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Coral reefs create clouds to control the climate

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  • narodaleahcim@aol.com
    When the temperature soars, coral reefs might cool off by creating their own clouds. Research from the Great Barrier Reef off the Australian coast shows that
    Message 1 of 1 , Feb 7, 2005
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      When the temperature soars, coral reefs might cool off by creating
      their own clouds.

      Research from the Great Barrier Reef off the Australian coast shows
      that corals are packed full of the chemical dimethyl sulphide, or
      DMS. When released into the atmosphere, DMS helps clouds to form,
      which could have a large impact on the local climate.

      In the air, DMS is transformed into an aerosol of tiny particles on
      which water vapour can condense to form clouds. This sulphur compound
      is also produced in large amounts by marine algae and gives the ocean
      its distinctive smell. Algae play a vital part in regulating Earth's
      climate, but no one had looked at whether coral reefs might have a
      similar role.

      Graham Jones of the Southern Cross University in Lismore, Australia,
      and colleagues measured DMS concentrations in corals in the Great
      Barrier Reef and its surrounding water. They found that the mucus
      exuded by the coral contained the highest concentrations of DMS so
      far recorded from any organism. A layer rich in DMS formed at the sea
      surface above the reef, where it was picked up by the wind.

      "Although globally the emission of DMS from the Great Barrier Reef is
      not huge, on a regional basis it is very significant," says Jones.
      Missing link

      The big question now is what effect this will have on the
      climate. "The coral is a concentrated source of DMS, which could
      affect the formation of clouds in that region," says Peter Liss, an
      environmental chemist and DMS expert at the University of East
      Anglia, Norwich, UK.

      The Australian team plans to study the impact of the reef and other
      corals on local climate over the next few years. "We don't know how
      the DMS emitted by the coral relates to cloudiness and the radiative
      climate over the reef," says Jones. "That's the missing link."

      But their findings help to solve a 30-year puzzle. Surveys in the
      1970s found very high concentrations of aerosol particles in the air
      above the Great Barrier Reef. The coral was thought to be the source,
      but the mechanism by which the reef might have caused the aerosol
      count to soar was not known. "They didn't know about DMS in the
      1970s," says Jones.
      Gaia-like feedback

      The research also raises another intriguing possibility: that coral
      can use a Gaia-like feedback mechanism to regulate the amount of
      sunlight they are exposed to. The "Gaia theory" is that life on Earth
      regulates its environment to keep itself healthy.

      In lab experiments, Jones and his team showed that corals produce
      more DMS when the symbiotic algae inside their tissues become
      stressed by high temperatures or UV radiation. If this DMS seeds more
      clouds, the coral could have evolved a way to reduce the water
      temperature or UV exposure. "We've got a long way to go to
      conclusively demonstrate this, but we've got a lot of ammunition,"
      says Jones.

      For 20 years, scientists have been hunting for evidence that free-
      floating marine algae can operate a DMS-dependent feedback mechanism
      to dampen global warming's effects. Because reefs are a static source
      of DMS, it might be easier to show an effect, says Jones. "Coral
      reefs would be a great place to show Gaia in action," he says. "This
      is the first time that processes going on in coral reefs are being
      connected to climatic processes."

      Journal reference: Marine and Freshwater Research (vol 55, p 849, and
      the upcoming issue)

      http://www.newscientist.com/article.ns?id=dn6953

      Comment:

      There is a methanogen which breaks down dimethyl sulfide into methane
      for hydrates and the dimethyl sulfide is a close intermediate to one
      of the chemicals used in the China paper. So you have w/ the
      hydrates a biogenic source toward CO2 for outgassing events and
      therefore local/regional modulations and then you have a cloud
      nucleation chemical but also you have per the China paper a cloud
      nucleation chemical that is going to be sensitive to the DC fields.
      Further a coral field, like the huge one just found in 200 feet of
      water off the Florida coast, you will have concentrations of CO2 and
      other biogenic materials (fish are attracted to them and so forth)
      associated with their ecologies a bio source of chemical containment
      that would go beyond diffusion from a relative conductivity
      standpoint. Associated rain feedbacks then bring from the
      terresphere nutrients. It's all a living deal.
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