Overview of analogue science activities at the McGill Arctic Research Station, Axel Heiberg Island, Canadian High Arctic
ABSTRACT The Canadian High Arctic contains several of the highest fidelity Mars analogue sites in the world. Situated at nearly 80° north, Expedition Fjord on Axel Heiberg Island is located within a polar desert climate, with the surrounding landscape and conditions providing an invaluable opportunity to examine terrestrial processes in a cold, dry environment. Through the Canadian Space Agency's Analogue Research Network program, scientific activities based out of the McGill Arctic Research Station (M.A.R.S.) are extremely broad in scope, representing physical, biological, and technological investigations. Some of the most unique hydrogeologic features under investigation near M.A.R.S. are a series of cold saline springs that maintain liquid-state flow year round regardless of air temperature. Previous studies have examined their geomorphic relation to discharge-related formations, water chemistry, temperature monitoring, discharge rates, and combined flow/thermal modeling. Recent investigations have identified microbial communities and characterized biological activity within the springs and within permafrost sections, having direct relevance to astrobiological analogue research goals. Another main thrust of research activities based at M.A.R.S. pertains to the detection, mapping, and quantification of subsurface ice deposits. A long-term study is presently underway examining polygonal terrain, comparing surficial patterns found in the region with those identified on Mars, and using surface morphology to estimate ice wedge volumes through a combination of aerial photography interpretation and ground-based geophysical techniques. Other technological developments include the use of in situ microscopy for the detection of biomarkers and improved permafrost drilling techniques. This paper presents an overview of previous studies undertaken at M.A.R.S. over the past decades and will describe in detail both present and upcoming work.
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ABSTRACT: In recent years evidence for spring deposits on Mars has been mounting. It seems increasingly likely that groundwater upwelling and surfacing as springs may be responsible for some mineral deposits on Mars’ surface. In order to more easily detect and better understand potential spring deposits on Mars, it is pertinent that we gain a better understanding of the distribution of minerals at cold spring systems on Earth. Here, we report on the detailed mineralogy and distribution of precipitates in crusts and sediments of three non-volcanic perennial saline cold spring systems associated with gypsum/anhydrite diapirs on Axel Heiberg Island, Canada: Wolf spring (WS; also known as Lost Hammer), Colour Peak springs (CP), and Gypsum Hill springs (GH). At these sites permafrost, frigid winter temperatures, and arid atmospheric conditions approximate conditions of present-day, as well as past, Mars. Mineralogy of the three springs is dominated by halite (NaCl), calcite (CaCO3), gypsum (CaSO4·2H2O), thenardite (Na2SO4), mirabilite (Na2SO4·10H2O), and elemental sulfur (S°). Minerals at WS are more sodium-rich than at the other two sites, and water salinity is much higher, suggesting water flows through halite in the subsurface. Mirabilite is likely deposit at WS during winter months and dehydrates to thenardite during summer months. Elemental sulfur is typically associated with gypsum, and may be related to microbial metabolism. Spring sediments are home to thriving microbial communities in winter and summer months, and presumably year round. If spring systems did exist on the surface of Mars, they may represent environments capable of supporting microbial life. It is not known to what extent mineral crusts in cold saline spring systems on Earth preserve evidence of microbial life, or if they ever did on Mars. Therefore, studying terrestrial saline spring mineral deposits such as those on Axel Heiberg Island may help us to better understand cold spring precipitation on Mars and guide us in the search for minerals that may have been precipitated in spring systems and that may contain evidence of life. Additionally, spectral data from Europa indicates the presence of mirabilite. While the depositional environment on Europa differs from Axel Heiberg Island, the springs may still be a good mineralogical analogue, given the precipitation of mirabilite by the upwelling of cold, salty subsurface water, in a cold, semi-arid desert environment.Icarus 06/2013; 224(2):364–381. · 3.16 Impact Factor
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ABSTRACT: Terrestrial analogue studies underpin almost all planetary missions and their use is essential in the exploration of our Solar system and in assessing the habitability of other worlds. Their value relies on the similarity of the analogue to its target, either in terms of their mineralogical or geochemical context, or current physical or chemical environmental conditions. Such analogue sites offer critical ground-truthing for astrobiological studies on the habitability of different environmental parameter sets, the biological mechanisms for survival in extreme environments and the preservation potential and detectability of biosignatures. The 33 analogue sites discussed in this review have been selected on the basis of their congruence to particular extraterrestrial locations. Terrestrial field sites that have been used most often in the literature, as well as some lesser known ones which require greater study, are incorporated to inform on the astrobiological potential of Venus, Mars, Europa, Enceladus and Titan. For example, the possibility of an aerial habitable zone on Venus has been hypothesized based on studies of life at high-altitudes in the terrestrial atmosphere. We also demonstrate why many different terrestrial analogue sites are required to satisfactorily assess the habitability of the changing environmental conditions throughout Martian history, and recommend particular sites for different epochs or potential niches. Finally, habitable zones within the aqueous environments of the icy moons of Europa and Enceladus and potentially in the hydrocarbon lakes of Titan are discussed and suitable analogue sites proposed. It is clear from this review that a number of terrestrial analogue sites can be applied to multiple planetary bodies, thereby increasing their value for astrobiological exploration. For each analogue site considered here, we summarize the pertinent physiochemical environmental features they offer and critically assess the fidelity with which they emulate their intended target locale. We also outline key issues associated with the existing documentation of analogue research and the constraints this has on the efficiency of discoveries in this field. This review thus highlights the need for a global open access database for planetary analogues.International Journal of Astrobiology 01/2014; 13(1):81-98. · 1.45 Impact Factor
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ABSTRACT: The Lost Hammer (LH) spring is the coldest and saltiest terrestrial spring discovered to date and is characterized by perennial discharges of subzero temperatures (-5°C), hypersalinity (24% salinity), along with reducing (≈-165 mV), microoxic, and oligotrophic conditions. It is rich in sulfates (10.0% w/w), dissolved H2S/sulfides (up to 25 ppm), ammonia (≈381 μM), and methane (11.1 g d(-1)). To determine its total functional and genetic potential and identify its active microbial components, we performed metagenomic and 16S ribosomal cDNA pyrosequencing analyses of the LH-spring outlet microbial community. Reads related to Cyanobacteria (34.8%), Bacteroidetes (24.8%), and Proteobacteria (18.4%) represented the dominant phyla identified among the classified sequences. Reconstruction of the enzyme pathways responsible for bacterial nitrification/denitrification/ammonification and sulfate reduction appeared nearly complete in the metagenomic dataset. In the LH 16S ribosomal cDNA active community profile, ammonia oxidizers (Thaumarchaeota), denitrifiers (Pseudomonas spp.), sulfate reducers (Desulfobulbus spp.), and other sulfur oxidizers (Thermoprotei) were present, highlighting their involvement in nitrogen and sulfur cycling. Stress-response genes for adapting to cold, osmotic stress, and oxidative stress were also abundant in the metagenome. Comparing functional community composition of the LH spring to metagenomes from other saline/subzero environments revealed a close association between LH and another Canadian High Arctic permafrost environment, particularly in genes related to sulfur metabolism and dormancy. Overall, this study provides insights into the metabolic potential and the active microbial populations that exist in this hypersaline cryoenvironment and contributes to our understanding of microbial ecology in extreme environments.Applied and environmental microbiology 04/2013; · 3.69 Impact Factor