Composition of variable seawater
The chemical composition of limestone varies depending on the age of the rock and, in turn, the sea water. Scientists realized this in the 1980s. Geologist Lawrence Hardie explained this change: the materials that emerge and bury within the boundaries between tectonic plates alter the composition of sea water. Science reports an experiment that confirms this hypothesis.
The salt crystals that form in the sea have holes that are usually full of crystals. Geologists have analyzed these drops of water in different parts of the world.
Water drops were about 30 micrometers. Therefore, its small extraction size allowed freezing the fluid, cutting it into plates and analyzing it by electron microscope. The proportion of calcium magnesium in drops from all over the world was the same in samples of the same age. But this proportion depends on the time when the drop was caught.
The chemical composition of the sea can influence the evolution of living beings, for example, in the population of planktonic algae that absorb calcium.
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