Study: How Moss Helped in Making the Earth Habitable

A new study revealed that the earliest land plants, such as moss, helped in making the ancient Earth more habitable by providing the atmosphere with oxygen.

The study, published in the journal Proceedings of the National Academy of Sciences, suggests that the emergence of bryophytes, such as moss, that colonized the land from 470 million years ago onwards are responsible for the flux or organic carbon into sedimentary rocks, driving up the oxygen levels in the atmosphere leading to the second oxygenation event.

"It's exciting to think that without the evolution of the humble moss, none of us would be here today," said Tim Lenton, professor of climate change and earth system science at the University of Exeter and lead author of the study, in a statement. "Our research suggested that the earliest land plants were surprisingly productive and caused a major rise in the oxygen content of the Earth's atmosphere."

For the study, Lenton and his team used computer simulations based on rock, fossils in the sea and few pores preserved in ancient sediments to estimate how much oxygen is being generated by moss.

Their computer models showed that about 445 million years ago, these non-vascular bryophytes, which means they do not have vein-like systems to conduct water and minerals around them, have generated 30 percent of today's global terrestrial net primary productivity.

Taking into account properties of modern bryophytes, including their elemental composition and effects on rock weathering, modern levels of atmospheric oxygen could have been achieved around 420 to 400 million years ago.

Their findings is consistent with the previous beliefs that the oxygen in the atmosphere approached modern levels roughly 400 million years ago, after the its first appearance in an incident known as Great Oxidation Event some 2.4 billion years ago.

With their findings, researchers noted that large, mobile, intelligent animal life, including humans, may not evolve at all if the humble moss did not create the stable oxygen-rich atmosphere.