Feb. 19, 2009 -- Whether devastating faults, dank caves or mud cracks on a drying desert plain, Earth's surface is riddled with fractures. Now a new study had found that the cracks exhale large quantities of gas, perhaps enough to affect global warming. Noam Weisbrod of Ben Gurion University of the Negev and a team of researchers monitored a crack about 2 meters long (6.5 feet) and 1 meter (3.3 feet) deep for two years in the Negev Desert is Israel. Each night, they watched as warm air in the crack drew water vapor out of the surrounding rock, and lifted it into the cold evening air. If air in the crack is just 7 degrees warmer than the ambient temperature, it is buoyant enough to rise out of any crack in the ground bigger than 1 centimeter (0.4 inch) across, bringing with it any gases that leak out of the surrounding soil or rock. But the team was surprised to find that the crack they studied gave off water vapor up to 200 times faster than areas without fractures. Related Content:
"Sometimes we go for walks at night, and you put your face over the mouth of a cave and you can feel a warm wind coming out," Weisbrod said. "Usually it's a nice hot wind in the cold air." Like carbon dioxide, water vapor is a greenhouse gas that plays a crucial role in the way Earth's atmosphere traps heat from the sun. Though the team only measured water vapor, Weisbrod said it's likely that cracks also regularly emit elevated amounts of CO2 and nitrogen oxides. This doesn't only happen in extremely dry areas, he added. The Negev is arid, but roughly equivalent in dryness to the area around Los Angeles, Calif., the American southwest, and many regions around the world. Fractures are common in soils and rocks in wet regions as well, Dan Yakir of the Weizman Institute of Science said. Taken as a whole, emissions from fractures in the uppermost meter of the planet's crust may make a significant contribution to greenhouse gases in the atmosphere. But Weisbrod stressed it's too early to make such a conclusion; the team only studied one crack in detail out of millions. "This has the potential to be important globally," Yakir said. "The biosphere soaks up 30 percent of the carbon, and soil respiration is a very large part of that. If cracks remove CO2 from soils much faster than usual, it's important. But this study is only a first step." Related Links: Get More NewsSpiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates.Oldest Hebrew Writing Possibly FoundAncient inscriptions on a 3,000-year-old pottery shard could make history.Rare, Prehistoric-Age Reptile Found in N.Z.A tuatara has been spotted on the New Zealand mainland for the first time in 200 years.Iceman Has No Living RelativesOetzi, the 5,300 year-old frozen mummy, left no living genetic legacy.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.It's Official: People Are Warming the PolesHumans are conclusively to blame for polar warming, say scientists.Eight-Armed Animal Preceded DinosaursWhat may be one of Earth's first animals was no bigger than a coaster and had eight arms.Phoenicians Live on in People's GenesOne in 17 Mediterranean men may be descended from ancient Phoenicians.Pesticides, Fertilizers Linked to Frog DeclineA pesticide is found to promote parasites among amphibians.Hubble Telescope Taking Photos AgainThe Hubble Space Telescope is once again snapping stunning photos of the universe.Andean Mummy Hairs Show Hallucinogen UseScientists find direct evidence of hallucinogenic drug use among ancient Andeans.Opals on Mars Reveal Planet's Long Wet PastOpals found on Mars suggest the planet has been wet for much longer. |
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