Abstract

Photoionisation of water generates reactive hydrogen ions and other light gases that escape to outer space by different mechanisms. The activity of the young Sun directed the lost light gases, primarily hydrogen and helium, to the outer gas giant planets. The total hydrogen loss on Earth in the past ~4 billion yearsunder the conditions that exist today showed that the H escape would have resulted in only about 0.02% loss of the recent ocean volume. The reason for this negligible loss could be the feeble rate of hydrogen escape by photolysis of water, but the Archean rate could have been much greater. Other suspected pathways for water losses could be the subduction of hydrate minerals or the increased amount of storage of water in the deeper layers of the mantle. Water loss is also accounted for by photosynthesis where water is photohydrolysed to oxygen and hydrogen and carbon dioxide reduced to carbohydrates. This study estimates the global loss of water based on the sinking generated low by converting them to sea volumes, indicating a significant (22%) loss of freshwater on Earth during evolution.

Keywords: Assessing sea volume; Evolutionary high sea-levels; Conversion of sea-levels and volumes; Osmolyte systems; Reasons of salination; Faltering thermohaline circulation