Changes in elemental abundances in Earth's oceans on geological time scales are intimately linked to evolutionary processes.
The concentrations of metal ions in the oceans (and in the earth's crust) have changed dramatically since the beginning. It is clear that they assisted the life on earth. All these are also tied to atmospheric conditions such as the concentration of certain gases and the temperature.
If you are into evolution and the elements' effects on it, this is a good start.