Tiny crystals of the iron mineral haematite provide evidence for an oxygenated water body 3,460 million years ago, reports a paper online this week in Nature Geoscience. This evidence indicates that microorganisms capable of producing oxygen through photosynthesis were present at this time, predating the oldest unambiguous fossils of photosynthetic microbes by about 800 million years.
Hiroshi Ohmoto and colleagues analysed the chemical characteristics of grains of haematite found in a jasper formation of Western Australia. They found that the grains, which developed in an early sea that existed over what is now Pilbara, Australia, probably formed as the result of an interaction between hydrothermal fluids and oxygen-rich sea water. The group suggests that organisms capable of photosynthesis must therefore have been present in sufficient numbers to at least occasionally oxygenate this body of water.
Climate change: Urban greening can help reduce accelerated surface warming in citiesCommunications Earth & Environment
Ecology: Drought has life-long consequences for red kitesNature Communications
Geoscience: Diamond from the deep reveals a water-rich environmentNature Geoscience
Environment: Human contribution to Middle East’s poor air quality underestimatedCommunications Earth & Environment
Planetary science: Mars InSight lander records impact of meteoroidsNature Geoscience
Climate change: Potential global threat to city greeneryNature Climate Change