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NSF PR 96-68 - October 31, 1996
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Antarctic Science Season Gears Up with Searches for
Meteorites, Neutrinos, and New Life Forms
Spring in Antarctica heralds new U.S. science efforts
on several fronts: a series of cruises in the Southern
Ocean to trace carbon cycling associated with plankton
blooms; drilling to assess the stability of the massive
ice sheets; and an expedition to search for more meteorites
on the continent that yielded ALH84001, the now-famous
meteorite from Mars that may contain fossil life.
The National Science Foundation (NSF) is supporting
approximately 145 Antarctic investigations, based
mainly out of three research stations during Antarctica's
summer, from now through February.
The bulk of the research -- astronomy and astrophysics,
earth science, glaciology, oceanography, atmospheric
science, and biology -- is supported out of NSF's
McMurdo Station, located on Ross Island, and at Amundsen-Scott
South Pole Station, inland on the heights of the ice
cap. Other projects are based at Palmer Station on
the Antarctic Peninsula and on two research vessels.
Antarctic research highlights this season:
- Carbon and Climate in the Southern Ocean Scientists
led by Robert Anderson of Columbia University
and Walker Smith of the University of Tennessee
are mounting a major effort to understand the
role of the Southern Ocean in the global cycle
of carbon, and ultimately to predict the ocean's
response to climate change. As the southern component
of the decade-long Joint Global Ocean Flux Study
(JGOFS), a study of carbon in the world's oceans,
thirteen cruises aboard two ships -- the National
Science Foundation's icebreaking research vessel,
the Nathaniel B. Palmer, and the University National
Oceanographic Laboratory System ship Thomas G.
Thompson -- will take place from September, 1996
through March, 1998. This field season's cruises
will center mainly on the Ross Sea, starting with
a cruise embarking in early October to study Antarctica's
largest and most predictable spring bloom of phytoplankton
in these waters, and its role in the carbon cycle.
Two subsequent cruises will track carbon over
the season, and investigate how trace metals,
especially iron, affect plant production.
- Deicing Dynamics of Sea Life The growth and retreat
of sea ice around Antarctica is one of the world's
great seasonal events, yet little is known about
how ice dynamics affect zooplankton and other
animals in the ocean's topmost waters (the upper
100 meters). Three cruises in the Weddell Sea
and associated studies, under a project led by
Kenneth Smith of the Scripps Institution of Oceanography,
will track the ecology of tiny animals -- zooplankton
(floating) and micronekton (swimming) -- over
one year, to capture how dramatic changes in sea-ice
cover affect the animal populations. The project
will develop an instrument to monitor populations
at different depths, and will launch a remotely-operated
vehicle to sample and observe animals beneath
the sea ice.
- The Rougher It Is, The Better They Like It Biologists
now agree that archea, or archeobacteria, are
one of the three major branches of life, in addition
to bacteria and eukaryotes (the latter embracing
plants, animals, and humans). Archea seem to like
environments that are very hot, or very salty,
or strictly lacking in oxygen -- places where
no other life can endure.
Recent studies, however, reveal a surprise:
archea comprise more than 30 percent of biomass
in waters off Palmer Station, Antarctica --
the highest rates measured in the ocean. A
team led by Edward DeLong of the University
of California-Santa Barbara will sample archea
in the region this season, illuminating the
ecology and biology of these mysterious organisms.
- Hot and Ultraviolet The greater amount of ultraviolet
light (called UV-B) let in by the ozone hole reduces
the productivity of marine phytoplankton, but
how does UV-B affect Antarctica's terrestrial
plants? How are such plants reacting to the 50-year
warming trend around the Antarctic Peninsula?
Thomas Day of the University of Arizona and his
team will study the impact of UV-B and warming
on the health of two vascular plant species near
Palmer Station on the Antarctic Peninsula. The
study may shed light on the possible consequences
of global warming for land plants.
- Drilling an Ice Dome in West Antarctica Fast-flowing
ice streams, analogous to rivers, drain part of
West Antarctica's ice sheet out to the floating
Ross Ice Shelf, and hence to the sea. How permanent
is this ice sheet, which is actually anchored
below sea level? As part of a major, multi-year
initiative, the West Antarctic Ice Sheet program,
scientists led by Kendrick Taylor of the Desert
Research Institute will begin drilling a 1000-meter
core from Siple Dome, a rise of ice located between
two ice streams on the coast of the Ross Sea,
and a critical location for taking the ice sheet's
pulse.
The core's ice record is expected to span
80,000 years, including part of the last glaciation,
and to have distinct annual ice layers back
at least 6,000 years. The core will shed light
on coastal climate and ice stream dynamics
in the past. It will also be compared with
the famous deep cores from the Greenland ice
sheet, to assess whether the rapid climate
changes recorded in Greenland had a global
reach.
- Flying Above the Rift If West Antarctica's ice
melted, sea level would rise worldwide by six
meters. West Antarctica's swift ice streams lie
above a geologic rift -- an area where the earth's
crust is pulling apart, possibly with profound
effects on the ice streams' behavior, and hence
on the ice sheet's overall stability. An aerogeophysical
survey headed by Donald Blankenship of the University
of Texas at Austin and Robin Bell of Lamont-Doherty
Earth Observatory is tracing how the sub-ice rift
architecture affects the ice streams. The team
uses an aircraft fitted with geophysical instruments
to image the surface and bed of the ice sheet,
while measuring the gravity and magnetic signature,
a clue to volcanism of the rock beneath (this
year's survey focuses on Ice Stream "D").
- Vostok: The World's Deepest and Oldest Ice Core
Drilling to complete the world's deepest and oldest
ice core will continue at Russia's Vostok Station
in East Antarctica this season. Some 30 researchers
from the United States, France, and Russia study
the ice record, expected to stretch back perhaps
half a million years. Studies of Vostok's ice
have already shown a close link between climate
over the past 200,000 years and changing concentrations
of greenhouse gasses in the atmosphere. The drillers
plan to halt at approximately 3650 meters depth,
stopping above Lake Vostok, the subglacial lake
beneath Vostok Station that is comparable in size
to Lake Ontario. The lake and any life it may
harbor have apparently been sealed off from the
atmosphere for hundreds of thousands of years.
NSF provides flight support for the project and
grants to glaciologists studying the ice core.
- More Favorite Martians? The news last summer that
ALH84001, a meteorite from Mars found in Antarctica's
Allan Hills, may contain fossils of early life
startled scientists and the public. It also drew
the spotlight to the Antarctic Search for Meteorites,
akin to a bargain-priced space mission on snowmobiles
led by Ralph Harvey of Case Western Reserve University.
Antarctica is actually unrivaled in its abundance
of meteorites. Since 1976, the program has found
more than 7800 specimens, including samples of
the Moon and Mars, expanding knowledge of the
primeval nebula that have birth to the solar system.
This season, the team returns to the Allan Hills
and will search other locations as well.
- AMANDA Expands Its Neutrino Search Antarctica's
ice sheet serves as the detector for an unusual
neutrino telescope, the Antarctic Muon and Neutrino
Detector Array (AMANDA), a project based at the
South Pole. AMANDA seeks to map the sources of
the ghostly subatomic particles called neutrinos
-- whether they come from active galactic nuclei,
supernovae remnants, pulsars, neutron stars, or
from elsewhere in or outside the galaxy. Such
studies are at the forefront of the new field
of neutrino astronomy.
The array already offers some provocative
results. From a sample during the first nine
months of observations, AMANDA has spotted
about 12 particles that seem to be evidence
of incoming neutrinos. This season, hot-water
drillers will bore out holes to install seven
new strings of detectors 2,000 meters deep,
to join the four strings already embedded
in the ice sheet.
- Probing the Aurora When the sixth Automatic Geophysical
Observatory is put into place in a remote location
on the Antarctic ice cap this season, it will
complete a network of instruments that take continuous
measurements of the aurora and the polar ionosphere
(the highest layer of the earth's atmosphere).
The AGOs will furnish data that could otherwise
be collected only by an entire flotilla of spacecraft.
- Retrieving the Flare Genesis Telescope One of
the world's largest solar telescopes circled Antarctica
last year suspended from a giant balloon, and
taking advantage of the 24-hour-long light, imaged
sunspots and mapped associated magnetic fields
which are believed to cause solar flares. The
balloon was cut down above the Adelie Coast, 1400
kilometers from McMurdo Station, but foul weather
permitted only the data recorder to be retrieved.
This year, the French Antarctic program will assist
the U.S. by mounting a traverse to recover the
balloon payload, including the $10-million telescope.
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