Oxygen isotope mass balance in the hydrosphere requires that the total mass-weighted δ18O of all water reservoirs (oceans + glacial ice) remains constant (conservation of isotopic mass) as ice sheets grow or shrink, redistributing water (and its isotopic signature) between reservoirs.
Initially: ice = 2% of surface water with δ18O = -30‰, ocean = 98% with δ18O ≈ 0‰ (by SMOW definition/reference). Total mass-weighted budget =...
Full option-by-option analysis available to enrolled students.