Australian National Antarctic Research Expeditions Research Articles

Antarctic iceberg distribution revealed through three decades of systematic ship-based observations in the SCAR International Iceberg Database

AbstractIn 1981, the Scientific Committee on Antarctic Research endorsed a program for ship-based collection of Antarctic iceberg data, to be coordinated by the Norwegian Polar Institute (NPI). From the austral summers 1982/1983 to 1997/1998, icebergs were recorded from most, and up to 2009/10 by fewer research vessels. The NPI database makes up 80% of the SCAR International Iceberg Database presented here, the remainder being Australian National Antarctic Research Expedition observations. The database contains positions of 374 142 icebergs resulting from 34 662 observations. Within these, 298 235 icebergs are classified into different size categories. The ship-based data are particularly useful because they include systematic observations of smaller icebergs not covered by current satellite-based datasets. Here, we assess regional and seasonal variations in iceberg density and total quantities, we identify drift patterns and exit zones from the continent, and we discuss iceberg dissolution rates and calving rates. There are significant differences in the extent of icebergs observed over the 30 plus years of observations, but much of these can be ascribed to differences in observation density and location. In the summer, Antarctic icebergs >10 m in length number ~130 000 of which 1000 are found north of the Southern Ocean boundary.

The effects of body size and climate on post‐weaning survival of elephant seals at Heard Island

AbstractThe population size of southern elephant seals in the southern Indian and Pacific Oceans decreased precipitously between the 1950s and 1990s. To investigate the reasons behind this, we studied the population of southern elephant seals at Heard Island between 1949 and 1954, using data collected by the early Australian National Antarctic Research Expeditions. Seals were marked and measured (lengths) as weaned pups, and resighted at Heard and Marion islands and in the Vestfold Hills, Antarctica in subsequent years. Bayesian state‐space mark‐recapture models were used to determine post‐weaning survival. Yearling survival was consistently lower (ϕy: 0.28–0.40) than sub‐adult survival (ϕs: 0.79–0.83). We found evidence for constant sub‐adult survival and time‐dependent resight probabilities. Weaning length was an important determinate of yearling survival, with the probability of survival increasing with individual length. There was some suggestion that the Southern Annular Mode influenced yearling survival but this evidence was not strong. Nonetheless, our results provide further support showing that size at independence affects yearling survival. Given the known sensitivity of southern elephant seal populations to survival early in life, it is possible that the decline in population size at Heard Island between the 1950s and 1990s like that at Macquarie Island was due to low yearling survival mediated through maternal ability to produce large pups and the dominant environmental conditions mothers experience during pregnancy.

Keith David Cole 1929–2010

Keith Cole grew up in Cairns, attended the local high school, and became the first in his family to attend university. Trained in physics and mathematics, he taught in secondary schools before joining the 1956 Australian National Antarctic Research Expedition to Macquarie Island as Auroral Physicist. This was the start of his lifelong career in space physics, exploring primarily the space environment of the Earth. He had a remarkable ability to identify the important physical processes underlying many phenomena, often when only limited data or observations were available. Thus early in his career he correctly explained several puzzling phenomena, particularly in the ionosphere and thermosphere, and quickly established himself as a leader in space physics, a position he maintained throughout his career. He also made very significant contributions as an educator (he was a Foundation Professor of Physics at La Trobe University) and through leadership positions in national and international science organizations.

Phillip Garth Law 1912 - 2010

Phillip Law is renowned as the first and best-recognized Director of the Australian Antarctic Division, responsible for conduct of the Australian National Antarctic Research Expeditions (ANARE) 1947-66, with the emphasis on science. He established most of the ANARE traditions and oversaw the location and establishment of all Australian Antarctic stations. He was widely recognized and decorated for both national and international influence. His main trait was perseverance in fighting to achieve his goals. In 1966, he became Chief Executive of the Victoria Institute of Colleges to develop, highly successfully, non-university tertiary education in Victoria. Throughout his professional career, he was a prolific diarist, writer and publicist.

Medical memorials in Antarctica: a gazetteer of medical place-names

In Antarctica an astonishing more than 300 'medical' place-names record the lives of surgeons and physicians who have served as leaders, clinicians and scientists in the field of polar medicine and other doctors memorialized for their service to medicine. These enduring medical memorials are to be found in the names of glaciers, mountains, capes and islands of the vast frozen Southern Continent. This Antarctic Medical Gazetteer features, inter alii, doctor-expedition leaders, including Jean-Baptiste Charcot (1867-1936) of France and Desmond Lugg (b. 1938) of Australia. The Medical Gazetteer lists 43 geographical features on Brabant Island that were named after famous doctors. This Gazetteer also includes a collection of medical place-names on the Loubet Coast honouring Dr John Cardell (1896-1966) and nine other pioneers who worked on the prevention of snow blindness and four islands of the Lyall Islands Group, including Surgeon Island, named after United States Antarctic Medical Officers. Eleven geographic features (mountains, islands, nunataks, lakes and more) are named after Australian doctors who have served with the Australian National Antarctic Research Expeditions based at Davis Station. Biographic memorials in Antarctica comprise a collective witness of esteem, honouring in particular those doctors who have served in Antarctica where death and injury remains a constant threat.

DR PHILLIP GARTH LAW AC CBE, 21 April 1912–28 February 2010

Phillip Garth Law c. 1996Source: photograph by Ian Toohill, reproduced with kind permission This redoubtable Australian polar explorer and recipient of the Royal Geographical Society's Founder's Medal (1960) died aged 97. Such was his stature, with no less than 28 expeditions to the Antarctic and its islands, he was frequently referred to as ‘Mr Antarctica’. Born in Tallangatta in rural northeast Victoria the year of Captain Scott's death, Law was educated in the Western District at Hamilton High School. He was an accomplished sportsman and thrived on many outdoor pursuits, including mountaineering. He went on to the University of Melbourne and Melbourne Teachers’ College, graduating with a BSc and MSc in 1939 and 1941 respectively. Law married the artist Nellie (Nel) Allan and joined the RAAF as a trainee Pilot Officer and Navigator in 1941. Later he was appointed to Australia's wartime Optical Munitions Panel and worked in New Guinea advising the Australian Army on perfecting the use of optical instruments under tropical conditions. His polar career began, somewhat unexpectedly, in 1947 whilst lecturing in physics. He was seconded as Senior Scientific Officer to the Australian National Antarctic Research Expeditions (ANARE) voyaging in HMAS Wyatt Earp. The Department of External Affairs established the Australian Antarctic Division (AAD) in 1948 which marked a major turning point in Australian polar affairs. Law was appointed Leader of ANARE and then Director of the AAD in 1949: the year in which he was elected a Fellow of the RGS. Within 10 years, Law had transformed Australia's Antarctic presence and capacity. He chartered the Danish ship Kista Dan and, in so doing, enabled Australia to establish a permanent foothold in Australian Antarctic Territory: a vast, unexplored region claimed by Australia in 1933. His determination ensured three permanent stations were established – Mawson (1954), Davis (1957) and Wilkes (renamed Casey after being handed over by the USA in 1959). Law's attention to detail distinguished him from his peers in many ways. His robust planning and preparation provided the capacity for Australia to initiate and maintain a comprehensive polar research programme. Training, selection, doctrine, policy, protocol, logistics, signals, victualling and more were developed and honed by Phil Law – often leading to vigorous federal government disagreement as he sought additional budgetary funding and support for his country's polar work. He was prepared to take risks. On one of his expeditions, his wife Nel accompanied him and she became the first Australian woman to set foot in Antarctica: this at a time when women were mostly, if not entirely absent. Her paintings remain a striking testimony of her brief time in that great ice-desert wilderness. Law was both a controversial and inspirational figure acknowledged by the likes of Sir Douglas Mawson, Captain John Davis and the Norwegian General, Riser-Larsen. However his name lives on, attached as it is to a number of features including islands, a shore establishment, a peninsula and Law Dome. He resigned as Director of the AAD in 1966 to embark on a second career until his retirement in 1977. This later work (as Vice President of the Victoria Institute of Colleges) served to develop and coordinate tertiary education in his home state of Victoria. He received many accolades, honours and awards during his long life. As stated earlier, he was awarded the Founder's Medal in 1960 (which his superiors prevented him from collecting in person) and honoured that same year by being appointed Patron to the British Schools Exploring Society. The following year Her Majesty recognised Law by creating him a Commander of the Order of the British Empire (Civil). He was awarded his Polar Medal in 1969 and made a Companion of the Order of Australia in 1995. Phillip Garth Law died peacefully on a Sunday afternoon in Melbourne just short of his 98th birthday. His much beloved wife Nel predeceased him. He is survived by his brother Peter and sister Wendy Suart.

SH13 A CENTURY OF POLAR MEDICINE

In 1909, when the heroic period of Polar Exploration was in full swing, parties venturing to the Polar Regions particularly to the Antarctic were totally isolated. Medical knowledge and resources compared to now were basic to say the least. Over and above this communication with the outside world was virtually non‐existent but for the Morse code which was not always entirely reliable.In 1909, when Mawson journeyed to the South Magnetic Pole knowledge of vitamins, antibiotics and vascular infusion techniques, all now commonplace, were in the future. All has now changed and the sheer immensity of the changes in medical knowledge and in communication is the subject of this presentation. The Australian National Antarctic Research Expeditions which evolved from Mawson's pioneering efforts have been at the forefront of these changes. Expeditioners now are safe in the knowledge that help is readily at hand both at their bases and in Australia.

An up‐to‐date quality‐controlled surface mass balance data set for the 90°–180°E Antarctica sector and 1950–2005 period

On the basis of thousands of surface mass balance (SMB) field measurements over the entire Antarctic ice sheet it is currently estimated that more than 2 Gt of ice accumulate each year at the surface of Antarctica. However, these estimates suffer from large uncertainties. Various problems affect Antarctic SMB measurements, in particular, limited or unwarranted spatial and temporal representativeness, measurement inaccuracy, and lack of quality control. We define quality criteria on the basis of (1) an up‐to‐date review and quality rating of the various SMB measurement methods and (2) essential information (location, dates of measurements, time period covered by the SMB values, and primary data sources) related to each SMB data. We apply these criteria to available SMB values from Queen Mary to Victoria lands (90°–180°E Antarctic sector) from the early 1950s to present. This results in a new set of observed SMB values for the 1950–2005 time period with strong reduction in density and coverage but also expectedly reduced inaccuracies and uncertainties compared to other compilations. The quality‐controlled SMB data set also contains new results from recent field campaigns (International Trans‐Antarctic Scientific Expedition (ITASE), Russian Antarctic Expedition (RAE), and Australian National Antarctic Research Expeditions (ANARE) projects) which comply with the defined quality criteria. A comparative evaluation of climate model results against the quality‐controlled updated SMB data set and other widely used ones illustrates that such Antarctic SMB studies are significantly affected by the quality of field SMB values used as reference.

Australian exploration of Heard Island, 1947–1971

In 1947 knowledge of Heard Island was confined to a rough mapping compiled by nineteenth-century sealers, and the results of four scientific expeditions that had briefly investigated the Atlas Cove area. Exploration continued in two distinct periods between 1947 and 1971. In the first period the Australian National Antarctic Research Expeditions (ANARE) built a scientific station at Atlas Cove in 1947, and occupied it continuously until 1955 as an ‘A Class’ meteorological station, a seismic and magnetic observatory, and a base for other scientific studies and for exploration of the island. In the second period four summer expeditions and one wintering expedition worked on the island between 1963 and 1971. The summer expeditions were an ANARE expedition in 1963, an Australian private expedition (The South Indian Ocean Expedition to Heard Island) in 1965, and ANARE expeditions in 1969 and 1971 associated with United States and French expeditions. A United States expedition wintered in 1969. There were no further expeditions until 1980. The years 1947–1971 saw many achievements. Expedition members recorded seven years of synoptic meteorological observations and four years of seismic and magnetic observations. They developed empirical techniques of work, travel, and survival that shaped the collective character of ANARE and were later applied in Antarctica. Despite difficult terrain and consistently bad weather, and the accidental deaths of two men in 1952, unsupported field parties of two or three men travelling on foot explored and mapped in detail the heavily glaciated island, and documented its topography, geology, glaciology and biology. They made three overland circuits of the island, the first ascent of Big Ben (2745 m), and the first recorded landing on the nearby McDonald Islands. Expedition members bred and trained dog teams for later use in Antarctica. They reported the commencement and subsequent progress of massive glacier retreat caused by regional warming, and of the island's colonisation by king penguins (Aptenodytes patagonicus) and antarctic fur seals (Arctocephalus gazella). They also reported measurements of glacier flow and thickness, the palaeomagnetism of Heard Island rocks, behavioural and population studies of southern giant petrels (Macronectes giganteus) and other birds, studies of southern elephant seals (Mirounga leonina) and leopard seals (Hydrurga leptonyx), and the cold stress and acclimatisation experienced by humans working in the island's wet-cold climate. In addition, Heard Island served as a testing ground for men, equipment, scientific programmes, huskies, general administration, and logistics, without which Mawson station could not have been established as successfully as it was in 1954. The American wintering expedition and the French summer expedition contributed to major international geodetic and geophysical investigations. In sum, the expeditions between 1947 and 1971 added much to our knowledge of Heard Island, and they laid down a solid foundation for the work of later expeditions.

Tardigrades of the Australian Antarctic: Hypsibius heardensis (Eutardigrada: Hypsibiidae: dujardini group) a new species from sub-Antarctic Heard Island

A new species, Hypsibius heardensis sp. nov. (Tardigrada: Eutardigrada: Hypsibiidae) is described from samples collected during the Australian National Antarctic Research Expeditions (ANARE) 1986-87 expedition to Heard Island, in the southern Indian Ocean. The new species belongs to the dujardini group and differs from similar species of Hypsibius by the absence of eyes, large apophyses, near equal macroplacoids, lack of a microplacoid, the presence of a small septulum, and cuticular bars near the base of all claws.

Gender differences in leader and follower perceptions of social support in Antarctica

The purpose of this study was to methodologically explore the links among social support, gender, age, prior experience, leader/follower status, and leadership effectiveness noted in previous accounts from Antarctic stations. Data for this study were collected from volunteers involved in Australian National Antarctic Research Expeditions conducted from 1996 to 2001. Multilevel analysis revealed that most of the variance in perceptions of social support was at the individual level (71%). Perceptions of social support had less variance at the group level (29%) and little variance at the weekly level. At the group level, the explanatory variables we examined included leadership effectiveness, gender similarity, and age similarity. At the individual level, the explanatory variables we examined included age, gender, prior experience, and leader/follower status. An interaction between gender and leader/follower status contributed to a significant model of variation in perceptions of social support.

Assessment of contamination by heavy metals and petroleum hydrocarbons at Atlas Cove Station, Heard Island

Located on the northwest coast of Heard Island, a World Heritage-listed sub-Antarctic territory of Australia, Atlas Cove served as the site of the first permanently occupied Australian National Antarctic Research Expedition (ANARE) station (1947–55). Subsequent to its closure, Atlas Cove Station was abandoned and left largely to the mercy of the natural elements, although it has been visited and occupied on an infrequent basis by ANARE. All activities on the island are now subject to the provisions of the Heard Island Wilderness Reserve Management Plan. During 2000–2001 a major clean-up of the site was undertaken, with most of the remaining structures demolished and material collected for return to Australia and disposal. To assess the extent and intensity of contamination within the station area, soil and water samples were collected and analysed for petroleum hydrocarbons and heavy metals. Assessment of site contamination was made with reference to specific background control limits calculated for Atlas Cove Station, and comparison was also made with Australian and New Zealand guidelines for the protection of aquatic and terrestrial ecosystems. Contamination by heavy metals is evident throughout the station but not at levels of sufficient magnitude to infer a significant potential toxic impact on local ecosystems. Hence remedial action to reduce the concentration and mobility of heavy metals in soil and water is not a high priority, although monitoring of changes at the site through time is recommended. Contamination by petroleum hydrocarbons is at a level that may cause a significant toxic impact on the environment and requires further investigation to assess impacts and possibly to undertake remedial action. Given the large quantity of petroleum-contaminated soil present, remediation processes that can be carried out in situ are likely to be the preferable clean-up options. The benefits of remediation, however, must be balanced against any negative effect this might exert on the plant and animal wildlife that have recolonised this historically important site.

The timing of pupping by pack-ice seals in East Antarctica

Data on the timing of pupping by the three species of phocid that breed on the Antarctic pack-ice (crabeater, Ross and leopard seals) are limited. Better information would improve our understanding of these species' population and reproductive ecologies, and could facilitate planning and design of population surveys. Observations of the presence or absence of pups with adults during numerous voyages of the Australian National Antarctic Research Expeditions to East Antarctica during spring and early summer months are analysed and presented. The earliest sighting in any year of a crabeater pup accompanied by an adult was on 2 October and the latest sighting on 15 December. The ratio of crabeater pups to adults increased rapidly during the 10-day period 16–25 October, implying a pulse of births over this time. Ross seal pups with an accompanying adult were sighted between 24 October and 22 November, with a peak in the pup-adult ratio occurring in the period 6–15 November. Leopard seal pups were sighted between 8 November and 25 December, with the pup-adult ratio relatively constant during this period. The data provide circumstantial evidence that the maximum durations of lactation reported in the literature for the three species may be over-estimates. If lactation is shorter than reported, asynchrony in the timing of pupping, either among or within years, is implied.

Ice-flow properties at Dome Summit South, Law Dome, East Antarctica

AbstractIce-flow properties within a polar ice sheet are examined using the comprehensive data gathered from ice-core drilling by Australian National Antarctic Research Expeditions (ANARE) at Dome Summit South (DSS), on Law Dome, East Antarctica. Using the shear strain rates derived from borehole inclination measurements we demonstrate the need to modify the ice-flow relations to treat enhanced shear deformation deep within the ice sheet. We show that the relation between enhanced flow and the measured crystallographic properties is generally in accord with expectations, at least in the upper parts of the ice sheet, but it becomes clear that nearer to the bedrock the situation is more complicated. We also compare the observed shear strain-rate profile with results from a model that describes flow enhancement as a function of the applied stresses.

Distribution of oxygen isotope ratios and snow accumulation rates in Wilhelm II Land, East Antarctica

AbstractRecords of recent oxygen isotope ratios (δ18O) and accumulation rates are presented for the region of Wilhelm II Land, East Antarctica, between 78˚ and 93˚E and from the coast to 2100m elevation. These records were derived from analysis of 21 shallow firn cores collected during the 1997/98 and 1998/99 Australian National Antarctic Research Expeditions summer operations. the accumulation rates were determined using comparisons between detailed analyses of density, δ18O, hydrogen peroxide (H2O2) levels and electrical conductivity. the δ18O distribution follows an approximately linear relationship with snow surface elevation, with values from –22‰ near the coast to –32‰ towards 2000m elevation. Accumulation-rate distribution does not display this simple relationship with topography. South of the West Ice Shelf the contours run parallel to lines of latitude (oblique to the coast and topography), with 400 kg m–2 a–1 towards the coast and 2000m elevation, and a lower zone of 300 kg m–2 a–1 along an axis of 68.4˚ S. This pattern of accumulation is also evident along the Mirny–Vostok traverse route. Southwest of the West Ice Shelf the rate of accumulation drops gradually from 300 to 200 kg m–2 a–1 towards Lambert Glacier basin. Surface-snow redistribution and variations in accumulation rate cause variability in the clarity of core records, but several sites show sufficient stratigraphic preservation to suggest potential for extraction of extended palaeoenvironmental records through further drilling.

Antibody responses to bacteriophage φX-174 in human subjects exposed to the Antarctic winter-over model of spaceflight

Background: It has been proposed that exposure to long-term spaceflight conditions (stress, isolation, sleep disruption, containment, microbial contamination, and solar radiation) or to ground-based models of spaceflight will alter human immune responses, but specific antibody responses have not been fully evaluated. Objective: We sought to determine whether exposure to the 8-month Antarctic winter-over model of spaceflight would alter human antibody responses. Methods: During the 1999 Australian National Antarctic Research Expeditions, 11 adult study subjects at Casey, Antarctica, and 7 control subjects at Macquarie Island, sub-Antarctica, received primary and secondary immunizations with the T cell–dependent neoantigen bacteriophage φX-174. Periodic plasma samples were analyzed for specific antibody function. Results: All of the subjects from Casey, Antarctica, cleared bacteriophage φX-174 normally by 1 week after primary immunization, and all had normal primary and secondary antibody responses, including immunologic memory amplification and switch from IgM to IgG antibody production. One subject showed a high normal pattern, and one subject had a low normal pattern. The control subjects from Macquarie Island also had normal immune responses to bacteriophage φX-174. Conclusions: These data do not support the hypothesis that de novo specific antibody responses of subjects become defective during the conditions of the Antarctic winter-over. Because the Antarctic winter-over model of spaceflight lacks the important factors of microgravity and solar radiation, caution must be used in interpreting these data to anticipate normal antibody responses in long-term spaceflight. (J Allergy Clin Immunol 2001;107:160-4.)

Epstein-Barr virus reactivation associated with diminished cell-mediated immunity in antarctic expeditioners.

Epstein-Barr virus (EBV) reactivation and cell-mediated immune (CMI) responses were followed in 16 Antarctic expeditioners during winter-over isolation at 2 Australian National Antarctic Research Expedition stations. Delayed-type hypersensitivity (DTH) skin testing was used as an indicator of the CMI response, that was evaluated 2 times before winter isolation and 3 times during isolation. At all 5 evaluation times, 8 or more of the 16 subjects had a diminished CMI response. Diminished DTH was observed on every test occasion in 4/16 subjects; only 2/16 subjects exhibited normal DTH responses for all 5 tests. A polymerase chain reaction (PCR) assay was used to detect EBV DNA in saliva specimens collected before, during, and after the winter isolation. EBV DNA was present in 17% (111/642) of the saliva specimens; all 16 subjects shed EBV in their saliva on at least 1 occasion. The probability of EBV shedding increased (P = 0.013) from 6% before or after winter isolation to 13% during the winter period. EBV appeared in saliva during the winter isolation more frequently (P < 0.0005) when DTH response was diminished than when DTH was normal. The findings indicate that the psychosocial, physical, and other stresses associated with working and living in physical isolation during the Antarctic winter result in diminished CMI and an accompanying increased reactivation and shedding of latent viruses.

Space analogue studies in Antarctica

Medical research has been carried out on the Australian National Antarctic Research Expeditions (ANARE) for 50 years. As an extension of this program collaborative Australian/United States research on immunology, microbiology, psychology and remote medicine has produced important data and insight on how humans adapt to the stress of extreme isolation, confinement and the harsh environment of Antarctica. An outstanding analogue for the isolation and confinement of space missions (especially planetary outposts), ANARE has been used as an international research platform by Australia and the United States since 1993. Collaborative research has demonstrated a lowered responsiveness of the immune system under the isolation and confinement of Antarctic winter-over; a reduction of almost 50% in T cell proliferation to mltogen phytohaemogglutinin, as well as changes in latent herpesvirus states and the expansion of the polyclonal latent Epstein-Barr virus infected B cell populations. Although no clinically significant disease has been found to result from these immune changes, research is currently assessing the effects of psychological factors on the immune system. This and associated research performed to date and its relevance to both organisations is discussed, and comment made on possible extensions to the program in both medical and other fields.

Geophysics as centrepiece: its role in the Australian Antarctic Territory

Geophysics, specifically the search for the South Magnetic Pole, was a major justification for voyages of exploration in the mid-19th century and was an important determinant of expeditions in the early days of this century. Geophysics has had a key role in the Australian National Antarctic Research Expeditions (ANARE) since their inception and government of the Antarctic depends on the spirit of scientific cooperation as exercised during the International Geophysical Year of 1957/58. The preamble to the Antarctic Treaty refers to the ‘…cooperation on the basis of freedom of scientific investigation as applied during the International Geophysical Year…’Most current Antarctic research depends on a geophysical foundation. Geophysics is seldom conducted as a discipline in isolation but as contributor to major scientific questions such as definition of cratonic units and boundaries constituting Antarctica, dynamics of intercontinental movement, nuclear test ban monitoring, delineation of continental margin features, substantiating that Antarctica has so few earthquakes and answering the question ‘why?’, and documentation of its few active volcanoes.Antarctic stations conduct observatory programs in seismology (including Nuclear Test Ban Monitoring) and magnetics, and with the advent of refined satellite positioning systems and interest in global change issues, geodesy has been rejuvenated.There is immense scope for expanded field geophysics programs especially in aeromagnetic and gravity surveys both onshore and offshore, and magnetic, gravity and seismic surveys offshore for global change and broader scientific value.Because of the great area, small number of workers, the cost of programs and lack of obvious client group, there are major gaps in our geophysical understanding of the Antarctic, and major questions have yet to be defined and answered.

Antarctic isolation: immune and viral studies.

Stressful environmental conditions are a major determinant of immune reactivity. This effect is pronounced in Australian National Antarctic Research Expedition populations exposed to prolonged periods of isolation in the Antarctic. Alterations of T cell function, including depression of cutaneous delayed-type hypersensitivity responses and a peak 48.9% reduction of T cell proliferation to the mitogen phytohaemagglutinin, were documented during a 9-month period of isolation. T cell dysfunction was mediated by changes within the peripheral blood mononuclear cell compartment, including a paradoxical atypical monocytosis associated with altered production of inflammatory cytokines. There was a striking reduction in the production by peripheral blood mononuclear cells of the predominant pro-inflammatory monokine TNF-alpha and changes were also detected in the production of IL-1, IL-2, IL-6, IL-1ra and IL-10. Prolonged Antarctic isolation is also associated with altered latent herpesvirus homeostasis, including increased herpesvirus shedding and expansion of the polyclonal latent Epstein-Barr virus-infected B cell population. These findings have important long-term health implications.