IN THE ICE CAN BE NICE
July 21, 2013
was walking around in a desert near Albuquerque around noon in the middle of July.
Not surprisingly, my mind wandered now and again to thoughts of cooler situations.
An air-conditioned restaurant was one such thought. Another idea was the desert
at night, which is usually pleasant and has an added advantage, it's when the
animals come out. Then I recalled an ecological study in an extreme habitat I
once wrote about. Scientists described it as "one of the coldest and driest
deserts on Earth" definitely a far cry from a New Mexico desert in midsummer.
The researchers were conducting studies in Antarctica in a region where freshwater
lakes are covered year-round by sheets of ice.
question being asked was whether any life would be found. Considering that living
organisms have been discovered inside volcanoes, deep underground in the darkest
caves, and even in scorching hot deserts, perhaps it should come as no surprise
that scientists found an "oasis for life in a polar desert."
Antarctic summers, up to 40 percent of the ice melts in layers in ice packs that
are up to 20 feet thick and sit above freshwater lakes. Melting occurs when sunlight
warms thin layers of sediment lying within the ice. The sediment layers, up to
a few inches thick, are presumably the result of windblown debris deposited when
the layer was on the surface. Once deep inside the ice pack, the sediments heat
up more than the surrounding ice during sunny periods and layers of water form
within the ice. These layers and pockets of meltwater within the ice packs support
an array of living organisms.
took ice samples, using four-inch-diameter cores. They removed and melted the
ice cores to determine the depths at which sediments and their associated living
organisms occurred. In one lake the sediment layer was about halfway down in an
ice layer more than 12 feet thick. The layers of sediments embedded in the ice
not only provide heat to melt ice but also serve as a source of nutrients. The
habitat, one of the most inhospitable environments imaginable, does not support
large mammals, big fish, or giant squids. It is, however, home to a variety of
bacteria and algae. The researchers discovered that even in a thick ice pack,
separate and identifiable ecosystems exist.
finding that life existed in the ice layers and identifying the species present,
the researchers were in for another surprise - the organisms living in the ice
did not resemble those found in the permanent lake waters far below. Thus, although
the deepest freshwater lakes in Antarctica are continually inhabited by an array
of plankton and other microorganisms, the species living in the incredibly thick
layer of ice above are different.
bacteria and algae living in the ice thrive independently from the lake water
below, with which they have no contact. In some manner the organisms in the ice
are able to live indefinitely in an environment that is frozen solid and in total
darkness half the year. Yet when summer comes and the sediment layers warm up
enough to create thin layers of water, life reappears.
the discovery that life persists in such an extreme situation might be used by
some people to justify any environmental modification or destruction in the name
of progress. That is, no matter what we do to the earth, life will go on. But
the fact that life will exist in some form in any place with water, light, and
nutrients (as well as in a few places without light) is no excuse for intentionally
creating hostile conditions for any plant or animal species. Life will indeed
go on, but the disappearance of the obvious and exciting life forms around us
may signal that we are on the verge of creating conditions unsuitable for human
life, too. Surely none of us would look forward to our last living companions
in the world being mostly bacteria and algae.
you have an environmental question or comment, email