Highlights of the 1997-1998 research season

The U.S. Antarctic Program will support 175 research projects, involving more than 750 science-team members, during the 1997-1998 austral summer season. This number is significantly higher than recent summer seasons because of the addition of a major oceanography program. In addition to oceanography, research will be performed in the scientific disciplines of biology, climate systems, geology and geophysics, atmospheric sciences, glaciology, and astronomy and astrophysics.

Projects are based out of three research stations--McMurdo, Amundsen-Scott South Pole, and Palmer--as well as on two research vessels--the R/V Nathaniel B. Palmer and a new vessel, the R/V Laurence M. Gould. In addition, researchers will be deployed to numerous small field camps.

The Cape Roberts Project

Preparations for ocean-bottom core drilling to 500 meters below the seafloor were begun in August at Cape Roberts on the Victoria Land coast about 125 kilometers northwest of McMurdo Station. The holes were to be positioned to provide an aggregate stratigraphic thickness of about 1,500 meters to give the first comprehensive data for the Cretaceous-Paleocene period (100 to 30 million years ago) in the Ross Sea region and East Antarctica. During that geologic period, the megacontinent of Gondwanaland underwent its final rupture as New Zealand and Australia moved northward away from Antarctica. The nearest existing sources for this period are in New Zealand, the southern ocean, and the northern Antarctic Peninsula.

Six nations are involved, including the United States. New Zealand has overall responsibility for the project's activities, which include the drill operations from a 2-meter-thick sea-ice platform. Researchers will have two goals as they study the cores extracted from the seafloor:

to discover if ice sheets covered Antarctica causing fluctuation in worldwide sea levels before the glaciations of the last 36 million years and
to date the rifting of the antarctic continent to help understand the formation of the Transantarctic Mountains and the Ross Sea.

For an update on the Cape Roberts Project, see "Sea-ice conditions force Cape Roberts drill team to withdraw early."

Glaciology studies continue at Siple Dome, end at Vostok

A field camp at Siple Dome near the east side of the Ross Ice Shelf will support up to 75 investigators studying the geophysics and glaciology of West Antarctica. Major fieldwork will involve airborne geophysics using an instrumented Twin Otter airplane, deep ice drilling, and instrumentation lowered into the ice-core holes. Researchers hope to improve understanding of the marine-based west antarctic ice sheet, which may yet be responding to global warming that has occurred since the end of the last ice age.

Siple Dome, a mound of ice between two fast-flowing ice streams that drain the ice sheet and are critical to its stability, is a key location for studying the west antarctic ice sheet. By studying the annual layers of ice deposited--and with them, the cloud water, atmospheric gases, and dust carried to Earth as snow fell and became ice--scientists hope to determine the nature of the current changes in the ice sheet and, ultimately, predict its future. In addition to studying the cores, scientists will also study the ice sheet's movement by dropping instruments into water-filled holes in the ice to measure vertical deformation of the ice. These in-hole instruments will take the first direct measurements of vertical velocity at a deep ice-core site.

The joint U.S.-Russian-French project drilling the world's deepest ice core at Vostok Station will come to an end during the 1997-1998 season. Drilling stopped in January 1996 at a depth of 3,350 meters, a depth that covered about 400,000 years of snowfall and four glacial-interglacial cycles. This season, drillers will go 300 meters deeper, stopping about 50 meters above Lake Vostok to avoid contaminating the huge lake sealed beneath the ice sheet. For additional information, see the home page for the U.S. National Ice Core Laboratory.

LTER work at the McMurdo Dry Valleys and near Palmer Station

In the ice-free polar deserts of the McMurdo Dry Valleys, researchers will continue work on the Long-Term Ecological Research (LTER) project. McMurdo LTER scientists seek to understand the influence of physical and biological constraints on the area's ecosystems and how material transport modifies these ecosystems. Projects for 1997-1998 will include

glacier mass balance, melt, and energy balance;
chemistry of streams, lakes, and glaciers;
flow, sediment transport, and productivity of streams;
lake and soil productivity;
meteorology;
RADARSAT studies of wind transport of material; and
ground-penetrating radar measurements of glaciers and frozen lakes.

The central hypothesis of the Palmer LTER project is that the annual advance and retreat of sea ice is a major physical determinant of spatial and temporal changes in the structure and function of the antarctic marine ecosystem. The 1997-1998 Palmer LTER studies will focus on the processes controlling the space/time variability of phytoplankton biomass and production. Team members will deploy near Palmer Station as well as aboard the R/V Laurence M. Gould.

The Joint Global Ocean Flux Study

During the 1997-1998 field season, the Joint Global Ocean Flux Study (JGOFS) will continue its international effort to examine the annual and seasonal variations in primary production rates. The movement, or flux, of carbon between the atmosphere and the ocean is greatly influenced by what happens in the southern oceans, and JGOFS researchers hope their studies will quantify and clarify those processes.

Two cruises aboard the R/V Nathaniel B. Palmer and four aboard the Scripps Institution of Oceanography vessel R/V Roger Revelle will take scientists to the Ross Sea and the Antarctic Polar Front Zone, respectively. In the Ross Sea, scientists will study the initiation of the phytoplankton bloom, the role of trace metals in controlling rates of production, and the fate of biogenic material. In the Polar Front Zone, the emphasis will be on the physical, chemical, and biological influences affecting the phytoplankton bloom; the temporal variability of the blooms; and the apparent paradox of high fluxes of biogenic material to the sea bed in a region of low mean annual primary production.

Long-duration ballooning

The National Scientific Balloon Facility will launch, track, and recover data and payload from an 81,200-cubic-meter, helium-filled long-duration balloon that will circumnavigate Antarctica in naturally occurring air currents at an altitude of about 38 meters for about 10 days. Two separate projects, one from the National Aeronautics and Space Administration's Goddard Space Flight Center in Maryland and one from the University of California at Berkeley, will gather information from the balloon's instrumentation. Sensors will measure gamma rays and x rays possibly originating from the highest known energy sources in the Universe: neutron stars, black holes, the center of the Galaxy, and other deep-space features.

The launches will be from McMurdo Station's Williams Field, on the Ross Ice Shelf, and will involve an LC-130 Hercules flying under the balloon to download data. As the balloon completes one circumnavigation of the continent, the mission will be terminated by radio from a plane, and the payload will be recovered.

Astrophysics research at Amundsen-Scott South Pole Station

At the geographic South Pole, astrophysics projects will continue to collect data from the earliest moments after the Big Bang, taking advantage of superior observing conditions in the infrared portion of the spectrum provided by the extremely clear and dry atmosphere overhead.

The Antarctic Muon and Neutrino Detector Array (AMANDA), which places photomultiplier tubes between 1 and 2 kilometers deep in the ice sheet as a giant detecting medium, will record the arrival of very-high-energy neutrinos from active galactic nuclei or supernova remnants. AMANDA promises to be a large contributor to the new field of neutrino astronomy.

A new infrared and submillimeter telescope called VIPER will be installed, tested, and put into service at the South Pole during the 1997-1998 season. Using a large-aperture mirror that allows for better data resolution than was previously possible, VIPER will collect data about cosmic background radiation stemming from the early formation of the Universe.

Ozone depletion and ultraviolet-B effects

When more than half of Antarctica's ozone cover disappears each austral spring, ultraviolet-B (UV-B) radiation from the Sun penetrates the stratosphere to the Earth's surface and into the sea. Scientists want to know how these increased UV-B levels affect the embryos and larvae of invertebrates in the shallow waters near Palmer Station on the Antarctic Peninsula. Another project at Palmer Station will study the photochemistry of seawater surrounding cells in organisms that are bombarded by increased UV-B. Such chemistry can influence how much damage is done to the cell surface. Still other work will quantify how ultraviolet light affects plankton, the base of the ocean food chain.

For information about the National Science Foundation's UV-B monitoring project, see http://www.biospherical.com/research/nsfrsrch/updates/austral/austral.htm and for the National Aeronautics and Space Administration's total ozone mapping updates, see http://jwocky.gsfc.nasa.gov/eptoms/epanim97.html

The 1997-1998 field season at the three U.S. stations

McMurdo Station on Ross Island is the operational center for the U.S. Antarctic Program's continental portion, which includes work at Amundsen-Scott South Pole Station and remote field camps. During the 1997 winter, the McMurdo population was 154. Four C-141 Starlifter flights from Christchurch, New Zealand, in mid-August raised the population to over 300, enabling early-season science projects and preparation for summer. Summer operations began on 30 September and will continue until late February 1998. Although McMurdo's population could peak at 1,200, the weekly average is expected to be nearer 1,000.

Amundsen-Scott South Pole Station at the geographic South Pole summer operations are scheduled to begin on 3 November 1997, preceded by two operational flights on 27 October. Thirty-seven science groups and 12 technical events are planned in physics, earth sciences, aeronomy and astrophysics, and climatology. In early December, the National Science Foundation will begin renovating existing facilities to modernize some and to make others safer for program participants at South Pole. Included in the renovations are the construction of a new garage and shop, fuel storage system, and power plant will be built. During the 1997-1998 season, the site will be prepared and a new arch to house the garage and shop will be erected. The new Atmospheric Research Observatory, completed in January 1997 to replace the old Clean Air Facility, will be dedicated in January 1998. The new observatory provides twice the space of the Clean Air Facility for research on climate, ozone, ultraviolet light, and other atmospheric studies. Winter isolation at South Pole Station will begin on 15 February 1998, when 28 people will remain through November to operate the station and conduct winter experiments.

Palmer Station, on Anvers Island west of the Antarctic Peninsula, will have 17 research and related events. Six more projects will be supported aboard the new R/V Laurence M. Gould, which will replace the now-retired R/V Polar Duke. Palmer Station opened on 15 September with the arrival of the R/V Nathaniel B. Palmer. Seven year-round monitoring projects will remain active when the station closes for the winter, despite the fact that few people stay at the station during the winter months.