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.
- 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.
- 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.
- 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.
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.
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.
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.