Moss

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Humble moss helped to cool Earth and spurred on life
http://www.bbc.co.uk/news/science-environment-16814669
By Pallab Ghosh
Science correspondent, BBC News

Moss under the microscope: could it have been responsible for the evolution of life as we know it?

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Primitive moss-like plants could have triggered the cooling of the Earth some 470 million years ago, say researchers.

A study published in Nature Geoscience may help explain why temperatures gradually began to fall, culminating in a series of "mini ice ages".

Until now it had been thought that the process of global cooling began 100 million years later, when larger plants and trees emerged.

The simple plants' interactions with rocks are believed to be the cause.

"The humble moss has created the climate which we enjoy today, from which the life we see all around us evolved," said Prof Tim Lenton of Exeter University, one of the lead researchers.

Carbon dioxide insulates the planet, rather like a duvet wrapped around it: the higher the concentration of CO2, the higher the average global temperature.

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The invasion of the land by plants was a pivotal time in our history. It brought about huge changes to our climate”

Prof Liam Dolan
Oxford University
Atmospheric levels of the gas 480 million years ago are thought to have been 16 times higher than they are now, and average global temperatures are thought to have been 25C, around 10C higher than they are now.

But by 460 million years ago, CO2 levels had fallen by half and the planet began to cool, allowing the formation of the polar ice caps.

The question is: what caused the drop in CO2 levels? The answer, according to an experiment by Prof Lenton and his colleague Prof Liam Dolan of Oxford University is "moss".

According to Prof Dolan, the invasion of the land by moss was a "pivotal" time in our history. "It brought about huge changes to our climate," he said.

The researchers wanted to investigate whether their interaction with rocks, in a process known as chemical weathering, could have been responsible for the drop in CO2 levels.

Weathering involves the mosses extracting nutrients from rock formations by dissolving them with acid. This chemical reaction also leads to CO2 reacting with the rocks and being removed from the atmosphere.

By studying this process with modern mosses, the researchers found that the plants' appetite for CO2 is voracious and could indeed explain the drop in temperature.

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Mystery moss rediscovered
October 18th, 2013 in Biology / Plants & Animals

(Phys.org) —A botanical puzzle more than 150 years old could soon be solved, thanks to a discovery by a second-year botany student in Queensland's far north.

James Cook University student Megan Grixti found a population of Sorapilla papuana, an extremely rare moss, growing on a single tree in remote rainforest near Mount Lewis, west of Mossman.

"Sorapilla is a mystery to botanists because its features are unlike any other moss," expedition leader David Meagher of The University of Melbourne said.

"This plant is so rare it's known to us only through a few herbarium specimens, which are too old to yield useful DNA samples, so at the moment we can only guess where it fits in the story of plant evolution," Mr Meagher said.

Ms Grixti was part of an expedition with botanists from James Cook University, The University of Melbourne and the Australian Tropical Herbarium when she spotted something interesting growing on the trunk of a tree about 30 metres away.

"I had seen dried specimens before, but they were so old we didn't even know what colour to look for. I knew we were looking for a moss that doesn't really look like a moss," she said.

"What I saw was a trailing plant with a distinctive blue-green colour that was catching the light. I was pretty sure it was something special, and other expedition members were able to verify straight away that it was Sorapilla papuana.

"As an undergrad student, I was excited just to be included in the expedition," Ms Grixti said. "To be the one who spotted it is a wonderful start to my career as a botanist."
The moss of mystery comes from a family with an intriguing history.

The only other Sorapilla species, Sorapilla sprucei, was discovered in 1857 in the headwaters of the Amazon in Ecuador by explorer-botanist Richard Spruce, but has never been found again. At that time it had no known relatives.

In 1892 Sorapilla papuana was discovered in the Owen Stanley Range, Papua New Guinea. It was later found in far north Queensland.

"This really is a significant and exciting find," Professor Darren Crayn, Director of the Australian Tropical Herbarium, said.
"We know of only two previous finds in Australia, the first in 1936 by the Cairns naturalist Dr Hugo Flecker.

"This new collection, of material suitable for DNA analysis, should finally allow us to fill a longstanding gap in the story of plant evolution, and to assess the conservation status of this apparently exceedingly rare plant.
"This find reminds us of how much more there is to discover about life on Earth."

A team from The University of Melbourne and The University of California at Berkeley is now working on extracting and sequencing DNA from the newly discovered population. If they are successful, the position of Sorapilla in the plant kingdom will finally be revealed.

"We have many questions about Sorapilla papuana," JCU botanist and expedition member Andi Cairns said.

"Is it a Gondwanan plant, separated from its Ecuadoran relative when the supercontinent broke up millions of years ago? The two are found in areas not considered to have been close before the break-up, but it's an intriguing thought."

Now that the mysterious moss has been located, Ms Grixti and other botanists plan to return to the area in search of other populations.
Provided by James Cook University

"Mystery moss rediscovered." October 18th, 2013. http://phys.org/news/2013-10-mystery-mo ... vered.html
 
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