Mountain erosion may contribute to CO2 emissions in the atmosphere: a study

According to a study, the process of mountain erosion can be a source of new carbon dioxide gas that can be released back into the atmosphere far faster than it is absorbed into newly exposed rock.

The source of this additional CO2 is not solely geological. Instead, it is a byproduct of tiny microbes in mountain soils that "eat" ancient sources of organic carbon trapped in the rock, according to researchers at the US-based Woods Hole Oceanographic Institution.

"This contradicts a long-held hypothesis that more mountains lead to more erosion and weathering, which leads to additional CO2 reduction," said Jordon Hemingway, a postdoctoral fellow at Harvard University.

"It turns out it's a lot more complicated than that," Hemingway, the lead author of the study published in the journal Science, said.

After studying one of the world's most erodible mountain ranges, Taiwan's mid-range, the researchers came to this conclusion.

Each year, this steep-sided range is battered by more than three significant typhoons, each of which mechanically erodes the soil and rock with heavy rains and winds. So Hemingway and his colleagues looked for telltale signs of organic carbon in the rock in samples of soil, bedrock, and river sediments from the mid-range. What they discovered there astounded them.

"At the good bottom of the soil profile, you have essentially unweathered rock," Hemingway explained.

"However, as soon as you hit the base of the soil layer, you see the rock that is loose but not yet fully broken down, also at this point, the organic carbon present in the bedrock appears to vanish entirely," he said.

He added that the team also noticed an increase in lipids, which are known to come from bacteria at that point in the soil.