The temperature rises
for a few weeks in the summer to start to melt some of the glacial
ice entering the Dry Valleys, this feeds freshwater streams
that feed into lakes at the bottom of the valleys.
These lakes are frozen above, but below the ice colonies of
bacteria and phytoplankton are supported by temperatures that
are warmed by the ice acting as a lens passing through the fleeting
Despite the apparent sterility of the environment
there is life in the Dry Valleys though not terribly advanced
life. The water of the lakes might at first appear to be as
pure as any water on the planet could be, but this is not the
case as discovered by Scott and his men a hundred years ago.
They drank water from lake Chad that had no
taste and no smell that they thought like the vast majority
of water available in Antarctica to be amongst the cleanest
and purest on earth, however it gave them dreadful diarrhoea
leading to the use of large amounts of toilet paper that went
by the brand name of "Chad" - hence the naming of the lake.
What had caused their illness was toxins released
by one of the most primitive organisms on the planet - Cyanobacteria,
a photosynthetic bacteria that may be seen around seasonal meltwater
streams and lakes in the Dry Valleys looking not unlike a small
cowpat. The Cyanobacteria is brown to protect it against high
levels of ultraviolet light.
There are other oddities in the region
of the Dry Valleys too, one of which is "Blood Falls"
first discovered by Griffith Taylor on Scott's Terra Nova expedition
in 1911 who was the first to explore the valley which is named
As well as being striking in appearance, Blood
Falls (picture below) has an unusual cause. The reddish-brown
colouration is due to iron oxides and not algae as was originally
thought. These iron compounds come from a lake under the Taylor
Glacier where the unusual chemical profile of the lake water
allows chemoautotrophic bacteria to survive without any sunlight
or input of organic molecules from the outside. These bacteria
take abundant Iron II ions (Fe2+) in the lake and
oxidize them to Iron III ions (Fe3+) releasing energy
in the process. This energy is used by the bacteria to synthesize
complex organic molecules from simple ones in a manner similar
to the way that plants use sunlight in photosynthesis.
Every now and then the lake water emerges
from small cracks in the glacier giving rise to the "Blood Falls".
It is thought that this locked away simple
bacterial ecosystem and others like it that do not need to derive
energy from sunlight may indicate the existence of similar ecosystems
elsewhere in the solar system such as Mars or ice covered moons
such as Europa (a moon of Jupiter). It shows that subsurface
liquid water can exist overlaid by thick ice which protects
the water and anything in it from harmful high surface levels
of ultraviolet light and cosmic rays while still being able
to support life.
Blood Falls - Taylor Valley - Dry Valleys
region Antarctica - the tent to the left gives a sense of
The top picture is a satellite image of
the Dry Valleys area,
the bottom is a map of almost exactly
the same area
Picture courtesy of Mike Usher
- Mike went on a Ross Sea expedition on board the Kapitan Khlebnikov
You can purchase a selection of Mike's pictures