Plan for the international study of Lake Vostok

A question was raised with regard to scientific research related to Lake Vostok at the workshops mentioned in earlier chapters - namely, where were the American scientists who have pursued the traditional directions of glaciological and geophysical studies and who have spent time studying bottom processes of the ice sheet before 1996? Except for a few relatively new American glaciologists, little effort or research was spent by the U.S.A. on the issues of Lake Vostok. The answer lies behind their main interest of present study, that of the bottom processes of the West Antarctic Ice Sheet, including the study of the known subglacial ice streams that feed the Ross Ice Shelf. However, the interest of American scientists in subglacial lakes peaked with the possibilities of finding new (or old) forms of life.

Interest by the U.S.A. became apparent when a further workshop on Lake Vostok was announced for 7-8 November 1998 in Washington, D.C., only 6 months after the meeting in St. Petersburg and 11 months before the Scientific Committee on Antarctic Research (SCAR) Workshop on Subglacial Lake Exploration, in Cambridge. The main topic of the workshop, sponsored by the U.S. National Science Foundation (NSF), was evident in the title of the final report -"Lake Vostok: A Curiosity or a Focus for Interdisciplinary Study?" (Figure 10.1).

The workshop's conveners were Dr. R. Bell from the Lamont-Doherty Earth Observatory and Dr. D. Karl from the School of Ocean and Earth Science and Technology, University of Hawaii. Dr. Bell reviewed the geology and geophysical aspects of the problem, and Dr. Karl the microbiological component. Four small parts of pages 2-8 from the final report of this workshop are cited below.

Part 1 (Bell and Karl, 1998, pp. 2-3). Life continues to appear in the unusual and extreme locations from hot vents on the seafloor to ice-covered hypersaline lakes in Antarctica. The subglacial environment represents one of the most oligotrophic environments on earth, an environment with low nutrient levels and low standing stocks of viable organisms. It is also one of the least accessible habitats. Recently the

LAKE VOSTOK WORKSHOP

FINAL REPORT

Lake Vostok:

A Curiosity or a Focus for Interdisciplinary Study?

National Science Foundation Sponsored workshop

Conveners;

Robin E Doll

Laimont-Doheriy Earth Observatory of Columbia University

David M Kail University of Hawal'i

Washington D.C. November 7 a 8, 199&

Figure 10.1. Front page of the Final Report of the Lake Vostok Workshop held in Washington, D.C., 1998. Sponsored by the National Science Foundation.

significance of understanding subglacial communities has been highlighted by discoveries including the thriving bacterial communities beneath alpine glaciers, to the evidence from African stratigraphy for a Neoproterozoic snowball Earth to the compelling ice images from Europa, the icy moon of Jupiter. If life thrives in these environments it may have to depend on alternative energy sources and survival strategies. Identifying these strategies will provide new insights into the energy balance of life.

The identification of significant subglacial bacterial action as well as the work on permafrost communities suggests that life can survive and possibly thrive at low temperatures. Neither the alpine subglacial environment nor the permafrost environment is as extreme as the environment found beneath a continent-wide ice sheet as Antarctica today. The alpine subglacial environment has a continual high level of flux of nutrients from surface crevasses. The Antarctic subglacial environment lacks a rapid flux of surface meltwater and subsequently is more isolated. In addition to being more isolated, the Antarctic subglacial environment is a high-pressure region due to the overburden of ice.

FINAL REPORT

Lake Vostok:

A Curiosity or a Focus for Interdisciplinary Study?

National Science Foundation Sponsored workshop

Conveners;

Robin E Doll

Laimont-Doheriy Earth Observatory of Columbia University

David M Kail University of Hawal'i

Washington D.C. November 7 a 8, 199&

The Antarctic subglacial environment may be similar to the environment beneath the widespread ice sheets in the Neoproterozoic, a time period from about 750 to 543 million years ago. It has been suggested that during this period the Earth experienced a number of massive glaciations - covering much of the planet for approximately 10 million years at a time. The evidence for an ancient ice covered planet comes from thick widespread sedimentary sequences deposited at the base of large ice bodies. These glacial units alternate with thick carbonate units - warm, shallow-water sedimentary deposits. These paired sequences have been interpreted as representing a long period when the Earth alternated between an extremely cold, completely ice-covered planet (the snowball Earth) and a hothouse planet. Some speculate that the extremes of these climates introduced an intense "environmental filter", possibly linked to a metazoan radiation prior to the final glaciation and an Ediacaran radiation. Portions of the Antarctic continental subglacial environment today, which have been isolated from free exchange with the atmosphere for at least 10 million years, are similar to the environment in this ancient global environment. Understanding the environmental stresses and the response of the microbes in a modern extreme subglacial environment will help us decipher the processes which lead to the post-glacial evolutionary radiation over 500 million years ago.

The third important analog for modern Antarctic subglacial environments is from the outer reaches of the Solar System, the ice moon of Jupiter, Europa. Recent images resembling sea ice, combined with the very high albedo of this moon have led to the interpretation that this moon is ice covered. Beneath the ice covering of Europa is believed to be an ocean. The thick cover of ice over a liquid ocean may be a fertile site for life. The Antarctic subglacial lakes have similar basic boundary conditions to Europa.

An investigation of Antarctic subglacial environments should target the unique role these lakes may have in terms of the triggers for rapid evolutionary radiation, for understanding the global carbon cycle through major glaciations and as an analog for major planetary bodies...

After a short description of what we already know about Lake Vostok (see above) the authors continue with Part 2.

Part 2 (Bell and Karl, 1998, p. 5). Prolonged preservation of viable microorganisms may be prevalent in Antarctic ice-bound habitats. Consequently, it is possible that micro-organisms may be present in Lake Vostok and other Antarctic subglacial lakes. However, isolation from exogenous sources of carbon and solar energy, and the known or suspected extreme physical and geochemical characteristics, may have precluded the development of a functional ecosystem in Lake Vostok. In fact, subglacial lakes may be among the most oligotrophic (low nutrient and low standing stocks of viable organisms) habitats on Earth. Although "hotspots" of geothermal activity could provide local sources of energy and growth-favorable temperatures, in a manner that is analogous to environmental conditions surrounding deep sea hydrothermal vents, it is important to emphasize that without direct measurements, the possible presence of fossil or living micro-organisms in these habitats isolated from external input for nearly 500,000 years is speculation.

Lake Vostok may represent a unique region for detailed scientific investigation for the following reasons:

• It may be an active tectonic rift which would alter our understanding of the East Antarctic geologic terrains.

• It may contain a sedimentary record of Earth's climate, especially critical information about the initiation of Antarctic glaciation.

• It may be an undescribed extreme Earth habitat with unique geochemical characteristics.

• It may contain novel, previously undescribed, relic or fossil micro-organisms with unique adaptive strategies for life.

• It may be a useful Earth-based analog and technology "test-bed" to guide the design of unmanned, planetary missions to recently discovered ice-covered seas on the Jovian moon, Europa.

These diverse characteristics and potential opportunities have captivated the public and motivated an interdisciplinary group of scientists to begin planning a more comprehensive investigation of these unusual subglacial habitats. As part of this overall planning effort, a NSF-sponsored workshop was held in Washington, D.C. (7-8 November 1998) to evaluate whether Lake Vostok is a curiosity or a focal point for sustained, interdisciplinary scientific investigation. Because Lake Vostok is located in one of the most remote locations on Earth and is covered by a thick blanket of ice, study of the lake itself that includes in situ measurements and sample return would require a substantive investment in logistical support, and, hence financial resources.

Over a period of two days, a spirited debate was held on the relative merits of such an investment of intellectual and fiscal resources in the study of Lake Vostok. The major recommendations of this workshop were:

To broaden the scientific community knowledgeable of Lake Vostok by publicizing the scientific findings highlighted at this workshop... The goal of the workshop was to stimulate discussion within the U.S. science community on Lake Vostok, specifically addressing the question: "Is Lake Vostok a natural curiosity or an opportunity for uniquely posed interdisciplinary scientific programs?''

Part 3 (Bell and Karl, 1998, pp. 6-7). The discussion of the major obstacles to advancing a well developed scientific justification and plan to study Lake Vostok hinged on several major factors including:

• The exploratory nature of the program coupled with the paucity of data about this unknown region making development of a detailed scientific justification difficult; the need for technological developments to ensure contamination control and sample retrieval, recognizing that Lake Vostok is a unique system whose pristine nature must be preserved.

• The need for a strong consensus within the U.S. science community that Lake Vostok represents an important system to study, and recognition that international collaboration is a necessary component of any study.

• The recognition that the logistical impact of a Lake Vostok program will be significant and that the scientific justification must compete solidly with other ongoing and emerging programs.

• That the lack of understanding of the present state of knowledge of the lake as a system within the U.S. science community remains a difficulty in building community support and momentum for such a large program.

These obstacles were addressed in workshop discussions and are specifically addressed in the report recommendations, the draft science plan and the proposed timeline.

Part 4 (Bell and Karl, 1998, p. 7). The overarching goal of the science plan is to understand the history and dynamics of Lake Vostok as the culmination of a unique suite of geological and glaciological factors. These factors may have produced an unusual ecological niche isolated from major external inputs. The system structure may be uniquely developed due to stratification of gas hydrates. Specific scientific targets to accomplish this goal include:

• Determine the geologic origin of Lake Vostok within the framework of an improved understanding of the East Antarctic continent as related to boundary conditions for a Lake Vostok ecosystem.

• Develop an improved understanding of the glaciological history of the lake including the flux of water, sediment, nutrients, and microbes into the Lake Vostok ecosystem.

• Characterize the structure of the lake's water column, to evaluate the possibility of density driven circulation associated with melting-freezing processes or geothermal heat, the potential presence of stratified gas hydrates, and the origin and cycling of organic carbon.

• Establish the structure and functional diversity of any Lake Vostok biota, an isolated ecosystem which may be an analog for planetary environments.

• Recover and identify extant microbial communities and a paleo-environmental record extending beyond the available ice core record by sampling the strati-graphic record of gas hydrates and sediments deposited within the Lake.

• Ensure the development of appropriate technologies to support the proposed experiments without contaminating the Lake.

The proposed timeline for all this research was (Bell and Karl, 1998, pp. 7-8):

1999-2000 Planning year Modeling studies

Develop international collaboration SCAR Lake Vostok workshop Begin technology development

2000-2001 Site survey year 1

Joint NSF/NASA Lake Vostok Proposals Airborne site survey

Preliminary ground-based measurements Preliminary identification of observatory sites

2001-2002 Site identification and site survey year 2 Ground-based site surveys Complete airborne survey if necessary

Test/access/contamination control at a site on the Ross Ice Shelf Finalize selection of observatory sites

2002-2003 In situ measurement year

Drill access hole for in situ measurements

Attempt in situ detection systems to demonstrate presence of microbial life Install a long-term observatory Acquire microscale profiles within surface sediments Conduct interface surveys (ice-water and water-sediments) International planning workshop (including data exchange)

2003-2004 Sample retrieval year Acquire samples of basal ice

Acquire samples of water and gas hydrates

Acquire samples of surface sediments

Stage logistics and second observatory

International planning workshop (including data exchange)

2004-2005 Installation of second long-term observatory Analysis of data

Building new models

International planning workshop (including data exchange)

2005-2006 Core acquisition year

Begin acquisition of long core

International planning workshop (including data exchange)

At the time of writing it is the beginning of 2006. It is worth saying that none of the points in this 5-year timeline, have been undertaken. Chapter 11 explains partly why this is the case.

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