Japanese scientists say that the evolution of photosynthesis caused Earth’s oceans to be formerly green, as per a report. The study suggests that the oceans supported only single-celled organisms and featured environments with barren landscapes of grey, brown, and black rocks. Within a period of 1.5 billion years, the slow changes in ocean chemistry could help explain why blue-green algae developed both types of photosynthetic pigments. The color of the planet’s oceans is linked to water chemistry and life influence. Before Blue: The Green Ocean Era According to the report, Earth’s oceans were once green. The chemistry and evolution of photosynthesis account for this shift. Discovered throughout the Archean and Paleoproterozoic ages, banded iron formations—which were laid between 3.8 and 1.8 billion years ago—were formed when life was limited to one-celled creatures in the oceans; the continents were desolate gray, brown, and black rock and silt terrain. Green Seas Sparked Life The first life using sunlight emerged in the Archean eon, when Earth’s atmosphere and seas lacked gaseous oxygen. These creatures started the “Great Oxidation …