One topic that comes up on the OGD every now and then is the use of carbon dioxide to speed up orchid growth. This is an interesting article on carbon dioxide and plant growth. One thing to keep in mind that AJ Hicks has pointed out in the past is that orchids are survivalist, and can grow in less then ideal situations when some nutrients are not available.
Carbon dioxide theory debunked Many scientists hope the rising concentration of carbon dioxide in the atmosphere will be offset by greater growth of plants on the Earth's surface. A study in the journal Science suggests this may be wishful thinking. Plant matter is made up largely of carbon-based molecules synthesized when plants capture carbon dioxide from the air during photosynthesis. The forests, grasslands and phytoplankton of the oceans are all huge sinks for carbon in the environment. If plants grow faster or bigger in the presence of more carbon dioxide, theoretically they could drain off some of the excess carbon entering the atmosphere through the burning of fossil fuels and other human activities. A research team led by Bruce Hungate at Northern Arizona University studied what happened to Galactia elliottii, a vine in the bean family that grows in coastal Florida, during a seven-year experiment in which enclosed but roofless plots of land were exposed to elevated concentrations of carbon dioxide. To accumulate carbon in the form of biomass, the vines also have to accumulate -- or /"fix"/ -- nitrogen, another essential element in living matter. Hungate and his colleagues used nitrogen fixation as a yardstick for growth. In the first year of the experiment, the vines doubled their nitrogen fixation -- clear evidence they were flourishing in response to the higher carbon dioxide levels. That response fell off rapidly, however. In the past three years, the elevated carbon dioxide levels suppressed nitrogen below normal fixation. Why did this happen? It turns out the vines were running out of molybdenum, a trace metal captured from soil that they need for one of their nitrogen-fixing enzymes. When molybdenum became scarce, the excess carbon dioxide became unusable. -- /Washington/ /Post/ The following are quotes from an article on carbon dioxide emissions credit trading of industries under the Kyoto treaty. It kind of gives you an idea of the problem with carbon dioxide and global warming. The US is not a signature to the Kyoto treaty. As world takes halting steps, some try trading `hot air' to buy time on climate By CHARLES J. HANLEY AP Special Correspondent "If carbon dioxide had a color, if people saw the sky getting darker, people would have no problem recognizing what's going on," said climatologist David Pierce of San Diego's Scripps Institution of Oceanography. Some scientists and engineers said so much time has been lost that only carbon "sequestration" -- technology to capture and store emissions -- can save the climate. One calculated, however, that a Lake Michigan in liquid CO-2 would have to be hoarded away in the next 100 years. The full article: http://www.sfgate.com/cgi-bin/article.cgi?file=/news/archive/2004/06/05/international1309EDT0538.DTL Mark Sullivan
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