6
Findings and Recommendations

Beneath the Antarctic ice sheet, water has accumulated over millennia, forming watery subglacial environments. Using both airborne and surface radar, researchers have now identified more than 145 subglacial lakes, the largest being Lake Vostok with a surface area of 14,000 km2, similar to that of Lake Ontario. Radio-echo sounding data also suggests that shallow, swamp-like features the size of several city blocks and water-saturated layers of soils or broken rocks may exist beneath the ice sheet, giving rise to a wide range of subglacial aquatic environments beyond just the large lakes. These features formed in response to a complex interplay of tectonics, topography, climate, and ice sheet flow over millions of years and remain virtually unexplored. They may have been sealed from free exchange with the atmosphere for millions of years, making it possible that unique microbial communities exist in these systems. Recent evidence shows that many of the subglacial aquatic environments comprise vast watersheds connected by rivers and streams that flow beneath the ice sheet.

Most of our current knowledge about the lakes and other subglacial aquatic environments is derived from interpretations of remote sensing data and chemical and biological analyses of samples of Lake Vostok water that froze to the bottom of the overlying Antarctic ice sheet (accretion ice). Although much can be learned about subglacial environments from remote sensing and ice core data, many of the key questions about these systems require that samples of water, microbial communities, sediments, and underlying rock be obtained. No one has yet drilled into a lake; thus, the next challenge in the exploration of subglacial aquatic environments is to determine the best way of drilling into, sampling, and monitoring these environments.

TOWARD EXPLORATION OF SUBGLACIAL ENVIRONMENTS

The possibility of the existence of subglacial water was first identified in 1968 from airborne radio-echo sounding data (Robin et al., 1970). Several years later, the first subglacial lake was reported beneath Sovetskaya Station, and data suggested the presence of water under Vostok Station. In 1974-1975, an airborne radio-echo survey of ice depths over central



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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship 6 Findings and Recommendations Beneath the Antarctic ice sheet, water has accumulated over millennia, forming watery subglacial environments. Using both airborne and surface radar, researchers have now identified more than 145 subglacial lakes, the largest being Lake Vostok with a surface area of 14,000 km2, similar to that of Lake Ontario. Radio-echo sounding data also suggests that shallow, swamp-like features the size of several city blocks and water-saturated layers of soils or broken rocks may exist beneath the ice sheet, giving rise to a wide range of subglacial aquatic environments beyond just the large lakes. These features formed in response to a complex interplay of tectonics, topography, climate, and ice sheet flow over millions of years and remain virtually unexplored. They may have been sealed from free exchange with the atmosphere for millions of years, making it possible that unique microbial communities exist in these systems. Recent evidence shows that many of the subglacial aquatic environments comprise vast watersheds connected by rivers and streams that flow beneath the ice sheet. Most of our current knowledge about the lakes and other subglacial aquatic environments is derived from interpretations of remote sensing data and chemical and biological analyses of samples of Lake Vostok water that froze to the bottom of the overlying Antarctic ice sheet (accretion ice). Although much can be learned about subglacial environments from remote sensing and ice core data, many of the key questions about these systems require that samples of water, microbial communities, sediments, and underlying rock be obtained. No one has yet drilled into a lake; thus, the next challenge in the exploration of subglacial aquatic environments is to determine the best way of drilling into, sampling, and monitoring these environments. TOWARD EXPLORATION OF SUBGLACIAL ENVIRONMENTS The possibility of the existence of subglacial water was first identified in 1968 from airborne radio-echo sounding data (Robin et al., 1970). Several years later, the first subglacial lake was reported beneath Sovetskaya Station, and data suggested the presence of water under Vostok Station. In 1974-1975, an airborne radio-echo survey of ice depths over central

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship East Antarctica near the Vostok Subglacial Highlands led to the discovery of a sub-ice lake with an area of about 10,000 km2, lying underneath almost 4 km of ice and apparently close to Vostok Station. In 1993, altimetric data from satellite measurements provided independent evidence of the areal extent of Lake Vostok, thus confirming it to be the largest known sub-ice lake. Momentum to begin direct sampling of subglacial aquatic environments has built over the last decade, and this objective has sparked a great deal of scientific interest in and debate on how to overcome the challenges associated with cleanly drilling and cleanly sampling these unique environments. In response to this debate, the Scientific Committee on Antarctic Research (SCAR1) constituted a group for Subglacial Antarctic Lake Exploration (SALE), composed of scientists from SCAR member nations, and charged the group to begin a process of discussion and collaborative planning. The SCAR SALE group has provided international organizing and planning for the exploration of subglacial aquatic environments. The main objectives of the SCAR SALE program are to understand the formation and evolution of subglacial lake processes and environments; to determine the origins, evolution, and maintenance of life in subglacial lake environments; and to understand the limnology and paleoclimate history recorded in subglacial lake environments. One of the key scientific questions posed in the SCAR SALE program is concerned with the origins, evolution, and maintenance of life in subglacial aquatic environments. The SCAR SALE group speculated that life in subglacial lake environments could be unique; thus, any attempt to sample the water, sediment, or organisms directly should ensure that the subglacial aquatic environment is not contaminated, especially by carbon substrates that might allow the aquatic ecosystem to change fundamentally. The SCAR SALE group recommended an integrated science plan for the future to ensure that one type of investigation does not accidentally impact other investigations adversely; that sampling regimes plan for the maximum interdisciplinary use of samples; and that all information is shared to promote greater understanding. The SCAR SALE group continues to foster international coordination and collaboration; however, the group has not examined stewardship issues in depth. Currently, no clear protocols for environmental stewardship or standards for minimizing contamination have been established for subglacial aquatic environments beyond the general guidelines of the Antarctic Treaty. This is critical because exploration of these environments is proceeding. Preparations for sampling Lake Vostok are well advanced; plans to explore subglacial Lake Ellsworth have been circulated through the international community; and two other subglacial aquatic environments are under consideration. The committee did not debate whether or not these plans should proceed and recognizes that these investigations are part of national science initiatives. 1 SCAR is an interdisciplinary committee of the International Council for Science (ICSU) charged with initiating, developing, and coordinating high-quality international scientific research in the Antarctic region and the role of the Antarctic region in the Earth system. The scientific business of SCAR is conducted by its Standing Scientific Groups, which represent the scientific disciplines active in Antarctic research and report to SCAR. In addition, to its primary scientific role, SCAR provides objective and independent scientific advice to the Antarctic Treaty Consultative Meetings and other organizations on issues of science and conservation affecting the management of Antarctica and the Southern Ocean. In that role, SCAR has made numerous recommendations about a variety of matters, most of which have been incorporated into Antarctic Treaty instruments. Foremost among these has been the advice offered for the many international agreements that provide protection for the ecology and environment of the Antarctic. SCAR has national representation from those countries with an active scientific interest in Antarctica.

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship Both Russian-led and U.K.-led consortia have followed the current protocols for scientific research on these lakes and have addressed issues brought forth through the Antarctic Treaty Protocol. These groups have had discussions with SCAR SALE and have satisfied their respective national science protocols. The purpose of this study is to provide independent guidance on how to minimize contamination of subglacial lake environments during exploration and how to provide responsible stewardship of these unique and possibly connected environments. NEXT STEPS IN SUBGLACIAL EXPLORATION Although no lake has been sampled directly, Lake Vostok has been studied using remote sensing, chemical analyses of ice accreted to the bottom of the Antarctic ice sheet, and geochemical modeling. Results of these analyses suggest that the upper waters in the lake have a low salinity and possibly extremely high concentration of gases such as oxygen. Lake Vostok has been isolated from the atmosphere for more than 15 million years (Christner et al. 2006); the water, which flows very slowly through the system, is estimated to reside in the lake on the order of tens of thousands of years. There is some controversy in the peer-reviewed literature whether or not there are microorganisms living in Antarctica’s subglacial lakes. The controversy is due mainly to the fact that there are currently no samples of lake water, only accreted ice. Based on published reports, the number of microbial cells in the accreted ice of Lake Vostok may be as high as 10,000 or as low as a few recognizable cells per milliliter. The water may also contain low levels of microbial nutrients, necessary to support microbial communities; estimates of dissolved organic carbon (DOC) concentrations range from undetectable to 250 µmol L−1, the latter being well above concentrations in the open ocean (typically about 70 µmol L−1). It should be noted that many types of microbes, including bacteria, yeasts, and fungal spores, are found in low abundances within the ice sheet and some of these microbes may still be viable as they enter the subglacial aquatic environment. These liquid-water systems may also contain low levels of microbial nutrients. As a result, despite the pressure and temperature regime of the subglacial environment, there is a possibility of microbial metabolism and growth. Rates of both growth and evolution are expected to be slow in these environments. Microbial cells and organic nutrients may be heterogeneous from sample to sample, but until a fresh sample of water is collected using precautions to avoid chemical and microbiological contamination, we will not know for sure. Even when freshly collected samples are available, it will be important to certify all measurements preferably by cross-calibrated measurements from several independent laboratories. Chemically, subglacial aquatic environments can be expected to vary widely from site to site, and the complete absence of viable microbes cannot be excluded until adequate sampling is done. However, from a scientific perspective, extreme oligotrophic environments are themselves unusual, interesting, and worthy of study. In light of potential, adverse consequences for environmental stewardship, the committee favors a conservative approach where it is assumed that actively growing microbial populations in the subglacial environments are present until proven otherwise. Current understanding of the sub-ice habitat and its inhabitants is based entirely on indirect observations that range in scope from theoretical predictions to direct chemical and microbiological analyses of accreted ice samples obtained from Lake

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship Vostok. Consequently, the committee considers the identity and diversity of life, the nature of the electron donors and acceptors to support life (if life exists), and all other related ecological and biogeochemical properties as fundamental, but unanswered, questions. Despite the initial investigations of Lake Vostok, great uncertainty remains about many basic physiochemical parameters, such as salinity and concentration of dissolved gases, especially in the deeper waters of the lake. Another problem is that the accreted ice excludes all gases, most of the dissolved material, and many of the particles when it froze. We do not know the partition coefficients for ice forming under these conditions. Thus, we cannot yet determine the chemical and microbial concentrations of the lake water by analyzing chemical and microbial concentrations in the ice accreted above the lake surface. In addition, questions about the presence of microbial populations and about their growth, diversity, and uniqueness cannot be answered until the subglacial waters and sediments are sampled directly. There is great value in setting the exploration of subglacial aquatic environments in motion now. These unique environments may hold critical information needed to answer many questions about microbiological life, evolution, and adaptations; Antarctic and global climate over the past 65 million years; ice sheet dynamics; and the evolution of subglacial aquatic environments and their associated hydrological and biogeochemical processes. Scientific interest in the subglacial hydrology of ice sheets has become increasingly important, because we need to learn as much as possible about how the subglacial water system operates beneath ice sheets. The question of whether ice sheets can have a large dynamic response to changes at their margins (e.g., the breakup of ice shelves) partly involves the question of whether or not fast flow processes will be activated by changes in subglacial conditions. Thus, there are conceivable links to the important question of sea level rise. It is important for us to acquire this information in the next 5 to 10 years—not several decades from now. During the Vostok investigation (Box 1.1), data will be gathered that may help determine whether microbial life is present or absent from this environment. Chemical analyses of water samples will help spark speculative discussions about partition coefficients, which will improve geochemical modeling of these environments. Plans for the exploration of Lake Ellsworth (Box 1.2) include physicochemical and biological measurements and water and sediment sample recovery. The results of both of these investigations will only begin to develop an initial understanding of these environments, but these first samples will provide all-important evidence about how conservative we should be in moving forward. From a scientific perspective, the data and lessons learned from these endeavors should be used to guide future environmental stewardship, scientific investigations, and technological developments. The pursuit of scientific knowledge, however, needs to be balanced against environmental stewardship and cleanliness. Responsible stewardship during the exploration of subglacial aquatic environments should proceed in a manner that minimizes the possible damage to these remarkable habitats and protects their value for future generations, not only in terms of their scientific value but also in terms of conserving and protecting a pristine, unique environment. This is particularly important because it now appears that these environments are hydrologically and potentially biologically connected and that activities at one site may affect other sites within the system.

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship The international system of governance through the Antarctic Treaty system2 works by consensus whereby all signatory nations must agree on changes in regulations and protocols. This unique system provides perhaps the best global forum in which to agree and implement the concept of stewardship. The Protocol on Environmental Protection to the Antarctic Treaty provides a coherent framework for conservation and environmental management. Antarctic Specially Protected Areas (ASPAs) have been established in many areas of the continent to legally protect the vegetation or the fauna for both scientific and conservation reasons. Subglacial lake environments can be managed under existing approaches, whereby these environments are designated according to the Antarctic Treaty as “resources in need of special protection either for scientific research or conservation purposes.” Under this designation, subglacial aquatic regions selected for “scientific research” would have management plans that dictate the range of permitted investigations and ensure, through permitting and reporting requirements, that an audit trail exists of all the research undertaken. Lakes or subglacial regions designated for “conservation” would be set aside to conserve untouched examples of the diversity of subglacial aquatic environments for future generations In addition, the Committee for Environmental Protection (CEP) oversees the Comprehensive Environmental Evaluation (CEE) of proposed activities that are predicted to have more than a minor and/or transitory impact on the Antarctic environment. Steps within the regulatory framework of the Antarctic Treaty expose the proposals to a wide range of expert comment and ensure that the scientific community uses best-available practices. The requirement inherent in the treaty protocol to review the management plans every five years will provide the opportunity to assess how well these designations are working. In the exploration of subglacial aquatic environments, there are important scientific goals to achieve in a difficult and expensive operating environment. Jointly planned international activities will maximize the value of this research while ensuring that the latest technology is used. A multinational approach will bring the widest range of expertise to bear and, by focusing research efforts, reduce the number of subglacial aquatic environments investigated, thereby reducing the impact of science research on these remarkable resources. This international cooperation would also be consistent with the terms of the Antarctic Treaty, specifically the agreement by all signatory parties “to endeavour … to promote cooperative programs of scientific, technical and educational value, concerning the protection of the Antarctic environment and dependent and associated ecosystems” (Article 6 of the Protocol on Environmental Protection to the Antarctic Treaty, the Madrid Protocol). 2 The governance of Antarctica is guided by the Antarctic Treaty, which came into force in on June 23, 1961. The Antarctic Treaty system includes a series of agreements that regulate relations among states in Antarctica. Under the treaty, 45 signatory countries have agreed to protect the relatively unspoiled environment of Antarctica and its associated ecosystems; preserve and pursue unique opportunities for scientific research to understand Antarctica and global physical and environmental systems; maintain Antarctica as an area of international cooperation reserved exclusively for peaceful purposes; and ensure the conservation and sustainable management of living resources in the oceans surrounding Antarctica.

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship Recommendation 1 Direct exploration of subglacial aquatic environments is required if we are to understand these unique systems. Exploration of subglacial aquatic environments should proceed and take a conservative approach to stewardship and management while encouraging field research. Recommendation 2 Exploration protocols should assume that all subglacial aquatic environments contain or may support living organisms and are potentially linked components of a subglacial drainage basin. Recommendation 3 As soon as adequate survey data have been gathered to provide a sound basis for description, all subglacial aquatic environments intended for research should be designated Antarctic Specially Protected Areas to ensure that all scientific activities are managed within an agreed international plan and are fully documented. Recommendation 4 As soon as adequate survey data have been gathered to provide a sound basis for description, actions should be taken to designate certain exemplar pristine subglacial environments as Antarctic Specially Protected Areas for long-term conservation purposes. Recommendation 5 Multinational projects should be encouraged in the study of subglacial aquatic environments, and all projects aiming to penetrate into a lake should be required to undertake a Comprehensive Environmental Evaluation. Recommendation 6 The National Science Foundation should work in conjunction with the U.S. representatives to the Scientific Committee on Antarctic Research and to the Committee on Environmental Protection to involve all Antarctic Treaty nations in developing a consensus-based management plan for the exploration of subglacial aquatic environments. This plan should seek to develop scientific understanding and ensure that the environmental management of subglacial aquatic environments is held to the highest standards. TOWARD ESTABLISHING LEVELS OF CLEANLINESS The problem of how to penetrate kilometers of the ice sheet and sample subglacial aquatic environments in the cleanest and least intrusive manner possible remains a considerable technological challenge. Current drilling technologies are not sterile; drilling fluids may contain both microbes and substrates for microbial growth. In addition, the

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship ice sheet itself contains living microbes, and the extreme climate makes it impossible to carry out drilling without introducing microbes from humans. The inadvertent introduction of microbes that might grow in these waters is of highest concern. Not only will living microbes potentially alter the aquatic systems, but also exogenous DNA3 will interfere with research using molecular technology. Accordingly, it is of critical importance to minimize the introduction of exogenous microbes,4 and even exogenous nucleic acids,5 to allow for proper investigation of the “true” microbial community (and not contaminants) and prevent changes in microbial communities through the introduction of growth substrates or toxic materials to the subglacial aquatic environment. Drilling and sampling apparatuses may also add water-soluble oils used in metal working during the fabrication of the instruments and equipment, as well as phthalate ester additives that are used extensively in the plastics industry. The impact of minute quantities of oils and additives may be small and much reduced if they are rapidly diluted by mixing processes in the subglacial environment. Localized effects are possible, however, if mixing is slow; if the mixing volume is small relative to the quantities added; or if the contaminant does not dilute in water (e.g., nonaqueous-phase liquids). It is likely that contamination of subglacial aquatic environments during drilling, sampling, and monitoring cannot be eliminated, only minimized. Given that some contamination with microbes is inevitable, what level is acceptable? The only known quantity is the number of microbes present in the deep glacial ice. Using this quantity as a baseline, the committee suggests that fluids, drilling, or sampling equipment introduced into the subglacial aquatic environment should not contain more microbes than are present in an equivalent volume of deep glacial ice. From the available evidence, this amount is expected to be a few hundred cells milliliter. This level of contamination should be considered a provisional rule; when new data become available on microbial populations in these subglacial environments, the standard should be changed to reflect this new information. Research activities targeting one component of the environment may potentially contaminate or alter another component. For example, sampling may disturb the internal stratification of the lake and change its physical and chemical structure. Sediment sampling may transfer biota from sediments and near-bottom waters to overlying water and ice, which may compromise subsequent measurements of the upper waters and ice. Sediments are likely to contain orders-of-magnitude higher concentrations of microbes, nutrients, and metals than are present in the water column. These benthic microbial communities also are likely to be different from those in the water column. In addition to assessing potential impacts of research activities prior to their start, the committee recognizes the importance of initially sampling sites furthest downstream within a subglacial drainage system to reduce the impact of any contaminants introduced into the drainage system and the importance of maintaining records of materials introduced into the environment to inform future investigations. Cleanliness requirements for the exploration of subglacial aquatic environments include (1) cleaning hardware (and quantifying microbial levels) prior to penetration, (2) maintaining hardware cleanliness during penetration, and (3) designing research 3 DNA that originates outside an organism. 4 Microbes that are introduced to closed biological systems from the external world. 5 Nucleic acids that originates outside an organism.

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship techniques that minimize the possibility for cell transfer between different levels in the ice and the lake bed itself. If an environment has unique biological systems, transfer may also occur as a robotic sampling device moves between different environments. Thus, it will be important to minimize the level of microbial contaminants on drilling, sampling, and monitoring equipment to ensure that these activities have a minor and/or transitory impact on the environment. Although there is no definition of minor or transitory in the Antarctic Treaty, in practice, Antarctic Treaty parties have considered the chemical impacts on the Antarctic environment; these considerations may provide a context in which to evaluate potential microbial impacts. The primary concerns surrounding addition of chemicals to the environment have been to determine the contaminant level that can be detected, how long it would continue to be detectable, and what effect the total amount might have on the system. This has been of particular concern for example, in assessing the impact of chemical species in coastal sewage outlets. In practice, if the chemical is not detected, due to dilution, within a short distance from the end of the pipe, then the effect of the contaminant on the environment has been considered as less than minor and transitory. With this definition of minor and or transitory in mind, the committee considers the addition of contaminants which do not change the measurable chemical and/or biological properties in a volume equivalent to the borehole as a less than minor impact. Based on these considerations, the committee offers the following recommendations: Recommendation 7 Drilling in conjunction with sampling procedures will inevitably introduce microorganisms into subglacial aquatic environments. The numbers of microbial cells contained in or on the volume of any material or instruments added to or placed in these environments should not exceed that of the basal ice being passed through. Based on research to date, a minimum of 102 cells / mL−1 should not be exceeded, until more data are available. Recommendation 8 Drilling in conjunction with sampling procedures will inevitably introduce non-living chemical contaminants into lakes and associated subglacial aquatic environments. Toxic and biodegradable materials should be avoided, as should the introduction of nonmiscible substances. At a minimum, the concentrations of chemical contaminants should be documented and the total amount added to these aquatic environments should not be expected to change the measurable chemical properties of the environment. The amount added would be expected to have a minor and/or transitory impact on the environment. Recommendation 9 Notwithstanding their compliance with Recommendations 7 and 8, investigators should continue to make every effort practicable to maintain the integrity of lake chemical and physical structure during exploration and sampling of water and sediments.

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship EXPLORATION PROTOCOLS Responsible environmental stewardship for the exploration of subglacial aquatic environments requires investigations to progress from the least invasive techniques to more invasive ones in a stepwise manner. An iterative progression of investigations will generate scientific data while simultaneously providing important information to define standards and protocols that in turn may be refined based on newly acquired data. The ideal approach would be to characterize as many subglacial lake environments as possible using remote sensing and ground seismic sounding and then select examples of different types of environments for progressive investigation. Although the committee recognizes that the ideal approach may be difficult to implement, nonetheless, an incremental approach to and identification of future research sites are strongly suggested. Once the decision is made to directly sample a particular subglacial aquatic environment, the committee believes that the biology of these environments needs to be protected and is therefore the first priority. Accordingly, good stewardship requires that the cleanest technologies practicable be employed during the exploration of these lakes, and that exploration does not permanently alter the biological and chemical nature of these environments (see Recommendations 7 and 8). A simple first step would be collection of a water column profile (i.e., using in situ sensors on some kind of profiling package) and a small sample of the water. It is not necessary to sample the environment in its entirety during the initial stages of exploration, because the physical, chemical, and biological properties of the water column need to be understood before realistic standards for contamination can be set and required advancements in engineering for more advanced exploration can be determined. Key data to be acquired in the first step of this progressive approach would ideally be geared toward helping understand partition coefficients, mixing regimes, habitats that have the potential for microbiological activity, and the fate of contaminants. The simplest approach would involve a CTD cast with other sensors, followed by a vertical profile and sample return of water and surface sediment. Although investigation of Lake Vostok is the most advanced, three other lakes (Concordia, Ellsworth, and South Pole) are under investigation or consideration. These lakes represent different categories based on their geologic characteristics. Vostok is a rift lake, Ellsworth and Concordia are basin lakes, and South Pole Lake may be small and shallow or may consist only of sediments and, therefore, not actually be a lake. The proximity of Vostok, Concordia, and South Pole lakes to existing research stations has great logistical benefits. Although Lake Ellsworth is not located near an existing research station, a reasonable case can also be made for a temporary drilling camp at Lake Ellsworth where a hot-water drill would penetrate the ice sheet in a few weeks (Box 1.2). This site is located along a crevasse-free path to the Patriot Hills, where a blue ice runway exists and supplies and personnel can be flown directly from Punta Arenas, Chile. These locations make the drilling easier to manage, strong environmental protocols more easily to apply, and the access for international inspection easier. These subglacial aquatic environments are thus good candidates for investigations based on logistical criteria. Unfortunately, the basic hydrology of Lake Concordia and South Pole Lake is completely unknown, so the potential environmental impact of sampling these lakes on other subglacial aquatic environments in their respective drainage basins is also unknown. However, the basic hydrology of Lake Vostok and Lake Ellsworth is understood, and they appear to be good candidates for exploration.

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship It is important that lessons learned in exploring a particular lake be transmitted quickly and effectively to the broader scientific community and that all progress in this field be adequately documented for each site. In this way, technology can advance as quickly as possible. Also, hydrologic connections between the lakes need to be carefully monitored and updated because these connections will have an impact on potential exploration strategies. During exploration, it will be important to establish systems that to allow for clean monitoring of the lake, to both assess the impact of the sampling and to provide for easier and cleaner access in the future. These systems may include in situ devices for long-term monitoring of the lake, technologies such as probes that transmit data back to the ice surface, and devices to provide clean access to the lake water for future sampling. Setting aside some lakes to test sampling techniques is a potential strategy to aid in the development of practical and minimally contaminating sampling equipment. Maintaining detailed information about activities associated with these environments is a requirement of the Antarctic Treaty protocol. A record of any material components used in the exploration of subglacial lakes that may influence future research and information regarding drilling components, such as the microbial content of drilling fluids will be important to the development of the exploration protocols and future investigations. Recommendation 10 Allowances should be made for certain objects and materials to be placed into experimental subglacial aquatic environments for scientific purposes—for example, for monitoring or tracing dynamics. These additions should follow the microbiological constraints in Recommendation 7 and include discussion of an environmental risk versus scientific benefit analysis in the Comprehensive Environmental Evaluation. Recommendation 11 As the initial step to define an overall exploration strategy, the United States, together with other interested parties, should begin immediately to obtain remote sensing data to characterize a wide range of subglacial aquatic environments. As a second step, preliminary data and samples should be obtained from subglacial aquatic environments immediately to guide future environmental stewardship, scientific investigations, and technological developments. Recommendation 12 Remote sensing of the potential aquatic environments beneath the Antarctic ice sheet is underway but is far from complete. The following actions should proceed in order to make a decision about which subglacial aquatic environments should be studied in the future: Continent-scale radio-echo sounding data should be assembled and subglacial aquatic environments identified; All regions where the basal melt-rate is likely high should be identified; Detailed radio-echo sounding of known lakes should be done;

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship A hydrologic map of the subglacial drainage system for each catchment should be constructed; Potential target environments should be identified based on the subglacial drainage system. Once potential research sites are identified, the likelihood of attaining scientific goals should be evaluated based on the representativeness for other lakes and settings, for accessibility, and for the constraints of logistics and cost. The committee recognizes that plans are underway to sample Lake Vostok, and in the longer term Lake Ellsworth and Lake Concordia. The data collected from these endeavors should be used to assess whether the levels of cleanliness suggested in Recommendation 7 are appropriate. RESEARCH NEEDS At present, no clean drilling, sampling or monitoring technologies have been developed for exploration of subglacial aquatic environments. Development of new technologies needs to focus on methods to reduce contamination and to assess the contaminant load after sterilization. A standard method to ensure cleanliness that can be verified in the field is a critical need. To achieve these goals, research is needed in two main areas: (1) microbial background levels and instrument cleanliness, and (2) clean drilling fluids. The baseline levels of microbes in the glacial ice and subglacial waters and the basic chemistry of all phases of these environments are not well established. In the case of background microbial levels, it may be possible to obtain ice samples from the ICECUBE project to investigate microbial background loadings in the glacial ice and the base-level contamination of hot-water drilling. Research from accretion ice cores is also needed to establish partition coefficients, which will help establish contamination limits. Using various technologies, it is necessary to assess the impacts of access and sampling and provide data to develop improved technologies for easier and cleaner access in the future. Although hot-water drilling presents the greatest possibility for clean drill fluids, the time that a hole can be kept open and the depth to which hot-water holes can be drilled are limited. Drill fluids that do not freeze (e.g., jet fuel) have significant levels of biological contamination, but these fluids can provide indefinite access to a lake with periodic maintenance of the hole. New types of drilling fluids are needed that would not be substrates for microbial growth. Methods to clean the fluids prior to field deployment, as well as methods to clean them in the field, are also required. Development of filtering methods for borehole and drilling fluids may prove effective, along with in-line ultraviolet (UV) sterilization techniques or the addition of bactericides to the drilling fluids. It will be important to assess and document the biological and chemical contaminant content of all fluids used. Cleaner monitoring and sampling technologies will have to be developed. Some priority areas include the following examples. Inert tracers in the drill fluid or fluid used to enter the lake need to be developed to track the level and distribution of contaminants within the lake. Development of miniaturized monitoring equipment will make it easier both to insert observatories into the water bodies and to retrieve them. A remote observatory designed for subglacial aquatic environments that could be inserted through a small borehole could provide long-term monitoring of the water or

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship sediments. To achieve this type of observatory, there is a need for probes that transmit data back to the ice surface and devices to provide clean access to the lake water for future sampling. Technological advances are needed for clean sediment sampling that will not disturb the water column. Recommendation 13 Research and development should be conducted on methods to reduce microbial contamination throughout the drilling, sampling, and monitoring processes, on methods to determine the background levels of microbes in glacial ice and lake water, and on development of miniaturized sampling and monitoring instruments to fit through the drilling hole. The following methods and technologies need to be improved or developed: A standard method to ensure cleanliness for drilling, sampling, and monitoring equipment that can be verified in the field; New ways of drilling through the ice sheet that include drilling fluids that would not be a substrate for microbial growth; Inert tracers in the drill fluids or fluids used to enter the lake to track the level and distribution of contaminants within the lake; Methods to determine baseline levels of microbes in the glacial ice and subglacial waters; Instrumentation scaled to fit through a bore hole, to measure chemistry and biology of these environments and transmit data back to the ice surface; Methods to provide clean access to the lake water for extended periods. The committee recognizes that plans are underway to sample Lake Vostok, and in the longer term, Lake Ellsworth and Lake Concordia. The data collected from these endeavors should be used to better assess the requirements of future methodologies and technologies. GUIDELINES FOR STEWARDSHIP, MANAGEMENT, AND PROJECT REVIEW This report provides an initial framework for the environmental stewardship for exploration of subglacial aquatic environments. Recommendations are based on current understanding of these environments, which is limited and incomplete. As the science and exploration of subglacial environments grow beyond their infancy, the initial methodologies and protocols recommended in this report will need further development and regular revision on both a national and an international scale. All aspects of management, stewardship, and project review and approval will continue to involve absolute requirements mandated by the Antarctic Treaty, government standards specific to particular parties, and scientific standards such as those recommended by SCAR. The recommendations of the committee are thus intended for integration into this important multifaceted framework. An overview of the committee’s recommendations and a suggested sequence and framework to address the key areas of importance for subglacial lakes—stewardship, management, and project review is shown in Figure 6.1, definitions are in Box 6.1. This framework is deliberately consistent with the guidelines of the Antarctic Treaty,

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship FIGURE 6.1 Sequence and framework to address stewardship, management, and project review for subglacial aquatic environments. SOURCE: Dr. Margaret S. Race, Committee Member.

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship BOX 6.1 Explanation of Terms in Figure 6.1 Antarctic Specially Protected Area (ASPA): A specially designated area that provides protection for outstanding environmental, scientific, historic, or aesthetic values or for ongoing or proposed scientific research. Each area has a management plan that provides the details of what actions can and cannot be undertaken in the area. All entry to ASPAs is by permit only issued by individual parties on application. Antarctic Treaty: Provides governance via the annual Antarctic Treaty Consultative Meetings (ATCMs) at which the ATCM Plenary makes the final decision on recommendations from its constituents’ working groups and committees. Antarctic Treaty Secretariat: Supports the treaty between sessions, helps organize and run the annual ATCM meetings, and acts as the repository for official papers and information (which at present does not include scientific information). Committee for Environmental Protection (CEP): Advises the ATCM Plenary on all aspects of environmental management covered by the Protocol on Environmental Protection. Comprehensive Environmental Evaluation (CEE): A project review document undertaken when the predicted environmental impact is greater than minor and/or transitory. A CEE requires considerable detailed information; the draft must be made publicly available and circulated to parties, allowing at least 90 days for comment, and submitted to the CEP at least 120 days before the next Consultative Meeting. A final CEE must address all the comments received and must be circulated to parties and made publicly available at least 60 days before the start of the proposed activity. Initial Environmental Evaluation (IEE): Environmental review document undertaken when the predicted environmental impact of a proposed project is minor and/or transitory. It is normally reported to the treaty parties but is not circulated for comment. National Authorities: The governance structure of each nation (Consultative Party) for implementing the Antarctic Treaty. For the United States: State Party = U.S. Department of State (political aspects of the treaty); Science Group = NRC Polar Research Board, U.S. representative to SCAR; Management / Logistics = NSF Office of Polar Programs (the U.S. representative to COMNAP, the Council of Managers of National Antarctic Programmes) Scientific Committee on Antarctic Research (SCAR): an interdisciplinary committee of the International Council for Science (ICSU), that initiates, develops, and coordinates high-quality international scientific research in the Antarctic region and on the role of the Antarctic region in the Earth system. SCAR also provides objective and independent scientific advice to the Antarctic Treaty Consultative Meetings and other organizations on issues of science and conservation affecting the management of Antarctica and the Southern Ocean. SCAR has national representation from those countries with an active scientific interest in Antarctica. Subglacial Antarctic Lake Program (SALE): Created by SCAR as a major international research program that provides the framework within which the science objectives are agreed upon by scientists interested in subglacial lakes; SALE also coordinates the pooling of data and specimens, and organizes workshops

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Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship as well as national and international programs or authorities that are involved in the treaty process.6 It also has the necessary flexibility to update information and evolve over time as new findings accumulate about drilling, biological and geological information, and exploration methods. The committee’s recommendations can be tracked in the diagram (Figure 6.1). Recommendations 1 and 2 state the committee’s strong belief that carefully managed scientific research on subglacial lakes should begin while preserving the environment for future potential discoveries through a suitably conservative approach. Working through SCAR, it will be important to develop criteria and research specifications that may be incorporated into management plans for subglacial aquatic environments (Recommendations 3, 4, 6, 7, 8, 9, 10, and 12). An initial research protocol is outlined in Recommendation 12 and is intended for both international and national levels. Exploration will continue to be subject to formal peer review through Antarctic Treaty protocols (e.g., CEE), as soon as adequate survey data have been gathered to provide a sound basis for description and include comment by SCAR where appropriate. Stewardship for the future is best addressed by establishing a dynamic multinational approach and specific scientific archive that preserves and quantifies pertinent information associated with current scientific research, nationally and internationally (Recommendations 5, 11, 12, 13). Maintaining detailed information about activities associated with these environments is a requirement of the Antarctic Treaty protocol and the committee hopes that information regarding drilling components, such as the microbial content of drilling fluids and any material components that may influence future research will be an important part of the stewardship for the exploration of subglacial aquatic environments. The exploration of subglacial aquatic environments is in its initial stages, with fundamental questions remaining to be answered about these unique environments. Much debate and speculation have occurred based on the limited data available; no definitive answers will be forthcoming until these environments are sampled directly. The existence of these environments on the Antarctic continent makes them a part of the common heritage of all humankind. Accordingly, the management of subglacial aquatic environments requires responsible environmental stewardship while allowing field research in accordance with the Antarctic Treaty. Although this study is being produced by a U.S. scientific advisory body, and the U.S. National Science Foundation (NSF) requested this study to guide scientific programs originating in the United States, the committee hopes that its multinational makeup will be recognized and that the recommendations in this report will serve as a basis for broad international discussion about environmental stewardship for the exploration of subglacial aquatic environments. 6 (1) Management of the subglacial aquatic environments via the Committee for Environmental Protection and the Scientific Committee on Antarctic Research; (2) continuing stewardship of these environments through the processes of the Antarctic Treaty, and the formal request that specific subglacial aquatic environments be designated as Antarctic Specially Protected Areas, either for long-term conservation or for agreed scientific research; and (3) the scientific project review and approval process involving national authorities and international oversight through the CEP.