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The
Origin of Life at a submarine alkaline seepage III. Flow reactor (component generation) In chemical parlance the limbs of the freely convecting medium temperature hydrothermal cell can be considered as a complex natural flow reactor. The nature of this notional reactor contrasts somewhat with the high temperature flow reactor envisaged by Corliss (1986b) to approximate the workings of the magmatically forced hydrothermal system feeding the 400°C 'black smokers' (see Potter et al. 1987). The crustal residence time of the convecting 100° to 150°C aqueous solutions derived from the percolating ocean waters we envisage feeding the first metabolist is of the order of 1,000 years (Cathles 1990). Additions to the fluid from the mantle made en route included CO, CO2, NH3 and H2S (e.g., Gerlach 1981; Naughton et al1974). Native iron acted as catalyst and, with "FeO", also as a redox buffer. Hydration (serpentinization) of the crust generated another catalyst, awaruite (Ni3Fe) (Krishnarao 1964; Russell et al. 1998). As we have seen, hydration generated thermal energy in the system (Fyfe 1974). Strecker syntheses in this reactor at ~100°C would have generated cyanide (~100 millimoles) and formaldehyde (~10 millimoles) (extrapolation from Schulte and Shock 1995) (Fig. 8). Other "ready-made organic" components generated in and/or delivered from the flow reactor in micro to millimole concentrations were methane, dimethyl ether, methanol, formate, methyl-formate, hydrosulfide and simple thiols (Cairns-Smith 1982; Ferris 1992; Russell et al. 1994; Heinen and Lauwers 1997; Chen and Bahnemann 2000; McCollom 2001). Fig. 1. |
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