"With respect to the hydrosphere, Gaia theory proposes a prospective research program: that organisms have actively retained water by thwarting its tendency to be lost. Without the involvement of life’s complex and often metabolic innovations (e.g., lipid monolayer biosynthesis, calcium ion extrusion that induces changes in carbonate, bicarbonate and CO2 equilibria, oxygenic photosynthesis, reversible protein absorption and release of water, etc.), Earth long ago also would have lost its water to space by atmospheric photolysis and hydrogen escape. We propose that life does not regulate the amount of water on the planet through a specific feedback process, but rather that it greatly reduces the rate of water loss by metabolic hydrogen capture and by regulation of relevant variables such as planetary temperature. Here we explore the major abiological processes that drive the loss of water from our planet, including the photo-dissociation of water and methane by solar UV radiation at the top of the troposphere and the chemical reactions in sea floor basaltic rocks that strip out oxygen atoms from water molecules. We then go on to outline the various ways in which life prevents such processes from drying out the planet. We include a discussion of how, by contributing to the regulation of the planetary carbon cycle over geological time, organisms have kept the planetary temperature suitable for the existence liquid water despite an ever brightening sun and ongoing outgassing of carbon dioxide from volcanic activity." wildethics.org/essays/water-gaia.html
Posted on: Mon, 29 Jul 2013 23:40:08 +0000
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