In reply to Jones Beene's message of Mon, 27 Nov 2006 16:11:28 -0800 (PST): Hi, > >--- Robin > >> I think the explanation for the high concentration >can in this case be found in the mundane... > >No, no - I should have been clearer - it is not that >'local' concentration which is the precise anomaly in >question. But yes there is the mundane explanation for >the salt lake also. > >The 18O/16O ratio in the interstellar region (and >presumably the 'normal' ratio found at the time earth >cooled) has been measured as 0.18, almost three times >lower than the present ratio found in earth's oceans >(~.5) and much lower than the total planetary ratio >(.3)which includes CO2. (Wilson & Rood 1994). The best >explanation for this is that the ratio is altered in a >planetary environment by some unknown mechanism >vis-a-vis interstellar space.
Same explanation. The 16O is produced preferentially during photosynthesis (a guess), and then when it becomes O under influence of solar radiation, it can more easily attain escape velocity and leave altogether (Boltzmann tail). Similar reasoning also applies to stars where O forms. Regards, Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition provides the motivation, Cooperation provides the means.
