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2006 Annual Science Report

Indiana University, Bloomington Reporting  |  JUL 2005 – JUN 2006

Executive Summary

Team IPTAI continues to focus on field sampling and borehole monitoring of sub-permafrost brines in fractured Archean strata from the deep subsurface of northern Canada. Our principal research site will shift in the coming year from an extensively mined gold deposit at Lupin to a minimally explored base-metal deposit at High Lake, Nunavat Territory (Figure 1). The High Lake mining property is located in an Archean green stone belt containing both felsic and mafic metavolcanics and comprising a significant copper-zinc deposit that is frozen to a depth of about 450 meters. A site for scientific drilling will be selected on the basis of fracture patterns evident from surface mapping and minimal contamination from exploration drilling. We anticipate drilling in July 2006 and plan for one borehole at an angle of 40° to 75° from horizontal with recovery of 20 to 30 meters of aseptic core having a diameter of 75 mm. Optimistically, this scientific borehole will penetrate to the base of the permafrost and will allow extraction of gas and brine samples from beneath the permafrost. The majority of costs for the High Lake drilling campaign will be covered by supplemental funds from the NASA Astrobiology Institute awarded to IPTAI for microbiological and geochemical studies and by research funds awarded to Timo Ruskeeniemi and others at the Finnish Geological Survey for assessing the long-term performance of deep underground constructions such as nuclear waste repositories. Additional financial support for the High Lake campaign will be provided by Shaun Frape at the University of Waterloo for borehole instrumentation and by Wolfden Resources Incorporated for lodging and logistical support. This highly collaborative, international campaign would not be possible without extraordinary trust and respect fostered over the past two years among participating researchers, students, and mine owners.

Figure 1Figure 1. High Lake camp.

Laboratory experiments are an important facet of investigating energy and nutrient cycles in the deep sub-surface of Earth and Mars. Abiotic reduced compounds forming in the crust or mantle are continuously moving upward and sustaining redox gradients in deep ground water systems. Laboratory experiments can be used to address the molecular structures and stable isotopic compositions of hydrocarbons produced during abiotic water/mineral reactions. Experiments conduced by Team IPTAI in the past year include hydrothermal simulations, Fischer-Tropsch synthesis, and spark discharge. In a major analytical breakthrough, carbon and hydrogen isotopic measurements on hydrocarbon products from methane polymerization were sucessfully determined in the Sherwood-Lollar laboratory at the University of Toronto. These results are timely because the scientific community needs definitive criteria for distinguishing abiogenic and biogenic hydrocarbons in order to refine the debate concerning origins of methane in crystalline rocks on Earth and in the atmosphere on Mars.

Gold mines in South Africa provide access to microorganism-bearing fluids that emanates from fractures at depths ranging from about 0.5 to 5 km below the surface. Phylogenetic classification of the microbial species using 16S rRNA analyses of environmental samples reveals a number of new generii, families, orders, and, in some cases, new phyla of archaea and bacteria. For microbial ecologists this is both exciting, because it indicates the extent to which the deep subsurface harbors novel life forms, and frustrating, because the lack of similarity of the 16S rRNA sequences to existing isolates precludes confident inference of their metabolic interactions with the environment. One phylotype belonging to the Firmicutes has been found to be the dominant organism in almost all fracture fluids emanating from depths greater than 1.5 km across the entire Witwatersrand Basin. Terry Hazen and research associates at Lawrence Berkeley National Laboratory have obtained a complete genome for this organism. During consideration of an appropriate name for this organism, the following passage captured the imagination of these researchers:

“In Sneffels Joculis craterem quem delibat Umbra Scartaris Julii intra calendas descende, Audax viator, et terrestre centrum attinges.” (“Descend, bold traveller, into the crater of the jokul of Sneffels, which the shadow of Scartaris touches before the kalends of July, and you will attain the center of the earth.”)

This hidden message was deciphered from an Icelandic saga and prompted the fictional Professor Lidenbrock to undertake his travels in the Jules Verne’s novel entitled “Journey to the Center of the Earth.” The proposed name for the Witwatersrand microbe is Desulforudis audaxviator in honor of its bold travels. Similar phylogenic study of microbes recovered from sub-surface environments in northern Canada will allow us to understand potentially successful strategies for microbial metabolism on Mars.

Laboratory studies of radiolysis by Team IPTAI utilize gamma radiation as well as reaction with hydrogen peroxide to simulate radiolysis. A series of experiments have successfully produced sulfate and nitrate by radiolytic oxidation of pyrite and ammonium ion, respectively. The presence of naturally occurring, peroxide-containing minerals such as studtite in association with uranium deposits on Earth encourages us to pursue field study of this oxidation pathway in deep ground water settings. Several lines of evidence indicate that hydrogen peroxide is a key catalytic component of the Martian atmosphere and an important oxidizing reactant in Martian regolith. The chemical activity of hydrogen peroxide is inferred to be significant on the surface and beneath the ice cover of Jupiter’s moon Europa. Experimental and field studies are urgently needed to characterize the concentration and isotopic composition of sulfate and nitrate produced by radiolytic oxidation. The decay of naturally occurring radionuclides could be a source of bioavailable chemical energy for microbes in the deep subsurface of Earth and other planetary bodies.