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  • Pawnfart
    Forest-soil fungi emit gases that harm ozone layer Sid Perkins Laboratory tests have revealed for the first time that certain types of common fungi
    Message 1 of 702 , Jan 5, 2002
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      Forest-soil fungi emit gases that harm ozone
      layer <br>Sid Perkins <br><br>Laboratory tests have
      revealed for the first time that certain types of common
      fungi can produce ozone-destroying methyl halide gases.
      The origin of substantial fractions of these gases in
      the atmosphere has eluded scientists.
      <br><br>Ectomycorrhizal fungi�literally, fungi that envelop roots�form
      symbiotic relationships with trees. The fungus pulls
      nitrogen and phosphorus from the soil and then provides
      some of those nutrients to its arboreal partner. In
      return, the microbes receive carbohydrates produced by
      the tree (SN: 6/16/01, p. 372. These fungi are often,
      by weight, the most prevalent group of microbes in
      the soil of temperate forests, says Kathleen K.
      Treseder, a biogeochemist at the University of Pennsylvania
      in Philadelphia. <br><br>The ectomycorrhizal fungi
      (pink) coating these oak roots nourish the tree but also
      produce ozone-destroying gases. J. Lansing/University of
      Pennsylvania <br><br>Treseder and her colleagues studied gases
      produced by four types of ectomycorrhizal fungi. They
      found that each gram of fungi churned out methyl
      halides�which include methyl chloride, methyl bromide, and
      methyl iodide�at a daily yield of a few millionths of a
      gram. That doesn't sound like much, she notes, but
      these fungi occur in forests worldwide and can make up
      as much as 15 percent of the organic matter in soil.
      The researchers presented their findings last week at
      the American Geophysical Union's fall meeting in San
      Francisco. <br><br>Many of the natural sources of methyl
      halide gases haven't been identified, says Kelly R.
      Redeker, an atmospheric scientist at the University of
      California, Irvine and a coauthor of the study. For example,
      scientists don't know where 25 percent of the atmosphere's
      methyl bromide comes from. One known source is
      agriculture in which the gas is applied to sterilize soil.
      <br><br>Methyl bromide is responsible for about 10 percent of
      the high-altitude ozone destruction in Earth's
      stratosphere, and methyl chloride gets between 10 and 15
      percent of the blame, Redeker notes. <br><br>Although
      human-made gases, such as chlorofluorocarbons, account for
      much of the stratospheric-ozone loss, production of
      those substances is being phased out. Chemical
      reactions in the atmosphere will eventually eliminate those
      gases already released, so identifying the sources of
      natural ozone destroyers such as methyl halides is
      becoming more important, says Redeker. Such knowledge
      could enable scientists to better predict the long-term
      influence of those gases, which may fluctuate in response
      to a changing climate. <br><br>The discovery by
      Redeker's team is "an intriguing first result," says Ray F.
      Weiss, a geochemist at the Scripps Institution of
      Oceanography in La Jolla, Calif. "People haven't found a lot
      of natural sources for these [methyl halide] gases."
      Field tests that measure the methyl halides escaping
      from soil are needed to determine whether the fungi
      indeed contribute significant amounts of
      ozone-destroying gases, he adds.
    • b1blancer_29501
      On Feb 28th, the Interplanetary Magnetic Field swung to a strong south-pointing orientation. That, coupled with an elevated solar wind speed and density,
      Message 702 of 702 , Mar 1, 2002
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        On Feb 28th, the Interplanetary Magnetic Field
        swung to a strong south-pointing orientation. That,
        coupled with an elevated solar wind speed and density,
        triggered a G-1 class geomagnetic storm. The result was
        some high latitude aurora. See this link for a
        photgraph of aurora observed over Quebec :
        <a href=http://www.spaceweather.com/aurora/images/01mar02/Moussette2.jpg target=new>http://www.spaceweather.com/aurora/images/01mar02/Moussette2.jpg</a> . As of right now, there are 3 sunspot regions,
        namely 9839, 9842, and 9845, that appear to be capable
        of producing M-class flares. Regions 9839 and 9842
        are close to rotating out of view over the western
        limb of the solar disk. Sunspot region 9845, however,
        is close to the sun's central meridian. A rather
        large coronal hole is also approaching the sun's
        central meridian, and coming into an Earth-pointing
        position. High speed colar wind gusts are likely around the
        first of next week.<br><br>The current solar and
        geomagnetic conditions are :<br><br>NOAA sunspot number :
        153<br>SFI : 188<br>A index : 10<br>K index : 1<br><br>Solar
        wind speed : 372.3 km/sec<br>Solar wind density : 4.4
        protons/cc<br>Solar wind pressure : 1.1 nPa<br><br>IMF : 8.4
        nT<br>IMF Orientation : 0.7 nT North<br><br>Conditions for
        the last 24 hours : <br>Solar activity was low. The
        geomagnetic field was quiet to unsettled. Stratwarm Alert
        exists Friday.<br><br>Forecast for the next 24 hours
        :<br>Solar activity will be low to moderate. The geomagnetic
        field will be quiet to unsettled.<br><br>Solar Activity
        Forecast :<br>Solar activity is expected to be low to
        moderate for the next three days. Region 9845 is a
        possible source for isolated M-class
        flares.<br><br>Geomagnetic activity forecast :<br>Geomagnetic field activity
        is expected to be mainly quiet to unsettled, until
        the onset of high speed stream effects from a
        recurrent coronal hole begin to develop by day three of the
        forecast period. Isolated active conditions are
        anticipated thereafter.<br><br>Recent significant solar flare
        activity :<br>None
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