Answer:
conecentrations of 18O increase
conecentrations of 16O decrease
Step-by-step explanation:
16O is also known as light oxygen and 18O is also known as heavy oxygen.
Ocean waters become rich in heavy oxygen during ice ages.
The water vapor containing light oxygen moves toward the poles, eventually condenses, and falls onto the ice sheets where it stays.
The water remaining in the ocean develops increasingly higher concentration of heavy oxygen compared to the universal standard, and the ice develops a higher concentration of light oxygen.