Oliver, Bear in mind that the North East Pacific is a high-nutrient, low-chlorophyll (HNLC) area that is known to be limited by iron. The paper gives estimated sea water concentrations of silicate in the North East Pacific in the top 20 metre mixed layer in August 2008 when the volcanic eruption occurred of 5,000-15,000 nM (nana molar) compared to an estimated 6-20 nM supply from the ash fallout over the fertilized area in the Gulf of Alaska. Your second point was unclear but I assumed you were querying the release rate of the silicate from the ash. The ash used in the experiment was collected on a fishing boat during the eruption and stored dry in containers. The experiment only used the < 2 mm size fraction. The release rate of silicate in the experiments was 170 nmol silicate per gram of ash in the first hour and up to 585 nmol silicate per gram of ash after 20 hours. Chris.
On Wednesday, August 21, 2013 10:12:19 AM UTC+1, Oliver Tickell wrote: > > IMHO the significance of the silicic acid would depend on the time of > year. In the spring silicic acid is generally abundant so adding more of it > would make little difference. One it has all been used up and diatoms are > giving way to other phytoplankton a boost of silicic acid would give rise > to a second diatom bloom - so it would be very significant. And of course > the other question is how effectively the chemical composition of the > silicate in the ash and its particle size as this will determine its > quality as a source of silicic acid. > > Have the authors given any serious examination to such questions? Oliver. > > On 21/08/2013 09:55, Chris Vivian wrote: > > Oliver, > � > I have seen the paper but cannot post a copy online. In the paper the > authors did measure the release of nitrate, nitrite, ammonia, phosphate and > silicate in leaching experiments and concluded that the impact of these > macronutrients released from Kasatochi ash on primary productivity was > probably minimal.�They also suggested that the release of trace metals > other than iron could also have influenced phytoplankton growth. > > � > Chris. > � > On Monday, August 19, 2013 4:23:59 PM UTC+1, Oliver Tickell wrote: > >> I have not found an open source version of this paper yet, but here is >> a related one. >> http://www.biogeosciences.net/10/3715/2013/bg-10-3715-2013.pdf >> They do recognise that diatoms need silicic acid but do not seem to have >> thought of volcanic ash as a source of silicic acid, only of iron. >> >> Re olivine application, it is worth noting that olivine is a mixture of >> Mg silicate and Fe silicate. Some proportion, to be determined, of the iron >> in olivine will become bioavailable as weathering progresses. >> >> Oliver. >> =============== >> >> The ocean response to volcanic iron fertilisation after the eruption of >> Kasatochi volcano: a regional-scale biogeochemical ocean model >> study >> A. Lindenthal1 >> , B. Langmann1 >> , J. Patsch � >> 2 >> , I. Lorkowski2 >> , and M. Hort1 >> 1 >> Institute of Geophysics, KlimaCampus, University of Hamburg, Hamburg, >> Germany >> 2 >> Institute of Oceanography, KlimaCampus, University of Hamburg, Hamburg, >> Germany >> Correspondence to: B. Langmann ([email protected]) >> Received: 29 June 2012 � Published in Biogeosciences Discuss.: 26 July >> 2012 >> Revised: 18 April 2013 � Accepted: 8 May 2013 � Published: 5 June 2013 >> >> >> >> >> On 19/08/2013 15:03, Oliver Tickell wrote: >> >> This is very odd. Based on the abstract only (article behind paywall) it >> appears that they attribute the diatom bloom to iron fertilisation. Oddly >> they have not considered the role of silicic acid from the dissolution of >> Mg silicate species in the finely powdered volcanic ash. Silicic acid is >> often the limiting nutrient for diatoms, as they use it to make their >> silica shells. There is ample geological evidence of diatom (specifically) >> blooms being associated with falls of volcanic ash. >> >> Is anyone able to post the actual article? Oliver. >> >> On 17/08/2013 17:13, Wil Burns wrote: >> >> FYI. wil >> >> MEPS - Vol. 488 - Table of >> contents<http://www.int-res.com/abstracts/meps/v488/> >> *Mar Ecol Prog Ser (Print ISSN: 0171-8630; Online ISSN: 1616-1599)* >> Copyright � 2013 Inter-Research. Published August 15 >> >> >> *Olgun N, Duggen S, Langmann B, Hort M, Waythomas CF, Hoffmann L, Croot >> P * >> Geochemical evidence of oceanic iron fertilization by the Kasatochi >> volcanic eruption in 2008 and the potential impacts on Pacific sockeye >> salmon >> MEPS 488:81-88 <http://www.int-res.com/abstracts/meps/v488/p81-88/> | Full >> text in pdf format<http://www.int-res.com/articles/meps2013/488/m488p081.pdf> >> >> -- >> Dr. Wil Burns, Associate Director >> Master of Science - Energy Policy & Climate Program >> Johns Hopkins University >> 1717 Massachusetts Avenue, NW >> Room 104J >> Washington, DC� 20036 >> 202.663.5976 (Office phone) >> 650.281.9126 (Mobile) >> [email protected] >> >> http://advanced.jhu.edu/academic/environmental/master-of-science-in-energy-policy-and-climate/index.html >> >> SSRN site (selected publications): http://ssrn.com/author=240348 >> >> � >> Skype ID: Wil.Burns >> >> Teaching Climate/Energy Law & Policy Blog: >> http://www.teachingclimatelaw.org >> >> -- >> 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. >> 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. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] <javascript:>. > To post to this group, send email to [email protected]<javascript:> > . > 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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