Perhaps I've missed something, but if you are advocating increased ventilation of the subsurface ocean, this water is not only nutrient rich, but is is also supersaturated in CO2 (relative to air). Natural ocean upwelling is a huge CO2 source for the atmosphere. So unless you can show that stimulation of biological CO2 fixation (via the nutrient upwelling) more than offsets the upwelled CO2 degassing to the atmosphere, what's the point? -Greg Rau
>A simple way to achieve this would be to force air down into deep >pipes and allow it to bubble to the surface. The same principle is >used in fishtanks to create upwelling water and increase the surface >area for gaseous exchange. There's a tradeoff between little bubbles >(for gaseous exchange) and big bubbles (to force mixing). > >Flow tubes would probably be necessary to create a defined upwelling >column of water. These tubes would provide a reasonably good mount >for a wind turbine or sea turbine, provided they could be anchored to >the sea bed. The most obvious engineering problem I can think of is >stability and resonances. > >What do other people think? > >A > >2009/1/13 John Nissen <j...@cloudworld.co.uk>: >> >> Hi all, >> >> Could there be a case for geoengineering to increase sea "ventilation" and >> thereby increase CO2 absorption by the sea? (I'm thinking of those millions >> of wave-powered tubes suggested by Chris Rapley and James Lovelock to bring >> deep cool water to the surface.) >> >> http:// www. >>guardian.co.uk/environment/2009/jan/12/sea-co2-climate-japan-environment >> >> --- >> >> >> Sea absorbing less CO2, scientists discover >> >> David Adam, environment correspondent >> The Guardian, Monday 12 January 2009 >> Article history >> >> Scientists have issued a new warning about climate change after discovering >> a sudden and dramatic collapse in the amount of carbon emissions absorbed by >> the Sea of Japan. >> >> The shift has alarmed experts, who blame global warming. >> >> The world's oceans soak up about 11bn tonnes of human carbon dioxide >> pollution each year, about a quarter of all produced, and even a slight >> weakening of this natural process would leave significantly more CO2 in the >> atmosphere. That would require countries to adopt much stricter emissions >> targets to prevent dangerous rises in temperature. >> >> Kitack Lee, an associate professor at Pohang University of Science and >> Technology, who led the research, says the discovery is the "very first >> observation that directly relates ocean CO2 uptake change to ocean warming". >> >> He says the warmer conditions disrupt a process known as "ventilation" - the >> way seawater flows and mixes and drags absorbed CO2 from surface waters to >> the depths. He warns that the effect is probably not confined to the Sea of >> Japan. It could also affect CO2 uptake in the Atlantic and Southern oceans. >> >> "Our result in the East Sea unequivocally demonstrated that oceanic uptake >> of CO2 has been directly affected by warming-induced weakening of vertical >> ventilation," he says. Korea argues that the Sea of Japan should be renamed >> the East Sea, because it says the former is a legacy of Japan's military >> expansion in the region. >> >> Lee adds: "In other words, the increase in atmospheric temperature due to >> global warming can profoundly influence the ocean ventilation, thereby >> decreasing the uptake rate of CO2." >> >> Working with Pavel Tishchenko of the Russian Pacific Oceanological Institute >> in Vladivostok, Lee and his colleague Geun-Ha Park used a cruise on the >> Professor Gagarinskiy, a Russian research vessel, last May to take seawater >> samples from 24 sites across the Sea of Japan. >> >> They compared the dissolved CO2 in the seawater with similar samples >> collected in 1992 and 1999. The results showed the amount of CO2 absorbed >> during 1999 to 2007 was half the level recorded from 1992 to 1999. > > >> Crucially, the study revealed that ocean mixing, a process required to >> deposit carbon in deep water, where it is more likely to stay, appears to >> have significantly weakened. >> >> Announcing their results in the journal Geophysical Research Letters, the >> scientists say: "The striking feature is that nearly all anthropogenic CO2 >> taken up in the recent period was confined to waters less than 300 metres in >> depth. The rapid and substantial reduction ... is surprising and is >> attributed to considerable weakening of overturning circulation." >> >> Corinne Le Quéré, an expert in ocean carbon storage at the University of >> East Anglia, said: "We don't think the ocean is just going to completely >> stop taking our carbon dioxide emissions, but if the effect weakens then it >> has real consequences for the atmosphere." >> >> --- >> >> >> Cheers, >> >> John >> >> > >> > > --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
