Greg raises a good point. The riverine organic carbon flux is on the order of 10**14 mol / yr. If there are about 4 x 10**19 mol of O2 in the atmosphere, this would give a residence time of O2 in the atmosphere relative to microbial decomposition in the ocean of several hundred thousand years.
I wonder how much of this organic carbon would oxidize abiotically. (Recall that in an abiotic ocean, deep ocean waters would have O2 concentrations similar to surface O2 concentrations in deepwater formation areas.) If some of this riverine matter did not decompose abiotically, then we would expect atmospheric O2 concentations to go up and not down (in the counterfactual and extremely hypothetical case of biotic land and abiotic ocean). -------------- *Please regard this as a thought experiment, and not a recommended policy goal !!!* On Sunday, June 9, 2013, Rau, Greg wrote: > Also, if the ocean were sterilized, the ocean bio C pump would be turned > off, so as the old CO2 rich deep water thermo haline circulates to the > surface, CO2 would degas to the air/surface ocean without a marine bio > uptake counterbalance. So the earth would get hotter and the surface ocean > more acidic (how much?). The oceans would get more alkaline because bio > CaCO3 precip is turned off and land/ocean mineral weathering is increased. > DMS and other marine bio aerosols turned off - consequences? Seabirds > would be up a creek unless they liked McNuggets - seagulls? Uphill > nutrient hauling by salmon turned off - the grizzlies would be pretty > bummed, not to mention native Americans and fishermen lobby. Anyway, an > earth mode hopefully only experienced by someone's ocean biogeochem model. > -Greg > ------------------------------ > *From:* [email protected] <javascript:_e({}, 'cvml', > '[email protected]');> > [[email protected]<javascript:_e({}, 'cvml', > '[email protected]');>] > on behalf of Greg Rau [[email protected] <javascript:_e({}, 'cvml', > '[email protected]');>] > *Sent:* Saturday, June 08, 2013 8:13 AM > *To:* [email protected] <javascript:_e({}, 'cvml', > '[email protected]');> > *Cc:* Ken Caldeira; David Lewis; Emily Lewis-Brown; geoengineering > *Subject:* Re: [geo] The Caldeira "If you Sterilize the Ocean We'd Still > Have Chicken McNuggets Hypothesis" questioned by Ocean expert > > If the ocean was sterilized, then presumably there wouldn't be any > marine microbes to consume O2 or generate H2S, CH4, etc. Good final exam > written question for Biogeochemistry 476 - what would happen to the earth? > > As for McNuggets, some Asia countries get 40% of their protein from the > ocean. I'd buy stock in KFC. > Greg > > Sent from my iPad > > On Jun 8, 2013, at 2:25 AM, Andrew Lockley <[email protected]> > wrote: > > For a start, oceans provide 12% of the global food supply. Losing all > that could be the tipping point on its own, as a starving society unravels > into a vicious circle of conflict, de-industrialisation and > de-urbanisation. > However, a far more serious concern is the change in the oceans which > would lead to them becoming sterilised. Likely, an ocean anoxic event is > the precursor event. > > As I understand it, the Great Dying (P-T extinction) provides an analogue. > Anoxic oceans were linked with a mass extinction of land biodiversity. I > understand that a proposed mechanism for this is the creation of an > atmosphere laden with H2S and lacking a functioning ozone layer. > > That's wouldn't be promising for the Chicken McNugget supply. > > A > On Jun 8, 2013 10:01 AM, "Ken Caldeira" <[email protected]> > wrote: > > Andrew, > > Please respond to what I said and not what you imagine I said. > > The issue has to do with a hypothetical case of sterilization of the > oceans. There was no reference to climate change in my statement. > > I challenge anyone to construct a plausible causal chain that would lead > from sterilization of the oceans to downfall of human civilization. > > This is not an expression of my values, this is an expression of my > scientific understanding. > > Let all realize that I spend a large chunk of my time trying to > investigate and protect human threats to ocean ecosystems. > > *This Scientist Aims High to Save the World's Coral Reefs* > > http://www.npr.org/player/v2/mediaPlayer.html?action=1&t=1&islist=false&id=176344300&m=178462367<http://www.npr.org/player/v2/mediaPlayer.html?action=1&t=1&islist=false&id=176344300&m=178462367> > (Aired Monday, 4/22 on NPR's All Things Considered; 7 minutes, 49 seconds) > > Best, > > Ken > > On Saturday, June 8, 2013, Andrew Lockley wrote: > > In my view, history provides the best guide to the future. > > Civilisations are not long lived at the best of times, and their messy and > painful demise is usually accompanied by minor climate disruption. > > The more complex the civilisation, the less robust it is, as there is a > greater interconnectedness, and hence a greater ability to transmit shocks > through the system. To further explain : our ancestors would not have heard > about an antipodean earthquake, whereas now such a tremor can send markets > into meltdown in minutes. > > The idea that despite this much more vulnerable society, the American > middle class will survive the worst climate change in human history without > disruption to the Chicken McNugget supply, or to the ability of Hollywood > to produce Game of Thrones, is completely bizarre. > > Someone, somewhere will likely be eating a piece of battered chicken meat. > Someone, somewhere will probably still have a working digital camera and > some kind of transmission equipment . This does not equate to an > uninterrupted experience for the US middle class. > > A > On Jun 8, 2013 8:42 AM, "Emily L-B" <[email protected]> wrote: > > ** > Hi all, I'd propose you put this hypothesis to Dan Laffolley (you can g > > -- > 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:_e({}, > 'cvml', 'geoengineering%[email protected]');>. > To post to this group, send email to > [email protected]<javascript:_e({}, 'cvml', > '[email protected]');> > . > Visit this group at http://groups.google.com/group/geoengineering?hl=en. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- _______________ Ken Caldeira Carnegie Institution for Science Dept of Global Ecology 260 Panama Street, Stanford, CA 94305 USA +1 650 704 7212 [email protected] http://dge.stanford.edu/labs/caldeiralab @kencaldeira *Caldeira Lab is hiring postdoctoral researchers.* *http://dge.stanford.edu/labs/caldeiralab/Caldeira_employment.html* Check out the profile of me on NPR's All Things Considered<http://www.npr.org/2013/04/22/176344300/this-scientist-aims-high-to-save-the-worlds-coral-reefs> -- 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?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
