Methane Bubbles in Arctic Sea

chewan

OSLO, March 5 — Large amounts of a powerful greenhouse gas arebubbling up from a long-frozen seabed north of Siberia, raising fearsof far bigger leaks that could stoke global warming, scientists said.

It was unclear, however, if the Arctic emissions of methane gas werenew or had been going on unnoticed for centuries — since before theIndustrial Revolution of the 18th century led to wide use of fossilfuels that are blamed for climate change.
The study said about 8 million tonnes of methane a year, equivalentto the annual total previously estimated from all of the world’soceans, were seeping from vast stores long trapped under permafrostbelow the seabed north of Russia.

“Subsea permafrost is losing its ability to be an impermeable cap,”Natalia Shakhova, a scientist at the University of Fairbanks, Alaska,said in a statement. She co-led the study published in today’s editionof the journal Science.The experts measured levels of methane, a gas that can be releasedby rotting vegetation, in water and air at 5,000 sites on the EastSiberian Arctic Shelf from 2003-08. In some places, methane wasbubbling up from the seabed.

Previously, the sea floor had been considered an impermeable barriersealing methane, Shakhova said. Current methane concentrations in theArctic are the highest in 400,000 years.“No one can answer this question,” she said of whether the ventingwas caused by global warming or by natural factors. But a projectedrise in temperatures could quicken the thaw.
“It’s good that these emissions are documented. But you cannot saythey’re increasing,” Martin Heimann, an expert at the Max PlanckInstitute for Biogeochemistry in Germany who wrote a separate articleon methane in Science, told Reuters.

“These leaks could have been occurring all the time” since the lastIce Age 10,000 years ago, he said. He wrote that the release of 8million tonnes of methane a year was “negligible” compared to globalemissions of about 440 million tonnes.
Shakhova’s study said there was an “urgent need” to monitor theregion for possible future changes since permafrost traps vast amountsof methane, the second most common greenhouse gas from human activitiesafter carbon dioxide.
Monitoring could resolve if the venting was “a steadily ongoingphenomenon or signals the start of a more massive release period,”according to the scientists, based at US, Russian and Swedish researchinstitutions.

The release of just a “small fraction of the methane held in (the)East Siberian Arctic Shelf sediments could trigger abrupt climatewarming,” they wrote.

The shelf has sometimes been above sea level during the earth’shistory. When submerged, temperatures rise by 12-17 degrees Celsiussince water is warmer than air. Over thousands of years, that may thawsubmerged permafrost.
About 60 per cent of methane now comes from human activities such aslandfills, cattle rearing or rice paddies. Natural sources such aswetlands make up the rest, along with poorly understood sources such asthe oceans, wildfires or termites.

Most studies about methane focus on permafrost on land. But theshelf below the Laptev, East Siberian and Russian part of the Chuckchisea is three times the size of Siberia’s wetlands. — Reuters

cmf_aishiteru

she's right about not knowing if the rate of arctic CH4 release into the atmosphere is increasing or otherwise. there is just not enough data to demonstrate any significant rise or drop in the emission rate. and we also do not know if the phenomenon is a feedback to or a source of climate change. however, it's also good to know that CH4 contribution to greenhouse forcing is relatively small compared to water vapor. CH4 forcing is also comparatively small than CO2 forcing which has larger concentration in the atmosphere. And, despite all the effort, we have yet to understand how climate really works. there are too many variables in the equations.

mbhcsf

ini mempunyai implikasi ker  kepada pelbagai disiplin untuk gabung ( multi diciplinary involvement) ???
kalau ya siapa mereka

cmf_aishiteru

I don't get your question but I'll try my best to satisfy your curiosity.
Many parties involve - including politicians, policymakers and business people
But in scientific researches, physicist and chemist do most of the works such as asking questions, finding answers, deriving theories and climate models etc etc. Engineers work on developing tools for measurement - lidar, radar, balloon, rocket, satellite.

dauswq

seingat aku
gas methane pun terhasil dari methane clathrate
methane clathrate banyak dijumpai dalam batu karang + hidupan yang terdapat di perut lautan
apa yang aku baca....gas ini terhasil secara semulajadi
tp concentration tak sebanyak yg dihasilkan di Artic spt didakwa artikel di atas

cmf_aishiteru

aku igt daus, ko buat la satu thread khas utk atmospheric science
pastu merge semua thread lain2 jd satu thread

dauswq

aku igt daus, ko buat la satu thread khas utk atmospheric science
pastu merge semua thread lain2 jd satu thread
cmf_aishiteru Post at 9-3-2010 10:46

jap ya semua itu dalam plan
nanti ada mod baru bertugas...saya berbincang dengannya lebih senang

dauswq

tambahan

  

Methane-making microbes thrive under the ice   
        Antarctica's ice sheets could hide vast quantities of the greenhouse gas




BALTIMORE — Microbes living under ice sheets in Antarctica and Greenland could be churning

out large quantities of the greenhouse gas methane, a new study suggests.

In recent years scientists have learned that liquid water lurks under much of Antarctica’s massive

ice sheet, and so, they say, the potential microbial habitat in this watery world is huge. If the

methane produced by the bacteria gets trapped beneath the ice and builds up over long periods

of time — a possibility that is far from certain — it could mean that as ice sheets melt under


warmer temperatures, they would release large amounts of heat-trapping methane gas.

Jemma Wadham, a geochemist at the University of Bristol in England, described the little-known


role of methane-making microbes, called methanogens, below ice sheets on March 15 at an American Geophysical Union


conference on Antarctic lakes.

Her team took samples from one site in Antarctica, the Lower Wright glacier, and one in Greenland, the Russell glacier.


Trapped within the ice were high concentrations of methane, Wadham said, as well as methanogens themselves — up to 10


million cells per gram in the Antarctic sample and 100,000 cells per gram in Greenland. That’s comparable to the


concentration of methanogens found in deep-ocean sediments, she said. The species of microbes were also similar to those


found in other polar environments, such as Arctic peat or tundra.

The team then put scrapings from both sites into bottles and incubated them with water to see which microbes might


grow. For the Antarctic samples, Wadham said, “nothing happens for 250 days and then bam! You get tons of methane.”


The Greenland samples haven’t been growing for as long and so far don’t show much signs of giving off methane — but


perhaps they just need more time, she reported at the meeting.

Other researchers have also recently found methanogens in icy settings. Mark Skidmore, a microbiologist at Montana State


University in Bozeman, reported at the conference that his team has found methanogens in the Robertson glacier in the


Canadian Rockies. “It underscores the importance of subglacial methanogenesis,” Skidmore said.

The studies flesh out a picture of Antarctica as a much more dynamic and watery environment than the frozen, static one


once envisaged. At least 386 lakes have been identified buried beneath the ice sheet, scientists from the University of


Edinburgh reported at the meeting. Plans for major drilling projects are underway for several of them.



=>  


An intricate network of lakes and rivers below Antarctica's ice sheet could be home to lots of microbes churning out the


greenhouse gas methane

kehadiran gas methane yg bahaya memang berbahaya....tak lama lagi makin cairlah ais kt Antartica

off topic jap gas methane secara amnya terdapat di mana2 planet/object di alam semesta
Titan - Saturn's moon methane are mostly composed of methane gas sebagai ganti kepada air yg terdapat bumi..peranan methane sama seperti air di Titan
kt Titan ada hujan methane, bongkah ais methane....
tp bukan H20 mcm kt bumi ni....
so mereka concluded ada "life" juga kat Titan disebabkan appearance Titan seakan-akan bumi (methane(titan)=h20(bumi))