|
The
National Science Foundation (NSF) should work within the
environmental framework of the international Antarctic
Treaty system to develop a global scientific consensus
on minimally disruptive ways to investigate one of the
"last unexplored places on Earth"--a unique
system of lakes, and the aquatic systems that may connect
them, buried thousands of meters under the Antarctic ice
sheet--according to a newly released report.
To avoid contaminating these lakes and other features,
which scientists have only recently discovered and which
have been cut off from the outside world for millions
of years, the report calls for NSF to work with international
scientific organizations and Treaty signatories to develop
a management plan for any potential exploration efforts
and, as part of that plan, "ensure that the environmental
management of subglacial environments is held to the highest
standards."
The report, "Exploration of Antarctic Subglacial
Aquatic Environments: Environmental and Scientific Stewardship,"
was released in early May by the National Research Council
of the National Academies of Science.
But before any efforts are made to take any samples,
the report stresses, much more detailed surveys need to
be made to catalogue the subglacial aquatic network and
allow it to be afforded Treaty protection. Such a survey,
while enabling the protecting of the entire system, would
also allow for designating certain features more useful
for scientific research and presenting less of a risk
of widespread contamination of a subglacial "watershed."
The Department of State coordinates U.S. policy on Antarctica,
working closely with NSF, which administers and manages
the U.S. Antarctic Program. The State Department leads
the U.S. delegation to the annual Antarctic Treaty Consultative
Meeting (ATCM). NSF leads the ACTM's Committee on Environmental
Protection.
NSF had requested guidance from the Academies on developing
a set of environmental and scientific standards to guide
scientifically responsible exploration. The report is
the result of that request.
A subgroup of the Scientific Committee on Antarctic Research,
called the Subglacial Antarctic Lake Environments (SALE)
group, is scheduled to meet June 6 and 7 in Big Sky, Montana.
John Priscu, a researcher at Montana State University,
is organizing the meeting. A discussion of the report
and its findings will be among the items on the agenda.
Ice-penetrating radar and other studies have identified
more than 145 subglacial lakes under the ice of the southernmost
continent, including one under the South Pole itself.
The largest known is Lake Vostok, which has a surface
area of roughly 14,000 square kilometers (5,400 square
miles), making it roughly the size of Lake Ontario in
North America.
Other studies have revealed that shallow, swamp-like
features the size of several city blocks and layers of
soils and broken rock may exist beneath the ice, adding
to the diversity of subglacial aquatic environments. Scientific
evidence further indicates that these environments comprise
vast watersheds some of which appear to be connected by
rivers and streams that flow freely beneath the ice sheet,
which in most places is more than two miles thick.
"These lakes and their connected systems are among
the last unexplored places on Earth," the report
says. "Moreover, they have been sealed from free
exchange with the atmosphere for millions of years, making
it possible for unique microbial communities to exist."
In addition to the opportunity to study potentially unique
microorganisms that have evolved in isolation for millions
of years in extremes of cold and darkness, scientists
are interested in these environments because sediments
at the bottom of the lakes may contain evidence of past
climate on the continent over millions of years and possibly
even of a time before Antarctica was covered by ice.
This previously unknown system of aquatic features appears
to be interconnected in many ways, the report notes, requiring
that great care be taken in choosing which features to
eventually explore in order to prevent accidentally contaminating
an entire watershed.
But the 12-member expert panel that drafted the recommendations
also recognized that in order to fully understand these
unique environments it will eventually be necessary to
sample the waters, most likely by drilling through the
ice sheet to obtain the samples or introduce instruments.
"Direct exploration of subglacial environments is
required if we are to understand these unique systems,"
the report states. "Exploration...should proceed
and take a conservative approach to stewardship and management
while encouraging field research."
Although previous drilling at Lake Vostok has reached
to 120 meters above the place where ice and lake water
meet, none of the Antarctic lakes has yet been breached.
But plans are being actively pursued to explore more than
one of Antarctica's lakes, with Russia having stated its
intention to drill into Lake Vostok during the 2007-2008
Antarctic research season, which begins in the fall.
NSF supported scientists have studied various biological
and geophysical aspects of Lake Vostok for several years.
Under its program of grants for the International Polar
Year 2007-2008 (IPY), NSF has funded genomic studies of
microbes found in Lake Vostok, not from the waters themselves,
but from the ice that melted and refrozen at the interface
of the ice sheet above and lake waters below. Another
IPY grant will support an airborne imaging system to map
the lake. The White House Office of Science and Technology
Policy has designated NSF as the lead U.S. agency for
IPY.
In the Academies' report, the panel recommends that before
any of the aquatic systems are penetrated that comprehensive
surveys should be made to insure that scientists have
identified and catalogued all of the existing subglacial
lakes and drainage systems to understand how the complex
system is connected and to identify the best potential
research sites.
Once the features are identified and catalogued, they
should then designated as specially protected areas under
the Treaty to ensure that scientific activities can be
managed within an international plan. Some of the features,
it adds, should be designated as "exemplar pristine"
environments and afforded additional environmental protection.
The panel recognizes that, as is typically the case with
spacecraft that visit other planets, it is likely impossible
to insure that physically entering the lake with drills
and other probes will not introduce contaminants. It therefore
recommends that any effort to physically explore the lake
be restricted to introducing concentrations of microbes
that are less than those that naturally occur as microscopic
life transported from other parts of the globe travel
down through the ice sheet and into the waters below.
Even so, the report recommends that "investigators
should make every effort practicable to maintain the integrity
of lake chemical and physical structure during exploration."
-
NSF.gov
-
|
