Dear Ernie, We carried out an iron addition experiment (SOFeX) with added silicic acid and the diatom Pseudonitzschia spp. was thus able to flourish. The added Si was unintentional and a result of the initial Fe fertilization happening at a front which sheared the patch horizontally which enabled vertical replenishment of the Si in a Si limited region [Coale et al., 2004 and Coale et al., suppl. 2004]. Otherwise we probably would have got even more flagellates, the majority group . The bloom resulted in a 5 fold increase of DMS (Wingenter et al., 2004).
Sincerely, Oliver Wingenter On Mar 15, 10:05 pm, arcolo...@aol.com wrote: > Hello, Dan, > > I think we are in really deep water here. The marine scientists are just > beginning to understand what's going on with open ocean phytoplankton. I > was captivated by work being done by Irina Marinov and others at Woods Hole > while she was a post-doc there, showing how other nutrients have a critical > role in how iron is used. She is now at U. of Penn. > _http://www.sas.upenn.edu/earth/marinov_r.html_(http://www.sas.upenn.edu/earth/marinov_r.html) > > I think to really understand the goings-on with phytoplankton, it would be > good to talk with someone like her or dig into the recent literature. I > think she was involved (not sure) with showing how the toxic blooms are > connected with insufficient dissolved silica in the water. Natural surface > fertilization usually involves application of iron-rich silica, say from dust > storms or colloidal minerals from glaciers. (That's my understanding, > could be way off) Silica shifts the productivity into diatoms which are the > bottom rung of the ocean food chain. As far as I know, no OIF experiments > involved adding finely-divided silica with the iron. > > I am very concerned about the acidification of sea water since silica > solubility decreases with decreasing pH. I wonder if this has a bearing on > the > falling oxygen concentration in sea water and the more frequent hypoxia > events in recent decades. > > My personal view is that ocean productivity is the real key to practical > geoengineering by way of CO2 removal. But you will find many that would > disagree. > > Ernie Rogers > > In a message dated 3/15/2010 3:15:42 P.M. Mountain Daylight Time, > > dan.wha...@gmail.com writes: > > A PNAS paper was released today commenting on studies finding domoic > acid in some of the samples from previous OIF projects. > > A variety of articles have > commented.http://www.nature.com/news/2010/100315/full/news.2010.124.htmlhttp://www.nytimes.com/2010/03/16/science/16obiron.htmlhttp://news.discovery.com/earth/geoengineering-carbon-sequestration-p... > nkton.html > > I commented here:http://climos.com/note_detail.php?pid=174 > > A PNAS paper released today which looks at domoic acid (DA) production > in past OIF experiments has concluded that DA was increased in some of > the projects. Though the conclusions from the paper itself were > relatively conservative... > > "Although there remain uncertainties in extrapolating our results to > large oceanic scales, the findings establish potential consequences > for developing toxic phytoplankton blooms in pelagic ecosystems, which > so far have not been adequately investigated." > > Headlines have ranged from the dramatic "Ocean Geoengineering Scheme > May Prove Lethal", and at the NY Times, the oddly phrased, "A Risk of > Poisoning the Deepest Wells" to the more subdued, "Carbon-capture > scheme could cause toxic blooms". > > All fail to explore the obvious. Namely, that phytoplankton underpin > open ocean productivity, that this productivity relies on iron, and > that when iron-fed naturally occurring blooms happen, they likely > favor--in certain regions--Pseudonitzschia or other DA producers. In > short, we know that the availability of iron drives much of the > oceanic carbon cycle. If DA is produced by artificially stimulated > OIF blooms, it is likely produced during natural ones as well. > > Moving forward, we need to understand exactly how deep-ocean > phytoplankton respond to iron--be it naturally or artificially > supplied, whether and in what situations DA is produced, and how the > ecosystem is or is not already adapted to this. If it occurs > naturally, are organisms that live there used to blooms containing > DA? In past climate cycles, when productivity in the deep ocean was > much greater, was DA characteristic as well? > > These are questions that remain unresolved and need well defined > research programs to address. > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To post to this group, send email to geoengineer...@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 geoengineer...@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.
