David A couple of papers that have studied the Si : N ratio and related issues in the Gulf of Mexico are -
http://www.pubmedcentral.nih.gov/articlerender.fcgi?&artid=23704 Officer and Rhyther (22) suggested that a shift in the Si:N atomic ratio from above 1:1 to below 1:1 would have two effects: altering the marine food web by reducing the diatom-to-zooplankton-to-higher trophic level food web, and increasing the proportion of flagellated algae, including those that produce harmful algal blooms. http://www.nature.com/nature/journal/v368/n6472/abs/368619a0.html The increases were substantial by 1980, by which time riverine nitrogen loading had doubled relative to the beginning of the century, even though the silica loading had declined by 50% over the same period. Thus changes in river-borne nutrient loadings can modify coastal food webs and affect the amount and distribution of oxygen in bottom waters on the scale of continental shelves. These indicate that reduction in silica : nitrogen ratio results in lower diatom population and that this has a negative impact on the ocean ecology. The development of the Gulf of Mexico dead zone and change in Si : N ratio over the past 50 years seem to be correlated. The point we are trying to make is, Is the reverse true? If Diatom population is increased will the tropic status of the water change for the better? No one seems to have studied this. A blog post about dams - silica - diatoms - red tides is available at http://friendsofsebago.blogspot.com/2009/12/silica-depletion-and-lake-regulation.html best regards Bhaskar www.kadambari.net On Dec 29, 10:07 pm, David Schnare <dwschn...@gmail.com> wrote: > B. > > Can you identify some papers on use of diatom algae on dead zones (fresh and > salt water)? > > Thanks, > d. > > On Tue, Dec 29, 2009 at 5:37 AM, M V Bhaskar <bhaskarmv...@gmail.com> wrote: > > > > > We have been using Diatom algae to increase dissolved oxygen levels in > > fresh water lakes. > > Our observation is that Cyanobacteria decrease dissolved oxygen level > > due to accumulation and decomposition and Diatoms increase dissolved > > oxygen levels since they do not accumulate, since they are consumed by > > zooplankton. > > The same would hold true even in oceans - both coastal waters and deep > > sea. > > We are sure that dead zones in coastal waters can be solved by causing > > Diatom Algae bloom in the dead zones. > > > In deep seas dead cyanobacteria may decompose near the surface and > > dead diatoms may sink deep. > > Discussing about 'Phytoplankton' in connection with ocean > > fertilization is inadequate. > > Different types of phytoplankton may cause diametrically opposite > > effects. > > > best regards > > > Bhaskar > >www.kadambari.net > > > On Dec 29, 11:11 am, Ken Caldeira <kcalde...@carnegie.stanford.edu> > > wrote: > > > Unless you do some pretty fancy things with nutrient ratios in sinking > > > organic matter, increasing ocean vertical mixing is not an efficient way > > to > > > store carbon but is an efficient way to store heat. > > > > A potential co-benefit is a likely increase in marine productivity. > > > > That said, this would involve perturbing marine ecosystems potentially on > > a > > > huge scale and would run counter to the goal, which many of us share, of > > > trying to preserve natural marine ecosystems to the greatest extent > > > possible. > > > > I do not think anoxia is a big issue as essentially you would be creating > > an > > > artificial upwelling/downwelling zone and possible environmental > > downsides > > > (e.g., anoxic regions) could be monitored for and act as a limit on scale > > of > > > deployment. In fact, one possible application of vertical pumps in the > > ocean > > > could be to bring oxygen into anoxic "dead zones". > > > > *As with many interventions in the Earth system, the interesting cases > > are > > > at the leading edge of the slippery slope: > > > * > > > As Behrenfeld and others have shown, warming in the tropics has led to > > > increased stratification and thus a decrease of nutrient transport into > > the > > > euphotic zone, with concomitant decreases in marine photosynthetic > > activity. > > > One could imagine a case where ocean vertical mixing was engineered > > simply > > > to bring local sea surface temperatures and vertical mixing rates closer > > to > > > the* status quo ante *-- ie, the main goal in this case would be to > > counter > > > direct impacts of global warming on a local marine environment. > > > > If you could show that you are countering some effects of global warming > > > locally and thus helping to preserve a natural marine environment, one > > might > > > consider this a good thing even if one feared the slippery slope towards > > > using the marine environment to store heat that would otherwise damage > > land > > > ecosystems (and human systems). > > > > ---- > > > > *By way of disclosure: I am listed as a co-inventor on several patent > > > applications related to vertical pumps in the ocean, but have stated that > > I > > > will donate to non-profit charities and NGOs any revenues that accrue to > > me > > > from application of these patents to climate intervention projects (an > > > unlikely event). > > > * > > > > ___________________________________________________ > > > Ken Caldeira > > > > Carnegie Institution Dept of Global Ecology > > > 260 Panama Street, Stanford, CA 94305 USA > > > > kcalde...@carnegie.stanford.eduhttp:// > > dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab > > > +1 650 704 7212; fax: +1 650 462 5968 > > > > On Mon, Dec 28, 2009 at 12:46 PM, Dan Whaley <dan.wha...@gmail.com> > > wrote: > > > > You're conflating two things Andrew, the limitation on growth and the > > > > consequences (usually on heterotrophs) of its decomposition / > > > > remineralization. Free oxygen is never limiting on photosynthesis, > > since it > > > > is not consumed in the process, but rather produced. > > > > > Anoxia or hypoxia as a result of phytoplankton growth are issues > > primarily > > > > in coastal enviornments when excess or continuous algal production in > > > > shallow environments leads to the depletion of oxygen in proximity to > > marine > > > > populations as that biomass decomposes. The question in the open > > ocean, > > > > where any kind of climate mitigation via phytoplankton would be done-- > > i.e. > > > > in 4-6km of water column vs. 100m-- is... what has happened in past > > climates > > > > when we know primary productivity was much higher over long time > > periods, > > > > and what might happen in today's ocean if productivity were increased > > by > > > > various degrees... obviously there is more water column for > > remineralization > > > > to be distributed through and advective currents will distribute the > > effects > > > > over a larger area. This is both a potential benefit as well as a > > potential > > > > concern. > > > > > Cao and Caldeira have looked at the effects of acidification at depth > > (and > > > > also at the surface) based on taking phosphate to zero in the southern > > > > ocean. More models and observations need to be made for a variety of > > > > effects, including oxygen, N2O and methane, downstream nutrient > > depletion, > > > > DMS cooling in addition to CO2 reduction (and to Oliver's point, what > > kind > > > > of deployment would be appropriate for what kind of intended > > scenario)-- and > > > > looking at other kinds of limiting factors like silicate-- to get a > > better > > > > understanding of the processes there. Observational programs should > > both be > > > > driven by and feed modeling throughout. > > > > > D > > > > > On Mon, Dec 28, 2009 at 11:06 AM, Andrew Lockley < > > andrew.lock...@gmail.com > > > > > wrote: > > > > >> The more you remove the micro and macro nutrient limitations from > > > >> phytoplankton growth, the more you make it likely that oxygen becomes > > the > > > >> limiting factor - ie. that all the available oxygen has been used up. > > This > > > >> is likely to lead to the creation or extension of 'dead zones' or > > anoxic > > > >> regions in the ocean, together with consequential disruption to the > > > >> ecosystem, and potential methane creation. > > > > >> It's this kind of effect which, I understand, worries ETC group and > > > >> others. (See Chan et al, 2008) > > > > >> I'm far from a marine biologist myself, and I'm raising the issue > > simply > > > >> to encourage caution, rather than to claim expertise. > > > > >> A > > > > >> 2009/12/28 Dan Whaley <dan.wha...@gmail.com> > > > > >> Steve, > > > > >>> In talking to Dave Karl a few years ago who was testing Phil Kithil's > > > >>> tube, it seemed like a core problem was trying to select for a depth > > where > > > >>> you had more nutrients (P, N) than CO2, so there was a net gain... > > since > > > >>> carbon is also greater at depth. Also-- Phil seemed to think he > > would keep > > > >>> the tubes equidistant from each other with a huge network of > > underwater > > > >>> cables... which seemed logistically (as well as aesthetically) > > problematic. > > > > >>> Curious as to your thoughts in these areas... > > > > >>> D > > > > >>> On Mon, Dec 28, 2009 at 10:17 AM, Stephen Salter <s.sal...@ed.ac.uk > > >wrote: > > > > >>>> Hi All > > > > >>>> The oceans are a big thermal store so the scheme would give us time > > for > > > >>>> a quiet think. However we can bring nutrients up to the photic > > layers > > > >>>> and grow more phytoplankton giving more dimethyl sulphide for cloud > > > >>>> nuclei and converting lots of CO2 to non acidic biomass, some of > > which > > > >>>> we can eat. > > > > >>>> There is a paper called /Hurricanes carbon and fish and a picture > > called > > > >>>> /MacNeill downtube in the /Hurricanes folder at the site below my > > > >>>> signature. /Chlorophyll comparison shows how empty most of the > > oceans > > > >>>> are for most of the time. Click through at about one a second for a > > > >>>> month-by-month animation. We need lots of permanent, private la Nina > > > >>>> events. > > > > >>>> Stephen > > > > >>>> Emeritus Professor of Engineering Design > > > >>>> School of Engineering and Electronics > > > >>>> University of Edinburgh > > > >>>> Mayfield Road > > > >>>> Edinburgh EH9 3JL > > > >>>> Scotland > > > >>>> tel +44 131 650 5704 > > > >>>> fax +44 131 650 5702 > > > >>>> Mobile 07795 203 195 > > > >>>> s.sal...@ed.ac.uk > > > >>>>http://www.see.ed.ac.uk/~shs<http://www.see.ed.ac.uk/%7Eshs<http://www.see.ed.ac.uk/~shs> > > > > >>>> Mike MacCracken wrote: > > > >>>> > Just a note that while pumping heat down into the ocean can lead > > to > > > >>>> > local cooling, storing heat in the ocean is adding and retaining > > > >>>> > energy, so will eventually emerge as warming. And, of course, it > > will > > > >>>> > contribute to sea level rise. Thus, while a local effort of this > > type > > > >>>> > to help limit hurricane intensification may be a good trade, it is > > not > > > >>>> > likely to be a global cure for the system (unless one can really > > pull > > > >>>> > the GHG concentrations down in other ways so heat from the ocean > > would > > > >>>> > moderate the rate of cooling—as it does now during winter). > > > > >>>> > Mike MacCracken > > > > >>>> > On 12/28/09 1:34 AM, "arcolo...@aol.com" <arcolo...@aol.com> > > wrote: > > > > >>>> > Hello, I'm new here and I expect to make a few blunders until > > I am > > > >>>> > better acquainted with previous discussions. I am a retired > > > >>>> > physicist and have some leadership role in the Sierra Club. > > > > >>>> > The Salter Sink is an excellent concept for raising cold water > > to > > > >>>> > the surface. the area that needs design attention is the > > injection > > > >>>> > system at the bottom of the tube. With careful design, it will > > > >>>> > raise probably ten times as much cold water as is pumped down. > > > >>>> > This design work is quite easy. > > ... > > read more » -- 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.
