US Antarctic Program Research Articles

Pilot study and cumulative risk framework to advance long-haul driver health

Commercial drivers are essential to the economic recovery, yet their work exposes them to many health and safety hazards. Research to improve driver health should be designed with an understanding of both the complex occupational environment and the risk management context. We present results of a small pilot study of driver health concerns and behaviors to illustrate concepts and frameworks from human health risk assessment and management that may assist in the design and translation of driver and other worker health research. The pilot study surveyed eighteen long-haul truck drivers at a truck stop using an instrument adapted from the International Physical Activity Questionnaire and a transient community needs assessment developed for the US Antarctic Program Recreation and Wellness Survey. Respondents’ characteristics and health concerns reflect existing literature: mostly male of older age with musculo-skeletal and chronic health conditions. The two most common barriers to physical activity were lack of time and physical limitations. Applying cumulative risk assessment and risk-based decision-making frameworks, we suggest that preventive health management opportunities can be improved for this transient community of workers through actions of employers, truck stop owners and their communities. Considering cumulative risk assessment and risk-based decision making in research design can facilitate holistic research considering co-exposures, risk factors and mitigators across multiple domains of health to inform worker protection.

Enhanced Cardiovascular Risk Assessment in United States Subjects for Deployment to Antarctica

Introduction: Coronary artery disease (CAD) is the leading cause of death in developed nations. Nearly half of asymptomatic CAD cases initially present as acute myocardial infarction (MI) or sudden cardiac death.Therefore, assessment of cardiovascular health is important in subjects who are deployed to remote stations with limited access to medical care, such as Antarctica. Effective screening strategies for detecting CAD and minimizing the risk of acute cardiovascular events in the deployed subjects are essential to mission success. Our study for the first time describes cardiovascular risk assessment in US subjects prior to their deployment to Antarctica. Methods: This report is a single center retrospective analysis of 135 subjects who underwent advanced cardiovascular screening from October 2013 to November 2017 prior to their deployment to Antarctica. Of the 135 subjects, 128 were assessed to be acceptable cardiac risk and were approved for deployment. However, only a total of 100 subjects proceeded for deployment to the South Pole. The deployment periods ranged from 6 to 324 days with a mean of 94.4 days (SD 73.8). All deployed subjects were exposed to the harsh cold climate in Antarctica. Primary outcomes include cardiovascular events such as acute myocardial infarction, unstable angina pectoris, congestive heart failure, cardiac arrhythmias, and sudden cardiac death. Results: None of the 100 subjects had cardiac events reported during their deployment. Conclusions: The current enhanced cardiovascular screening process, prior to deployment to US Antarctic Program stations, appears effective in identifying subjects with low risk of cardiac events.

A detailed radiostratigraphic data set for the central East Antarctic Plateau spanning from the Holocene to the mid-Pleistocene

Abstract. We present an ice-penetrating radar data set which consists of 26 internal reflecting horizons (IRHs) that cover the entire Dome C area of the East Antarctic plateau, the most extensive to date in the region. This data set uses radar surveys collected over the space of 10 years, starting with an airborne international collaboration in 2008 to explore the region, up to the detailed ground-based surveys in support of the Beyond EPICA – Oldest Ice (BE-OI) European Consortium. Through direct correlation with the EPICA-DC ice core, we date 19 IRHs that span the past four glacial cycles, from 10 ka, beginning of the Holocene, to over 350 ka, ranging from 10 % to 83 % of the ice thickness at the EPICA-DC ice core site. We indirectly date and provide stratigraphic information for seven older IRHs using a 1D ice flow inverse model, going back to an estimated 700 ka. Depth and age uncertainties are quantified for all IRHs and provided as part of the data set. The IRH data set presented in this study is available at the US Antarctic Program Data Center (USAP-DC) (https://doi.org/10.15784/601411, Cavitte et al., 2020) and represents a contribution to the SCAR AntArchitecture action group (AntArchitecture, 2017).

Enabling clean access into Subglacial Lake Whillans: development and use of the WISSARD hot water drill system.

Clean hot water drill systems (CHWDSs) are used with clean access protocols for the exploration of subglacial lakes and other subglacial aquatic environments (e.g. ice-shelf cavities) in Antarctica. A CHWDS developed for the Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project by the Science Management Office at the University of Nebraska-Lincoln (UNL-SMO), USA, was specifically designed for use in West Antarctica, where the US Antarctic Program's South Pole Traverse could assist with logistical support. The initial goal was to provide clean access holes through ice up to 1000 m thick following environmental stewardship guidelines; however, the existing design allows this CHWDS to be used for ice thicknesses up to 2000 m following modifications to accommodate longer hose lengths. In January 2013, the WISSARD CHWDS successfully provided for the first time a clean access borehole through 800 m of ice into Subglacial Lake Whillans beneath the West Antarctic Ice Sheet for the deployment of scientific instruments and sampling tools. The development and initial use of the WISSARD CHWDS required the project team to address a number of constraints while providing contingencies to meet the defined project scope, schedule and budget.

Bedrock meltwater channels in Palmer Deep, Antarctic Peninsula

The Antarctic Peninsula inner shelf has been deeply scoured by glacial erosion resulting in numerous deep troughs that funnelled ice flow out across the shelf. Palmer Deep is one of these erosional troughs located at the convergence of three distinct ice accumulation centres: Anvers Island, Bruce Plateau and the Graham Coast (Fig. 1a). A distinctive channelized morphology observed in swath-bathymetric data from the trough-outlet sill reflects a combination of subglacial meltwater scour and underlying structural weakness within the bedrock. The origin of these features can be linked to the development of a subglacial lake basin within Palmer Deep during or prior to the Last Glacial Maximum (LGM), its subsequent drainage and the recession of the Palmer Deep ice-stream system (Domack et al. 2006). Fig. 1. Multibeam bathymetry of Palmer Deep collected during NB Palmer cruises NBP9903 and NBP0107 (US Antarctic Program). Aquisition system Seabeam 2100. Frequency 12 kHz. Grid-cell size 50 m. ( a ) Multibeam image. VE×3. Land area from …

Antarctic Automatic Weather Station Program: 30 Years of Polar Observation

Antarctica boasts one of the world's harshest environments. Since the earliest expeditions, a major challenge has been to characterize the surface meteorology around the continent. In 1980, the University of Wisconsin—Madison (UW-Madison) took over the U.S. Antarctic Program (USAP) Automatic Weather Station (AWS) program. Since then, the UW-Madison AWS network has aided in the understanding of unique Antarctic weather and climate. This paper summarizes the development of the UW-Madison AWS network, issues related to instrumentation and data quality, and some of the ways these observations have and continue to benefit scientific investigations and operational meteorology.

Incidence and Symptoms of High Altitude Illness in South Pole Workers: Antarctic Study of Altitude Physiology (ASAP)

Introduction:Each year, the US Antarctic Program rapidly transports scientists and support personnel from sea level (SL) to the South Pole (SP, 2835 m) providing a unique natural laboratory to quantify the incidence of acute mountain sickness (AMS), patterns of altitude related symptoms and the field effectiveness of acetazolamide in a highly controlled setting. We hypothesized that the combination of rapid ascent (3 hr), accentuated hypobarism (relative to altitude), cold, and immediate exertion would increase altitude illness risk.Methods:Medically screened adults (N = 246, age = 37 ± 11 yr, 30% female, BMI = 26 ± 4 kg/m2) were recruited. All underwent SL and SP physiological evaluation, completed Lake Louise symptom questionnaires (LLSQ, to define AMS), and answered additional symptom related questions (eg, exertional dyspnea, mental status, cough, edema and general health), during the 1st week at altitude. Acetazolamide, while not mandatory, was used by 40% of participants.Results:At SP, the barometric pressure resulted in physiological altitudes that approached 3400 m, while T °C averaged −42, humidity 0.03%. Arterial oxygen saturation averaged 89% ± 3%. Overall, 52% developed LLSQ defined AMS. The most common symptoms reported were exertional dyspnea-(87%), sleeping difficulty-(74%), headache-(66%), fatigue-(65%), and dizziness/lightheadedness-(46%). Symptom severity peaked on days 1–2, yet in >20% exertional dyspnea, fatigue and sleep problems persisted through day 7. AMS incidence was similar between those using acetazolamide and those abstaining (51 vs. 52%, P = 0.87). Those who used acetazolamide tended to be older, have less altitude experience, worse symptoms on previous exposures, and less SP experience.Conclusion:The incidence of AMS at SP tended to be higher than previously reports in other geographic locations at similar altitudes. Thus, the SP constitutes a more intense altitude exposure than might be expected considering physical altitude alone. Many symptoms persist, possibly due to extremely cold, arid conditions and the benefits of acetazolamide appeared negligible, though it may have prevented more severe symptoms in higher risk subjects.

A new family of the Hoplonemertea: Cinclidonemertes mooreae fam., gen. et sp. nov. (Nemertea: Hoplonemertea)

Recent morphological, cladistic and molecular phylogenetic studies suggest a strong relationship between Cratenemertidae and Reptantia. In contrast to other hoplonemerteans, these groups have complex cerebral organs located behind the pre-cerebral septum possessing both sensory and “sac-type” epithelial components in the canal structure and a robust single-layered rhynchocoel wall composed of interwoven circular and longitudinal muscle fibres. Four specimens collected by the US Antarctic Program, listed in an earlier cladistic study as “Antarctic C”, distinct from other Hoplonemertea and related to Cratenemertidae and Reptantia, are described herein as Cinclidonemertes mooreae fam., gen. et sp. nov. They have complex cerebral organs, with the same two types of canal epithelium, lying against the sides of the brain and extending below and behind it ventrally, a lattice-like rhynchocoel wall with partial interweaving, and four large shallow cup-shaped eyes with little pigment as opposed to the numerous heavily pigmented deep-cup ocelli of Cratenemertidae and Reptantia.

Below the Convergence

Below the Convergence

δ 13C and δ 15N shifts in benthic invertebrates exposed to sewage from McMurdo Station, Antarctica

In an effort to identify biomonitors for contamination of Antarctic marine benthos by sewage, this study determines whether the US Antarctic Program’s McMurdo Station produces a benthic sewage footprint and whether resident megafauna are assimilating sewage-derived material. We identified strong C and N isotopic gradients in benthic sediment as a function of downstream distance from McMurdo Station’s point-source sewage addition. Sediment C and N isotope ratios approached marine background levels at the sampling end-point 612 m downcurrent. Based on isotope abundances in their tissues, at least some sewage C and N were assimilated by the sedentary, suspension feeding soft coral Alcyonium antarcticum, ascidian Cnemidocarpa verrucosa and bivalve Laternula elliptica. However, as inferred by tissue-sediment differences in downstream isotope trends, such assimilation was not in proportion to sewage exposure and input, therefore implying non-generalist feeding behavior by these species. In contrast, the motile, generalist feeding sea urchin Sterechinus neumayeri, sea star Odontaster validus and ribbon worm Parborlasia corrugatus showed isotopic evidence of sewage C and N assimilation roughly in proportion to sewage input. We recommend these generalist feeders for further use as biomonitors at this site now that sewage treatment has been implemented. As these species are circumpolar in distribution, they may also prove useful elsewhere in the Antarctic.

An Alien in Antarctica: Reflections upon Forty Years of Exploration and Research on the Frozen Continent

This is an eminent polar scientist's account of six expeditions to the 'frozen continent' while working with the US Antarctic Program. The book combines first-person narrative and outstanding photography to record the events, the feelings, the results, and the memories of conducting research in one of Earth's most remote and hostile environments. This book is not just about science, but about adventures in the pursuit of science.

An operating philosophy for the US Antarctic program

In the early days of Antarctica's exploration, there was scant consideration among expeditioners of human impact on its environment. Today, several national programmes of research in Antarctica have become regular undertakings. The time of the antarctic explorer and adventurer, where rules and sanctions were scant, is past. With their on-site laboratories; arrangements for accommodation; fleets of aircraft, ships, and land vehicles; and requirements for materials influx and removal, these programmes possess the characteristics of ‘big science’. As such they cannot, and do not, conduct their business as in the past. They require an overarching philosophy to guarantee compatibility with Antarctica's unique environment so as to ensure its value to future scientific investigation.