Kuva: Suedwand, CC BY-SA 3.0.
Joel Kontinen
Evolutionists believe that between roughly 1.25 million and 800,000 years ago, the climate system went through a major change during a period called the Middle Pleistocene Transition.
Evolutionists ask was the inventory of dissolved oxygen in the ocean affected by this episode? They believe that Earth was covered by ice at that time. Thomas et al. show that oxygen concentrations in glacial deep North Atlantic waters suffered a stepped reduction about 900,000 years ago, coincident with reductions in the concentration of glacial atmospheric carbon dioxide and global ice volume.
Source;
H. Jesse Smith Deep concentration Science 5-8.