Oxygen is vital to life. Without it, life on Earth would not be possible. Yet there was time then there wasn't much oxygen on Earth. Many scientists speculate that there wasn't life during that time. Early life forms survived without oxygen, as evidence shows.
Much of the Earth's early existence has been dominated by simple life forms. Bacteria have been one of the first to thrive during that time. Finding evidence of early bacteria has been hard, as they do not leave much evidence. Research done by the University of Cincinnati has found that there could be evidence of these early bacteria. Two separate locations are said to have this evidence.
Two locations in Northern Cape Province in South Africa have been studied for possible evidence of early bacteria. Andrew Czaja, an assistant professor of Geology at the University of Cincinnati said that the sites have the oldest fossil sulfur bacteria so far found. The bacteria are said to be much larger than modern bacteria. They are quite similar though to single-celled organisms found deep in the sea, where there is still little oxygen.
The fossilized bacteria found are very old. Czarja said that they have been around 2 billion years ago, before other plants and trees. The microfossils are preserved in hard silica-rich rocks called chert, according to UC Magazine. These rocks have been found within the Kaapvaal craton in South Africa.
Finding such rocks that old is rare. That is why many samples that have been taken earlier only come from few areas, as Science Daily notes. These rocks could be found in South Africa and Western Australia, leading scientists to speculate that the two areas have once been connected together.
The two areas are said to have been part of a large continent called Vaalbara, before the earlier continent broke apart. These bacteria have been living just before an event called the Great Oxidation Event, when oxygen increased due to photosynthesis. There is still much debate though when these bacteria actually first came out. While that is ongoing, there is no doubt that early life form survived without oxygen, as evidence shows. An earlier research has determined that life on land has come out much earlier than expected.