Earth’s oxygen source

Press, Volume CXII, Issue 32967, 13 July 1972, Page 10

Earth’s oxygen source

(N.Z. Press Assn. —Copyright) WASHINGTON, July 12.

Photosynthesis by green plants could be a less important oxygen source than has long been believed, according to findings from the United States Naval Research Laboratory (N.R.L.).

The findings came after the N.R.L. studied photographs taken on the moon with a itdrar-ultraviolet camera-spectrograph by John Young on April 21 to April 123.

i The camera-spectograph I indicated that the solar I effects on the Earth’s water that evaporated to the high i atmosphere might provide 'the primary oxygen source. I N.R.L.’s principal investigator, Dr George Carruthers, said that the studies were of practical importance to Earth.

Many of the photographs' showed a cloud of atomic) hydrogen enveloping the' some 40,000 miles.

This geocoronal hydrogen was believed to be the result of the dissociation of water vapour into hydrogen and oxygen caused by solar ultraviolet radiation in the upper atmosphere, said Dr Carruthers.

Since hydrogen is light it reaches high altitude, eventually to escape the Earth's gravity, but oxygen, being heavier, remains in the atmosphere. This, said Dr Carruthers, was the source of the atmosphere’s present oxygen conitent.

N.R.L. commented that this discovery could counter the popular belief that man I would be immediately ‘ doomed without nature’s 1 cycle of photosynthesis in plant life to replenish oxygen. ’