SRM in the lower troposphere (under the marine boundary layer) by natural emissions of DMS and other "anti-GHGs" gases, seems to deserve more consideration and research.
In 2008, in an EGU abstract, Reversing sea level rise by enhancing the natural sulfur cycle <https://www.cosis.net/abstracts/EGU2008/12210/EGU2008-A-12210-1.pdf>, O.W. Wingenter,, J. Moore, S.M. Elliot and D.R. Blake concluded that "... *full scale (iron) fertilization of the SO is not a viable geoengineering solution because it would lead to over cooling of the region. ...*" More recently (2015), B. S. Grandey and C. Wang have shown that Enhanced marine sulphur emissions (*can*) offset global warming (*but*) impact rainfall <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4543957/pdf/srep13055.pdf> Le mar. 20 août 2019 à 09:24, Andrew Lockley <[email protected]> a écrit : > Poster's note: scroll down for abstract > > https://www.inverse.com/article/58560-marsh-mud-anti-greenhouse-gas-climate > > Can We Actually Use the “Anti-Greenhouse Gas”? > > These findings lend themselves to a somewhat controversial idea: that we > might be able to manipulate these marine ecosystems to produce more DMS and > try to offset climate change that way. > > This idea dates back to 1987, when James Lovelock (the person who came up > with the “Gaia hypothesis > <https://courses.seas.harvard.edu/climate/eli/Courses/EPS281r/Sources/Gaia/Gaia-hypothesis-wikipedia.pdf> > ”) proposed <https://www.nature.com/articles/326655a0> that we could > actually use DMS-producing plankton to offset the warming climate. In 2007, > he wrote a letter <https://www.nature.com/articles/449403a> proposing an > “emergency treatment for the pathology of global warming”: the creation of > 100- to 200-meter-long pipes that could bring oceanic nutrients to the > surface, jumpstarting DMS production. > > In that letter, Lovelock admitted that a project like this “may fail > perhaps on engineering or economic grounds.” And it has since been > criticized because it could also cause dangerous algal blooms or other > unintended consequences. But the idea has never totally disappeared. In > 2015, another paper > <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4543957/> published in > *Scientific > Reports* used two climate models to show that increasing DMS production > would actually offset some changes in warming. > Personally I do not think there is a geo-engineering angle to the work, > others may disagree.” > > Still, even that paper acknowledged that there would likely be an > excessive “mixture of positive and negative impacts on the climate” to > attempt such an aggressive geoengineering scheme. > Sponsored > <https://www.inverse.com/article/56746-what-is-runner-s-high-how-to-achieve-it> > 00:0301:10 > > <https://www.inverse.com/article/56746-what-is-runner-s-high-how-to-achieve-it> > The Science of a Runner's High > <https://www.inverse.com/article/56746-what-is-runner-s-high-how-to-achieve-it> > Celebrity trainer Jenna Willis breaks down the science behind a runner's > high and shares some tips to help get you there. > <https://www.inverse.com/article/56746-what-is-runner-s-high-how-to-achieve-it> > Watch More » > > <https://www.inverse.com/article/56746-what-is-runner-s-high-how-to-achieve-it> > > Todd, in the context of this new paper, doesn’t see his team’s work that > way. > > “We feel our study does provide important knowledge required to understand > the global production and cycling of DMSP and DMS,” he says. “Personally I > do not think there is a geo-engineering angle to the work, others may > disagree.” > > Still, as we continue to search for a solution, some may be inspired to > know that our saltwater marshes and estuaries could be far richer sources > of the “anti-greenhouse gas” that we once thought. > > Abstract: > > Dimethylsulfoniopropionate (DMSP) and its catabolite dimethyl sulfide > (DMS) are key marine nutrients1,2 that have roles in global sulfur > cycling2, atmospheric chemistry3, signal- ling4,5 and, potentially, climate > regulation6,7. The production of DMSP was previously thought to be an oxic > and photic pro- cess that is mainly confined to the surface oceans. > However, here we show that DMSP concentrations and rates of DMSP and DMS > synthesis are higher in surface sediment from, for example, saltmarsh > ponds, estuaries and the deep ocean than in the overlying seawater. A > quarter of bacterial strains isolated from saltmarsh sediment produced DMSP > (up to 73 mM), and we identified several previously unknown pro- ducers of > DMSP. Most DMSP-producing isolates contained dsyB8, but some > alphaproteobacteria, gammaproteobacteria and actinobacteria used a > methionine methylation pathway independent of DsyB that was previously only > associated with higher plants. These bacteria contained a methionine meth- > yltransferase gene (mmtN)—a marker for bacterial synthesis of DMSP through > this pathway. DMSP-producing bacteria and their dsyB and/or mmtN > transcripts were present in all of the tested seawater samples and Tara > Oceans bacterioplankton datasets, but were much more abundant in marine > surface sediment. Approximately 1 × 108 bacteria g−1 of surface marine > sediment are predicted to produce DMSP, and their contribu- tion to this > process should be included in future models of global DMSP production. We > propose that coastal and marine sediments, which cover a large part of the > Earth’s surface, are environments with high levels of DMSP and DMS > productiv- ity, and that bacteria are important producers of DMSP and DMS > within these environments. > > -- > 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 view this discussion on the web visit > https://groups.google.com/d/msgid/geoengineering/CAJ3C-045VxPkOpo13jDVVZq2hxOOot-vJoOKO-Wp916RohVZ%3DA%40mail.gmail.com > <https://groups.google.com/d/msgid/geoengineering/CAJ3C-045VxPkOpo13jDVVZq2hxOOot-vJoOKO-Wp916RohVZ%3DA%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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