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Destruction of ecosystems and infrastructure can be caused by melting of massive ice within permafrost. To predict potential melting caused by natural and human disturbance, we need to know the nature and origin of massive ice deposits. The purpose of this research was to evaluate the nature of massive ice in coarse-grained sediments that accepted theories suggest should not occur. / Degradation of ice-rich granular resources is expensive and difficult to rehabilitate and can cause developmental thermokarst, overestimation of granular resources, disturbance of wildlife habitat and create conflicts with traditional land uses. / To locate massive ice we used a resistivity geophysical technique and to characterize the ice we used geochemical, petrographic and stratigraphic techniques. The resistivity technique detected bodies of massive ice and ice-rich sediments and coarse-grained sediments at high resolutions and laboratory analysis reveal that the ice was of glacial origin. / These findings indicate that massive ice of glacial origin occurs in coarse-grained sediments in permafrost. The techniques used in this study could form the basis of a predictive model of massive ice occurrence.

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Winter roads, built from compacted snow and I or ice, are common throughout the circumpolar North. They are considered effective and economical means of providing seasonal access into permafrost terrain while minimizing the potential for environmental damage. The purpose of this study is an appraisal of long-term environmental impacts of winter roads by comparative assessment of terrain morphology, microclimate, permafrost, soils, and vegetation, on winter road right-of-ways and in adjacent undisturbed control areas.

The cold saline springs at Gypsum Hill (GH) and Colour Peak (CP) in the Canadian high Arctic are rare examples of perennial flows in thick continuous permafrost. We surveyed the microbial diversity of the springs by analyzing clone libraries of the small subunit rRNA gene. Half of the bacterial clones from the GH library classified as Delta- and Gammaproteobacteria. Clones related to Proteobacteria (82%), Firmicutes (9%) and Bacteroidetes (6%) constituted 97% of the bacterial library from CP. At least 56 and 76% of the bacterial clones from GH and CP, respectively, were from putative sulfur-metabolizers, and clones related to the sulfur-oxidizing bacterium Thiomicrospira psychrophila dominated in both springs. Archaeal clones were affiliated with uncultured Crenarchaeota, methanogens and haloarchaea. The eukaryotic clones were related to known Fungi, Viridiplantae (green algae), Strametopila (e.g. diatoms), Cercozoa and Alveolata in the CP sediment. Eukaryotic rRNA genes could not be amplified from the GH sediments. Forty-nine phylotypes of heterotrophic and sulfur-oxidizing bacteria (Thiomicrospira, Halothiobacillus ) were isolated from the GH springs. The strains were predominantly psychrotrophic and halotolerant, and were most related to bacteria also isolated from permanently cold environments. Some heterotrophic strains possessed genes for photosynthesis and thiosulfate oxidation, possibly enabling them to better compete in these sulfur-rich ecosystems exposed to continuous light in the summer. Assays of leucine and CO2 incorporation showed a low heterotrophic activity in the GH spring water, but significant autotrophic activity in complete darkness (chemoautotrophy). Microbial sulfur metabolism was demonstrated in microcosms of the GH sediment. Sulfur oxidation and chemoautotrophy were also demonstrated in microbial filaments that thrive in the GH spring channels. Fluorescence in situ hybridization (FISH) showed that the filaments were almost exclusively composed of rod-shaped Gammaproteobacteria that were further identified as Thiomicrospira. This work describes active microbial communities capable of sustainability in extreme environments that combine low temperature, moderate salinity, and prolonged periods of continuous light or darkness. Sulfur oxidation seems to be a major energetic process and chemolithoautotrophy appears to contribute significantly to primary production. Similar hydrosystems, formed by brines in the cold permafrost, are hypothesized to exist on Mars.

A detailed study of the water balance of a lichen-heath tundra underlain by permafrost was begun in September 1976 near Schefferville, Quebec. The study was centred on a 0.9 ha hillside and an adjacent 100 ha catchment. The study revealed that the transfer of latent heat by moisture transport occurs during the development of the active layer as well as during freeze-up. The transfer of sensible and latent heat does not have a major impact on the maximum depth of the active layer on hillslopes, but does strongly control the maximum depth of thaw in the valley bottoms. The study also demonstrated that a simple form of the Priestley-Taylor model yields accurate estimates of evapotranspiration from several types of surfaces. A water budget model based on the Priestley-Taylor model gave an accurate estimate of the seasonal runoff from the experimental catchment. A daily water budget model indicated that a significant proportion (31%) of the net runoff (precipitation minus evapotranspiration) is stored within the still-frozen part of the active layer (primarily in the valley bottoms) early in the thaw season. That stored water is released only when the active layer approaches its maximum depth of thaw.

This project concerns the effect of freeze-thaw cycles on the pore-scale structure of nonaqueous phase liquid (NAPL) contaminants in water-saturated porous media. This problem is of critical importance to the entrapment of such contaminants in cold temperate, polar and high altitude regions, and has not been examined in the literature to date. This research work is conducted in three stages: (i) two-dimensional nondestructive visualisation of residual light non-aqueous phase liquid (LNAPL), and dense non-aqueous phase liquid (DNAPL), in porous media subject to successive freeze-thaw cycles; (ii) three-dimensional experiments on LNAPL in porous media subject to freeze-thaw, with quantification of phase volumes by X-ray micro-computed tomography (micro-CT); and (iii) the explanation of results by several pore scale mathematical and conceptual models. The two-dimensional cell experiments (using a monolayer of 0.5 mm diameter glass beads held between two glass sheets), and three-dimensional X-ray micro-CT experiments reveal a substantial mobilisation and rupture of ganglia during successive freeze-thaw cycles; this includes the detachment of smaller ganglia from larger ganglia and the mobilisation of NAPL in the direction of freezing front. The experiments also reveal significant shedding of numerous single/sub-singlet ganglia along narrow pore corridors, their entrapment in growing polycrystalline ice, and the coalescence of such small ganglia during thawing to form larger singlets. These changes were more predominant where the freezing commenced. The results of the experimental studies were interpreted by developing several mathematical and conceptual models, including freezing-induced pressure model, Darcy's law model, multipore ganglia model (rupture coefficient) and ice-snap off model.

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