such as "Introduction", "Conclusion"..etc
January 14, 2009 — To many people, bacteria and
climate change are like chalk and cheese: the smallest creature versus
one of the biggest phenomena on earth. Not really. Scientists with the
Institute of Tibetan Plateau Research (ITP), Chinese Academy of
Sciences and coworkers recently reported that small bugs deposited in
ice and snow might tell how our climate has been changing.
The discovery might bring about a new indicator for climate change,
which is by nature different from all previous physical or chemical
According to Prof. YAO Tandong, chief scientist of the research,
bacterial abundances in ice cores vary in response to climatic
conditions. With ice and snow samples taken from the Guoqu glacier on
Mount Geladaindong, Yao and collaborators from ITP and Xiamen
University measured the annual abundances of bacteria trapped in ice
over the past seven decades. Analysis showed that bacterial levels rose
with higher temperatures and dust concentrations.
The experts found that the bacterial abundance, lowest in 1938 and
highest in 1997, increased in accordance with levels of oxygen-18, a
natural, stable isotope of oxygen known to be well correlated with
temperature. Usually, oxygen-18 concentration in ice will go up in
The bacteria also increased with levels of dust in the core,
scientists discovered when measuring calcium levels in visible dirty
layers. The dust was likely transported onto the glacier during the
spring dust storm season and trapped in ice through subsequent melting
of the snow and ice.
Further analysis showed that seasonal factor plays a part in
bacterial diversity. During the annual monsoon season, the microbes
originated from very diverse environments including animal and human
sources, while in non-monsoon seasons they mainly came from closer and
The study is the first of its kind to connect bacteria with climate
change for ecological studies. For a long time, world scientists kept
their eye on how bacteria survive in thousand-year-old cold and dark
ice cores in polar regions.
Since 2002, Prof. Yao and his colleagues have turned to exploring
the microbial community in Malan and Puruogangri Ice Cores on central
Tibetan Plateau. The present study on Geladaindong Ice Core is also the
first high-resolution restoration of annual abundances of trapped
Researchers will have to do more to quantify the above correlations, notes Yao, also director-general of ITP and a CAS Member.
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