摘要：一个阿尔伯塔大学领导的研究小组发现：生命在海洋中出现之前十亿年，浅水区微生物层已经能够释放出足够多的氧气，微小的、可移动的生命才得以出现。该研究在线发表于5月15日的《自然-地球科学》杂志上。
Microbial mat.
The researchers say worm-like creatures could have lived on the oxygen produced by photosynthetic microbial material, even though oxygen concentrations in the surrounding water were not high enough to support life. The research was conducted in shallow lagoons in Venezuela where the high salt content is comparable to oceans older than 500 million years.
The link between biomats and animals is demonstrated by the trace-fossil record, which are tracks left behind by the movements of the worm-like creatures. The trace-fossil records for these animals date to at least 555 million years ago.
These findings suggest that the appearance of animals was not dependent on an oxygenated ocean. Rather, the earliest animals could have live within photosynthetic biomats and derived life-sustaining oxygen from that source.
The most widely accepted date for the start of life on Earth is 700 to 600 million years ago when oxygen was produced in deep ocean water.
The researchers say their work opens the door to the search for life in early periods of Earth's history when it was believed there was absolutely no oxygen and no chance of finding life.
The research was led by U of A geologist Murray Gingras and geomicrobiologist Kurt Konhauser. The research was published May 15 online in Nature Geoscience.
