Oxygen isotope (delta-18O) records from benthic foraminifera and ice cores are key paleoclimate proxies: during glacial intervals, delta-18O of benthic foraminifera shows higher (more positive) values, reflecting both colder deep-ocean temperatures and the preferential storage of isotopically light oxygen (16O) in continental ice sheets, which enriches the remaining ocean water in 18O; correspondingly, ocean salinity is higher during glacial intervals (since large volumes of fresh water are locked up as ice, concentrating salts in the remaining ocean water) and lower during interglacial intervals; and ice core delta-18O records show lower (more negative) values during glacial intervals, reflecting colder condensation temperatures that produce isotopically lighter precipitation.