Dole effect

The Dole effect is a way of explaining the inequality between the heavy isotope 18O and the lighter isotope 16O. There are different isotopes of oxygen on earth. The atmosphere contains mostly 18O, the oxygen in seawater is mostly 16O. This is caused by the respiration of plants and animals. It is balanced by photosynthesis. Photosynthesis emits the same oxygen isotope as that of water. Malcolm Dole first described this effect in 1935. It is named Dole effect today.