Daniel Conley is investigating the seas of ancient times. His sights are set on finding a moment in time when the chemistry of the oceans changed completely, when the diatoms became common, which changed the Earth's ecosystem. In addition to be a major food source, the algae absorb large quantities of silicon from the oceans. They absorb carbon dioxide and give off oxygen. As much as 20 percent of the oxygen in the atmosphere today is believed to come from the diatom algae.