The discoloration arises from the presence of chlorophyll, a green pigment used for photosynthesis. Because phytoplankton contain chlorophyll, the distribution and abundance of phytoplankton in oceans ...

“Late Cretaceous dinosaurs lived in an oxygen tent,” Sloan said. “The oxygen was being used up in weathering of rock and was not being replaced by photosynthesis as fast as it was being used up.” ...