Quote:
Originally Posted by borman
Where does the water go?
As interesting as the local presence of methane is also its fast destruction.
It is too fast destroyed to be attributed to only photolysis or upper atmosphere chenistry. So there is given a role for superoxidants such as H2O2 and to a lesser extent perchlorates seen by Phoenix. Turboelectric destruction or scrubbing is also possible but that needs quite a few dust devils to be active at once to get so much methane destroyed. The oxidation route essentially has CH4 + 2O2 -> CO2 + 2H2O.
There were two interesting comments regarding biology. Atreya volunteered without being asked during the question period about a point raised above about the presence of other hydrocarbons. Life can not be too careless in making just any hydrocarbons as some of them are not good for life...hence the purity of methane is a possible biomarker. Purely abiotic methods can be more careless and make other hydrocarbons as well as methane. A greater presence of these other hydrocarbons would be an indicator for abiotic mechanisms whether or not the production was recent or released from clathrates where the gas was trapped from an earlier time.
Dr. Pratt, the biologist, reminded us that methane is not only one organism's waste product, but another organism's food product. Considering how dry Mars is today, it would be to the organism's advantage to not only oxidize the methane but to also trap and save any water from the reaction. So it remains as a posibility that where the methane is destroyed but there is no water evidence left over to point to normal chemical avenues that leave a spectral water signature in the wake of the destruction of methane, that some biota might be invloved with the missing water as well as the methane destruction.
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My bold emphasis---
As is fairly well known--(?) -- the Antarctic has been a proving ground for Martian missions since at least the 1970s--- one of current considerations of Antarctic research is the prevalence of CH4 that is incorporated into the ice crystal structure via clathrate encapsulation ( the alarm was first sounded on CH4 when global warming was considered ), --in late 1999 or 2000 --- in regards to CH4 disappearance -- one possible culprit that you cited might be the perchlorate in the ice. It may be safe to assume that the perchlorate oxidizes the CH4 into CO2 and HCl .. the stoichiometry is not so obvious because I don't have all the data in front of me.... The solid ice serves as a penetrable "
vessel" -- of sorts that allows the perchlorate to oxidize the CH4 and in the end products HCl and CO2 ... some of this borders on speculation but it is a safer way to go if there really is no biological mechanism to speak of... The solid water ( or ice-- if you want to say...) has more "?weird" properties than I can shake the proverbial stick at it...
especially in such an interesting milieu as Mars