Thursday, February 14, 2013

Breaking Discovery: Eighteen species of bacteria found in troposphere (between 8-15 km above the earth)

Microbes  are  said  to be in every part of earth including the hottest (under sea volcanoes)  and coldest (Polar regions) places of earth. What is being studied in Microbiology is those microbes which can be cultured. They constitute less than 1% of the total microbes in the earth.  Can you believe the news that  microbes exist  even in troposphere which is eight kilometres above the earth.  A recent study conducted by Scientists from School of Biology, School of Earth and Atmospheric Sciences, School of Civil and Environmental Engineering, School of Chemical and Biomolecular Engineering of  Georgia Institute of Technology at  Atlanta, USA and Chemistry and Dynamics Branch/Science Directorate, National
Aeronautics and Space Administration Langley Research Center, Hampton, USA  revealed the  composition and prevalence of microorganisms in the middle-to-upper troposphere (8–15 km altitude) and their role in aerosol-cloud-precipitation. They studied the  microbiome of low- and high-altitude air masses sampled onboard the National Aeronautics and Space Administration DC-8 platform in the Caribbean Sea. The samples were collected in cloudy and cloud-free air masses before, during, and after two major tropical hurricanes, Earl and Karl.

Quantitative PCR and microscopy revealed that viable bacterial cells represented on average around 20% of the total particles in the 0.25- to 1-μm diameter range and were at least an order of magnitude more abundant than fungal cells, suggesting that bacteria represent an important and underestimated fraction of micrometer-sized atmospheric aerosols. The samples from the two hurricanes were characterized by significantly different bacterial communities, revealing that hurricanes aerosolize a large amount of new cells. Seventeen bacterial taxa, including taxa that are known to use C1–C4 carbon compounds present in the atmosphere, were found in all samples, indicating that these organisms possess traits that allow survival in the troposphere. Further studies  are needed to find the role of these microbes  on the hydrological cycle, clouds, and climate.

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