Southern Ocean, validating previous interpretations of the ice core data. The extension of the record beyond the interval covered by the Antarctic ice cores reveals that, in contrast to the relatively gradual intensification of glacial cycles over the past three million years, Southern Ocean dust and iron flux rose sharply at the Mid-Pleistocene climatic transition around 1.25 million years ago. This finding complements previous observations over late Pleistocene glacial cycles5, 8, 9, providing new evidence of a tight connection between high dust input to the Southern Ocean and the emergence of the deep glaciations that characterize the past one million years of Earth history. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to geoengineering@googlegroups.com. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to geoengineering@googlegroups.com. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
