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[Fwd: Earth Observatory: What's New Week of 31 January 2006]

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  • Sonya
    ... Subject: Earth Observatory: What s New Week of 31 January 2006 Date: Tue, 31 Jan 2006 18:15:02 -0500 (EST) From: eoannounce@eodomo.gsfc.nasa.gov To:
    Message 1 of 1 , Feb 1, 2006

      -------- Original Message --------
      Subject: Earth Observatory: What's New Week of 31 January 2006
      Date: Tue, 31 Jan 2006 18:15:02 -0500 (EST)
      From: eoannounce@...
      To: eo-announce@...

      The latest from NASA's Earth Observatory (31 January 2006)
      In the News:
      * Latest Images:
        Drought in East Africa
        Cloud Streets in the Bering Sea
        Lassen Volcanic National Park
        Sierra Nevada, Spain
        Nouakchott, Mauritania
        Dust Storm over Iraq
        Global Surface Temperatures in 2005
        IMAGE Spacecraft Pictures Aurora 
      * NASA News
      	- NASA Assesses Strategies To 'Turn Off The Heat' In New York City
      	- NASA Satellite Catches A Hurricane Transforming Itself
      	- Converging Satellites Unlock Hurricane Lili's Sudden Demise
      	- NASA News Events At The AMS Annual Meeting
      * Media Alerts
      	- Satellite Portrait of Global Plant Growth Will Aid Climate Research
      	- Yale Group to Study Atmospheric 'Tsunamis'
      	- Mountain Ranges Rise Dramatically Faster than Expected
      	- Of Mice, Men, Trees and the Global Carbon Cycle
      	- Satellites Show Amazon Parks, Indigenous Reserves Stop Forest Clearing
      	- Two New Lakes Found Beneath Antarctic Ice Sheet
      A team led by a University of Minnesota researcher has found a universal rule 
      that regulates the metabolism of plants of all kinds and sizes and that may also 
      offer a key to calculating their carbon dioxide emissions, a number that must be 
      known precisely in order to construct valid models of global carbon dioxide 
      cycling. Emissions of the gas occur in both plants and animals through the 
      process of respiration; Peter Reich, a professor of forest resources, and his 
      colleagues have found that plant emissions can be deduced from the nitrogen 
      content of any plant. The study also reveals that the respiration, or metabolic, 
      rates of plants and animals follow different laws of scaling with respect to 
      body size. The work will be published in the Jan. 26 issue of the journal 
      In revealing nitrogen content as the key to plant metabolic rates, the work 
      uncovered a fundamental difference between plants and animals in how their 
      metabolism varies with size. The larger an animal, the slower its metabolism on 
      a per-weight basis. Thus, although an elephant burns many more calories per hour 
      than a mouse, the mouse has a much higher rate per pound of body weight. An 
      elephant with the same rate per pound as a mouse would generate so much heat it 
      would have serious problems maintaining body temperature and eating fast enough 
      to keep up. Instead of a one-to-one ratio between body size and metabolic rate, 
      as an animal’s body weight quadruples, its respiration rate only triples.
      In contrast, when Reich and his colleagues studied 500 plants from 43 
      species, they found that within a wide range of plant sizes, a quadrupling of 
      weight leads to a quadrupling of respiration rate. The important variable was 
      nitrogen content: The more nitrogen in a plant, the more it respired and the 
      more carbon dioxide the plant emitted. Similarly, if two plants were the same 
      size but had different concentrations of nitrogen in their tissues, the one with 
      the higher nitrogen concentration had a higher respiration rate. Conversely, a 
      big plant and a small plant with the same total nitrogen content would put out 
      equivalent amounts of carbon dioxide over the same time period.
      The universal rule linking plant metabolism to nitrogen can also assist 
      efforts to measure the global carbon cycle. Through the process of 
      photosynthesis, plants absorb and store more carbon dioxide than they emit 
      through respiration. But global plant respiration is a huge variable that must 
      be taken into account.
      “If we estimate the nitrogen content of plants, we can model their metabolic 
      rates, helping us to better assess the global plant metabolic rate,” said Reich, 
      a professor in the university’s College of Natural Resources. “The amounts of 
      carbon dioxide given off by plants is one of the weak spots in models of global 
      carbon cycling.”
      To predict how fast atmospheric carbon dioxide will rise in the future, it is 
      important to know all the sources that emit the gas and all the sources that 
      soak it up. The amount of carbon dioxide in the atmosphere is well known, as is 
      the rate of emissions from fossil fuel burning. The rate of photosynthesis, in 
      which carbon dioxide is absorbed and stored as plant tissue, is difficult to 
      measure but can be estimated globally from satellites, based on the visible 
      plant cover. The plant cover indicates how much light the plants will intercept. 
      Even harder to calculate are the global amounts of carbon dioxide released by 
      living, respiring plants; the amounts released as plants are decomposed by 
      microbes; and the amounts being absorbed and emitted by oceans.
      “If all the carbon dioxide emitted from fossil fuel burning were to stay in 
      the atmosphere, its rate of accumulation in the atmosphere would be 
      two-and-a-half times as fast as it actually is and climate would change 
      two-and-a-half times faster,” said Reich. “Therefore, somewhere there’s a 
      ‘fantastically important global carbon sink’ that’s soaking up 60 percent of the 
      carbon dioxide that’s emitted, with the oceans and land surfaces each playing a 
      major role. However, researchers have estimated that plant respiration releases 
      five to 10 times as much carbon dioxide as fossil fuel burning. It’s crucial, 
      therefore, to know the amount of plant emissions more accurately because that 
      number makes a huge difference in calculating how much of the gas is being 
      absorbed from the atmosphere and staying in the biosphere. This in turn will 
      help scientists figure out what the carbon sink is and what its capacity might 
      Deane Morrison, University Relations
      University of 
      This text derived from http://www1.umn.edu/twincities/index.php

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