Siberia's pools burp out nasty surprise
Pastor Dale Morgan
Siberia's pools burp out nasty surprise*
* 06 September 2006
* From New Scientist Print Edition.
Northern Siberia's thaw lakes are belching out up to five times as much
methane as previously thought. And as global warming causes the
permafrost to melt, lakes worldwide could emit even more methane,
reinforcing climate change.
Katey Walter at the University of Alaska Fairbanks and her colleagues
developed a new technique to measure the amount of methane bubbling out
of two lakes in northern Siberia. In autumn, when the lakes froze over,
they identified regions where methane was being released by searching
for gas bubbles pushing through the ice. They then placed
umbrella-shaped bubble traps over the hotspots and measured emissions
daily for one year. At both lakes, the gas flux was five times as high
as previously estimated. Walter's team also got similar figures from
smaller studies on more than 100 other lakes in the region (Nature, vol
443, p 71)
Human activity is still the biggest source of atmospheric methane, but
lakes can no longer be ignored. "Until now we didn't realise that lakes
were such an important source," says Walter. Over the coming years
methane flux from Siberian lakes is likely to increase, as melting
permafrost releases carbon into the lakes. "Bacteria eat this carbon and
burp out methane," says Walter.
From issue 2568 of New Scientist magazine, 06 September 2006, page 20