By: Blanca Ortega
Microbial
communities are found almost everywhere. Interestingly polar glaciers are not
the exception. Microbes can be found in the Antarctic in mainly three places:
ice surface, cryoconite holes and in cryolakes. Since the Antarctic is
completely covered by an ice lid the Photosynthetically Available Radiation
(PAR) is limited. A study carried out by Bagshaw and colleagues analyzed PAR as
an important control on primary production in cryoconite and cryolakes
ecosystems. The researchers settled up incubators in the laboratory for the study
of both ecosystems (cryoconite and cryolakes). The incubator containing the cryolakes
perfectly resembled the original environment. It was exposed to an increased amount
of light. The increment of light directed to an increased efficiency of primary
production. In another scenario, the researchers increased the light to levels
in which they are adapted to receive on the ice surface, but without the
protection that resembled the ice lid. The efficiency decreased dramatically
and the photophysiology showed that the communities suffered light stress. On the
other hand, cryoconite communities are not covered by an ice lid, but the
organisms also presented stress to the light. This means that on the natural environment
of cryoconites the communities manage strategies to survive and protect
themselves against photodamage. In essence, both communities are well adapted
to low light levels.
Figure 1. Map showing the exact location where samples were collected
for laboratory incubations. Figure taken from Bagshaw et al. 2016.
Elizabeth A. Bagshaw, Jemma L. Wadham, Martyn Tranter, Rupert Perkins, Alistair Morgan, Christopher J. Williamson, Andrew G. Fountain, Sean Fitzsimons, Ashley Dubnick; Response of Antarctic cryoconite microbial communities to light, FEMS Microbiology Ecology, Volume 92, Issue 6, 1 June 2016. fiw076, doi: 10.1093/femsec/fiw076
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