Post by thedirtman on Sept 4, 2014 22:41:51 GMT -5
Warning over vulnerability of soil carbon to warming
By Matt McGrath
Environment correspondent, BBC News
The huge stores of carbon locked in the world's soils are more vulnerable to rising temperatures than previously thought.
Researchers found that microbes in the soil were more likely to enhance the release of CO2 in a warming world.
Soils from colder regions and those with greater amounts of carbon were seen to emit more as temperatures went up.
The research has been published in the journal Nature.
The world's soils hold about twice the amount of carbon as the atmosphere.
Every year the activities of microbes in the soil on organic matter release around 60bn tonnes of carbon dioxide into the air.
Some studies have shown that these microbes can swing both ways when it comes to warming, with some able to reduce or even eliminate the potential carbon losses.
This new work set out to test 22 different soil samples from the Arctic to the Amazon.
In their experiments the researchers cooked and cooled the material to ascertain how it responded to increased temperatures, over the mid to long term, in this case defined as 90 days.
"There were some suggestions that microbes could get accustomed to higher temperatures with climate warming and then the temperature sensitivity of soil respiration would decline," lead author Dr Kristiina Karhu from the University of Helsinki told BBC News.
"We show that for these 22 soils, this type of acclimation of microbial respiration doesn't really happen. Sometimes the opposite happens, in response to long term temperature change, the microbes enhance the short term effect of temperatures so that the sensitivity of respiration gets actually higher."
The research team found that soils from boreal regions and the Arctic were impacted the most, while arable or managed lands were the only ones where microbes reduced the effects of a temperature change on the amount of carbon dioxide released.
continued at link:
www.bbc.com/news/science-environment-29050800#
By Matt McGrath
Environment correspondent, BBC News
The huge stores of carbon locked in the world's soils are more vulnerable to rising temperatures than previously thought.
Researchers found that microbes in the soil were more likely to enhance the release of CO2 in a warming world.
Soils from colder regions and those with greater amounts of carbon were seen to emit more as temperatures went up.
The research has been published in the journal Nature.
The world's soils hold about twice the amount of carbon as the atmosphere.
Every year the activities of microbes in the soil on organic matter release around 60bn tonnes of carbon dioxide into the air.
Some studies have shown that these microbes can swing both ways when it comes to warming, with some able to reduce or even eliminate the potential carbon losses.
This new work set out to test 22 different soil samples from the Arctic to the Amazon.
In their experiments the researchers cooked and cooled the material to ascertain how it responded to increased temperatures, over the mid to long term, in this case defined as 90 days.
"There were some suggestions that microbes could get accustomed to higher temperatures with climate warming and then the temperature sensitivity of soil respiration would decline," lead author Dr Kristiina Karhu from the University of Helsinki told BBC News.
"We show that for these 22 soils, this type of acclimation of microbial respiration doesn't really happen. Sometimes the opposite happens, in response to long term temperature change, the microbes enhance the short term effect of temperatures so that the sensitivity of respiration gets actually higher."
The research team found that soils from boreal regions and the Arctic were impacted the most, while arable or managed lands were the only ones where microbes reduced the effects of a temperature change on the amount of carbon dioxide released.
continued at link:
www.bbc.com/news/science-environment-29050800#
