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U.S. Antarctic Program, 1998-1999 ...... iii

Biology and medical research ...... 1

Long-term ecological research...... 14

Environmental research...... 16

Geology and geophysics ...... 17

Glaciology ...... 35

Ocean and climate studies ...... 40

Aeronomy and astrophysics ...... 45

Technical projects...... 56

U.S. Antarctic Program, 1998-1999 iii

U.S. Antarctic Program, 1998-1999

In Antarctica, the U.S. Antarctic Program will · a U.S.–French–Australian collaboration to support 142 research projects during the 1998- study katabatic winds along the coast of 1999 austral summer and the 1999 austral East Antarctica winter at the three U.S. stations (McMurdo, · continued support of the Center for Astro- Amundsen-Scott South Pole, and Palmer), physical Research in Antarctica at the geo- aboard its two research ships (Laurence M. graphic South Pole Gould and Nathaniel B. Palmer) in the Ross Sea and in the Antarctic Peninsula region, at re- · measuring, monitoring, and studying at- mote field camps, and in cooperation with the mospheric trace gases associated with the national antarctic programs of the other Ant- annual depletion of the ozone layer above arctic Treaty nations. Many of the projects Antarctica. that make up the program, which is funded Science teams will also make use of a conti- and managed by the National Science Foun- nent-wide network of automatic weather sta- dation (NSF), are part of the international ef- tions, a network of six automated geophysical fort to understand the Antarctic and its role in observatories, ultraviolet-radiation monitors global processes. NSF also supports research at the three U.S. stations, and a high-altitude, that can be best or only performed in long-duration balloon that will circumnavi- Antarctica. gate the continent and carry instruments for The scientists who will conduct the projects two projects—a study of cosmic microwave described in this book come primarily from background radiation and an optical investi- U. S. universities and have won NSF support gation of the genesis of solar activity. in response to Antarctic Research Program An- Logistics resources to support these research nouncement and Proposal Guide. Operational projects include heavy-lift, ski-equipped C- resources in Antarctica are also used to sup- 130 airplanes operated by the U.S. Navy and port scientists from other Federal agencies. the New York Air National Guard, ski- Highlights of this year's austral summer pro- equipped Twin Otter airplanes chartered gram include: from a Canadian firm, and C-141 and C-5 airplanes provided by the U.S. Air Force be- · continued geological work at Cape Roberts tween New Zealand and McMurdo Station. near McMurdo Station Contract helicopters are headquartered at · long-term ecological research in the McMurdo Station to provide operational and McMurdo Dry Valleys and in the Palmer close science support. Ground vehicles are Station region of the Antarctic Peninsula operated and maintained by an NSF contrac- tor (Antarctic Support Associates), which also · recovery of a 1,000-meter ice core from provides specialized science support and Siple Dome in West Antarctica other services. Annually, a U.S. Coast Guard · interdisciplinary study of atmospheric icebreaker opens a channel to McMurdo Sta- forcing, ocean hydrography, sea-ice dy- tion and provides additional science support. namics, primary productivity, and pe- A tanker and a cargo ship, operated by the lagic-benthic coupling in the southwestern Military Sealift Command, bring fuel, cargo, Ross Sea and equipment each January.

U.S. Antarctic Program, 1998-1999 iii This book, which is intended to keep scien- · Antarctic Journal of the United States review tists and others informed about the U.S. ant- issues, which contain short reports by in- arctic research program, is arranged in scien- vestigators about research recently per- tific discipline order, except for one section formed in Antarctica. These issues are online focused on multi-investigator, multi-discipli- (http://www.nsf.gov/od/opp/antarct/jour- nary long-term ecological research projects nal) and are available in print from the and a short list of technical projects. The or- Office of Polar Programs (dfriscic der reflects the organization of the Antarctic @nsf.gov). Sciences Section of NSF's Office of Polar Pro- grams, which funds projects in biology, medi- · A Library of Congress bibliography covers cal research, ocean sciences, climate studies, the world literature back to 1951. Principal geology and geophysics, glaciology, aero- products are the monthly Current Antarctic nomy, astronomy, and astrophysics. Literature—online at http://www. crrel.usace.army.mil/ library/aware/ ant- Related information products that are pro- lit.htm—and annual Antarctic Bibliogra- duced or funded by NSF include: phy—available from the Government Print- ing Office, Washington, D.C. 20402. Na- · Press releases issued by the Foundation’s tional Information Services Corporation Public Affairs Office to describe specific re- (410-243-0797 or [email protected]) sells a search progress. See the NSF World Wide CD-ROM holding this database and other Web page at http://www.nsf.gov or call polar bibliographies. 703-306-1070.

iv U.S. Antarctic Program, 1998-1999 This graph shows the number of projects (by science program) that the U.S. Antarctic Program will support in Antarctica during 1998- 1999. Tech- nical support includes maintenance and upgrade of such equipment as the UV monitors at Mc- Murdo and Palmer Sta- tions and other projects like ice core drilling at Siple Dome. The table below shows the number of projects by science program and location. The "McMurdo Station and vicinity" count includes projects in the McMurdo Dry Valleys and at Cape Roberts.

Aeronomy & Biology & Geology & Glaciology Ocean & Environ- Technical Astrophysics Medicine Geophys- Climate mental Re- support ics Studies search

McMurdo Station 9 13 13 1 1 1 2 and vicinity McMurdo and 7 1 2 0 0 0 2 South Pole Sta- tions Remote continen- 0 3 12 11 3 0 0 tal sites Palmer and 1 1 0 0 0 0 1 McMurdo Stations McMurdo/Ross 0 5 0 0 6 0 0 Sea region, shipboard Palmer Station/ 1 9 1 0 4 0 0 Peninsula region Peninsula region 0 10 6 0 1 1 0 (ship-board only) South Pole only 14 0 1 0 3 1 1

TOTAL 32 42 35 12 18 3 6

U.S. Antarctic Program, 1998-1999 v Biology and medical research Evidence is strong that the climate of the Ant- Photochemical and optical properties of antarctic Peninsula has changed appreciably in arctic waters in response to changing ultraviolet-B radiation. Kenneth Mopper, Washing- this century. Weather records indicate that ton State University, and David Kieber, State mean summer air temperatures have risen University of New York. The decrease in strato- more than 1°C over the past 45 years at some spheric ozone over the Antarctic results in an peninsula locations. In addition to this warm- increase in the ultraviolet-B (UV-B) flux in the ing trend, springtime ozone depletion events euphotic zone. The increase leads to cellular have resulted in well-documented increases in damage to aquatic organisms, as documented ultraviolet-B (UV-B) radiation levels. These by photoinhibition and decreased productiv- rapid changes in regional climate provide a ity. Cellular damage can occur either intracel- unique opportunity to assess the impacts of lularly or externally at the cell surface from climate change on vascular plants. biomolecular reactions with externally gener- Although the presence of only two native vas- ated reactive transients. The extent of this ex- cular plant species (Deschampsia antarctica and tracellular damage will depend on the photo- Colobanthus quitensis) and their sparse distri- chemistry of the seawater surrounding the bution in Antarctica attest to the severe condi- cell. Until recently, nothing was known about tions for plant survival, there are already indi- the type of photochemical processes, rates, cations that climate changes are exerting a and steady-state concentrations of transients strong influence on these species. Regional in antarctic waters. warming appears to be leading to rapid in- Our field experiments will allow the construc- creases in populations of these species, based tion of predictive models of photochemical on censuses taken along the peninsula. The production rates in surface waters and with influence of enhanced UV-B levels on these depth. These studies will involve further species is less clear. quantum yield measurements, development of An experiment has been initiated in which a sensitive underwater actinometer system, temperature and UV radiation levels are ma- and use of a new underwater multichannel nipulated around naturally growing Des- photometer. The model will allow the predic- champsia and Colobanthus plants on the Ant- tion of the impact of varying levels of UV-B on arctic Peninsula to assess their responses to the photoproduction and steady-state concen- these factors. Assessment involves examining tration of several key reactive transient species changes in photosynthesis, growth, and re- in the upper water column. In addition to this production of these plants following warming effort, experiments will also be performed to or exclusion of different UV components. study the photodegradation of dissolved organic matter and to determine whether bio- During the first two field seasons, growth sig- logically utilizable substrates that are formed nificantly improved under warming treat- photochemically can enhance secondary pro- ments. Although exclusion of UV did not have ductivity in antarctic waters. (BO-002-A and any significant effects over the first field sea- BO-002-B) son, over the second field season, exclusion of UV improved vegetative growth, and it ap- Impacts of climate change on antarctic vascu- pears that levels of UV in Antarctica can re- lar plants: Warming and ultraviolet-B radia- duce leaf elongation as well as leaf production tion. Thomas Day, Arizona State University. in native plants. Field manipulations will be

U.S. Antarctic Program, 1998-1999 1 continued and expanded in the current as- vide us with new insight into the adaptability sessment of plant responses in four key areas: of life. Their biomolecules and metabolism photosynthesis, general thermal adaptations, must be unique and could have great value for reproduction, and soils. These areas are critical molecular engineering research. (BO-004-O) to understanding plant responses to climate change in Antarctica. (BO-003-O) Role of antifreeze proteins in freezing avoidance in antarctic fishes: Ecological and organ- LEXEN: Biology and ecology of South Pole ismal physiology, structure-function and snow microbes. Edward J. Carpenter, State Uni- mechanism, genetics, and evolution. Arthur versity of New York at Stony Brook. Scientists DeVries, University of Illinois. Ongoing and have always assumed that the interior ice new studies of the role of antifreeze glycopep- sheets of the continent of Antarctica are de- tides (AFGPs) and peptides (AFPs) in freezing void of indigenous organisms. Although avoidance of antarctic fishes in five specific plants, protozoa, and bacteria are present at areas constitute this project: the fringes of the continent, the combination of · the relationship of the severity of environ- low temperatures, long periods of darkness, ment and association of ice in fish, and the absence of liquid water makes the interior extremely hostile to life. · the uptake of endogenous ice and its fate,

Recent examination of snow from the South · structure-function of antifreeze proteins Pole, however, indicates the presence of mi- including the molecular mechanism of anti- crobes that contain DNA and photosynthetic freeze proteins adsorption and inhibition of pigments. Snow samples were collected at ice growth, Amundsen–Scott South Pole Station in Janu- · structures and organizations of antifreeze ary 1997 and flown immediately to the Crary protein genes and gene families and their Laboratory at McMurdo Base. Examination of relationship to protein characteristics and snowmelt using epifluorescence microscopy gene evolution, and showed the presence of rod-shaped particles approximately 1´2.5 micrometers in size and a · tissue specificity of AFGP expression. concentration of 130 (standard deviation = 64) The extent of exogenous and endogenous ice cells per milliliter. The particles fluoresced or- will be determined for McMurdo area fishes, ange under blue excitation light and reddish- which experience the coldest and most orange under green excitation, indicating the ice-laden waters of the antarctic region. Simi- presence of phycobiliproteins and chlorophyll. lar experiments will be conducted for the less These fluorescence signatures, combined with severe marine environment of the Antarctic the particles' shape, suggest that they are cya- Peninsula. These studies will correlate freez- nobacteria. Subsequent analysis using fluores- ing extremes with circulating levels of AFGPs cent DNA stains and scanning electron mi- in the fishes associated with these two envi- croscopy confirmed the presence of DNA- ronments. (BO-005-M) containing microbes identical in shape to the autofluorescing particles seen with epifluores- The Polar T3 Syndrome: Metabolic and cog- cent microscopy. nitive manifestations, their hormonal regulation and impact upon performance. H. Lester Further research will confirm whether these Reed, H.M. Jackson Foundation for Military Medi- microbes are indigenous to the antarctic inte- cine. People who live and work in Antarctica rior and will investigate their biology and for longer than 4 to 5 months develop a char- ecology. The discovery of organisms capable acteristic constellation of symptoms and hor- of survival in interior Antarctica would pro- monal changes called the Polar T3 Syndrome.

2 U.S. Antarctic Program, 1998-1999 These people have previously been described tation without disadvantageous effects upon as having a 40 percent increase in energy re- their energy metabolism. Additionally, this quirement; frequent mood disorders; doubling project will expand information regarding the of the production, utilization, and tissue stores ultimate regulation and maintenance of the of the most active thyroid hormone, triiodo- increased T3 production, which is a central thyronine (T3); a decline in central nervous determinant of the Polar T3 Syndrome. (BO- system thyroxine (T4); and acquisition of 008-O) physiologic cold adaptation. Use of a long-term database and molecular Over a 4-year period, we are studying these genetic techniques to examine the behavioral apparent discordant and compartmentalized ecology and dynamics of Weddell seal (Lep- tissue responses using a multidisciplinary ap- tonychotes weddellii) population. Donald B. proach carried out by experienced polar Siniff, University of Minnesota-Twin Cities. The physiologists, endocrinologists, and psycholo- Weddell seal is found in regions of pack ice or gists. We are examining the possible cognitive fast ice close to the antarctic continent. This and metabolic changes in performance from species has been the focus for long-term declines in central nervous system T4 and ele- population studies in McMurdo Sound since vations in skeletal muscle T3 content. We use the mid-1960s. This data set, one of the few of placebo-controlled T4 replacement directed at its kind in the world, has provided valuable the central nervous system deficit and meas- knowledge leading to an understanding of the ure with cognitive instruments. T3 content survival and reproductive patterns of a within the cardiovascular system is evaluated long-lived vertebrate. by using submaximal exercise testing to dif- Using recently developed molecular biology ferentiate resting from activity-mediated en- techniques, we will examine the breeding ergy-use contributions by the skeletal muscles. system and reproductive fitness. By examining Additionally, tissue samples of skeletal muscle the behavioral ecology and mating system provide information regarding the genetic through paternity analysis of breeding males, coding for T3 responsive proteins to help bet- we will be able to estimate reproductive suc- ter characterize the thyroid status of these cess and effective population size in this muscles. Moderate energy restriction is used aquatic breeding species. A second aspect of along with T4 supplementation to study the the study will examine population demo- dependence of T3 production, distribution, graphics (which is a continuation of the an- and tissue stores upon both pituitary genera- nual analyses), parameter estimation, and hy- tion of thyrotropin and energy intake. We pothesis testing associated with the existing compare each subject's baseline in the prede- 30-year database. As part of this second as- ployment situation of California to periods pect, a comprehensive analysis of the popula- and standardized measures obtained during tion dynamics will focus on the role that im- the antarctic summer and winter. migration and emigration play in the popula-

We believe that a correction of the low T4 state tion dynamics. in the central nervous system can be managed As the southernmost breeding mammal in the with T4 supplementation without dramatically world, the Weddell seal exemplifies an ex- changing energy requirements as suggested treme in environmental adaptability. Under- by previous human studies using cold air standing the strategies seals employ in this chamber experiments. If this thesis is correct, environment will contribute to the basic un- then characteristic declines in mood and derstanding of pinniped evolution and popu- memory during winter seasons in circumpolar regions may be attenuated by T4 supplemen-

U.S. Antarctic Program, 1998-1999 3 lation dynamics and competition in marine The role and regulation of chloride cells in mammals. (BO-009-O) antarctic fish. David Petzel, Creighton Univer- sity. Antarctic fish have the highest serum os- New approaches to measuring and under- molality of any seawater teleost. Maintenance standing the effects of ultraviolet radiation of fluid balance is crucial for survival. Upon on photosynthesis by antarctic phytoplank- warm acclimation from -1.5° to 4°C, the fish ton. Patrick Neale, Smithsonian Institution. In- lose 20 percent of their serum osmolality creases in ultraviolet-B radiation (UV-B, through extrusion of sodium chloride (NaCl) 280-320 nanometers) associated with the ant- across the gill. NaCl extrusion in fish is pri- arctic ozone hole have been shown to inhibit marily performed by chloride-secreting cells the photosynthesis of phytoplankton, but the located on the gill arches and gill opercula. overall effect on water column production is The driving force for NaCl transport is the still a matter of debate and continued investi- sodium/potassium-ATPase. To date, no in- gation. Investigations have also revealed that formation is available concerning the role and even at "normal" levels of antarctic strato- regulation of the elevated serum osmolarity in spheric ozone, UV-B and UV-A (320-400 na- antarctic fish. Questions that arise include nometers) appear to have strong effects on these: water column production. The role of UV in the ecology of phytoplankton primary pro- · What role does the chloride cell play in duction has probably been underappreciated mediating salt extrusion? in the past and could be particularly important · Which hormones regulate chloride cell ac- to the estimation of primary production in the tivity? presence of vertical mixing. We will quantify UV effects on photosynthesis of antarctic We will compare the chloride cell physiology phytoplankton by defining biological weight- and regulation in antarctic fish with a New ing functions for UV-inhibition. Zealand fish that is eurythermal. We hope to determine the plasticity of antarctic and New We will use new theoretical and experimental Zealand fish gill function at the physiological approaches to investigate UV responses in level (through studies of ion transport activity) both the open waters of the Weddell-Scotia and molecular level (through studies of the confluence and coastal waters near Palmer sodium/potassium-ATPase enzyme). Specifi- Station. In particular, we will measure the ki- cally, this research will netics of UV inhibition and recovery on timescales ranging from minutes to days. Variabil- · determine the gill extrusion mechanisms ity in biological weighting functions will be underlying the increase in gill calculated for pelagic and coastal phyto- sodium/potassium-ATPase activity upon plankton in the Southern Ocean. Our results warm acclimation in antarctic fish and will · determine the hormonal regulation of the · provide absolute estimates of photosynthe- gill extrusion mechanisms. sis under in situ, as well as under altered, The results of our research will, for the first UV irradiance; time, describe in detail the underlying mecha- · broaden the range of assemblages for which nism(s) mediating the enhanced hypo- biological weighting functions have been osmoregulation observed in antarctic fish and determined; and will allow the comparison of these results to those observed in a eurythermal New Zealand · clarify how kinetics of inhibition and recov- fish. (BO-012-O) ery should be represented in mixed-layer models. (BO-010-O) 4 U.S. Antarctic Program, 1998-1999 Weddell seal foraging: Behavioral and ener- · data are available on their diving ability, getic strategies for hunting beneath the antarctic fast ice. Randall Davis, Texas A&M Uni- · the isolated-ice-hole protocol in McMurdo versity at Galveston. To forage efficiently be- Sound enables recorders to be attached and neath the extensive, unbroken fast ice along recovered reliably, and the antarctic coast, Weddell seals (Leptonycho- · they make daily foraging dives when tes weddellii) have adapted to an environment placed in the isolated ice hole. (BO-017-O) that is very challenging for an air-breathing predator. These adaptations enable Weddell Impacts of increased solar ultraviolet-B ra- seals to hunt for prey at depth while holding diation on antarctic marine heterotrophs. H. their breath for 20 minutes or longer. This feat William Detrich, III, and Kirk D. Malloy, North- is analogous to a lion or other large terrestrial eastern University. Recent decreases in strato- predator holding its breath while it locates, spheric ozone have resulted in dramatic in- pursues, and captures prey. In addition, Wed- creases in the flux of mid-ultraviolet light dell seals must return to the same hole at the (UVB) reaching the Earth's surface, especially end of a dive or know the location of other over Antarctica but, to a lesser extent, in tem- breathing holes. Failure to locate a breathing perate zones. Ozone depletion is expected to hole will result in a seal's death by drowning. continue well into the next century and to worsen at lower latitudes over time. Recent We will investigate the behavioral and ener- evidence suggests that present intensities of getic adaptations that enable Weddell seals to UVB are sufficient to produce significant im- forage in the antarctic fast-ice environment. To pacts on phytoplankton communities in the achieve this goal, we will measure the under- Southern Ocean, as well as to negatively affect water behavior, locomotor performance tropical marine communities and populations (swimming velocity, stroke frequency and of temperate amphibians. The abbreviated amplitude, and three-dimensional move- trophic structure of the antarctic marine eco- ments), and energy metabolism of Weddell system places an increased importance on seals during foraging dives. We will test hy- primary and secondary consumers, especially potheses on general foraging strategies, on many species of zooplankton, which form a searching behavior, searching mechanics, critical link between primary production and modes of swimming, metabolic costs of for- top predators such as adult fish, marine aging, and foraging efficiency for different en- mammals, and birds. Although these zoo- vironmental conditions and prey type. Until plankton species and other heterotrophs, now, it has not been possible to investigate the which include larval and adult fish, krill, and foraging behavior of marine mammals in de- copepods, are important components of the tail. To accomplish this study, we will attach a trophic structure in the antarctic ecosystem, small video system and data logger to the researchers have no information regarding the seals' backs and measure oxygen consumption effects of increased UVB on natural popula- during voluntary dives from an isolated ice tions of these organisms. Laboratory and field hole in McMurdo Sound, Antarctica. studies on nonpolar species suggest, however, that the impact of increased UV on antarctic Observing the foraging behavior and heterotrophs, and therefore on the antarctic prey of marine mammals has been and con- ecosystem, could be substantial. tinues to be a major obstacle to the advance- ment of studies on their foraging ecology. The Using established methods, we will Weddell seal may be the single best species in · measure the vulnerability of antarctic zoo- which to study the foraging behavior and en- plankton to UVB damage in the field and in ergetics of deep-diving pinnipeds because the laboratory, U.S. Antarctic Program, 1998-1999 5 · measure DNA repair rates of antarctic het- · effects of climate change, mediated through erotrophs at ambient temperatures (-2°C to changes in sea-ice cover, on penguin +4°C), and populations. · determine the relationship between UVB In addition, results will provide a context in exposure and decreases in organismal fit- which to interpret conflicting data on penguin ness (measured as RNA-to-DNA ratios and population trends from existing programs that transcription rates). use Adélie penguins as an indicator species for point-source anthropogenic impact on antarc- The field component of this research is a tic resources (e.g., fishery catches, disturbance unique effort to determine the in situ vulner- by tourism). ability of natural populations of antarctic heterotrophs during normal and depleted ozone Our 5 years of research (3 full years funded by conditions. These studies are critical for de- the National Science Foundation) include in- veloping predictive models of the relative im- tensive field study conducted at three Ross pact of increased UVB on antarctic marine Island penguin colonies. We quantify repro- heterotrophs and for relating ozone depletion ductive effort and success, food availability on decreased fitness, survival, and population (access to food), diet quality, habitat use, and dynamics of these species. (BO-029-O) immigration/emigration relative to colony size and environmental conditions (i.e., Factors regulating population size and col- pack-ice cover). Methods will bring together ony distribution of Adélie penguins in the several well-established techniques that have Ross Sea. David G. Ainley, H.T. Harvey and As- been successfully but infrequently used in sociates. In this collaborative project, we will antarctic biological research: investigate the demographic mechanisms responsible for dramatic growth in existing · aerial photography to evaluate availability Adélie penguins (Pygoscelis adeliae) colonies of nesting habitat, over the past few decades. We will also inves- · microwave images of sea-ice concentration tigate the possibility that growth is related to to assess availability of feeding habitat, documented climate change in the region by · analysis of stable isotopes to evaluate food · distinguishing the relative importance of quality, the key resources that constrain growth of colonies (availability of nesting habitat ver- · radio telemetry to assess overlap in colony sus access to food) and feeding areas, and · examining behavioral and demographic · automatic systems to log aspects of repro- mechanisms (philopatry— the immigration ductive effort. /emigration balance, and/or breeding effort/success) that influence colony Our research builds on, and collaborates with, growth as a function of initial size and the efforts of Landcare Research New Zealand distribution. (LCRNZ), which has conducted two preliminary field seasons, including testing of new This will be the first empirical study to con- equipment, and will continue their effort and sider the geographic structuring of a seabird collaborate with us throughout the lifetime of population. Results will increase understand- the project. The LCRNZ work is independ- ing of ently funded. Researchers from the University of California Santa Cruz, the University of · population regulation and patterns of dis- Wisconsin, and Beigel Technology, will col- persion and laborate with those from H.T. Harvey and As-

6 U.S. Antarctic Program, 1998-1999 sociates and LCRNZ to accomplish project Structure, function, and expression of goals. (BO-031-O) cold-adapted tubulins and microtubule- dependent motors from antarctic fishes. H. Evolution of an oxygen-binding hemoprotein William Detrich, III, Northeastern University. in a unique environment: Myoglobin in the Microtubules, which are subcellular "pipelike" hemoglobinless antarctic icefishes. Bruce D. filaments composed of the protein tubulin, Sidell, University of Maine at Orono. For ap- and their associated motors, dynein and proximately the last 40 million years, a unique kinesin, participate in many fundamental fish fauna has been evolving in the frigid seas cellular processes, including cell division, surrounding Antarctica. Physiological func- nerve growth and regeneration, cell motility, tion of these water-breathing animals has de- and the organization and transport of manded many adaptations to ensure proper organelles within cells. In these processes, mi- metabolism and regulation of biochemical crotubules serve as rigid "railroad tracks" for processes at cell temperatures of about 0°C. the movement of motors and their cargoes Among the polar fishes, one family is particu- ("trains"), and the motors themselves are effi- larly unusual: the Channichthyid icefishes. cient, high-velocity, regulative "locomotives." Species in this family lack hemoglobin in their The microtubules and microtubule motors of circulating blood and, at least the majority, do cold-adapted antarctic fishes are unique in not possess the intracellular respiratory pro- their capacity to assemble and function at tein, myoglobin, that is normally responsible body temperatures (-2°C to +2°C) well below for enhancing movement of oxygen through those of warm-blooded and temperate organ- aerobic muscle tissues. Recently, however, two isms. species of icefish that express myoglobin, Pseudochaenichthys georgianus and Chionodraco The long-range goal of our project is to deter- rastrospinosus, have been found, but these spe- mine, at the molecular level, the adaptations cies express myoglobin in only one tissue— that enhance the assembly of microtubules, heart ventricle. The metabolism of all icefish the expression of tubulin genes, and the activ- species is highly aerobic and is based largely ity of microtubule motors from antarctic fishes on the combustion of fatty fuels as energy in this extreme thermal regime. Our objectives sources. are

Our fieldwork will consist of a combination of · to determine the structural features (e.g., shipboard trawling to capture icefish species changes in their amino acid sequences) that and laboratory work at Palmer Station using enable the tubulins of antarctic fishes to tissues from these animals. At Palmer Station, polymerize efficiently at low temperatures; we will conduct experiments and prepare pu- · to characterize the structure, organization, rified, fixed, and/or frozen material for ship- and expression of an alpha-tubulin gene ment back to the United States for further cluster from an antarctic rockcod, Notothe- analyses. The overall goals of this project are nia coriiceps; and · to determine whether myoglobin protein · to examine the biochemical adaptations remains physiologically significant at the required for efficient function of antarctic cold body temperatures of antarctic fishes, fish flagellar dynein motors at low tem- · to reconstruct the evolution of the myoglo- peratures. bin gene within the icefish family, and We will determine molecular adaptations of · to identify the mechanisms controlling ex- the antarctic fish tubulins by comparing the pression of myoglobin within icefish and amino acid sequences of alpha- and related species. (BO-036-O) beta-tubulins from N. coriiceps, to those from U.S. Antarctic Program, 1998-1999 7 its temperate relative, the New Zealand black The Pygoscelis species, the major predators of cod, Notothenia angustata. We will analyze krill (Euphausia superba) in the Antarctic Penin- gene expression in N. coriiceps by defining the sula region, are key species used to monitor organization and transcription-regulating the potential impacts of fishery activities in elements of an alpha-tubulin gene cluster. In this area. To understand the structure and the broadest sense, this research should ad- function of the antarctic marine ecosystem vance the molecular understanding of the thoroughly, it is imperative to determine the cold-adapted mode of life. (BO-037) impact of environmental variation on the structure and regulation of upper trophic level Penguin-krill-ice interactions: The impact of predators such as the Pygoscelis penguins. environmental variability on penguin de- (BO-040-O) mography. Wayne Trivelpiece, Montana State University. We will study populations of Adé- Shell morphogenesis in giant agglutinated lie, gentoo, and chinstrap penguins at Admi- foraminifera. Samuel S. Bowser and Charles R. ralty Bay, King George Island. These popula- Hauer, Health Research, Inc. A dominant mem- tions have exhibited fluctuations in abundance ber of cold, deep-sea sediments ecosystem is a that have been related to long-term changes in group of giant protozoa, the aggulatinated environmental conditions, in particular sea-ice foraminifera, also known as forams. For pro- coverage and its possible effects on prey (krill) tection, these single-celled organisms encase availability. themselves in architecturally elegant shells that they construct by collecting, sorting, and We will test the following five hypotheses re- cementing together sediment grains. The lating penguin demography to environmental unique occurrence of these giant cells (greater variability via its effect on krill recruitment in than 1 millimeter in size) in the shallow waters the antarctic marine ecosystem. of McMurdo Sound, Antarctica, allows for the · Krill population structure is strongly af- study of the cellular and molecular aspects of fected by pack ice extent through its impact shell constructions. on female fecundity and larval survival. In our project, we will use novel light-micro- · Recruitment of penguins to their respective scopic methods to examine how agglutinated populations is affected by the extent of forams secrete and sculpt the adhesive matrix pack-ice cover during the winter prior to that binds sediment particulate in their shells. the breeding season. Comparative time-lapse photography of dif- · The survival of penguin fledglings is cor- ferent foram species constructing shells will related to the extent of pack ice cover the identify key steps in the processes that lead to the various shell morphologies. Peptide se- winter following the breeding season. quence analyses of the elastic proteins of the · Adélie penguins return to the pack-ice shells will provide valuable insight into the habitat during their first 2-week-long for- chemical nature of foram bioadhesives. From a aging trips following clutch competition to practical standpoint, these cements have im- recover from the prolonged fasting of the portant biotechnological and medical applica- courtship period. tions.

· Accessible pack ice in the early breeding We will also continue a study of the effects of season has led to the evolution of discrete collection activities, as well as natural physical population centers of Adélies from the Bel- disturbances, in this unique environment. The lingshausen, Weddell, and Ross Sea popu- interdisciplinary research conducted for this lations. project has implications in a number of fields,

8 U.S. Antarctic Program, 1998-1999 including cellular development, evolution, Influence of seasonal ice cover on pelagic paleontology, marine products chemistry, and and benthic communities: Long time-series ecosystem management. (BO-043-O) studies. Kenneth L. Smith, Scripps Institution of Oceanography. The annual expansion and con- LEXEN: Microbial life within the extreme traction of ice cover in the Southern Ocean— environment posed by permanent antarctic the largest seasonal process in the world lake ice. Christian H. Fritsen, Edward E. Adams, ocean—cause primary production to fluctuate James A. Raymond, John C. Priscu, and Christo- extensively and to affect strongly the pelagic pher P. McKay, Montana State University. The 3- and benthic communities. We will initiate a to 20-meter-thick permanent ice covers on long time-series study of the water column lakes in the McMurdo Dry Valleys, Antarctica, and seafloor using long-term, autonomous contain viable microbial cells in association monitoring and sampling systems developed with sediment aggregates. These aggregates for use in the Antarctic. Our study will be lo- are now recognized as sites where physical, cated in Post Foster, Deception Island, which chemical, and biological interactions promote supports a pelagic and benthic fauna repre- microbial growth under extreme conditions sentative of the antarctic coastal zone and ex- inherent to the ice environment. periences seasonal ice cover.

In this interdisciplinary research program, we We will deploy a bottom-moored, up- will define specific processes that allow ward-looking acoustic instrument on the sea- · the creation of liquid water (the essential floor for 1 year to monitor the vertical distri- element for life) in the permanent ice, bution, abundance, and biomass of acousti- cally detectable macrozooplankton and mi- · the survival and structuring of microbial cronekton in the water column. Collections populations subjected to freezing and will be made over this period using newly de- thawing, veloped, vertically profiling pump sampling. · the production of substances that alter the Simultaneously, a time-lapse camera system physical attributes of the ice-crystal habitat, will be moored on the seafloor to monitor the and spatial distribution, sizes, and movements of the epibenthic megafauna component of the · the nutrient supply to the microbial popu- benthic community. The instrumentation de- lations, which is essential not only for sur- velopment will allow us to focus on the effect vival but also for net microbial growth and of the seasonal sea-ice cycle on the distribu- biomass accumulation. tion, abundance, and biomass of the macro- We will study ice aggregates embedded in the zooplankton and micronekton in the water permanent ice covers on the lakes in the Tay- column. Similar questions on the distribution, lor Valley, which have been tentatively char- abundance, size, and movements of the acterized in previous studies. epibenthic megafauna will be addressed. Re- sults from this study will provide a valuable Research on microbes in permanent ice pro- database for the evaluation of the pelagic and vides information on the ecology of microbes benthic community responses to seasonal in ice ecosystems and promises to have bio- variability in the Southern Ocean. (BO-050-O) technological implications. Furthermore, these studies will provide insights into the condi- Adaptations of organisms at the sulfide- and tions that support or have supported life be- methane-containing hydrothermal areas of yond our own planet in association with water Deception Island, Antarctica. Horst Felbeck, ice, which has been detected within and be- Scripps Institution of Oceanography. Deception yond our own solar system. (BO-044-O) Island is a flooded caldera in the South Shet-

U.S. Antarctic Program, 1998-1999 9 land Islands, Antarctica. The most recent for the benthic nearshore habitat in the Ross eruption, in the 1970s, caused the formation of Sea region of Antarctica. These baselines will new islands in the caldera and various other be useful in distinguishing between natural structures. Deception Island harbors many hot environmental variability from anthropogenic springs and fumaroles submerged in the cal- impacts and in assessing the recovery capacity dera and intertidally. Sulfide and methane are of coastal marine populations that have been prominent chemicals in the outflowing waters. exposed to natural and anthropogenic stresses. Bacterial densities in the caldera reach unusually high values probably due to the input of Our study, which will take place in Terra reduced chemicals as energy sources. The en- Nova Bay, will be conducted in cooperation vironment around the springs resembles that with the Italian Antarctic Program. We will found at hydrothermal vents where whole study populations of the scallop Adamussium communities are based on the input of chemi- colbecki from a natural-impact site (meltwater cal energy by the hot waters. Similarities to stream), an anthropogenic-impact site (near hydrothermal vent environments include cold Terra Nova Bay Station in Tethys Bay), and a waters surrounding the hot springs resulting control site (no meltwater stream in a pristine in large distances to the next warm-water area of Tethys Bay). Integration of biochemi- habitat and a lack of external food sources. cal, physiological, and population assays will The latter is due to ice cover during winter at provide examples of biological baselines for Deception Island and the large distance to the assessing indicator species' responses to natu- euphotic zone at the vent sites. These pa- ral and anthropogenic impacts in the antarctic rameters encourage the evolution of alterna- coastal zone. (BO-086-O) tive ways to support life such as the estab- Ultraviolet-radiation-induced DNA damage lishment of a bacterial symbiosis. in bacterioplankton in the Southern Ocean. Wade H. Jeffrey, University of West Florida. In this project, we will examine the warm Strong evidence now shows that ultraviolet springs around Deception Island for the pres- (UV) radiation is increasing over certain loca- ence of marine invertebrates with chemoauto- tions in Antarctica and the Southern Ocean as trophic symbionts. We will map any sub- a result of ozone depletion. A reduction in merged fumaroles as well as warm and hot ozone concentration selectively limits strato- springs in the intertidal zone. If animals are spheric adsorption of UV radiation and results found near the fumaroles or in the hot springs, in a higher UV irradiance reaching the Earth's we will collect specimens and examine them surface. Although research on the impact of for the presence of chemoautotrophic bacteria increased UV radiation due to ozone depletion and other adaptations to a hot sulfide- and has focused primarily on phytoplankton, a methane-rich environment using enzyme test much smaller effort is being directed to other experimental incubations to analyze metabolic trophic levels. pathways and microscopic examination. (BO- 085-O) During this collaborative project, we will address UV-radiation-induced damage and UV- Biological baselines and responses for assessing environmental impacts in antarctic radiation effects on bacterioplankton. We will coastal areas. Paul Berkman, Ohio State Univer- examine interactions between bacterioplank- sity. Antarctic coastal environments have been ton and photochemical processes and interac- the site of recent studies on the effects of hu- tions with higher trophic groups such as man activities on marine ecosystems. This in- phytoplankton and zooplankton. We will ad- ternational, collaborative study will develop dress these topics: methodologies to generate biological baselines

10 U.S. Antarctic Program, 1998-1999 · whether bacterial-phytoplankton coupling than 100 micrometers) in ocean water, sea- modifies bacterial response to UV radiation, ice, and sediment environments and · how seasonal changes in UV radiation af- · to obtain baseline physiological information fect bacterial community dynamics, and on the growth rates, feeding rates, and growth efficiencies of cultured protozoa · how chemical photoproducts affect bacte- under pertinent temperature regimes. rial production. As part of our molecular biological studies, we We will elucidate the molecular determinants will examine small subunit ribosomal RNA responsible for changes in productivity and gene (srDNA) diversity. Approaches and the molecular and physiological responses to techniques developed will be applicable to changing UV radiation. The overall goal is to any other water body or sediment and would provide a greater understanding of the poten- provide a means to examine the representa- tial impact that changes in UV radiation have tiveness of protistan cultures in extant culture on marine microbial communities. (BO-200-O) collections. (BO-207-O) LEXEN: Protistan biodiversity in antarctic The role of oceanographic features and prey marine ecosystems: Molecular biological and distribution on foraging energetics and re- traditional approaches. David A. Caron and productive success. Daniel Costa, University of Rebecca J. Gast, Woods Hole Oceanographic Insti- California at Santa Cruz. Marine coastal and tution. The analysis of microbial biodiversity pelagic environments of the Southern Ocean of extreme environments is difficult because are characterized by seasonal high productiv- traditional methods for examining diversity ity. Over the last several decades, it has be- are often ineffective for assessing species rich- come clear that these environments, although ness within these communities. Additional generally productive, also undergo consider- obstacles arise because of the difficulties of able inter- and intra-annual variability. Con- recreating and maintaining pertinent envi- sequently, available prey resources for verte- ronmental features during sample collection brate predators can be highly variable spa- and procession. tially and temporally. We will study the protistan assemblages (al- This spatial and temporal variability of prey gae and protozoa) in the sea-ice, sediment, resources has been measured empirically for and ocean environments of the Ross Sea, Ant- the northern South Shetland Islands region of arctica. The identification of protistan species the Antarctic Peninsula since the late 1980s. in natural assemblages traditionally has en- The antarctic fur seal, a subpolar migratory tailed direct microscopical analyses as well as otariid with a short lactation period, is an in- enrichment and culture techniques for assess- creasingly dominant marine predator of the ing biodiversity. Determining diversity for South Shetlands region. Its life-history pattern these assemblages is, therefore, susceptible to is characterized by foraging trips alternating biases as a consequence of sampling, enrich- with short visits to provide for a single off- ment, and culture, as well as selective losses spring; this pattern allows scientists to meas- due to sample preservation and concentration ure maternal investment on the same temporal for microscopy. and spatial scale as measurements of distribu- Our goals are tion and abundance of prey. · to develop and apply molecular biological In our project, we will quantify the foraging approaches to assess species diversity of costs and maternal investment associated with small protists (algae and protozoa smaller changes in strategies observed in populations

U.S. Antarctic Program, 1998-1999 11 of South Shetland antarctic fur seals. Using flagellates in the genus Alexandrium, has been state-of-the-art techniques, we will determine introduced to antarctic waters, possibly by energetic costs and benefits of different for- vessel traffic between South America and the aging patterns while simultaneously measur- Antarctic Peninsula. This mechanism of spe- ing energy expenditure, food intake, dive cies dispersal has been implicated in the sud- depth, dive duration, time of day, and dive den appearance of toxic algae in other areas of frequency, swim speed, and foraging location. the world. Short and frequent transport path- These measurements will coincide with small- ways do exist between Antarctica and the and large-scale oceanographic surveys to be high-toxicity waters of southern Chile and Ar- conducted by the National Oceanic and At- gentina. It is also possible that the saxitoxin- mospheric Administration's Antarctic Marine producing organism is indigenous to Antarc- Living Resources program, which is also con- tica and was only recently noticed. In either tributing to the support of this project. The case, the implications to the antarctic food web research will allow scientists to link biological are significant. characteristics (prey composition, distribution, and abundance) and physical characteristics of The objectives of our project are to identify the foraging environment with foraging suc- and characterize the possible source(s) of cess, maternal investment, and reproductive saxitoxins in Antarctica to determine whether success for a free-ranging marine vertebrate the causative organisms are indigenous or in- predator. (BO-267-O) troduced species, and if introduced, to identify the probable origin and transport pathway. Characterization of indigenous and intro- (BO-300-O) duced toxic phytoplankton in Antarctica. Donald Anderson, Woods Hole Oceanographic 1998–1999 McMurdo Station biology course. Institution. Of the thousands of species of ma- Donal Manahan, University of Southern Califor- rine phytoplankton, only a few produce po- nia. This international, advanced-level, gradu- tent toxins. These species are found in the ate training course will be organized and massive "red tides" or blooms of cells that dis- taught in Antarctica for 1 month during aus- color the water. More commonly, the organ- tral summer 1998–1999. The course will intro- isms are present at low concentrations and are duce students to the diversity of biological or- noticed only by the effects their toxins have on ganisms in antarctic regions and allow them to aquatic organisms and humans. The nature of study unique aspects of biology that permit the toxic phytoplankton problem has changed life in such extreme environments. Long- considerably in recent years: many areas that standing questions in evolution and ecology were previously unaffected are now subject to (such as cold adaptation and food limitation) recurrent outbreaks. Therefore, it is alarming concerning the biology of antarctic organisms that marine algal toxins (saxitoxins) have been will be examined through physiological found in antarctic mollusks. experiments with organisms, studies of isolated cells and tissues, experiments on The implications of this discovery are pro- protein structure and function, and molecular found given the low number of trophic levels analysis of genetics systems. Lectures will em- between primary producers and top predators phasize physiological, biochemical, and mo- and the proven ability of the saxitoxins to alter lecular biological approaches to understand- the food web structure and dynamics. Saxi- ing the ecology and biological adaptations of toxins can affect zooplankton, fish larvae, antarctic organisms. Student research projects whales, porpoises, seabirds, and humans. Re- will follow these interwoven themes. The stu- searchers are concerned that the saxi- dents will gain a rigorous understanding of toxin-producing alga, presumably the dino- the power, but also the limitations, of physio-

12 U.S. Antarctic Program, 1998-1999 logical, biochemical, and molecular biological of water samples to assess viral infections and methods that are currently being used to an- viral populations in a variety of pack-ice swer research questions in environmental sci- communities from the Ross Sea. Our objec- ence and biological adaptation. tives are

The course will be held in the Crary Science · to determine the extent of the occurrence of and Engineering Center at McMurdo Station, viruses within cells of algae and protozoans Antarctica. This modern research facility pro- in ice communities and to estimate the per- vides state-of-the-art laboratory facilities a centage of infected cells, short distance from the marine and freshwater · to relate the extent of the occurrence of vi- environments where biological observations ruses within cells to the stages of succession and collections of material will be made. The of sea-ice communities, course will be taught as four modules: · to assess the potential for ice communities · Biological diversity of antarctic organisms: to seed viruses to the pelagial, Evolution and molecular phylogeny; · to determine the extent of ingestion of vi- · Ultraviolet radiation: Effects on antarctic ruslike particles by sea-ice protozooplank- organisms; ton, · Invertebrates: Physiology, energy metabo- · to compare these features of ice communi- lism, and development; and ties to those of phytoplankton and proto- · Fish: Biochemical adaptations. zooplankton assemblages in the seawater directly under the ice, and By attracting an extremely competitive group of young scientists, this course will introduce · to describe and quantify the size structure new researchers to Antarctica and will teach of the free viruslike particles in the intersti- students to use modern research methods to tial water of ice communities and in the study the mechanisms that are unique to biol- seawater directly under the ice. ogy in Antarctica. (BO-301-O). Our study will contribute to the understand- Viruses in pack-ice communities of the Ross ing of sea-ice community ecology and will al- Sea, Antarctica. Marcia M. Gowing, University low us to incorporate viruses of eukaryotic of California at Santa Cruz. Primary productiv- algae and protozoans into models of carbon ity of sea-ice algal communities in the South- flow for the Antarctic. (BX-039-O) ern Ocean is significant. In lower latitudes, Ecological studies of sea-ice communities in processes such as grazing and destruction by the Ross Sea, Antarctica. Marcia M. Gowing, viruses are thought to control algal popula- University of California at Santa Cruz. Sea ice tions, but science has little data on grazing forms an extensive habitat in the Southern within ice communities and no data on viruses Ocean. Reports dating from the earliest explo- of ice algae. Ice communities should be excel- rations of Antarctica have described high con- lent sites for studying viral control of popula- centrations of algae associated with sea-ice, tions of eukaryotic algae and protozoans be- suggesting that the ice must be an important cause populations are extremely dense and site of production and biological activity. The many habitats are nearly closed for parts of magnitude and importance of ice-based pro- the year. duction are difficult to estimate largely be- We will use transmission electron microscopy cause the spatial and temporal distributions of (TEM) of individual eukaryotic algal and ice communities have been examined in only a protozoan cells and light microscopy and TEM few regions, and the processes controlling

U.S. Antarctic Program, 1998-1999 13 production and community development in · populations within "snow-ice" layers to ice are still only superficially understood. determine if there is a seed population es- We will examine sea-ice communities in the tablished at the time of surface flooding; Ross Sea region of Antarctica in conjunction · to sample summer communities to deter- with studies of ice physics and remote sens- mine the extent that highly productive ing. The specific objectives of our study are "snow-ice" and "freeboard" communities · to relate the overall distribution of ice develop in the deep-water regions of the communities in the Ross Sea to specific Ross Sea: habitats that are formed as the result of ice · to collect basic data on the biota, activity, formation and growth processes; and general physical and chemical charac- · to study the initial formation of sea ice to teristics of the ice assemblages, so that this document the incorporation and survival of study contributes to the general understanding of the ecology of the ice biota in organisms, in particular to examine winter pack ice regions. (BX-325-O)

Long-term ecological research structure and function of dry valley ecosys- McMurdo Dry Valleys: A cold desert ecosystem. W. Berry Lyons, University of Alabama at tems. These objectives will be accomplished Tuscaloosa. The McMurdo Dry Valleys, located through a program of systematic environ- on the western coast of McMurdo Sound, form mental data collection, long-term experiments, the largest ice-free area in Antarctica. In 1993, and model development. In addition, LTER this area was selected as a study site in the researchers will study dry valley lakes as National Science Foundation's Long-Term analogs for past Martian environments. The Ecological Research (LTER) program. The dry objectives of this aspect of the project are valleys are among the most extreme deserts in · to define the biogeochemical processes re- the world, far colder and drier than any of the sponsible for controlling the isotopic car- other LTER sites. The biological systems in the bon-13 signature in present-day antarctic McMurdo Dry Valleys are composed of only lake sediments and use this calibration to microbial populations, microinvertebrates, infer the environment of paleolakes and mosses, and lichens. Nevertheless, complex · to determine other environmental markers trophic interactions and biogeochemical nutri- left in the lake sediments as well as de- ent cycles exist in the lakes, streams, and soils scribing the nature of ice/water/sediment of the dry valleys. Solar energy produces gla- interactions in the lakes. cial meltwater in the austral summer, and in turn, this meltwater exerts the primary influ- During the 1998–1999 field season, the fol- ence on the dry valleys by replenishing water lowing studies will be conducted in the and nutrients to the ecosystems there. All eco- McMurdo Dry Valleys as part of the LTER systems are shaped to varying degrees by cli- project: mate and material transport, but nowhere is this more apparent than in the McMurdo Dry · glacier mass balance, melt, and energy bal- Valleys. ance (Andrew Fountain, Portland State University); The overall objectives of the McMurdo Dry · chemistry of streams, lakes, and glaciers Valleys LTER are to understand the influence (W. Berry Lyons, University of Alabama); of physical and biological constraints on the 14 U.S. Antarctic Program, 1998-1999 · flow, sediment transport, and productivity the variability in sea ice). We hypothesize that of streams (Diane McKnight, University of sea ice is a major factor regulating for Colorado); · the timing and magnitude of seasonal pri- · lake pelagic and benthic productivity and mary production; microbial food webs (John Priscu, Montana · the dynamics of the microbial loop and State University at Bozeman); particle sedimentation; · soil productivity (Diana Wall, University of · krill abundance, distribution, and recruit- Nevada, Desert Research Institute, and ment; and Ross A. Virginia, Dartmouth College); · survivorship and reproductive success of · aeolian transport processes (Gayle L. Dana, top predators. Desert Research Institute); and · meteorological data collection (Peter T. Do- The magnitude and timing of sea ice may have ran, Desert Research Institute). different consequences for different key species, and it is still unclear what the ramifica- The McMurdo LTER project will emphasize tions would be for the whole antarctic ecosys- the integration of the biological processes tem. For example, high levels of survivorship within and material transport between the and reproductive success of Adélie penguins lakes, streams, and terrestrial ecosystems in appear to depend on high levels of availability the dry valley landscape. This season, several of antarctic krill, which in turn appear to be experiments will examine community struc- correlated with greater ice coverage. On the ture and function within benthic bicrobial other hand, high levels of breeding success of mats of the dry valley lakes. In addition, tracer south polar skuas appear to be determined by tests will be performed to investigate nutrient the availability of antarctic silverfish, which in transport and uptake in the streams. (BM- turn appear to be associated with lesser ice 042B-O, BM-042-F, BM-042-L, BM-042-M, BM- coverage. Thus, the overall objectives of the 042-P, BM-042-W, and BM-118-O) Palmer LTER project are

Long-Term Ecological Research on the ant- · to document not only the interannual vari- arctic marine ecosystem: An ice dominated ability of annual sea ice and the corre- environment. Maria Vernet, Scripps Institution sponding physics, chemistry, optics, and of Oceanography. The central hypothesis of the primary production within the study area Palmer Long-Term Ecological Research but also the life-history parameters of sec- (LTER) project is that the annual advance and ondary producers and top predators; retreat of sea ice is a major physical determi- · to quantify the processes that cause varia- nant of spatial and temporal changes in the tion in physical forcing and the subsequent structure and function of the antarctic marine biological response among the representa- ecosystem. Evidence shows that this dynamic tive trophic levels; variability of sea ice has an important, perhaps major, impact on all levels of the food web, · to construct models that link ecosystem from total annual primary production to processes to environmental variables and breeding success in top predators. For exam- which simulate spatial/temporal ecosystem ple, variability in sea ice may affect prey and relationships; and then predators directly (e.g., access to open water · to employ such models to predict and vali- or preferred habitats) or indirectly (e.g., food date ice-ecosystem dynamics. availability, which in turn may be affected by

U.S. Antarctic Program, 1998-1999 15 A key challenge for the Palmer LTER project is · Langdon Quetin, University of California at to characterize and understand the link be- Santa Barbara (BP-028-O); tween the different spatial and temporal scales · Raymond Smith, University of California at of the various physical and biological compo- Santa Barbara (BP-032-O); nents of the antarctic ecosystem. · William Fraser, Montana State University The participants for the 1998–1999 field season (BP-013-O); and will be · David Karl, University of Hawaii (BP-046- · Maria Vernet, Scripps Institution of Ocean- O). ography (BP-016-O); · Douglas Martinson, Columbia University (BP-021-O);

Environmental research modest exposure to toxic contaminants (trace Diagnostic indicators of biological commu- metals). This hypothesis will be tested near nity stress using benthic community analysis to tease apart impacts of organic enrichment McMurdo Station because and toxicity: An experiment in McMurdo · its relatively constant environment allows Sound. Charles Peterson, University of North experimental work to proceed on the sea- Carolina at Chapel Hill. Communities of benthic floor without compromise by confounding invertebrates are widely used to monitor and disturbances; evaluate biological impacts of pollution in the marine environment because their sessile life- · previous benthic studies at this site have styles, longevity, functional diversity, well- revealed significant confounded patterns of known taxonomy, and ecological significance sediment contamination and benthic com- render this system an ideal ecological template munity degradation; and on which biological consequences are im- · low rates of natural bioremediation in cold printed. Benthic communities have been used polar oceans make study of pollution im- successfully in environmental assessments for pacts especially critical at high latitudes. convincing demonstrations that impacts of pollution are readily detectable at the level of Our first objective will be to establish a field family and phylum for macrofaunal inverte- experiment near McMurdo Station where the brates. investigators will manipulate organic loading and trace metal concentrations in sediment Our project is designed to test the hypothesis within colonization trays to test whether the that indices of abundance and production for separate taxa respond independently to the individual phyla of macrofauna and/or meio- classes of pollution. Treatments will also in- fauna can be used as independent diagnostics clude access of larger mobile predators and to tease apart the typically confounded im- time for community development to assess pacts of these two separate classes of marine whether biological interactions within the eco- pollution. We will test the hypothesis that an- system with the diagnostic capability of the nelid worms and nematodes are enhanced by indices of pollution stress. Second, we will modest organic loading and arthropods and complete a rigorous review and meta-analysis echinoderms are depressed preferentially by 16 U.S. Antarctic Program, 1998-1999 of all available data sets on effects of pollution and other toxics, may harm marginal biota on marine invertebrate communities to test the and near coastal stations. hypothesis using the wealth of pre-existing information from monitoring discharges, oil Previous work showed that extremely small, spills, and previous experimentation. (EO-302- but detectable, concentrations of black carbon O) aerosol are brought to the Amundsen–Scott South Pole Station in the background atmos- Measurement of combustion effluent aero- phere in amounts consistent with models of sols from the Amundsen–Scott South Pole long-range transport; however, the program Station. Anthony Hansen, Magee Scientific Com- that made this determination terminated in pany. Anthropogenic activities in Antarctica 1990. A 1986 study of surface snow and ice have the potential of producing both contem- showed a clear plume of soot downwind of poraneous and long-term environmental im- the station. We will install more modern pacts on the nearly pristine surroundings. One equipment both upwind and downwind of the of these impacts arises from the emission of South Pole Station to re-establish the back- "black" or "elemental" carbonaceous aerosols ground aerosol measurements and to provide from the exhaust of diesel-powered generators a direct assessment of the station's emissions. and vehicles used to support antarctic opera- The results of our work will contribute to de- tions. When deposited on the snow and ice termining the station's environmental impact cover, this pollutant may be preserved indefi- resulting from combustion-derived emissions. nitely. Its high optical absorption will alter the This information may be used to design miti- surface albedo and the radiative properties of gation and abatement strategies. The upwind surface cover. Its ability to promote catalyti- data will contribute to the global monitoring cally certain chemical reactions may lead to record and to assessments of the global circu- modifications of snow and ice chemistry. Its lation of anthropogenic emissions capable of absorbed content of fuel-derived organic spe- influencing atmospheric optics and chemistry. cies, such as polycyclic aromatic hydrocarbons (EO-314-O)

Geology and geophysics the Ross embayment and western Marie Byrd Air-ground study of tectonics at the boundary between the eastern Ross embayment Land may be a result of and western Marie Byrd Land, Antarctica: · Cenozoic extension on the eastern shoulder Basement geology and structure. Christine S. of the Ross Sea rift; Siddoway, Colorado College. Our project com- bines air and ground geological–geophysical · uplift and crustal extension related to Neo- investigations to understand the tectonic and gene mantle plume activity in western geological development of the boundary be- Marie Byrd Land; or tween the Ross Sea Rift and the Marie Byrd · a combination of the two. Land volcanic province. Our objective is to determine the Cenozoic tectonic history of the Faulting and volcanism, mountain uplift, and region and to learn whether Neogene struc- glacier downcutting appear to be active now tures that localized outlet glacier flow devel- in western Marie Byrd Land, where generally oped within the context of Cenozoic rifting on east-to-west-flowing outlet glaciers incise Pa- the eastern Ross embayment margin or within leozoic and Mesozoic bedrock, and deglaci- the volcanic province in Marie Byrd Land. The ated summits indicate a previous north-south geological structure at the boundary between glacial flow direction.

U.S. Antarctic Program, 1998-1999 17 Our study requires data collection using crop and ice covered areas. These data may SOAR, or Support Office for Aerogeophysical also help and may be used to distinguish be- Research, a facility that uses high-precision tween Ross Sea rift-related structural activity differential global positioning system technol- from uplift and faulting on the perimeter of ogy to support a laser altimeter, ice- the Marie Byrd Land dome and volcanic penetrating radar, a towed proton mag- province. Outcrop geology and structure will netometer, and a Bell BGM-3 gravimeter. Data be extrapolated with the aerogeophysical data will be acquired over several key features in to infer the geology that resides beneath the the region including, among others, west antarctic ice sheet. The new knowledge of Neogene tectonics in western Marie Byrd · the eastern edge of the Ross Sea rift, Land will contribute to a comprehensive · the transition from the Edward VII Penin- model for the Cenozoic Ross rift and to under- sula plateau to the Ford Ranges, standing of the extent of plume activity in Marie Byrd Land. Both are important for de- · the continuation to the east of a gravity termining the influence of Neogene tectonics high known from previous reconnaissance on the ice streams and the west antarctic ice mapping over the Fosdick Metamorphic sheet. (GF-088-O) Complex, and · the extent of the high-amplitude magnetic Global positioning system measurement of anomalies (volcanic centers?) detected isostatic rebound and tectonic deformation southeast of the northern Ford Ranges by in Marie Byrd Land, West Antarctica. Bruce other investigators. Luyendyk, University of California at Santa Bar- bara. The Ross embayment and western Marie SOAR products will include glaciology data Byrd Land are part of the west antarctic rift useful for studying driving stresses, glacial system. Most scientists agree that this region is flow, and mass balance in the west antarctic undergoing active deformation, but the rates ice sheet. and causes of deformation remain essentially unknown. Tectonic extension may be occur- During our ground program, centered on the ring in the Ross embayment as West and East southern Ford Ranges, we will map small- Antarctica separate today. Crustal uplift could scale brittle structures for regional kinematic be occurring in western Marie Byrd Land due interpretation, glaciated surfaces and deposits, to isostatic rebound following the last glacial and datable volcanic rocks for geochronologic age. control. We will also determine the relative significance of fault and joint sets, the timing Tectonic extension, if it is occurring in the em- relationships between them, and the probable bayment, could greatly influence global plate context of their formation along with exposure circuit calculations, depending on its magni- ages for erosion surfaces and moraines. To aid tude. The tectonic extension rate also can con- in the interpretation of potential field data, we strain our understanding of the history of ex- will sample magnetic properties and density tension in the embayment and the uplift his- as well as take ground-based gravity meas- tory of the Transantarctic Mountains. Postgla- urements and oriented samples for paleomag- cial rebound in western Marie Byrd Land netic studies. would depend on the configuration of the ice sheet during the Last Glacial Maximum and By combining airborne and ground investiga- when this occurred. The main question is tions, we will obtain basic data for describing whether the ice sheet collapsed in the geology and structure at the eastern mid-Holocene time. boundary of the Ross embayment both in out-

18 U.S. Antarctic Program, 1998-1999 Our plan is to install three continuous and Paleocene occur in New Zealand, the northern autonomous global positioning system (GPS) Antarctic Peninsula, and the Southern Ocean. stations on outcrops in western Marie Byrd Benthic and planktic foraminifera from the Land on baselines of around 100 kilometers. core will be used, together with data from These stations, which will gather data over a other fossil groups, to provide on-site age and 4-year period, will operate in concert with stratigraphic control as drilling progresses. GPS stations being installed in the Age correlations will be made with Deep-Sea Transantarctic Mountains in a separate project, Drilling Project/Ocean Drilling Project resulting in a long baseline array across the (DSDP/ODP) biostratigraphy from Southern Ross embayment. We will download data Ocean drill sites and also with New Zealand twice each season to acquire up to 6 months of planktic and benthic zonal/stage schemes. coverage. If a cost-effective satellite communications system is in operation at the time of Our principal task is to provide a comprehen- our survey, we will use that. sive accounting of foraminiferal material present to assist planning of postdrilling investi- We expect to determine crustal strain rates to gations. Basic information to be recorded on an accuracy of 1 millimeter per year horizontal the foraminifera will include presence, abun- and 2 millimeters per year vertical. The array dance, preservation, species dominance and will also detect strain gradients in western diversity, stratigraphic distribution, levels of Marie Byrd Land. The strain data from west- endemism or cosmopolitanism in faunas, and ern Marie Byrd Land and the Transantarctic completeness or fragmentation of population Mountains will enable us to construct models structures. for tectonic extension and glacial rebound. The data we record will be used to address a This is a joint project between Bruce Luyendyk variety of geological problems. Disconformi- of the University of California at Santa Bar- ties and acoustic reflectors, which extend bara and Andrea Donnellan, Carol Raymond, across the rift system basins and are also ex- and Erik Ivins of the Jet Propulsion Laboratory pected to be encountered in the drill hole, will at the California Institute of Technology. Our be dated. Major basin subsidence/uplift team brings together experts in western Marie trends resulting from compaction and/or rift Byrd Land geology and tectonics, tectonic ge- margin faulting will be deduced from benthic odesy, and lithospheric deformation. (GF-121- foraminiferal bathymetric indicators. More O) subtle cyclicity in the stratigraphic distribution of benthic species will be used to recognize Cretaceous-Paleogene foraminifera of the and document phases of transgression and Victoria Land Basin (Cape Roberts Project). regression, which, in turn, may indicate a re- Peter-Noel Webb, Ohio State University. We will lationship between sea level oscillation and characterize the foraminifera in drill core re- terrestrial glacial events. covered by the Cape Roberts Project (CRP) in the southwest Ross Sea. Geophysical site sur- The final disintegration of Gondwanaland oc- veys suggest that the drill holes will provide curred during the Cretaceous–Paleocene; spe- an aggregate thickness of about 1,500 meters cifically, New Zealand and Australia moved of core and span about 30 to about 100 million north, away from Antarctica. Foraminifera years (Cretaceous-Paleocene). This interval of from the CRP drill holes will contribute to an geological time is not yet documented by in understanding of the paleogeography and situ stratigraphic sections in either the Ross paleoceanography between the highlands and Sea or East Antarctica. The nearest compre- Pacific margin of East Antarctica (the location hensive data sources for the Cretaceous and of the proto-Transantarctic Mountains), and

U.S. Antarctic Program, 1998-1999 19 the west antarctic rift system basins between of, for example, environmental changes in this suspected island chain and the highlands water depth, primary productivity, and the of West Antarctica. This will help scientists presence or absence of sea ice. CRP cores will know whether the marine margin of East Ant- provide an excellent opportunity to study ad- arctica, near the drill holes, was located in a aptation of diatoms to strong polar seasonality Cretaceous cul-de-sac, or whether it occupied, and diatom evolution. By integrating CRP at times, a position on a major oceanic circula- studies with ongoing studies of Paleogene sili- tion pathway between the southwest Indian ceous microfossils in Arctic strata (for exam- Ocean, southwest Pacific, and southwest At- ple, Ocean Drilling Program Leg 151), the CRP lantic Oceans. (GL-049-A and GL-049-B) cores will also offer the possibility of gaining a bipolar perspective on Paleogene high-latitude Diatom biostratigraphy and paleoenviron- phytoplankton evolution. (GL-051-O) mental history of Cape Roberts Project cores. David Harwood, University of Nebraska at Lin- Downhole logging for the Cape Roberts Pro- coln. We will characterize the diatom fossils in ject. Richard Jarrard, University of Utah. We will drill core recovered by the Cape Roberts Proj- do continuous-core and downhole logging at ect (CRP), a major program in the interna- the Cape Roberts Project (CRP) scientific drill tional antarctic earth science community de- holes. The goal of CRP is to study the Early signed to sample antarctic continental margin Tertiary and Cretaceous record of climate, strata of late Cretaceous through Paleogene tectonics, and sea-level change and to deter- age (30 million to 100 million years ago). mine the time of onset of antarctic glaciation. Drilling operations will include continuous Geophysical well logs will be converted into coring from a sea-ice platform on the flank of continuous records of variation, and these rec- the Victoria Land basin in the western Ross ords can be interpreted as indicating varia- Sea. tions in mineralogy and porosity. The detailed one-dimensional records at each hole will be Our particular project involves initial field- integrated with available high-resolution based paleontologic analysis of siliceous seismic data to produce a two-dimensional microfossils in Cape Roberts cores. Core sec- interpretation of the stratigraphy. This geo- tions will be ferried to the Crary Science and physical logging program is an essential com- Engineering Center (CSEC) for immediate ponent of basic characterization of the drill site analysis. Diatoms and other siliceous micro- and is a fundamental part of the effort to pro- fossils will provide rapid age-and-paleoenvi- duce a stratigraphic framework for interpreta- ronmental information during drilling operation of other scientific work on the core. (GL- tions. Each season will include preparation of 055-O) a preliminary biostratigraphic/paleoenvironmental report based on siliceous microfossils. This report Calcareous nanofossil biostratigraphy and will become part of the CRP Initial Reports vol- paleoenvironmental history of the Cape ume, which will include the preliminary re- Roberts Project cores. James J. Pospichal and sults from other microfossil groups, litho- Sherwood W. Wise, Florida State University. We stratigraphic, magnetostratigraphic, and other will characterize calcareous nanofossils as part analyses. of the development of the biostratigraphic framework for drill core recovered by the Analysis of diatoms and other siliceous micro- Cape Roberts Project (CRP). CRP is a major fossils in CRP cores will greatly aid in the de- program in the international antarctic earth velopment of an integrated biostratigraphy for science community, designed to sample the this poorly known interval in the southern stratigraphic record that spans the time inter- high latitudes. Diatoms will provide evidence val from 30 to 100 million years ago, by drill-

20 U.S. Antarctic Program, 1998-1999 ing four sites on the flank of the Victoria Land Project (CRP). The core will be described, cu- basin. We will support the drilling program by rated, and sampled for scientific research. The providing rapid age-and-paleoenvironmental CRP has the potential to answer significant information through the study of calcareous questions regarding the history of the west nanofossils. Working at the Crary Science and antarctic rift system, the development of con- Engineering Center (CSEC) at McMurdo Sta- tinental ice sheets in Antarctica during the tion, Antarctica, we will systematically sample Cretaceous and Paleogene, and the response the recovered sedimentary cores and analyze of biota to climatic deterioration and the de- their calcareous nanofossil content. The prepa- velopment of seaways. ration of an initial reports volume at the end of each of the two drilling seasons will include Organic geochemical measurements are rele- the results of our work as part of the initial vant to these issues and so are included in the characterization of the cores. The calcareous initial core characterization studies. We will nanofossil biostratigraphic record spans the measure whole-rock carbonate carbon, total entire interval to be cored by the CRP. carbon, total nitrogen, and total sulfur, analyze the elemental composition of kerogen in Recent work on calcareous nanofossils from selected samples, and perform gas chroma- ocean drilling sites around Antarctica has tographic analysis of the solvent-soluble or- yielded a refined zonation for the Paleogene ganic matter in selected samples. These data and Upper Cretaceous of the Southern will be collected in the Crary Science and En- Ocean that will provide a high-resolution gineering Center (CSEC) at McMurdo Station biostratigraphic framework for hemi- and will be reported as part of the initial core pelagic and pelagic sediments recovered characterization study of the CRP. (GL-064-O) by Cape Roberts drilling. This research, when combined with data from other fossil Beryllium in granulite-facies pegmetites in groups, magnetostratigraphic data, and other Archean Napier Complex, Antarctica. Edward age-dating methods, will provide integrated S. Grew, University of Maine. I will accompany age control that is essential for other geologi- the Japanese Antarctic Research Expedition cal investigations. In addition, calcareous (JARE) to study beryllium-enriched minerals nanofossils are excellent paleoenvironmental in Enderby Land. Beryllium is a rare element indicators for surface-water temperature and in crustal rocks, and enrichments are espe- productivity. Statistical analysis of quantita- cially unusual in granulite-facies (high tem- tive population census data will be used to in- perature and pressure and relatively dry con- fer paleoenvironmental variations during the ditions) metamorphic rocks. I will study Paleogene and Cretaceous. These data, in unique beryllium-enriched pegmatites in the combination with data from other fossil Archean ultrahigh temperature (up to 1,000°C) groups and sedimentological studies, will be granulite-facies Napier Complex in eastern useful for assessing climatic change through Casey Bay, Enderby Land, East Antarctica. My the critical period of 30–100 million years be- primary objective is to test the hypothesis that fore the present. (GL-057-O) the beryllium originated in the metasediments hosting the pegmatites rather than being a Initial characterization of organic matter in component of a pegmatitic magma. Cretaceous–Paleogene sedimentary rocks, Cape Roberts, Antarctica. Richard M. Kettler, My fieldwork will be conducted during the University of Nebraska at Lincoln. We will char- 1998–1999 austral field season in Enderby acterize the organic geochemical nature of Land as a part of the Japanese Antarctic Re- Cretaceous–Paleogene sedimentary rocks from search Expedition's project entitled "Structure drill core recovered during the Cape Roberts and Evolution of East Antarctic Lithosphere." I

U.S. Antarctic Program, 1998-1999 21 will use mineral and rock compositions to de- mental database for other analyses. The strati- termine the evolution and conditions of crys- graphic sections will also be used as reference tallization of the pegmatites and their host sections for modeling observed marine and rocks. The results of the project will provide geophysical events. Initial sedimentological some important insights into geochemical be- characterization of the successions will allow havior of beryllium under the high-tempera- the definition of facies, the construction of fa- tures and low-water regime characteristic of cies sequences, and the interpretation of depo- the granulite facies. (GL-067-O) sitional environments through time. The end result of the proposed work will be an Ocean Initial sedimentological characterization of Drilling Program-style initial report for each the Late Cretaceous-Early Cenozoic drill drilling season. These reports will include the cores from Cape Roberts, Antarctica. Ross stratigraphic log, initial facies and deposi- Powell, Northern Illinois University, and Law- tional system interpretations, sedimentary rence Krissek, Ohio State University. An interna- petrologic and petrogenetic analyses, and ini- tional initiative to collect 1,500 meters of drill tial clay mineralogical analysis. Information core from offshore of Cape Roberts, McMurdo provided by other specialists will also be in- Sound, Antarctica, is intended to provide a cluded in the reports, including biostratigra- better understanding of antarctic history phy, magnetostratigraphy, geophysical logs, through the late Cretaceous and early Ceno- and geochemical interpretations. The initial zoic. Events during this period, which extends interpretations of regional history will be pre- from before the final breakup of Gond- sented in these reports, and the regional and wanaland through the onset of antarctic glaci- global ramifications of this history will be ation, are ill-defined by existing data. The highlighted. (GL-070-O) Cape Roberts Project (CRP) aims to provide new data about the development of the west Paleomagnetic and mineral magnetic charac- antarctic rift system, the subsidence history of terization of drill cores from the Cape Rob- the Ross Sea, and ice-sheet fluctuations on erts Project. Kenneth Verosub, University of Antarctica through this critical time interval. California at Davis, and Gary Wilson, Ohio State University. The goals of the Cape Roberts Proj- CRP is partly an extension of previous drilling ect (CRP) are to elucidate the history of frag- efforts on the antarctic continental margin and mentation of the Pacific margin of Gond- is partly a new initiative to document more wanaland and the history of antarctic glacia- completely the developmental history of the tion from Cretaceous through Oligocene time. Ross Sea sector of the Antarctic and southern The CRP will operate with an integrated sci- Pacific region through the late Cretaceous- ence plan in which all of the initial scientific early Cenozoic. It will draw on the successes characterization of the cores will be done at of previous drilling efforts to document McMurdo Station. The scientific activities as- regional and environmental development with sociated with characterization of the cores will good spatial and temporal resolution, and it include magnetostratigraphy, biostratigraphy, will also draw upon newly compiled geo- petrography, mineralogy, and sedimentology. physical databases. Age determination is of principal importance CRP is a collaborative endeavor and is cur- in such a project because a temporal frame- rently being supported by six participating work is necessary to obtain a history of cli- countries. Tasks involved in our segment of matic and tectonic events. the project will include initial description and Our research will determine high-quality pa- characterization of the stratigraphic succes- leomagnetic stratigraphy, with the appropri- sions; these results will be used as the funda-

22 U.S. Antarctic Program, 1998-1999 ate mineral magnetic studies, in support of the stress fractures, and we will examine the CRP. For the on-site magnetic studies, we will borehole via downhole televiewer and dip- meter for any wellbore breakouts and frac- · undertake logging of the whole-core mag- tures reactivated by the contemporary stress netic susceptibility, which will help corre- field. The stress data will be analyzed to ad- late the several overlapping cores to be re- dress questions relevant to the paleo- and covered during the CRP; neotectonic evolution of the antarctic plate. · determine a magnetostratigraphic frame- The results will contribute to the resolution of work for dating the cores; outstanding questions such as the cause of the anomalous aseismicity of the continent, the · undertake mineral magnetic and environ- geometry of stresses along the lithospheric mental magnetic studies to assess the reli- boundary between the Transantarctic Moun- ability of the paleomagnetic signal; and tains and the west antarctic rift system, and · determine if environmental magnetic prop- the evolution of the antarctic intraplate stress erties yield information concerning changes field and its relation to rifting episodes associ- in the tectonic, sedimentologic, diagenetic, ated with Gondwanaland breakup. Contem- or climatic influences on the sedimentary porary stress data obtained from this research record at Cape Roberts. will be added to the global stress database and will help to fill the current void in the global Detailed environmental and mineral magnetic stress coverage marked by the Antarctic Plate. studies will also enable evaluation of the (GL-079-O) sediments as recorders of the geomagnetic field. The Cape Roberts records provide the Initial palynological characterization of Cape potential to obtain rare high southern latitude Roberts drill cores. Rosemary Askin, Ohio State constraints on geomagnetic field behavior. University, and John Wrenn, Louisiana State Uni- Paleomagnetic studies should also provide versity. We will characterize palynomorph as- important data concerning crustal movements semblages recovered from cores from the and rift development in the Ross Sea sector. Cape Roberts Project (CRP). The CRP is de- (GL-075-O) signed to core submarine deposits in the western Ross Sea that range in age from middle Stress field history, Cape Roberts, Antarctica. Late Cretaceous through Miocene. Objectives Terry Wilson, Ohio State University. As part of a include collaborative research program, we will obtain the first age-calibrated stress-field history · obtaining a late Cretaceous–Cenozoic pa- within the west antarctic rift system of Ant- leoclimatic record, arctica. The opportunity to acquire the stress · studying glacial-deglacial and eustacy cy- data is provided by the international drilling cles, and program planned at Cape Roberts, which is located along the margin between the uplifted · determining the Gondwanaland breakup Transantarctic Mountains and the rifted crust and rifting history of the Ross Sea embay- of the Victoria Land basin. Information on the ment. paleostress history of the Mesozoic and Ceno- Palynomorphs have proven to be invaluable zoic rift-basin fill will be obtained from the tools for biostratigraphic and paleoenviron- core and downhole logging of natural frac- mental interpretation of younger Ross Sea se- tures and faults. quences drilled in the Ross Sea embayment. To establish the contemporary stress state, we They include both marine (dinocysts) and will examine the cores for coring-induced nonmarine (spores, pollen) types, record extensive and diverse geologic information, and U.S. Antarctic Program, 1998-1999 23 are preserved in a wide variety of lithofacies preliminary data reflect uncertainty in the formed in various paleoenvironments. This geologic relations of these rocks, and they in- project will provide initial palynological char- dicate that the Neoproterozoic tectonic history acterization of the CRP drill cores in collabo- for the region must be revised. ration with New Zealand palynologists. Analyses will focus on providing palynologi- To improve understanding of its depositional cal input for an integrated biostratigraphic history and its role in orogenic events shaping and paleoenvironmental framework based on the outer margin of Gondwanaland, we will all microfossil groups present. This framework investigate the Beardmore Group. The project is of fundamental importance to all future will include geologic, geophysical, and paleontologic · detailed field study of the stratigraphy, studies conducted on the cores and in the sedimentology, and structure; drilling area. (GL-080-O) · provenance (source) study of graywackes Structure and sedimentology of the Beard- to constrain the depositional setting of the more Group, Antarctica: Latest Neoprotero- turbidites; zoic to Early Paleozoic tectonic evolution of · determination of carbonate isotopic compo- the east antarctic margin. John W. Goodge, sitions for comparison with the global car- Southern Methodist University. The Neopro- bon-isotopic refinement of depositional terozoic to early Paleozoic transition (700–500 age(s) through uranium-lead dating of de- million years ago) was a critical period in trital and igneous zircons; and Earth history. During this period, one supercontinent known as Rodinia was coalesced, · constraint on the age(s) of deformation(s) then fragmented, prior to amalgamation of a with argon-isotope thermochronology. second supercontinent referred to as Gond- wanaland. During these events, major moun- During the 1998–1999 and 1999–2000 austral tain building, continental erosion, species di- summers, we will test a recently proposed versification, sea-level fluctuations, and model for Beardmore Group deposition and changes in seawater composition took place. deformation that involves latest Neoprotero- Continental margin sedimentary sequences zoic–early Paleozoic(?) rift-margin sedimenta- from this era provide detailed records of sea- tion and structural inversion as an early ex- level fluctuations, faunal distributions, and pression of Ross activity. The results will help postdepositional tectonism. to resolve directly long-standing uncertainties in the geologic history of the Antarctic, and One of these sequences, the Beardmore Group they will improve our understanding of global in Antarctica, represents a significant element paleogeographic and plate-tectonic relations in the evolution of the east antarctic craton, yet during supercontinent transformation at the very little is known about its depositional or close of the Proterozoic. (GO-014-O) tectonic history. Previous workers have suggested that the entire Beardmore Group is Antarctic surveying and mapping program. Neoproterozoic in age and that it records two Richard E. Witmer and Jerry L. Mullins, U.S. distinct deformations, the well-known Ross Geological Survey. Production and publication orogeny and an earlier cryptic "Beardmore" of maps of Antarctica serve four U.S. policy orogeny. Reconnaissance field and geochro- objectives. nologic studies indicate that portions of the · Maps are essential for research, the princi- Beardmore Group are significantly younger pal expression of U.S. interest in Antarctica. than previously thought, and that it shows evidence for Ross deformation only. These

24 U.S. Antarctic Program, 1998-1999 · Maps are also essential for operations and complete understanding of past climatic and logistics in support of research or other ac- environmental conditions. The dynamic na- tivities (including search and rescue). ture of climate has received growing public attention because of the occurrence of seem- · Maps provide a knowledge base for sup- ingly extreme weather events recently, and port of future U.S. antarctic interests. growing concerns about warming. El Niño · By their authoritative coverage of large and global greenhouse warming have become portions of the continent, maps serve to familiar topics in the news. In this context, maintain the active and influential presence understanding the inherent variability of of the United States in Antarctica. Earth's climate and how humans can affect Earth's environment is becoming increasingly Surveying and mapping comprise a variety of more important. activities necessary for the successful operation of a multifaceted scientific and explora- One important means of improving our un- tion effort in Antarctica. Year-round data ac- derstanding of the Earth's climate system is to quisition, cataloging, and data dissemination treat the Earth as a natural laboratory and ex- will continue in the Scientific Committee for amine its past behavior. One of the most ex- Antarctic Research (SCAR) Library for Geod- treme changes in the Earth's climate system esy and Geographic Information. Field sur- during the last few million years has been the veys are planned as part of a continuing pro- transition from a warm period in the Pliocene gram to collect data suitable for future satellite to an ice-age world. Scientists believe that mapping programs and to densify extant data during this interval in Antarctica, relatively for 1:50,000-scale mapping programs. These mild conditions gave way rapidly to intense maps will provide a base to portray scientific glacial conditions that catalyzed the growth of information, such as geologic data, in an espe- the largest ice sheet on Earth. This inference is cially accurate manner for expert analysis. based on geologic indicators of past climate They will also support future expeditions with from which some scientists suggest that East a base to design scientific investigations and Antarctica was relatively warm and largely data-collection activities. free of glaciers about 3–4 million years ago (during parts of the Pliocene). The mild con- The U.S. Geological Survey has been selected ditions ended abruptly by rapid ice-sheet to perform the nation's antarctic mapping be- growth and development of the very cold, dry cause it is the designated agency for mapping climate that now characterizes this region. A of the United States and because it possesses contrasting view, based on substantial geo- the necessary expertise, antarctic experience logic evidence, suggests that East Antarctica (developed since 1959), and institutional con- has been cold and the ice sheet stable for at tinuity. A 1991 Memorandum of Agreement least 8 million years, and perhaps considera- between the U.S. Geological Survey and the bly longer. These views lead to drastically dif- National Science Foundation established the ferent interpretations of the stability of Earth's purpose and tasking for the antarctic map- climate. ping. (GO-052-O) We hope this project will contribute to re- Stability of land surfaces in the dry valleys: solving this important dilemma by introduc- Insights based on the dynamics of subsur- ing independent new evidence and insights face ice and sand-wedge polygons. Bernard derived from studies of the stability of ground Hallet, University of Washington. We will study ice and land surfaces in the dry valleys of features of the landscape and soils of the dry Antarctica. We will study modern-day proc- valley region of Antarctica to provide a more esses that have important implications for un-

U.S. Antarctic Program, 1998-1999 25 derstanding the occurrence of buried ice Continued recovery of antarctic meteorites is found recently in Beacon Valley. This ice may important because they are the only currently be the oldest ice on Earth and, if so, will pro- available source of new, nonmicroscopic ex- vide strong evidence of long-term stability of traterrestrial material, and they provide es- the east antarctic ice sheet and may provide a sential ground truth about the composition of rare glimpse at atmospheric conditions mil- asteroids, planets, and other bodies of our so- lions of years ago. lar system.

Specific processes to be investigated include During the 1998–1999 field season, ANSMET will travel to the Graves Nunataks icefields · exchange at the ground surface that affects near the top of the Scott Glacier, just east of ground temperature, the La Gorce Mountains. The general region is · water-vapor transport and other processes just a little "northeast" of where the leading to the formation or loss of ice in the Transantarctic Mountains reach their most soil, and southerly point. The region was visited by ANSMET for 11 days during the 1995–1996 · frost cracking due to contraction during field season, and although weather conditions rapid cooling of the frozen ground in the reduced our searching to only a few days, the winter and its resulting disruptions of the area proved its potential as a meteorite con- soil. (GO-053-O) centration when 33 specimens were recovered. Antarctic search for meteorites. Ralph Harvey, ANSMET's objective for the 1998–1999 season Case Western Reserve University. Since 1976, is to return to these icefields and conduct sys- ANSMET (the Antarctic Search for Meteorites tematic searching there, as well as reconnoiter program) has recovered more than 9,000 me- several other icefields within a short travers- teorite specimens from locations along the ing distance. (GO-058-O) Transantarctic Mountains. Antarctica is the Tracking the west antarctic rift flank. Paul world's premier meteorite hunting ground for Fitzgerald and Suzanne L. Baldwin, University of two reasons. Arizona. Scientists believe that the uplifted Ce- · Although meteorites fall in a random fash- nozoic rift shoulder of the west antarctic rift ion all over the globe, the likelihood of system extends along the Transantarctic finding a meteorite is enhanced if the back- Mountains and the northwestern flank of the ground material is plain and the accumula- Ellsworth–Whitmore Mountains crustal block. tion rate of terrestrial sediment is low, Available fission track data from the making the east antarctic ice sheet the per- Ellsworth–Whitmore Mountains block indi- fect medium. cate that although most of the erosion exposing the rock strata (denudation) occurred there · Along the margins of this ice sheet, ice flow in Late Jurassic–Early Cretaceous, a significant is sometimes blocked by mountains, nuna- component of denudation is permissible in the taks, and other obstructions, exposing Cenozoic. In contrast, most of the rock uplift slow-moving or stagnant ice to the fierce and denudation in the Transantarctic Moun- katabatic winds. These winds, in turn, ab- tains occurred in the Cenozoic. The timing of late away the ice, leaving behind a lag de- uplift and denudation at key localities, plus posit of meteorites representing those that the patterns of uplift and denudation along were sprinkled throughout the volume of the west antarctic rift shoulder, revealed from ice lost to the wind. When such a process the thermochronologic studies we will con- continues for a long enough time (10s or duct, will be used to address this hypothesis. 100s of thousands of years), the concentration of meteorites can be spectacular. 26 U.S. Antarctic Program, 1998-1999 Our objectives are Heat and chemical exchange during the early stages of back-arc rifting in a polar region: · to determine the extent and timing of de- Hydrothermal activity in Bransfield Strait, nudation of the west antarctic rift flank; Antarctica. Gary Klinkhammer and Martin R. · to further delineate patterns of uplift and Fisk, Oregon State University. We will investi- denudation along the length of the gate hydrothermal venting in Bransfield Strait, Transantarctic Mountains and document between the South Shetland Islands and the the thermal history of basement rocks from Antarctic Peninsula. During earlier explora- different crustal blocks; and tions in the strait, researchers found several sites where hot hydrothermal fluids emanate · to compare and contrast the thermal histo- from the seafloor. An instrument package de- ries of East Antarctica (Transantarctic signed to detect and map the thermal and Mountains) and West Antarctica chemical signature that hydrothermal activity (Ellsworth-Whitmore Mountains crustal leaves on the overlying water column enabled block). scientists to locate the hydrothermal sites, We will address these objectives using ther- which range in water depth from less than 200 mochronologic techniques: namely, apatite meters to 1,300 meters and occur on the vol- fission track thermochronology and argon- canic outcrops that periodically protrude 40/argon-39 (40Ar/39Ar) thermochronology. through the sediment cover along the strike of During our first field season, we will be in the the rift zone. These sites are aligned with the Thiel Mountains and travel from there to se- Deception Island caldera, which has active hot lected nunataks in the Ellsworth–Whitmore springs. Because these sites are the first sub- Mountains crustal block: Pagano Nunatak, marine hydrothermal sites discovered in Ant- Stewart Hills, Mount Moore, and Mount arctica, they represent unique research op- Woollard. Our second field season will be in portunities. the Horlick Mountains and the Ohio Range. We will return to the strait to continue map- Each field season will be followed by a year ping and sampling these areas. Four compel- for sample preparation, data collection and ling reasons lead scientists to believe that fur- analysis, and ongoing interpretation and pres- ther exploration of vent systems in the Brans- entation of results. All laboratory work will be field will yield exciting new information. undertaken at the Center for Thermochronol- ogy and Noble Gas Studies at the University · The vent fluids and mineral deposits asso- of Arizona. ciated with venting in the Bransfield Strait (a back-arc system) appear to be unlike The application of low-temperature thermo- anything sampled so far from submarine chronologic methods has made fundamental vents. contributions to our understanding of the uplift and denudation history of the · Preliminary evidence suggests that venting Transantarctic Mountains and the Ellsworth in the Bransfield Strait region occurs in two Mountains. It is expected that additional data different volcanic substrates: andesite and that integrates both fission track and 40Ar/39Ar rhyolite. This situation provides a natural thermochronology will lead to a better under- laboratory for investigating the effects of standing of the geological evolution and rela- substrate chemistry on vent fluid composi- tionship between the west antarctic rift sys- tion. tem, its uplifted rift shoulder, and East and · The Bransfield Strait, isolated from the West Antarctica. (GO-059-O) system of midocean ridges, has a relatively short history of rifting (approximately 4

U.S. Antarctic Program, 1998-1999 27 million years). So, although the region southern Gondwanaland from Australia to straddles the Atlantic and Pacific, vent biota Antarctica to South America and in the strait may well have a distinct gene- · of a complex of marsupials composed of alogy. Biochemical information on vent relict peradectids and more derived early species in the Bransfield will add to our members of australidelphians. knowledge of the dispersal of life in the deep ocean. In the past, such discoveries The australidelphians should include early have led to the identification of new species members of the (currently) South American and the isolation of previously unknown Microbiotheriidae as well as early lineages of biochemical compounds. the (currently) Australian Peramelina, Dasyu- · The fire-and-ice environments of hy- romorphia, and Diprotodontia. drothermal sites in the Bransfield Strait We will test this hypothesis in terms of the may prove to be the closest analog for pri- composition of the Maestrichtian land mam- mordial environments on Earth and extra- mal fauna by conducting field research in terrestrial bodies. The Bransfield Strait is Vega Island of the James Ross Island basin, one of the most productive areas of the Antarctic Peninsula. The location has been world's oceans and lies close to the antarctic chosen on the basis of its known productivity continent, far removed from the midocean in yielding Maestrichtian-age vertebrates ridge system. The combination of organic- (presbyornithid birds and hypsilophodont di- rich sediment and heat produced by vol- nosaurs) in near-shore fine-grained shallow- canism in this back-arc setting creates a water marine sandstones of the Lopez de situation conducive to unusual fluids, Bertodano Formation that are amenable to dry unique vent biota, and exotic hydrothermal or wet sieving collecting methods. Such meth- deposits. (GO-060-O) ods have proven successful in obtaining fossil Maestrichtian Land Mammals of Vega Is- mammals from similar facies in the medial land, Antarctic. Judd A. Case, St. Mary's Uni- Eocene La Meseta Formation of Seymour Is- versity. The Maestrichtian is considered to land. have been a key interval in the development of This is a cooperative project with the Antarctic the land mammal fauna of southern Gond- Institute, Argentina, (IAA) and the Museo de wanaland from Australia to Antarctica and La Plata, Argentina (MLP). MLP personnel are South America. Until now, no Maestrichtian collaborating on research into the evolutionary fossil land mammals have been found in any history of Late Cretaceous to early Tertiary of these continents. The Lopez de Bertodano therian mammals in South America and Ant- Formation of Vega Island, Antarctic Peninsula, arctica and the potential relationship of these shows the best potential of yielding remains of to the early population of Australia. The col- land mammals of Maestrichtian age in any laboration with IAA personnel is focused on southern Gondwanaland location. This proj- litho- and biostratigraphy of the marine suc- ect, a collaborative venture between St. Mary's cessions. The first grant year (1997–1998) fo- University, the University of California at Riv- cused on examining existing material. Years 2 erside, and Argentine scientists, is designed to (1998–1999) and 3 (1999–2000) will focus on take advantage of that opportunity. Current fieldwork on Vega Island and follow up ex- theory predicts that the presently unknown amination of any fossil discoveries. (GO-061- Maestrichtian-age land mammal fauna in Ant- O) arctica should consist The SWEAT model and Neoproterozoic– · of a suite of nontherian taxa remnant from Cambrian orogenies in Antarctica: Tests from an Albian–Campanian fauna that occupied

28 U.S. Antarctic Program, 1998-1999 the Nimrod Glacier region. Anne Grunow, unlikely. We will conduct a GPR survey of Ohio State University. The Southwest U.S.–East the best example, which is below Denton Antarctica (SWEAT) model, which places the Glacier in eastern Wright Valley. ancient continent Laurentia against East Ant- · Large moraines. Using form and structure arctica and Australia in the Neoproterozoic, analyses, we postulate that large moraines continues to be a controversial and exciting are stratified. If we are correct, these fea- subject for researchers. We will test the tures reflect deposition from valley glaciers SWEAT hypothesis by providing tighter age with strong melting margins. Deposition of constraints on the purported Rodinia rifting- this type implies that at least the regional related sedimentary and volcanic rocks and antarctic ice/climate system was in a sub- determining a paleolatitude and paleopole for polar state that was warmer, wetter, and the central Transantarctic Mountains at this more dynamic than the high-polar state. time. Using GPR, we will study two such mo- Researchers believe that following rifting, raines in central McKelvey Valley possibly these Neoproterozoic rocks were deformed associated with glaciolacustrine sediment during the poorly understood Beardmore and and one such moraine in central Wright Ross orogenies. In addition to testing the Valley associated with glaciomarine sedi- SWEAT hypothesis, we will also provide fur- ment. The internal composition of these ther structural and geochronologic data to features is presently unknown. constrain the timing and kinematics of these In addition, we will use conventional surficial deformational events. (GO-062-O) geologic techniques to examine a few distinc- A test for Tertiary-age deep fluvial incision tive drift patches that crop out asymmetrically and strongly melting valley-glaciers in the on trunk-valley walls. These patches appear to dry valleys using ground-penetrating radar: be traceable into high alpine valleys and so A pilot project. Michael Prentice, University of may have been deposited from expanded al- New Hampshire. During our project, we will pine glaciers that merged with trunk-valley study two types of large morphologic features glaciers. If we are correct, these patches record in the McMurdo Dry Valleys using ground- the synchronous advance of alpine and penetrating radar (GPR), a technique not pre- trunk-valley glaciers. A synchronous advance viously used on antarctic sediments. implies that the coeval climate was significantly wetter and warmer than in the · Spurlike aprons. Situated below tributary high-polar state. (GO-063-O) valleys that project into trunk valleys, spurlike aprons are inferred to be remnants Holocene paleoenvironment change along of bedrock fluvial spurs that document the Antarctic Peninsula: A test of the bipo- preglacial fluvial incision of trunk-valley lar/solar signal. Eugene Domack, Hamilton Col- floors to sea level. If this interpretation is lege. During this multidisciplinary, multi- correct, the implication is that a major sec- institutional project, we will work to elucidate tor of the Transantarctic Mountains land- the detailed climate history of the Antarctic scape is largely fluvial and not glacial in Peninsula during the Holocene epoch (the last origin. For this to be true, the antarctic 10,000 years). The Holocene is an important, ice/climate system must have been re- but often overlooked, portion of the antarctic stricted to its current high-polar state and paleoclimatic record because natural variabil- so quite stable throughout the Tertiary ice ity in Holocene climate on timescales of dec- ages. We think that the bedrock-spur inter- ades to millennia can be evaluated as a model pretation is unsupported and, from the for our present "interglacial" world. standpoint of form and structure analyses, U.S. Antarctic Program, 1998-1999 29 Our project builds on over 10 years of prior station consists of a triaxial broadband bore- investigation into the depositional processes, hole seismometer at 100 meters depth and a productivity patterns, and climate regime of vertical short-period instrument at 30 meters the Antarctic Peninsula. This previous work depth. These data are digitized at the remote identified key locations that contain ultra-high- location and then are radio-frequency teleme- resolution records of past climatic variation. tered via repeaters on Mount Newell and These data indicate that solar cycles operating Crater Hill, eventually to the recording com- on multicentury and millennial timescales are puter located in the Hatherton Laboratory at important regulators of meltwater production Scott Base. Although archived at Scott Base for and paleoproductivity. These marine records backup purposes, the data do not stop flowing can be correlated with ice-core records in at this point. The data pass via a point-to-point Greenland and Antarctica. protocol link to the Internet at McMurdo Sta- tion and then on to the Albuquerque Seismol- We will study sediment dispersal patterns ogical Laboratory for distribution to the seis- across the Palmer Deep region. The objective mological community. This data set has beau- is to understand the present links between the tifully complemented the data from the other modern climatic and oceanographic systems seismic stations that the Albuquerque Seis- and sediment distribution. In particular, addi- mological Laboratory operates on the antarctic tional information is needed regarding the in- continent at Amundsen–Scott South Pole Sta- fluence of sea ice on the distribution of both tion, Palmer Station, and the Australian sta- biogenic and terrigenous sediment distribution, Casey. (GO-078-O) tion. Sediment samples will be collected with a variety of grab sampling and coring devices. Global positioning system measurements of Two additional objectives are the deployment crustal motion in Antarctica. Barclay Kamb, of sediment traps in front of the Muller Ice California Institute of Technology. We will estab- Shelf in Lallemand Fjord and seismic reflec- lish a global positioning system (GPS) geo- tion work in conjunction with site augmenta- detic network in the Transantarctic Mountains tion. The goal of sediment-trap work is to ad- of Antarctica to measure vertical and hori- dress whether sand transport and deposition zontal crustal velocities. The vertical crustal adjacent to the ice shelf calving line results velocities measured by GPS reflect the vis- from meltwater or aeolian processes. In addi- coelastic response of the solid Earth to antarc- tion, the relationship between sea-ice condi- tic deglaciation. Data from this GPS network tions and primary productivity will be inves- will be used to test models of late Pleistocene– tigated. The collection of a short series of early Holocene versus late Holocene deglacia- seismic lines across the Palmer Deep basins tion of Antarctica. These data will also con- will fully resolve the question of depth to strain the length of time over which the ant- acoustic basement. (GO-072-A) arctic ice sheet disintegrated and the distribution of the peak glacial load. A mid-Holocene Dry valleys seismograph project. Bob Rey- deglaciation model produces a predicted up- nolds, U.S. Geological Survey. The dry valleys lift pattern near the Transantarctic Mountains seismograph project was established in coop- that can be measured by high-precision GPS eration with the New Zealand Antarctic Pro- geodetic measurements within a time span of gram to record broadband, high-dynamic- 4 years. range digital seismic data at a remote site removed from the environmental and anthropo- Horizontal deformation induced by rebound genic noise on Ross Island. The Wright Valley will also be measured. These data will also offers one of the few locations on the continent help constrain present-day changes in antarc- where bedrock can be accessed directly. The tic ice mass by monitoring the elastic defor-

30 U.S. Antarctic Program, 1998-1999 mation of the lithosphere resulting from on- · characterizing variations in the ice-sheet going glacial loading and unloading. The grounding zone in a latitudinal transect lithospheric response to ongoing ice-mass extending from Ross Sea to Bransfield Ba- changes is predicted to be an order of magni- sin, tude less than the viscoelastic response to late · reconstructing conditions at the ice/bed Pleistocene–Holocene deglaciation. Tectonic interface before and after ice-sheet retreat, uplift rates are also predicted to be very small and compared to the predicted rebound signal for this region. Baselines across faults in the · radiometrically dating ice-sheet retreat Transantarctic Mountains may capture co- along this transect. seismic motion, if an earthquake were to occur, or aseismic slip. Detailed seafloor imagery (multibeam and deep-tow side-scan sonar), high-resolution During the 1998–1999 field season, we will seismic reflection profiles, and sediment cores visit existing autonomous GPS station (AGS) will be used to map and characterize prior sites at Mount Coates and Mount Cox to per- grounding zones. form maintenance, upgrades, and repairs. We will also perform geodetic surveys at Mount Of particular concern are features that indicate Coates and Mount Cox to assess site stability the amount and organization (channelization) and to ensure recovery of the site in case the of basal meltwater and the extent of bed de- original pin is damaged or unstable. Finally, formation that occurred in different ice we will search for areas that would be suitable streams. The timing of ice-sheet retreat pro- for future sites in the AGS network, and we vides information about the link between may install a new AGS this season. Northern and Southern Hemisphere ice expansion and the role of eustasy in ice-sheet The AGS network sends daily data reports to decoupling. Our research should lead to better McMurdo Station. The network is designed to predictive models to determine which ice be a permanent installation that will continue streams are most unstable and likely, there- to monitor motion in the region beyond the fore, to serve as "weak links" in the long-term term of this project. Advanced processing behavior of west antarctic ice sheet. (GO-083- techniques have been employed to increase O) the accuracy of the crustal velocity measurements, especially for the vertical component. Scotia Arc GPS Project (SCARP). Lawrence A. These include orbit modeling, troposphere Lawver, Ian W. Dalziel, and Frederick W. Taylor, University of Texas at Austin. Antarctica, Earth's correction, ionosphere correction, and extraction of annual and seasonal solid Earth and most isolated continent, is surrounded by ac- tively spreading ridges except in the South ocean tidal signals. (GO-082-O) American sector. The motion of South Amer- Mechanism and timing of west antarctic ice ica with respect to Antarctica is latitudinal and sheet retreat at the end of the last glacial left-lateral at approximately 22 millimeters per maximum. John B. Anderson, Rice University. year and is distributed along the boundaries of We will continue a long-term investigation of the intervening Scotia Plate. A prominent but the continental shelf sediments to examine the discontinuous bathymetric high, known as the configuration of the west antarctic ice sheet Scotia Ridge surrounds the Scotia Plate on during the last glacial maximum, the events three sides, and includes some continental and mechanisms involved in its retreat, and material detached from the South America the timing of retreat. Our project involves and Antarctica, but its eastern closure is a volcanically and seismically active group of is-

U.S. Antarctic Program, 1998-1999 31 lands, the South Sandwich arc, that is sepa- · strain partitioning within the South Amer- rated from the Scotia Plate by a vigorously ica–Scotia Plate boundary zone, Tierra del spreading back-arc ridge. The entire east- Fuego; closing, locally emergent bathymetric feature · the rate of extension across the volcanically joining the two continents is known as the active Bransfield trough and the present Scotia Arc. rate of uplift or subsidence of the extinct The D-shaped Sandwich Plate and arc appear South Shetland Islands volcanic arc; and to be moving rapidly east with respect to both · with our British colleagues, the rate of roll- South America and Antarctica, thereby for the back of the South Sandwich Trench in a first time introducing a subduction system South American-African framework. (GO- into the otherwise rift-bounded South Atlantic 087-O) Ocean basin. During this Scotia Arc GPS Proj- ect (SCARP), we will use the global position- Logistics support for global seismic station at ing system (GPS) to measure the plate motions the South Pole. Rhett Butler, Incorporated Re- between South America, Antarctica, and Af- search Institution for Seismology. With logistics rica, and around the Scotia Arc using multi- support from the National Science Founda- modal occupation strategy (MOST). We will tion, we will install, maintain, and operate set up permanent GPS receivers at a small IRIS seismic equipment at Amundsen–Scott number of sites in South America and Antarc- South Pole Station and at Palmer Station, Ant- tica and use additional receivers to position arctica. numerous stations relative to this continu- The Incorporated Research Institution for ously operating network. Two seasonally occupied stations in the South Sandwich Islands Seismology (IRIS) is a consortium of research institutions created to implement critically will be tied to permanent GPS sites in South needed national facilities for support of seis- America, Antarctica, and Africa and to inter- mological research on the Earth's interior in vening stations in the Falkland, South Geor- the coming quarter century. With a member- gia, and South Orkney Islands that will be oc- ship of 57 universities, IRIS includes nearly all cupied occasionally by our British collabora- U.S. universities that have seismological re- tors. search programs. During the initial 3 years, the South Sandwich IRIS has developed a 10-year plan for the im- Arc motion will be easily resolved, and using plementation of a global seismographic net- roving stations in the Antarctic Peninsula– work (GSN) of about 100 broadband, digital, South Shetland Islands area, it should be wide-dynamic-range stations that transmit possible to determine if extension is occurring data via satellite in a broadcast mode so that across Bransfield Strait. We will also construct any site on Earth can access the complete a relatively dense subnetwork in Patagonia/ global data set, if desired, in real time. The in- Tierra del Fuego and a moderately dense stallation of a state-of-the-art, broadband, subnetwork in the Antarctic Peninsula. digital seismic observation for the South Pole The objectives of SCARP are to determine is part of an effort by the National Science Foundation to improve seismic instrumenta- · the relative motions of the Antarctic, South tion globally. A modern seismic station at American, Scotia, and South Sandwich South Pole and Palmer will provide a crucial plates; link in the global seismic network and is essential for seismic studies of the antarctic continent. (GO-090-O and GO-091-O)

32 U.S. Antarctic Program, 1998-1999 A broadband seismic experiment for study of Answering these questions will help to con- the tectonics and structure of the Antarctic strain important tectonic questions such as the Peninsula and Scotia Sea. Douglas Wiens and cause of plate motion changes, what processes Dapeng Zhao, Washington University. The pres- initiate back-arc spreading, and the relation- ent-day tectonics and seismological structure ship between mantle flow and surface tecton- of the Antarctic Peninsula and Scotia Plate re- ics. (GO-097-O) gion are among the most poorly understood of any location in the world. This region offers a Study of the structure and tectonics of the unique and complex geodynamic setting, as South Shetland Trench and Bransfield back- illustrated by the recent cessation of volcanism arc using ocean-bottom seismographs. LeRoy along the South Shetland Trench and onset of M. Dorman, Scripps Institution of Oceanography. volcanism and rifting in the Bransfield Strait, The South Shetland Arc/Bransfield Strait re- the possible presence of diffuse deformation gion presents an intriguing and unique tec- and/or microplates in the Drake Passage re- tonic setting that exhibits slowing of subduc- gion, and fast back-arc spreading behind the tion, cessation of island arc volcanism, as well South Sandwich arc. as the apparent onset of back-arc rifting occurring within the last 4 million years. To investi- We constitute the U.S. component of an inter- gate the seismicity and tectonics of the region, national effort to study the seismotectonics we will use a 5-month deployment of 14 and seismic structure of the Antarctic Penin- ocean-bottom seismographs (OBSs) to com- sula and Scotia Sea regions using a large-scale plement and extend a deployment of six deployment of broadband seismographs that broadband land seismic stations that were began during the 1996–1997 field season. The successfully installed during early 1997. The project will deploy nine broadband PASSCAL OBSs include two instruments that have seismographs for 2 years in the Antarctic broadband sensors; all have flowmeters for Peninsula region, southernmost Chile, and measuring and sampling hydrothermal fluids. South Georgia Island. The following questions will be addressed. The OBSs will be used to examine many of the characteristics of the Shetland–Bransfield tec- · Is there seismological evidence, in the form tonic system, including the following. of either subduction zone earthquakes or seismic structure, for current subduction · The existence and depth of penetration of a beneath the Antarctic Peninsula? Shetland Slab. · Is there evidence from seismic anisotropy · The possibility of shallow Shetland trench for large-scale mantle flow around South seismicity. America into the South Atlantic? · The mode of deformation along the Brans- · Are regional earthquakes and focal mecha- field rift. nisms consistent with current kinematic · The identification of volcanism and hy- Scotia Plate models, which imply compres- drothermal activity. sional deformation in the Drake Passage · The possibility that upper mantle structure region? of the Bransfield is evidence of partial · What is the deep structure of the South melting. (GO-135-O) Sandwich subduction zone? Antarctic network of unattended broadband · What is the seismological structure of active integrated seismometers (ANUBIS). Sridhar back-arc spreading centers in the Bransfield Anandakrishnan, Pennsylvania State University. Strait and South Sandwich regions? The antarctic crust and mantle composition

U.S. Antarctic Program, 1998-1999 33 and geometry are poorly known. The primary powered and heated by wind turbines during method for studying the crust, upper mantle, the austral winter. (GO-180-O) and the deeper asthenosphere is interpretation of seismic data, either by "active" methods ac- Ferrar Large Igneous Province Study (FLIPS). quired through use of explosives or by "pas- Philip Kyle, New Mexico Institute of Mining and Technology. This international collaborative sive" means, using natural sources and interpreting various earthquake phase arrival times research project will involve the New Mexico and amplitudes. Integrating passive and active Institute of Mining and Technology and the seismology can result in efficient use of re- British Antarctic Survey (BAS). The objective sources to produce detailed images of the is to understand the origin, emplacement, and lithosphere. Our project will develop a passive evolution of antarctic Jurassic (180-million- seismic network for the antarctic interior. year-old) basaltic rocks, which formed when the Gondwanaland supercontinent started to The Antarctic is a gaping hole in the rapidly disintegrate. We will test a new unified model improving field of global seismic imaging and for this 180-million-year-old magmatic activity tomography. On this huge continent, there are in which the magmatism is caused by a single only eight broadband seismic observatories. mantle superplume and is a major factor in Further, with the exception of South Pole, all continental rifting. of those stations are along the margins of the continent and none are in West Antarctica. By In Antarctica, the Jurassic basaltic rocks are contrast, there are 200 permanent stations divided into two provinces: Ferrar Large Ig- worldwide in the FDSN (Federation of Digital neous Province (FLIP) and the Dronning Seismograph Networks) and on the order of Maud Igneous Province (DMIP). (The official 1,000 in national networks not yet integrated U.S. name for Dronning Maud Land is Queen into the FDSN. Maud Land. The foreign term will be used for this project because it is a collaboration with We will develop and deploy 11 long-term BAS.) The origin of the FLIP is problematical broadband seismic stations on the continent and a plume origin has generally been dis- itself. Because 98 percent of the continent is ice counted because of its lateral distribution over covered, these stations will be installed at the 3,000 kilometers along the Transantarctic surface of the ice sheet. The body-wave data Mountains and also in southern Australia. The thus recorded from regional and teleseismic FLIP is characterized by unusual geochemical earthquakes can be analyzed at each station compositions, which have been attributed to for local crustal thickness, lamination, Pois- their origin from an enriched mantle source. In son's ratio (a measure of crustal composition), the model we are investigating, the FLIP crust and mantle anisotropy (a measure of magma would have been significantly con- current and former stress regimes), and identi- taminated in an upper continental crustal fication of rift zones and crustal block bounda- magma chamber (probably the Dufek Intru- ries. In addition, the data from all the stations sion) whereas the DMIP has distinctly mantle- (including the existing peripheral ones) can be like chemical characteristics but still shows used for seismic tomographic analysis to de- some evidence of modification by crustal ma- tail lateral variations in these properties. Six of terial. the stations will be installed at existing automatic geophysical observatory sites (in East In this research, we will examine and sample Antarctica), which will provide heat and the rocks of the DMIP and rocks of the FLIP in power for the data loggers. The remaining five the Theron and Pensacola Mountains and stations will be in West Antarctica and will be Dronning Maud Land and conduct an integrated study of the age, geochemistry, and

34 U.S. Antarctic Program, 1998-1999 structural relationships of the FLIP and DMIP. The UNAVCO facility in Boulder, Colorado, Radiometric age determinations will examine offers a complete support program for univer- the age relationship between the FLIP and sity-based investigators including DMIP. Models for upper crustal contamina- · preseason planning, tion of the FLIP magmas will be tested using isotopic studies and geochemical modeling. · GPS equipment, Other studies, conducted by our BAS collabo- · training, rators, include a regional aerogeophysical survey to determine the size and shape of the Du- · field support and technical consultation, fek Intrusion and a detailed survey to search and for a feeder dike system from the body. (GO- · data processing and archiving. 182-O) UNAVCO also represents the academic re- UNAVCO's global positioning system research community and acts as a central clear- ceiver. Randolph H. Ware, University Center for inghouse for information on the scientific ap- Atmospheric Research. UNAVCO, a consortium plications of GPS. As a part of its service to of 30 U.S. universities, manages a satellite fa- investigators, UNAVCO tests GPS equipment cility at McMurdo Station and provides and techniques and works to improve GPS equipment and logistical assistance to earth surveying accuracy. (GO-295-O) scientists making use of the global positioning system (GPS) for research in crustal dynamics, Support Office for Aerogeophysical Research earthquake, volcano, and global change re- (SOAR). Donald D. Blankenship, University of search. Using GPS, vector baselines between Texas at Austin. The function of the Support receivers separated by 100 kilometers or more Office for Aerogeophysical Research (SOAR) are routinely measured with 1 centimeter (or is to facilitate aerogeophysical research over 100 parts per billion) accuracy. UNAVCO is continental Antarctica to help researchers un- also able to support researchers in investiga- derstand the dynamic behavior of the ice sheet tions of global, regional, and local crustal mo- and the nature of the lithosphere beneath the tions where maximum accuracy (in the milli- ice sheet. SOAR supports peer-reviewed re- meter range) of baseline measurement is research requiring high-precision laser altime- quired. In addition to supporting researchers try, gravity, magnetics, and navigational data in the U.S. Antarctic Program, UNAVCO's sets. equipment and expertise also support operations at McMurdo Station and Taylor Valley. SOAR provides information essential to site selection decisions for a west antarctic ice core GPS measurements can be completed using as well as critical information for selection of portable equipment in a few hours or less. The locations of over-snow seismic transects. ability to make such measurements has found SOAR represents a unique experiment in re- immediate applications in research on global search support for the U.S. Antarctic Program. plate tectonics, earthquake mechanics, volcano It has the potential to revolutionize the con- monitoring, and regional tectonics. duct of earth science and glaciology research in Antarctica. (GS-098-O)

Glaciology lor, Desert Research Institute. Our project, which Recovery and science coordination of an ice core at Siple Dome, Antarctica. Kendrick Tay- will recover a 1,000-meter ice core from Siple

U.S. Antarctic Program, 1998-1999 35 Dome, Antarctica, and coordinate a science diation penetration processes have a signifi- management office for the scientific program, cant effect. is part of the West Antarctic Ice Sheet (WAIS) program, which seeks to understand the cur- Field studies at the two west antarctic ice sheet rent behavior of the west antarctic ice sheet deep-drilling sites will be conducted to deter- and to decipher its past climate history. Siple mine the spatial and temporal extent for key Dome is located between ice streams C and D parameters and boundary conditions needed and is well situated to investigate coastal cli- to model the advection, conduction, and ra- mate conditions and the dynamics of the Siple diation transmission/absorption processes. Coast ice streams, which drain the west ant- An existing multidimensional numerical arctic ice sheet. The annual accumulation at model is being expanded to simulate the proc- the site is 7 to 11 centimeters of ice per year, esses and to serve as the basis for ongoing and and it is anticipated that annual layers will be future work in transport and distribution of identifiable to an age of at least 6,000 years. reactive chemical species. (II-155-O) The length of the usable climate record will Physical and structural properties of the extend to at least 80,000 years. Siple Dome Core. Anthony Gow, Cold Regions We provide the background for the Siple Research and Engineering Laboratory. We will Dome drilling program, develop the opportu- investigate the visual stratigraphy, index nity for individual scientists to work on the ice physical properties, relaxation characteristics, core, and establish a science coordination of- and crystalline structure of ice cores from fice to coordinate the activities of the various Siple Dome, West Antarctica. Our investiga- organizations involved in the project, includ- tion will include time-sensitive measurements ing the National Science Foundation (NSF), that must be initiated at the drill site on the Polar Ice Coring Office (PICO), Antarctic freshly drilled cores. This need will be espe- Support Associates (ASA), and the National cially pressing for cores from the brittle ice Ice Core Laboratory (NICL). (II-152-O) zone, which is expected to constitute a significant fraction of the ice core. The brittle zone Near-surface processes affecting gas ex- includes ice in which relaxation, resulting change: West antarctic ice sheet. Mary Albert, from the release of confining pressure, is Cold Regions Research and Engineering Labora- maximized and leads to significant changes in tory. We will examine the physical processes the mechanical condition of the core that must that affect how heat, vapor, and chemical spe- be considered in relation to the processing and cies in air are incorporated into snow and po- analysis of ice samples for entrapped gas and lar firn. The processes include advection, dif- chemical studies. This relaxation will be fusion, and the effects of solar radiation pene- monitored via precision density measure- tration into the snow. An understanding of ments made initially at the drill site and re- these processes is important because they peated at intervals back in the United States. control the rate at which reactive and nonre- active chemical species in the atmosphere be- Other studies will include measurement of the come incorporated into the snow, firn, and annual layering in the core to as great a depth polar ice and, thus, will affect interpretation of as visual stratigraphy can be deciphered, polar ice-core data. Currently, the interpreta- crystal size measurements as a function of tion of polar ice-core data assumes that diffu- depth and age, c-axis fabric studies, and sion controls the rate at which chemical spe- analysis of the physical properties of any de- cies are incorporated into firn. We will deter- bris-bearing basal ice and its relationship to mine whether ventilation, or advection of the the underlying bedrock. Only through careful species by air movement in the firn, and ra- documentation and analysis of these key

36 U.S. Antarctic Program, 1998-1999 properties can we hope to assess accurately Technology. To obtain observational evidence the dynamic state of the ice and the age-depth of the cause of rapid flow of the great ice relationships essential to deciphering the pa- streams in the west antarctic ice sheet, we leoclimate record at this location. (II-165-O) have drilled a number of boreholes through ice stream B and C for measurement of the The evolution of a polar ice sheet in East physical conditions and sampling of materials Antarctica. George Denton, University of Maine at the base of the ice, where lubrication of the at Orono. We hope to determine the sequence rapid flow is thought to take place. In the and chronology of events that led to the de- 1998–1999 season, the scope of our study will velopment of the antarctic ice sheet. A conti- be widened to include ice stream D, situated nental-scale ice sheet probably first developed some 100 kilometers north of C. Several bore- in East Antarctica close to the Eocene- holes will be drilled by the hot-water drilling Oligocene boundary under temperate climatic method to measure the basal water pressure, conditions. We hope to learn, from landscape basal water transport, basal melt rate, basal analysis (with a numerical chronology), when sliding velocity, deformation, and sedimentol- (and why) these early temperate conditions ogy including fossil content of subglacial till if gave way to a polar environment in present, basal shear strain rate in the ice, and Antarctica. ice temperature profile. Our objective is to find From previous fieldwork and recent photo- out if the physical conditions and materials graphic analysis, an extensive relict landscape observable by borehole geophysics at the base (older than 17 million years) with landforms of ice stream D are consistent with those and erosional features characteristic of tem- found in ice stream B and point to a common perate glaciation has been delineated. This basal mechanism of ice streaming. We will relict landscape has been called the Sessrumnir obtain hot-water drilled ice cores to reveal the erosion surface, and it extends over 3 degrees of internal structure of the ice stream for evalua- latitude and covers almost 10,000 square kilo- tion of the basal shear stress and rock debris meters in three fault blocks of the Trans- content of the ice and for comparison with B antarctic Mountains (Convoy, Dry Valleys, and C. (IO-157-O) and Royal Society). From this relict land Digital imaging for ice core analysis. Joan J. surface, we will collect data that record Mid- Fitzpatrick, U.S. Geological Survey, National Ice dle and Early Miocene glacial history and pa- Core Laboratory. Over 2 years we will develop leoclimate. The results should allow an identi- the technology and methodology for digitiz- fication of the transition from temperate to ing photographs and analyzing thin sections polar conditions. Our work will involve land- from ice cores. Besides applying digital tech- scape analysis, stratigraphy of glacial deposits, nology to whole-core stratigraphy, we will and argon-40/argon-39 dating of volcanic ash- investigate the use of digital photography, im- falls. The rates at which erosion is exposing age enhancement and image processing. The the rock strata (denudation) will come from thin section analysis will be piloted with sam- fission-track analyses and from exposure-age ples already in hand from the Taylor Dome ice analyses of bedrock surfaces and erratic boul- core. During the 1998-1999 austral summer, ders. The overall results will elucidate the ori- we will identify visual characteristics of ice gin and stability of the polar antarctic cryos- from the West Antarctic Ice Sheet near Siple phere. (IO-156-O) Dome. As the deep core is recovered it will be Basal conditions of ice stream D and related cut, sectioned, photographed, and analyzed. borehole studies of antarctic ice stream me- The original digital images, along with the chanics. Barclay Kamb, California Institute of original annotated data files, will be distributed to Siple Dome principal investigators to

U.S. Antarctic Program, 1998-1999 37 use in interpreting their own data. All soft- ferent, relatively new, high-resolution systems ware and hardware acquired for this project for its measurement in hot-water drilled holes will become part of the permanent equipment will be employed. The iceflow model resulting inventory at the U.S. National Ice Core Labo- from the measurements and flow-law deter- ratory and will be available for use by clients mination will be used to interpret the shapes at the facility. (II-160-O) of radar internal layering in terms of the dynamic history and accumulation patterns of Internal stratigraphy and basal conditions at Siple Dome over the past 10,000 years. The the margins of active ice streams of the Siple resulting improved model will also be applied Coast, Antarctica. Charles F. Raymond, Univer- to the interpretation of the thicknesses of the sity of Washington. To examine the geometry of annual layers (to produce annual accumula- the internal layering and the presence or ab- tion rates) and borehole temperatures from the sence of thawed zones outside the margins of ice core drilled at Siple Dome. The results active ice streams B and E and across the flow should permit an improved analysis of the ice band feeding ice stream D, we will use sur- core, relative to what was possible at recent face-based radio-echo sounding. coring sites in central Greenland. This is a Melting in the marginal shear zone and/or on collaborative project between the University of the bed outside an ice stream relates to the Alaska, the University of California at San Di- amount of support of the ice stream from the ego, and the University of Washington. (IO- sides compared to the bed and the conditions 164-O) that limit expansion of its width. Radar obser- Stress transmission at ice-stream shear mar- vations will be extended over the crest of adja- gins. Ian Whillans, Ohio State University. Our 3- cent inter-ice-stream ridges (B/C and D/E) year project will study stress transmission at and areas next to the flow band in the onset of three ice-stream shear margins. The objectives D. The purpose is to examine internal layering are indicative of the histories of these areas adjacent to ice streams and to determine whether, · to determine how much of the motion of in the past, ice streams have expanded into the ice streams is controlled from the inter- these presently stable areas. These goals con- stream ridges, cerning the physical controls and history of · to compare the magnitude of this lateral ice-stream width relate to how the discharge drag with the driving stress on the ice of ice streams has changed in the past and stream and with ice-stream width, and could change in the future to affect sea level. (IO-163-O) · to determine whether lateral drag support is associated with lateral migration of the Ice dynamics, the flow law, and vertical margin. strain at Siple Dome. William Harrison, Uni- versity of Alaska Fairbanks. Our 3-year project The net force per unit ice-stream length will measure the vertical strain rate as a func- transmitted between ridge ice and ice-stream tion of depth at two sites on Siple Dome, Ant- ice will be deduced from measurements of arctica. Iceflow near a divide such as Siple strain rate. Dome is unique because it is predominantly Fieldwork will entail Twin Otter installation of vertical. As a consequence, the component of remote camps that will each be occupied for ice deformation in the vertical direction, the about 12 days during the first season and vertical strain rate, is dominant. Its measure- about 6 days during the second. The Support ment is, therefore, important for the calibra- Office for Aerogeophysical Research in Ant- tion of dynamic models of iceflow. Two dif- arctica (SOAR) facility will conduct aerial sur-

38 U.S. Antarctic Program, 1998-1999 veys to determine ice thickness on the inter- Late Pleistocene inland west antarctic ice stream ridges, as well as the ice thickness and sheet elevations at Mount Takahe. William C. surface slope on the ice streams. The field McIntosh, Thomas I. Wilch, and Nelia W. Dunbar, measurements will be complemented by re- New Mexico Institute of Mining and Technology. peat SPOT imagery of ice stream E adjacent to Our objective is to establish a detailed record the field site, to allow velocities in the of volcanism at Mount Takahe volcano in ice-stream side of the margin to be deter- Marie Byrd Land and provide absolute age mined. Comparing these velocities to those and elevation data on inland paleoice levels on obtained from the strain-grid surveys will the west antarctic ice sheet during the most provide an estimate of the amount of soften- recent glacial cycle. ing of the ice in the margins. (IO-169-O) Previous work at Mount Takahe documented West Antarctic Glaciology V. Robert Bind- volcanic deposits located on the lower flanks schadler, National Aeronautic and Space Admini- that were erupted beneath, at, or above the stration. Our 3-year project is designed to an- level of the west antarctic ice sheet. These de- swer two questions of critical importance to posits have been dated to between 104,000 and understanding the iceflow of the west antarc- 7,000 years before present and suggest that the tic ice sheet: inland west antarctic ice sheet was much higher during the last glacial cycle than it is · Are the Ross ice streams (B, D, and E) cur- today. rently surging? · What has been the buttressing effect of an The inland paleoice level can be used to test enlarging Crary Ice Rise on the flow of ice conflicting hypotheses about the configuration stream B? of the west antarctic ice sheet in the late Wis- consin and the role of ice-sheet retreat in Both questions will be answered based on a global sea-level rise. Well-constrained limits combination of data collected on the surface, on inland paleoice levels during the past from the air, and from space. Although many 100,000 years can be compared with global past indications of change in West Antarctica records of climate change to assess the rela- have been based on interpolations and calcu- tionship between the west antarctic ice sheet lations with large uncertainties, these meas- and the climate system. Finally, precisely urements will be direct, making use of rapid dated paleoice levels can be used as "hard" and accurate global positioning system data to input data for numerical models of ice-sheet minimize field logistic requirements. Direct dynamics. (IO-277-O) measurement of expected thinning in the upper portion of ice stream D and repeated sat- SOAR laser: Calibration and first measurement for ice-sheet change detection. Ian ellite image measurements at the heads of ice Whillans, Ohio State University. During a 3-year streams B, D, and E to detect the inland migration of the onset area (as is required by study, we will make precise and accurate sustained surging) will enable a test of a surge measurements of the elevation of the antarctic hypothesis developed by Bindschadler. The ice sheet to detect ongoing changes in the sur- buttressing impact of Crary Ice Rise on ice face of the ice sheet. The location and pattern stream B's flow will be studied by comparing of change discovered may be used to deduce new measurements of ice thickness, surface the causes of the changes. Suitable equipment elevation, and velocity with data collected for these measurements are part of the Sup- during the 1950s, 1970s, and 1980s, thus pro- port Office for Aerogeophysical Research in viding a multidecadal time series of change. Antarctica (SOAR) facility. We will evaluate (IO-173-O) the quality and calibrate the measurements to be made by SOAR. Tests will be made both U.S. Antarctic Program, 1998-1999 39 while the aircraft is parked and during flights capability of the SOAR facility to determine over ground-surveyed sites near the aircraft surface elevation accurately and precisely will base camp. After the validation and calibra- be established. SOAR will then be useful to all tion is complete, a limited measurement pro- investigators who are interested in precision gram to detect time changes in surface eleva- mapping and detection of change in the ant- tion of glaciologically interesting sites will be arctic ice sheet. (IS-166-O) started. At the conclusion of the program, the

Ocean and climate studies meteorological data from various sources: Antarctic Meteorological Research Center: 1996–2000. Charles R. Stearns and John T. Young, standard synoptic observations, radiosonde University of Wisconsin at Madison. The Ant- profiles, satellite-based visible and infrared arctic Meteorological Research Center imagery, atmospheric profiles inverted from multispectral scanning sensors, and nonstan- (AMRC), one of three research centers in the dard data such as thematic ozone mapping Science and Engineering Technology Center at spectrometer (TOMS) data, synthetic aperture McMurdo, is a resource for meteorological radar (SAR) sea-ice information, and the AWS research and a test bed for improving opera- network observations. The system automati- tional synoptic forecasting. cally registers, calibrates, and locates (by geo- The Man-Computer Interactive Data Access graphical coordinates) the input information System (McIDAS), a versatile computer-based and allows a user at a work station to ma- system for organizing, manipulating, and in- nipulate the database. The manipulations integrating antarctic environmental data, forms clude sectorization, false color, enhancements, the basis of AMRC. It captures the flow of brightness stretching, overlays, looping, and meteorological information from polar- differencing and are quite definitely keyed to orbiting satellites, automatic weather stations synoptic meteorological research and weather (AWSs), operational station synoptic observa- forecasting. The antarctic system is based pri- tions, and research project reports. It also re- marily on data streams provided by polar or- ceives environmental data products, such as biters (AVHRR/HRPT and DMSP), since the weather forecasts, from outside Antarctica and look angles from geostationary satellites are so acts as a repository for existing archived data- extremely low. The full utilization of McIDAS bases. capabilities in producing meteorological data products useful in both forecasting and re- Phase I began in the 1992–1993 summer sea- search will include a data transfer and com- son and consisted of the installation and op- munications capability to, for example, the eration of work stations capable of manipu- Australian Bureau of Meteorology (ABOM), lating and displaying Advanced Very High the University of Wisconsin Space Science and Resolution Radiometer (AVHRR) data based Engineering Center (SSEC), the Fleet Numeri- on the existing satellite imagery acquisition cal Oceanography Center (FNOC) in Mon- system. This effort was followed by the acqui- terey, and the European Center for Medium sition and integration of a system that pro- Range Weather Forecasts (ECMRWF) in vided data collection, data display and ar- Reading, U.K. (OO-202-O) chiving, scientific applications, network communications, and remote-user access. Atmospheric oxygen variability in relation to annual-to-decadal variations in terrestrial The McIDAS system, developed at the Univer- and marine ecosystems. Ralph F. Keeling, sity of Wisconsin in the mid-1970s, receives 40 U.S. Antarctic Program, 1998-1999 Scripps Institution of Oceanography. In this tory; Palmer Station: James T. Peters, Environ- project, we will continue measuring the mental Research Laboratories, National Oceanic concentration of molecular oxygen and carbon and Atmospheric Administration. The National dioxide in air samples. The samples are col- Oceanic and Atmospheric Administration lected at a series of baseline sites around the (NOAA) Climate Monitoring and Diagnostic world. The data will lead to improved esti- Laboratory team will continue long-term mates of the net exchange of carbon dioxide measurements of trace atmospheric constitu- with land biota and the oceans, marine photo- ents that influence climate and the ozone synthesis rates, and atmospheric mixing rates. layer. Four scientists will work at the Amund- These results are needed to improve our un- sen–Scott South Pole Station observatory derstanding of the processes regulating the during the austral summer, and two NOAA buildup of carbon dioxide in the atmosphere personnel will stay over the winter to measure as well as our understanding of the processes carbon dioxide, methane, carbon monoxide, regulating marine and terrestrial ecological aerosols, water vapor, surface and strato- functions in relation to various agents of spheric ozone, chlorofluorocarbons, wind, change, especially climate changes. In support pressure, air and snow temperatures and at- of the measurement program, we will develop mospheric moisture and other trace constitu- absolute standards for oxygen in air to ensure ents from the Atmospheric Research Obser- stable long-term calibration. We will conduct a vatory. These measurements are part of survey of the oxidative oxygen/carbon ratios NOAA's effort to determine and assess the of terrestrial and marine organic carbon to long-term buildup of global pollutants in the improve the quantitative basis for linking the atmosphere. The measurements will be used oxygen and carbon dioxide geochemical cy- for time-series analyses of multiyear data rec- cles. (OO-204-O) ords that focus on

Chlorine- and bromine-containing trace · seasonal and temporal variations in green- gases in the Antarctic. Reinhold A. Rasmussen house gases, and M.A.K. Khalil, Oregon Graduate Institution of · stratospheric ozone depletion, Science and Technology. We will collect a year-long suite of air samples at Palmer Sta- · transantarctic transport and deposition, tion to investigate the seasonal trend of the · interplay of the trace gases and aerosols trace gas concentration. At the Oregon Gradu- with solar and terrestrial radiation fluxes on ate Center, we will analyze the samples for a the polar plateau, and number of trace components, especially chlorine- and bromine-containing species. These · the development of polar stratospheric trace constituents have come from both bio- clouds over Antarctica. genic and anthropogenic sources, and they We will also determine the rates at which con- have the capacity to alter the Earth's climate centrations of these atmospheric constituents and to deplete the ozone layer in the way it change and will examine their sources, sinks, has recently been depleted above Antarctica. and budgets. Working with climate modelers This work is considered vital for a better un- and diagnosticians, we will use these data to derstanding of the buildup of trace constitu- determine how the rates of change of these ents, particularly those of high-latitude marine parameters affect climate, particularly when origin. (OO-254-O) the data are included in climate model studies. South Pole monitoring for climate change. In support of this project, Palmer Station per- Amundsen–South Pole Station: David Hof- sonnel also will collect carbon dioxide sam- man, Climate Monitoring and Diagnostics Labora- ples. (OO-257-O and OO-264-O)

U.S. Antarctic Program, 1998-1999 41 Drake Passage expendable bathythermo- oped by our French colleagues. In conjunction graph program. Ray Peterson, University of with the Australian and Japanese station net- California. In this project, we will analyze data works to the west of this study area, this work from bottom pressure gauges deployed across will allow an assessment of the influence of chokepoints for the southern ocean flow. Bot- cyclonic storm systems on the drainage flow tom pressure gauges were deployed between along the antarctic coast. (OO-263-O) South Africa and the antarctic coast close to the Greenwich Meridian and at two locations Investigation of Sulfur Chemistry in the spanning the Antarctic Circumpolar Current Antarctica Troposphere (ISCAT). Douglas D. (ACC) south of Tasmania. Simultaneously, the Davis and Fred L. Eisele,Georgia Institute of Tech- British deployed similar instruments in the nology. During this 4-year study, we will ex- Drake Passage. The main scientific goal of amine the sulfur chemistry in the antarctic at- these deployments was to determine the fluc- mosphere, working at Amundsen–Scott South tuations in the transport of the ACC and to Pole Station for two field seasons, 1998–1999 relate it to those in the subtropical and sub- and 2000–2001. The study, which includes 10 polar gyres and to the wind field over the principal and senior investigators at five in- southern oceans. (OO-260-O) stitutions with seven additional contributing investigators, has two broad-based goals: Katabatic winds in eastern Antarctica and · to improve substantially our current under- their interaction with sea ice. Gerd Wendler, standing of the oxidation chemistry of bio- University of Alaska Fairbanks. Our project is the genic sulfur in the polar environment, and continuation of an internationally collaborative (U.S.–French–Australian) study of kata- · to improve the climatic interpretation of batic winds along the coast of East Antarctica. sulfur-based signals in antarctic ice-core re- It is based on two lines of automatic weather cords. stations, one from Dumont d'Urville, the French station, inland to Dome C at an alti- The South Pole was selected because at this tude of greater than 3,200 meters, the other site, the atmospheric boundary layer presents along the coast. The coastal array includes a homogeneous and relatively simple envi- stations at Cape Denison and Port Martin, ronment from which to unravel the photo- which have recorded the highest average sur- chemically driven oxidation chemistry of di- face wind speeds on the globe (a monthly av- methyl sulfide. erage of 27.8 meters per second). One addi- Atmospheric sulfur chemistry is an important tional automatic weather station will be in- component in climate change issues because stalled 15 kilometers inland where model re- both naturally (i.e., from volcanic emissions sults predict even higher average wind and oceanic phytoplankton production) and speeds. These winds drive the sea ice offshore anthropogenically emitted sulfur compounds and are responsible for extremely high heat form minute particles in the atmosphere—the fluxes from the ocean to the atmosphere. so-called aerosols—that reflect solar radiation, Satellite-based active microwave imagery produce atmospheric haze and acid rain, and (synthetic aperture radar) will be combined affect ozone depletion. Sulfate particles in the with the observed meteorological data to atmosphere may also act as condensation nu- analyze the formation persistence and size of clei for water vapor and enhance global offshore polynyas as a function of wind speed. cloudiness. On the millennial timescale, the The effort to produce a numerical model of the variability and natural background level of regional atmospheric structure will continue, atmospheric aerosols can be reconstructed with the incorporation of a more detailed ter- from the preserved paleorecords of sulfur oxi- rain map, and a new mesoscale model devel-

42 U.S. Antarctic Program, 1998-1999 dation products in ice cores. It is necessary, at Palmer provides significant input for EML's however, to understand how the physical and database. (OO-275-O) chemical environment of the oxidation process affects the relative concentrations of the oxi- Particulate organic carbon production and dation products that become buried in the ice. export in the Indian sector of the Southern Ocean: A United States–China collaborative This study requires simultaneous observations research project. Cynthia Pilskaln, University of of a wide-ranging suite of sulfur species such Maine at Orono. As part of a collaboration be- as DMS and its oxidation products: sulfur di- tween the University of Maine and the Chi- oxide, dimethyl sulfoxide, dimethyl sulfone, nese Antarctic Research Expedition (CINARE), methane sulfonic acid, and sulfuric acid, as we will study the biological production and well as photochemically important com- export flux of biogenic matter in response to pounds such as carbon monoxide, nitrous ox- ventilation of intermediate and deep water ide, water vapor, and nonmethane hydrocar- masses within the Polar Front Zone. The ship- bons. board work will be done aboard the Chinese antarctic resupply vessel off Prydz Bay in the Secondary objectives will be Indian Ocean sector. In the austral spring, this · to examine interior antarctic air samples for region experiences phytoplankton blooms that other significant DMS oxidation products scientists believe are the result of nutrient such as sulfurous acid and methane sulfinic transport by the ventilation of intermediate acid and and deep water masses. Researchers believe that each year such blooms are the primary · to assess the local variation in hydroxyl and source of particulate organic carbon and bio- perhydroxyl radicals, a measure of the oxi- genic silica flux to the ocean bottom. At this dizing power of the atmosphere. time, however, no data exist on the amount of This study will provide, for the first time, a particulate organic matter that sinks through quantitative picture of exactly which atmos- the water column, leaving the quantitative re- pheric sulfur compounds are advected into the lationships between production and export antarctic interior and a detailed picture of the largely undefined in this region. The initial sulfur chemistry that is active in the antarctic phase of our work consists of setting out a atmosphere. (OO-270-O) time-series sediment-trap mooring at approximately 64°S 73°E to take advantage of the Operation of an aerosol sampling system at historical data set that CHINARE has obtained Palmer Station. Gail dePlannque and Colin G. in this area over the past decade. The biweekly Sanderson, Environmental Measurements Labora- to monthly trap samples will be analyzed for tory, U.S. Department of Energy. In 1990, a team their organic constituents and, in conjunction from the U.S. Department of Energy, Envi- with primary productivity observations, will ronmental Measurements Laboratory (EML) provide the basic data from which export val- in New York City, installed a high-volume ues can be derived. aerosol sampler, a gamma-ray spectrometer, and satellite data transmission system at Our work will be carried out in collaboration Palmer Station. This installation is part of with the State Oceanic Administration (SOA) EML's Remote Atmospheric Measurements of the People's Republic of China and the Chi- Program, which is an extension of its world- nese Antarctic Research Expedition. In addi- wide surface air-sampling program. The sys- tion to providing time on the antarctic resup- tem transmits data through the National Oce- ply vessel, the SOA will sponsor the shipboard anic and Atmospheric Administration's primary productivity experiments and the ARGOS satellite system. The sampling station supporting hydrographic measurements. The

U.S. Antarctic Program, 1998-1999 43 collaborating American scientists will provide control primary production in the sea ice and both guidance in making these observations to in the open water system. The structure, standards developed for the Joint Global standing stock, and productivity of Ocean Flux Study and the hardware for the bottom-dwelling biological communities are moored sediment trap. There will be a mutual also linked to meteorological processes sharing between the U.S. and Chinese investi- through interseasonal and interannual varia- gators of all samples and data sets, and the tions in horizontal and vertical fluxes of or- data analysis will be carried out jointly. (OO- ganic carbon produced in the upper ocean. 278-O) During this 3-year study, we will investigate Antarctic automatic weather station program: links among the atmospheric, oceanic, and 1998–2001. Charles Stearns, University of Wis- biological systems of the southwestern Ross consin at Madison. Our project will maintain Sea ecosystem. Direct measurements will in- and augment, as necessary, the network of clude nearly 50 automatic weather stations estab- · regional wind and air temperatures derived lished on the antarctic continent and on sev- from automatic weather stations; eral surrounding islands. These weather stations measure surface wind, pressure, tem- · ice cover, ice movement, and sea-surface perature, humidity, and in some instances, temperatures derived from a variety of sat- other atmospheric variables, such as snow ac- ellite-based sensors; cumulation and incident solar radiation, and · hydrographic characteristics of the upper report these readings via satellite to a number ocean and primary productivity in the ice of ground stations. The data are used for op- and in the water derived from research erational weather forecasting in support of the cruises and satellite studies; U.S. Antarctic Program, for climatological records, and for research purposes. The AWS · vertical flux of organic material and water network, which began as a small-scale pro- movement derived from oceanographic gram in 1980, has been extremely reliable and moorings containing sediment traps and has proven indispensable for both forecasting current meters; and and research purposes. (OO-283-O) · the abundance, distribution, and respira- Research on Ocean–Atmosphere Variability tion rates of biological communities on the and Ecosystem Response in the Ross Sea. seafloor, derived from box cores, benthic Robert B. Dunbar, Rice University. This interdis- photographs, and shipboard incubations. ciplinary study, "Research on Ocean, Atmos- Based on archived meteorological data, we phere and Ecosystem Response in the Ross expect that the atmospheric variability during Sea" (ROAVERRS), focuses on atmospheric the study period will allow us to monitor forcing, ocean hydrography, sea-ice dynamics, changes in air-flow patterns and their influ- primary productivity, and pelagic-benthic ence on oceanographic and biological patterns coupling in the southwestern Ross Sea. The and to deduce the direct and indirect links, primary goal is to examine how changes in which are the focus of the research. Results aspects of the polar climate system, in this case from this study will contribute to our knowl- wind and temperature, combine to influence edge of atmospheric and oceanic forcing of marine productivity on a large antarctic conti- marine ecosystems and lead to a better under- nental shelf. In the Ross Sea, katabatic winds standing of marine ecosystem response to cli- and mesocyclones influence the spatial and matic variations. temporal distribution of sea ice, as well as the upper ocean mixed-layer depth, and thus

44 U.S. Antarctic Program, 1998-1999 During the 1998–1999 research season, the open water is reflected in satellite-based syn- following researchers will conduct studies as thetic aperture radar (SAR) imagery. The field part of the ROAVERRS project: investigations, which will be carried out from the R/V Nathaniel B. Palmer in winter 1998 and · Robert B. Dunbar, Rice University (OR-216- summer 1999, will produce observations of the A), lead; snow and ice distribution; the crystal struc- · Jacqueline Grebmeier, University of Ten- ture, stable isotopes, salinity and temperature nessee (BR-216-E); structure of ice cores; and the stratigraphy, grain size, and water content of the snow · Giacomo R. DiTullio, University of cover. The SAR images from ERS-2 and Charleston (BR-272-O); RADARSAT will be acquired at the McMurdo · James Barry, Monterey Bay Aquarium Re- ground station and processed at the Alaska search Institute (OR-216-B); SAR Facility. These images will provide in- · Michael Lizotte, University of Wisconsin formation about the large-scale ice-motion (OR-216-C); field and the small-scale ice-deformation field, both of which contribute to the observed ice- · Michael Van Woert, Office of Naval Re- thickness distribution. In addition, a study of search, U.S. Navy (OR-216-D); and the spatial and temporal variation of the back- · Amy Leventer, Colgate University (OR-216- scattered microwave energy will contribute to F). the development of numerical models that simulate the dynamic and thermodynamic Dynamic/thermodynamic processes and their interactions among the sea ice, ocean, and at- contribution to the sea-ice thickness distribu- mosphere. The surface data are vital for the tion and radar backscatter in the Ross Sea. extraction of environmental information from Martin O. Jeffries and Shusun Li, University of the radar data, and for the ultimate validation Alaska Fairbanks. We will study the effects of of interactive models. (OX-286-O) antarctic sea ice in the global climate system through an examination of how the spatial distribution of ice and snow thickness and of

Aeronomy and astrophysics regions and highest energy events of the cos- RICE—Radio Ice Cherenkov Experiment. David Besson, University of Kansas. Electromag- mos. netic radiation (such as light, x-rays, and When an electron-type neutrino does interact gamma rays) cannot escape from inside the in a dielectric medium (such as the deep gla- most active regions of the Universe, for in- cial ice beneath South Pole), it will produce an stance from the nuclei of galaxies, nor can the electron and positron shower that will rapidly highest energy gamma rays propagate radiate away the energy of the original neu- through intergalactic space because they will trino as electromagnetic radiation. The prob- be absorbed by the cosmic background infra- ability of such interactions increases with in- red photons. Neutrinos, however, can traverse creasing energy, so that a detector's sensitivity a considerable amount of material unimpeded. increases with energy. Thus, a modest-sized If they can be detected in such a way that their (by neutrino detector standards) instrumented arrival direction and energy can be deter- volume of ice—about a 100-meter cube—could mined, they can be used to study high-density have an effective volume of a cubic kilometer,

U.S. Antarctic Program, 1998-1999 45 a size deemed necessary to do astronomy. Our diation started on its journey to us just a few project will determine the feasibility of the ra- hundred thousand years after the Big Bang. dio detection of neutrino interactions in ice. The details of the distribution on angular (AA-123-O) scales from a few degrees to a few minutes can cleanly discriminate between competing mod- AMANDA—Antarctic Muon and Neutrino els of the dark matter that makes up most of Detector Array, Robert Morse, University of the gravitationally attracting mass of the Uni- Wisconsin. The primary objective of AMANDA verse. This balloonborne microwave tele- is to discover sources of very-high-energy scope—called BOOMERANG—will measure neutrinos from galactic and extragalactic variations on a scale from 12 minutes to 3.6 sources. These neutrinos could be of diffuse degrees. BOOMERANG has already been origin, coming from the contributions of many flown for a short flight in the United States active galactic nuclei (AGNI), or they could be and will be flown on a long-duration balloon point sources of neutrinos coming from su- from McMurdo Station, Antarctica, in Decem- pernova remnants (SNRs), rapidly rotating ber 1998 with an expectation of getting up to 2 pulsars, neutron stars, individual blazars, or weeks of continuous data. (AB-033-O) other extragalactic point sources. Long-Duration Balloon program. Steven Pe- The AMANDA array, which consists of pho- terzen, National Scientific Balloon Facility. The tomultiplier tubes embedded between 1 and 2 National Scientific Balloon Facility's (NSBF) kilometers deep in the antarctic ice near the effort in Antarctica, known as the Long- South Pole, uses natural ice as a Cherenkov Duration Balloon (LDB) program, launches detector for high-energy neutrinos of astro- high-altitude balloons carrying scientific pay- physical origin that have passed through loads into the stratosphere. These large- Earth. Recently, new sources of high-energy volume (804,199-cubic-meter), helium-filled gamma rays have been discovered, such as the balloons circumnavigate the continent for up source Mrk-421 discovered by the CGRO and to 24 days. For each circumpolar flight, NSBF Mt. Hopkins Observatory. Believed to be co- performs the launch operations, designs and pious emitters of high-energy neutrinos, ob- manages the telemetry links, and then termi- jects like this are what AMANDA has been nates and recovers the flight system. During designed to study. To date, neutrino astron- the 1998–1999 field season, the LDB program omy has been limited to the detection of solar will support research by Andrew Lange of the neutrinos and one brief burst from the super- California Institute of Technology and David nova that appeared in the Large Magellanic Rust of Johns Hopkins University. (AB-145-O) Cloud in February 1987 (SN-1987a). Only now is it becoming technically feasible to build An optical investigation of the genesis of so- large neutrino telescopes, and as one of the lar activity. David M. Rust, Johns Hopkins Uni- first-generation detectors, AMANDA prom- versity. The Flare Genesis Experiment will use ises to be a large contributor to this new an 80-centimeter telescope to make images branch of neutrino astronomy. (AA-130-O) and magnetograms of unprecedented resolution (0.2 arcsec) of the solar photosphere and Antarctic long-duration balloonborne obser- chromosphere while flying from a high- vations of the anistropy of the cosmic mi- altitude, long-duration balloon around the crowave background on angular scales of 0.2 antarctic continent. The purpose of the ex- to 4 degrees. Andrew Lange, California Institute periment is to further understanding on how of Technology. The angular intensity distribu- the energy stored in the Sun's magnetic fields tion on the sky of the cosmic microwave back- is converted to energetic events such as flares ground radiation carries a wealth of informa- and coronal mass ejections. This experiment tion about the early Universe because this ra- 46 U.S. Antarctic Program, 1998-1999 can be done only from an antarctic balloon CARA supports research using three major (short of building a large, special-purpose telescope facilities. spacecraft) for two reasons. First, continual · The Astronomical Submillimeter Tele- viewing of the Sun is necessary for periods scope/Remote Observatory (AST/RO) much exceeding a day, and that can be project uses a 1.7-meter-diameter telescope achieved only at polar sites. Second, to achieve to survey interstellar gas in the galactic the required resolution, the telescope must be plane, the galactic center, and the Magel- above most of the atmosphere, and LDBs can lanic Clouds. carry the telescope to that height. This project is jointly sponsored by the National Science · The South Pole Infrared Explorer (SPIREX) Foundation, the National Aeronautics and project uses a 0.6-meter-diameter telescope Space Administration, and the Air Force. (AB- to observe distant galaxies, cool stars, and 146-O) heavily obscured star-forming regions.

Center for Astrophysical Research in Antarc- · The Cosmic Background Radiation tica (CARA)—Administration, Stephan Meyer, Anisotropy (COBRA) project helps re- University of Chicago. Infrared and submilli- searchers test current theories of the origin meter astronomy has the potential for an- of the Universe. swering major questions about the formation In addition to projects using these three tele- of the Universe: scopes, CARA's Advanced Telescopes Project · What are the processes by which stars form collects data on the quality of polar plateau from interstellar gas? sites for astronomical observations and to plan for future telescopes and facilities. · How did the planets form? · What was the nature of primeval galaxies? Projects and principal investigators included as part of CARA are the following. · How was matter and energy distributed in the early Universe? · CARA-wide operations and activities (Stephan Meyer, University of Chicago) Because of the cold temperatures and the near (AC-132-A). absence of water vapor in the atmosphere · The AST/RO project, which will receive above the polar plateau, the infrared skies are new array receivers to permit rapid map- consistently clearer and darker in Antarctica ping of chemical species (Antony Stark, than anywhere else on Earth. These conditions Smithsonian Institution) (AC-132-B). enable researchers to make measurements that would be extremely difficult or impossible · The SPIREX project, which will be revital- from other sites. ized during the 1998–1999 field season with a state-of-the-art array to make possible To capitalize on these advantages, in 1991 the wide-field surveys of star formation in our University of Chicago and several collaborat- Galaxy and in the Magellanic Clouds at ing institutions established the Center for As- wavelengths between 2 and 5 micrometers trophysical Research in Antarctica (CARA), (Bob Lowenstein, University of Chicago) which is one of 24 Science and Technology (AC-132-C). Centers funded by the National Science Foun- dation. To support its scientific mission, · The Advanced Telescopes Project (Bob CARA is working to establish an observatory Lowenstein, University of Chicago) (AC- at the South Pole and to investigate the condi- 132-E). tions for astronomy at the South Pole and other sites on the polar plateau. Currently, U.S. Antarctic Program, 1998-1999 47 · Activities of the COBRA project related to Alan Wolfe, New York City Technical College. preparation for deployment of the Viper Magnetometers installed at selected sites in telescope, a new, 2-meter class telescope both polar regions continue to measure the that will extend the observations now being magnitude and direction of variations in made with the 0.75-meter Python telescope Earth's magnetic field in the frequency range to structures in the cosmic microwave from 0 to about 0.1 hertz. We will measure background having smaller angular scales these variations using magnetometers in- (Jeffrey Peterson, Carnegie-Mellon Univer- stalled at conjugate sites in the Northern and sity) (AC-132-F). Southern Hemispheres, specifically at McMurdo and Amundsen–Scott South Pole Besides making measurements of "seeing" Stations, Antarctica, and at Iqaluit, Northwest quality using the SPIREX telescope, the Ad- Territories, Canada. We are also analyzing vanced Telescopes Project also supports a these data in association with similar data ac- number of other efforts including wide-field quired from several automatic geophysical cameras, a near-infrared sky brightness observatories that are part of the polar ex- monitor (in collaboration with the University periment network for geophysical upper- of New South Wales), and an instrument for atmosphere investigations (PENGUIN) pro- monitoring mid-infrared sky brightness and gram (AO-112-O). Using these systems, we transmission (in collaboration with the Na- gather data on the coupling of the interplane- tional Aeronautics and Space Administration's tary medium into the dayside magnetosphere, Goddard Space Flight Center). including the magnetospheric cusp region, as The operation of an extremely-low-fre- well as the causes and propagation of low- quency/very-low-frequency radiometer at frequency hydromagnetic waves in the mag- Arrival Heights, Antarctica. A.C. Fraser-Smith, netosphere. Because of unique climatic condi- Stanford University. During the 1998–1999 field tions at the South Pole, we are also able to cor- season, we will continue to operate an extremely- relate optical measurements with particle- low-frequency and very-low-frequency (ELF/VLF) precipitation measurements and with hydro- radiometer at McMurdo Station, Antarctica, to magnetic-wave phenomena recorded by the monitor radio noise from natural sources such as magnetometer. (AO-101-O) thunderstorms. The Arrival Heights site is one An investigation of magnetospheric bounda- of a network of eight such radiometers ries using ground-based induction magne- operated by Stanford University for the Office tometers operated at manned stations as part of Naval Research. Characterizing the possible of an extensive ground array. Roger Arnoldy, sources of radio interference is important for University of New Hampshire. We operate an operational purposes. Additionally, because array of induction-coil magnetometers located the variations in global noise reflect variations at high geomagnetic latitudes in the Arctic and in global thunderstorm activity, they can Antarctic, and we analyze the data collected. provide information on global climate change. The sites, located at Sondre Stromfjord, The antarctic site was chosen about 15 years Greenland, and Iqaluit, Northwest Territories, ago because it is unusually free from Canada, in the Arctic and at Amundsen-Scott manmade electromagnetic interference. The South Pole and McMurdo Stations in the Ant- ELF/VLF record of data collected by this arctic, complement similar magnetometers in project now extends unbroken for more than the U.S. and British automatic geophysical ob- 10 years. (AO-100-O) servatory (AGO) networks and the MACCS Magnetometer data acquisition at McMurdo array in Canada. The measurements of mag- and Amundsen–Scott South Pole Stations. netic pulsations at these high geomagnetic Louis Lanzerotti, AT&T Bell Laboratories, and latitudes are used to study the plasma physics 48 U.S. Antarctic Program, 1998-1999 observe the polar cap and cleft regions by of some of the important boundaries of the measuring auroral-precipitation patterns and magnetosphere, particularly those surround- interpreting the results in terms of coordinated ing the area through which the solar wind observations of magnetic, radio-wave absorp- enters the magnetosphere and where the tion images and high-frequency, coherent- magnetosphere transfers the solar wind's en- scatter radar measurements. Through this ergy to the Earth's atmosphere in the form of investigation, we hope to learn about the aurora and similar phenomena. This project is sources and energization mechanisms of jointly supported by the U.S. Arctic and Ant- auroral particles in the magnetosphere and arctic Programs. (AO-102-O) other forms of energy inputs into the Antarctic auroral imaging. Steven Mende, high-latitude atmosphere. (AO-104-O) University of California, Berkeley; Space Sciences Laboratory. In the past, space satellites have A study of very high latitude geomagnetic phenomena. Vladimir Papitashvili, University of performed detailed exploration of the Michigan. Our project is a continuation of a magnetosphere, and the average distribution joint U.S.–Russian program to operate an ar- of the energetic particle plasma content of the ray of high-latitude automated magnetome- magnetosphere has been mapped. This form ters in Antarctica. We will use these instru- of measurement is unsuitable, however, for ments to investigate the polar cap current observing the dynamic behavior of the systems in the Earth's magnetosphere. The magnetosphere. Auroral phenomena are antarctic continent is uniquely suited to these produced when particles from the investigations because it is the only land mass magnetosphere precipitate into the atmos- at very high latitudes and is, therefore, an ex- phere causing the atmosphere to fluoresce. cellent and stable location for an array of Because particles tend to travel along the magnetometers. These investigations are par- magnetic field line, the aurora can be regarded ticularly important to the understanding of the as a two-dimensional projection of the three- coupling of energy and momentum from the dimensional magnetospheric regions. Thus, solar wind to the magnetosphere, ionosphere, observing the morphology of the aurora and and upper atmosphere. The data will also be its dynamics provides an important way to extremely useful for analyses coordinated study the dynamics of the three-dimensional with a number of satellite-based experiments magnetosphere. This method requires knowl- that are currently in progress or are planned edge of which type of auroras represent which for the near future. The specific tasks to be energy of precipitation and their connection to undertaken include design improvements in the various regions of the magnetosphere. the digital geomagnetic data-acquisition sys- Amundsen–Scott South Pole Station is tems at Vostok and Mirnyy and the continued uniquely situated for optical observations of operations and maintenance of autonomous polar aurora because during the winter, the stations along the Russian traverse route to aurora can be monitored 24 hours a day unlike Vostok. One improvement will be to add a most other places, where the sky becomes too satellite data-transmission capability at Vostok bright near local mid-day. An intensified opti- so that a polar cap magnetic index will be cal, all-sky imager, operating in two parallel available in near real-time for space weather wavelength channels—4,278 and 6,300 Ång- and research applications. (AO-105-O) stroms—will be used to record digital and Global thunderstorm activity and its effects video images of aurora. These wavelength on the radiation belts and the lower iono- bands allow us to discriminate between more sphere. Umran Inan, Stanford University. Very- or less energetic electron auroras and other low-frequency (VLF) radio receivers at Palmer precipitation. From South Pole Station, we can Station, Antarctica, operated by this project, transporting and accelerating magnetospheric study ionospheric disturbance caused by and ionospheric plasmas, processes that result global lightning. The principal mode of op- from a variety of physically different wave- eration is to measure changes in amplitude particle interactions. Because measuring and phase of signals received from several ELF/VLF waves from multiple sites provides distant VLF transmitters. These changes occur a powerful tool for remote observations of in the VLF signals following lightning strokes magnetosphere processes, we maintain a sys- because radio (whistler) waves from the light- tem at Amundsen–Scott South Pole Station ning can cause very energetic electrons from that measures magnetospheric ELF/VLF phe- the Van Allen radiation belts to precipitate into nomena; data from this system are correlated the upper atmosphere. This particle with data from the automatic geophysical ob- precipitation in turn causes increased servatory system. (AO-108-O) ionization in the ionosphere, thus affecting the propagating VLF radio waves. Because the South Pole Air Shower Experiment–2. Thomas directions to the VLF transmitters are known, Gaisser, University of Delaware. The South Pole it is possible to track remotely the path of the Air Shower Experiment–2 (SPASE-2) is a thunderstorms that cause the changes. The sparsely filled array of 120 scintillation detec- Palmer Station receivers are operated in col- tors spread over 15,000 square meters at South laboration with the British and Brazilian Pole. It detects energetic charged particles Antarctic Programs, both of which operate (mostly electrons), which are produced in the similar receivers. This project contributes to upper atmosphere by cosmic rays. The array the Global Change Initiative. (AO-106-O) also includes a subarray, called VULCAN, of nine photodetectors to detect Cherenkov ra- Study of polar stratospheric clouds by lidar. diation produced by the same showers high in Guido Di Donfrancesco, Instituto De Fisica Del- the atmosphere. l'Atmosfere, Rome, Italy. In cooperation with the U.S. Antarctic Program and in collabora- Our experiment has several goals, the most tion with the University of Wyoming (AO-131- important of which is to determine the ele- O), we will use lidar to study the polar strato- mental composition of the primary cosmic spheric clouds (PSCs), their formation, evolu- rays at energies above approximately 100 tion, and other peculiar characteristics. Con- teraelectronvolts. To do this, SPASE-2 works tinuous lidar observations permit studies of in conjunction with the Antarctic Muon and PSCs and stratospheric aerosol and the ther- Neutrino Detector Array (AMANDA), which mal behavior and dynamics of the atmosphere has several hundred optical detectors so deep above McMurdo Station. (AO-107-O) in the ice sheet that the only products of the cosmic ray interactions that can be seen by Extremely-low-frequency/very-low-frequency AMANDA are muons. The ratio of muons to (ELF/VLF) waves at the South Pole. Umran S. electrons in a cosmic ray shower depends on Inan, Stanford University. Advancing our un- the mass of the original primary cosmic ray derstanding of the electrodynamic coupling of nucleus. In addition, in showers also detected upper atmospheric regions and refining our with VULCAN, two other ratios that also de- quantitative understanding of the energy pend on primary mass can be determined. In- transport between the magnetosphere and the terpretation of the combined data will lead to ionosphere are two important objectives of the a determination of the relative importance of U.S. Antarctic Program's automatic geophysi- different groups of nuclei in the cosmic radia- cal observatory program. Particle precipitation tion in an energy region not accessible to di- driven by extra-low-frequency/very-low- rect measurement. This, in turn, will shed light frequency (ELF/VLF) waves has a part in on the origin and mechanisms of acceleration

2 U.S. Antarctic Program, 1998-1999 of this extremely energetic, naturally occur- instruments constitute a unique network with ring radiation. This project is cooperative with which to study auroral effects in both mag- the University of Leeds in the United King- netic hemispheres simultaneously. (AO-111-O) dom. (AO-109-O) Polar experiment network for geophysical High-latitude antarctic neutral mesospheric upper-atmosphere investigations (PEN- and thermospheric dynamics and thermody- GUIN). Theodore Rosenberg, University of namics. Gonzalo Hernandez, University of Maryland at College Park. A consortium of U.S. Washington. The temperature and windspeed and Japanese scientists will use a network of of the atmosphere can be deduced by meas- six automatic geophysical observatories uring the emission spectra of certain trace (AGOs), established on the east antarctic polar gases, especially the spectra of those that are plateau and equipped with suites of instru- confined to fairly narrow altitude regions. We ments to measure magnetic, auroral, and ra- use a Fabry-Perot infrared interferometer lo- diowave phenomena. The AGOs, which are cated at Amundsen-Scott South Pole Station, totally autonomous, operate year round and Antarctica, to look at the band spectra of sev- require only annual austral summer service eral trace species, most importantly the hy- visits. We will use these arrays of instruments, droxyl radical (OH), in orthogonal directions. along with measurements made at select By determining the doppler shift of the lines, manned stations, to study the energetics and researchers can measure the winds. The dynamics of the high-latitude magnetosphere brightness and line ratios within the bands on both large and small scales. The research provide density and temperature information. will be carried out along with in situ observa- The OH in the atmosphere is primarily found tions of the geospace environment by space- in a narrow band near 90 kilometers altitude. craft, in close cooperation with other nations The fact that the measurements are being working in Antarctica and in cooperation with made at the axis of rotation of Earth signifi- conjugate studies performed in the Northern cantly limits the types of planetary waves, Hemisphere. thus simplifying the study of the large-scale dynamics of the atmosphere. (AO-110-O) The data obtained from AGOs help researchers understand the Sun's influence on the Riometry in Antarctica and conjugate re- structure and dynamics of the Earth's upper gions. Theodore J. Rosenberg and Allan T. Weath- atmosphere. The ultimate objective of this re- erwax, University of Maryland at College Park. To search into how the solar wind couples with continue and expand the study of the upper the Earth's magnetosphere, ionosphere, and atmosphere, especially auroral phenomena, thermosphere is to be able to predict solar-ter- using photometry and riometric techniques, restrial interactions that can interfere with we have developed a new imaging riometer long-distance phone lines, power grids, and (relative ionospheric opacity meter) system satellite communications. (AO-112-O) called IRIS (imaging riometer for ionospheric studies). The first two IRISs were installed at All-sky-camera measurements of the aurora Amundsen–Scott South Pole Station and Son- australis from Amundsen–Scott South Pole dre Stromfjord, Greenland. A third IRIS has Station. Masaki Ejiri, National Institute of Polar been installed at Iqiluit, Northwest Territories, Research, Japan. Amundsen–Scott South Pole Canada, which is the magnetic conjugate to Station, located at the south geographic pole, South Pole. Broadbeam riometers also operate is a unique platform from which to undertake at several frequencies at South Pole, measurements of the polar ionosphere. Be- McMurdo, and Iqiluit; auroral photometers cause of the configuration of the geomagnetic operate at South Pole and McMurdo. These field in the Southern Hemisphere, the station is situated in such a way that dayside auroras high time-resolution (10-second) cosmic-ray can be viewed for several hours each day. Re- data to determine the three-dimensional search has shown that they are caused by pre- structure of turbulence in space and to under- cipitation of low-energy particles, which enter stand the mechanism by which energetic the magnetosphere by means of the solar charged particles scatter in this turbulence. wind. Since 1965, data have been acquired at (AO-120-O) the South Pole using a film-based, all-sky- camera system. Using advanced technology, Rayleigh and sodium lidar studies of the we can now digitize photographic images and troposphere, stratosphere, and mesosphere at McMurdo and Amundsen-Scott South Pole process large amounts of information auto- Stations. Jim Abshire, National Aeronautics and matically. Besides continuing to acquire 35- Space Administration, Goddard Space Flight Cen- millimeter photographic images with the all- ter. The automated geophysical observatory sky-camera system, U.S. and Japanese re- (AGO) lidar is an ongoing, National Aeronau- searchers will collaborate and use an all-sky- tics and Space Administration (NASA) funded camera processing system developed at Ja- project to develop and demonstrate a compact, pan's National Institute of Polar Research to low-power, and autonomous atmospheric li- analyze data. This system displays data in a dar for operation in the U.S. Antarctic Pro- geophysical coordinate framework and ana- gram's AGOs deployed to various locations in lyzes images over short and long intervals not Antarctica. The primary science mission of possible with individual photographic images. AGO lidar is detecting, monitoring, and pro- The data will be used to investigate dayside filing polar stratospheric clouds (PSCs). These auroral structure, nightside substorm effects, clouds form in the extremely cold polar strato- and polar-cap arcs. These studies can also be sphere during the austral winter, and a par- used to obtain further insight into the physics ticular type of PSC (type 1) has been impli- of the magnetosphere, the convection of cated in the annual springtime destruction of plasma in the polar cap, and solar winds in the stratospheric ozone. A secondary science mis- thermosphere. (AO-117-O) sion is long-term continuous monitoring of Solar and heliosphere studies with antarctic atmospheric transmission and backscatter cosmic-ray observations. John Bieber, Univer- from the surface. These data will be compiled sity of Delaware. Neutron monitors in Antarc- into a database that will provide statistics on tica provide a vital three-dimensional per- atmospheric conditions for the Geoscience La- spective on the anisotropic flux of cosmic rays ser Altimeter System (GLAS). that continuously bombards Earth. At The AGO lidar has redundant laser diode McMurdo and Amundsen–Scott South Pole transmitters operating at 670 nanometers, Stations, year-round observations will con- producing 500-milliwatt peak power pulses, at tinue for cosmic rays with energies in excess of 1- or 4-microsecond pulse lengths, and a 1 billion electronvolts. These data will advance pulse-repetition frequency of 4 kilohertz. The our understanding of a variety of fundamental backscattered laser light is collected by a 20- plasma processes occurring on the Sun and in centimeter diameter telescope and detected by interplanetary space. Neutron-monitor rec- all-solid-state single-photon counting modules ords, which began in 1960 at McMurdo Station in a cross-polarized detection scheme. Type 1 and 1964 at South Pole Station, will play a cru- PSCs will depolarize incident radiation. Be- cial role in efforts to understand the nature cause the laser transmitters in AGO lidar pro- and causes of cosmic-ray and solar-terrestrial duce highly linearly polarized light, it sends variations occurring over the 11-year sunspot back a depolarization signal (up to several cycle, the 22-year Hale cycle, and even longer percent) in the backscattered light. timescales. At the other extreme, we will study

4 U.S. Antarctic Program, 1998-1999 The lidar data are archived in the lidar in- rowband near 2.8 and 4.2 MHz, broadband struments' own flash memory as well as the noise bursts in the frequency range of 1.4–4.0 optical drive provided by the AGO platform. MHz, and broadband noise at frequencies be- The AGO lidar also contains its own Argos low 1 MHz. An accepted physical theory ex- transmitter, which telemeters at least one at- plains the third type, called auroral hiss, but mospheric profile per day back to NASA's the origins of the other two types are un- Goddard Space Flight Center in Greenbelt, known. Although these radio emissions con- Maryland. (AO-126-O) stitute a small fraction of the total energy of the aurora, they may provide important clues Rayleigh and sodium lidar studies of the to the more energetic processes, analogous to troposphere, stratosphere, and mesosphere at the way in which solar radio emissions are the Amundsen–Scott South Pole Station. used to infer the processes taking place in the George Papen, University of Illinois. During the solar corona. Using low-frequency/middle 1998–1999 field season, we will continue to frequency/high frequency receivers, we hope operate a sodium resonance lidar at the South to collect further clues about these emissions Pole to study the vertical structure and dy- from antarctic auroral zone and polar cap namics of the atmosphere from the lower sites, taking advantage of radio-quiet antarctic stratosphere to the mesopause. During this conditions. The receivers will be installed at third year of the project, an iron resonance li- Amundsen–Scott South Pole Station, in three dar will be added and will extend the meas- U.S. automatic geophysical observatories, and urements of the dynamics and temperature in two British automatic geophysical obser- structure to 100 kilometers altitude. Addition- vatories. (AO-128-O) ally, an airglow imaging camera will be used to study the horizontal structure. When used In situ measurements of polar stratospheric in conjunction with the normal balloonborne clouds (PSCs) spanning the austral winter radio sondes, which are flown regularly from and of ozone from late winter to early spring. South Pole, the final complement of instru- Terry Deshler, University of Wyoming. The an- ments will provide extensive data on nual stratospheric ozone hole above Antarc- tica is driven by chlorine compounds that in- · the temperature structure from the surface teract on the surfaces of polar stratospheric to 100 kilometers altitude; clouds, which form during the polar winter. · the nature of the polar stratospheric clouds, Thus, the ozone hole appears in the austral which are important to ozone chemistry; spring, and ozone depletion is much more se- · the variability and frequency of occurrence vere in polar regions than elsewhere. By using of metallic layers in the mesosphere, which balloonborne instruments, we provide de- play a role in communications as well as tailed information on the actual cloud particles and the distribution of the clouds and the chemistry; ozone. Our measurements will provide verti- · atmospheric gravity waves; and cal profiles of both the PSCs and ozone, size · many other phenomena, some of which are distributions of the PSC particles, and some unique to the South Pole. (AO-127-O) information on their composition and physical state (liquid or solid). Our project is enhanced High-latitude electromagnetic wave studies by cooperation with an Italian investigator using antarctic automatic geophysical obser- who operates a lidar system at McMurdo Sta- vatories. James LaBelle, Dartmouth College. At tion. The project contributes to the World radio frequencies between 0.05 and 5.0 mega- Meteorological Organization/UNEP Network hertz (MHz), three types of radio phenomena for the Detection of Stratospheric Change and related to auroral origin can be detected: nar- the Global Change Initiative. (AO-131-O)

U.S. Antarctic Program, 1998-1999 53 Measurement of stratospheric chlorine mon- dio spectrum, and each species has its own oxide and other trace gases over McMurdo unique spectrum. The shape of each individ- Station in the austral spring. Robert L. de Za- ual species' spectrum provides information on fra, University of New York at Stony Brook. Chlo- the temperature and pressure of the gas; thus, rine monoxide (ClO) is a product of the de- one can use the millimeter-wave spectrum of struction of stratospheric ozone by chlorine, the atmosphere to determine the relative which enters the stratosphere as a result of the abundances and height distribution of a num- breakdown of chlorofluorocarbons (CFCs). ber of trace species. In our investigation, we ClO, as well as other trace stratospheric gases will use a millimeter spectroscope to monitor that contribute to the development of the ant- ozone, carbon monoxide, nitrous oxide, nitric arctic ozone hole, can be measured from the acid, water vapor, and nitrogen dioxide above ground by millimeter-wave receivers, similar South Pole, Antarctica, over the period of a to those used for molecular radio astronomy. year. Several of these gases have important roles in the formation of the annual antarctic We will continue a decade-long series of such ozone hole, and others, particularly water va- measurements made at McMurdo Station to por and carbon monoxide, can provide infor- further understand climate dynamics and mation about the dynamics, particularly the phenomena but, more important, to provide a vertical transport, of the upper stratosphere cross calibration of the new Network for the and mesosphere. (AO-138-O) Detection of Stratospheric Change (NDSC) ClO microwave instrument, which has re- Cosmology from Dome-C in Antarctica. Lucio cently been installed nearby at New Zealand's Piccirillo, Bartol Research Institute, University of Scott Base. Because the NDSC instruments are Delaware. The thermal cosmic microwave being installed at a number of sites world- background radiation (CMBR) left over from wide, it is important to provide as much cor- the Big Bang carries the only information relative information as possible so that the available on the distribution of matter in the NDSC can be relied upon in the future to very early Universe. As part of an interna- monitor the health of the stratosphere. Our tional collaboration (the United States, Italy, goal is to provide as much continuity as possi- and France), we will measure the anisotropy ble between measurements made from 1986 to of the CMBR from Concordia Station, the new 1998 with the Stony Brook spectrometer at French/Italian station on Dome C in Antarc- McMurdo Station and the current and future tica. Concordia is one of the highest and cold- measurements made by the new NDSC in- est sites presently occupied in Antarctica. Be- strument at Scott Base. During the 1998–1999 cause of the extreme cold, the atmosphere field season, we will also test a second newly contains very little water vapor, making Con- rebuilt and improved spectrometer at cordia a potentially superb place from which McMurdo before final installation at Amund- to make CMBR anisotropy measurements. sen–Scott South Pole Station in early 1999. Evaluation of the site for future use is also a This spectrometer will be used concurrently to major goal of this project. (AO-140-O) measure other species photochemically or dy- namically linked to chlorine chemistry in the Ground-based infrared measurements in the stratosphere. (AO-137-O) Antarctic. Frank J. Murcray and Ronald Blather- wick, University of Denver. For this project, we Trace gas measurements over the South Pole will use an infrared (IR) interferometer to using millimeter-wave spectroscopy. Robert monitor selected trace constituents in the at- L. de Zafra, State University of New York at Stony mosphere above Amundsen–Scott South Pole Brook. Many atmospheric gases radiate energy and McMurdo Stations. The measurements in the millimeter-wavelength region of the ra- will be made in two modes: absorption and

54 U.S. Antarctic Program, 1998-1999 emission. The absorption mode uses the Sun, single-species crystals. Our research provides shining through the atmosphere, as a source of a unique mechanism for examining the crystal IR radiation and allows us to measure a num- growth and evolution process in the natural ber of trace constituents, especially during the atmosphere. By observing halos through po- local springtime when the antarctic ozone hole larizing filters, we will also be able to examine is forming. The emission mode, using radia- the atmospheric ice-crystal orientation, shape, tion emitted by the atmospheric gases them- and size. The results of our project will ad- selves, is less sensitive than the absorption vance our understanding of why well-formed mode but does allow critical measurements ice crystals grow in the antarctic atmosphere during the long, dark polar night, when the but are not generally observed elsewhere. chemistry that sets the stage for the springtime (AO-208-O) ozone depletion is taking place. The compounds we will measure include hydrogen Continued study of the Earth's ultra-low-fre- chloride, nitric acid, chlorofluorocarbon-11 quency wave environment using induction antennas on the British Antarctic Survey's and -12, nitrous oxide, methane, ozone, and automatic geophysical observatories in Ant- chlorine nitrate. Each of these gases has a role arctica. Mark J. Engebretson, Augsburg College. in ozone depletion, and several are also im- Earth's magnetic field undergoes variations on portant greenhouse gases. This project is many timescales. The low-amplitude fluctua- jointly funded by the National Science Foun- tions that have periods of a few tenths of a dation's Office of Polar Programs and Division second to a few seconds, called micropulsations, of Atmospheric Sciences and also by the Na- are the result of motion in the magnetosphere tional Aeronautic and Space Administration's such as waves on the magnetopause or other Office of Earth Sciences and Applications. surfaces. Because most of the magnetosphere (AO-148-O) is connected to the surface by magnetic field Antarctic halos and ice crystals. Walter Tape, lines that have their footprints at high geo- University of Alaska Fairbanks. Our project is an magnetic latitude, the large-scale dynamics of experimental and theoretical study of ice the space environment can best be studied crystals in the antarctic atmosphere and the from the polar regions. halos that they produce. For reasons that are Now, an extensive antarctic array of magne- not currently known, the antarctic interior ex- tometers supports research in this area. In periences more frequent and better developed particular, our team has installed magne- halos than any other location on Earth. Our tometers in the British Antarctic Survey auto- objectives are to observe natural halos at matic geophysical observatories and has ac- Amundsen–Scott South Pole Station and to cess to data from other similar instruments. sample ice crystals to validate computer mod- The data gathered will provide additional in- els of light refraction and reflection in ice sight into how solar activity affects Earth's en- crystals. Such models have the potential for vironment as well as humanity's technical the remote sensing of atmospheric conditions. systems and will increase the worldwide Controlled experiments, such as seeding the space data pool. (AO-273-O) atmosphere with dry ice, will produce artifi- cially generated but simple and well-formed

U.S. Antarctic Program, 1998-1999 55 Technical projects

These six specialized technical projects will be · Synthetic Aperture Radar project; Steve supported during 1998-1999: Currier, NASA Wallops Flight Facility (TO- 308-O) · PICO/AMANDA hot water drilling at South Pole Station, Antarctica; Karl · McMurdo Sound Metsat Station--Up- Kuivinen, University of Nebraska. (TA-177-O) grade, maintenance, and antarctic research center operation; and refurbish- · Polar Ice Coring Office support; Karl ment of Terascan satellite reception & Kuivinen, University of Nebraska (TI-150-O) processing system at Palmer Station; Rob- · Automatic Geophysical Observatory ert Whritner, Scripps Institution of Oceanog- (AGO)—servicing and installation; Ron raphy (TO-312-O) Rainbow, Antarctic Support Associates (TO- · UV-monitoring network; Charles Booth, 296-O) Biospherical Instruments, Inc (TO-513-O)

56 U.S. Antarctic Program, 1998-1999 The National Science Foundation (NSF) funds research and education in most fields of science and engineering. Grantees are wholly responsible for conducting their project activities and preparing the results for publication. Thus, the Foundation does not assume responsibility for such findings or their interpretation.

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NSF 98-155 (Replaces NSF 97-167)

U.S. Antarctic Program, 1998-1999