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The contribution of dissolved organic carbon (DOC) to mineral weathering was investigated under the changing Eh and pH conditions in three subarctic fens, near Schefferville, Quebec. No evidence of increased weathering rates nor different weathering patterns were found in the fen basal sediment despite DOC-rich and low Eh (0 to +200 mV) conditions. / Solutions containing 50 mg DOC/L derived from subarctic fen peat, and of 50 and 300 mg DOC/L, derived from deciduous leaf litter were used as weathering agents. Clinochlore, microcline and the Fe-rich basal till from the Schefferville fens were used as weatherable mediums. The DOC rich solutions and controls (made of distilled water buffered to the same initial pH) were used to investigate the relative weathering ability of DOC-rich waters under aerobic and anaerobic conditions. The relative ability was determined by comparing the changing cation concentrations in the solutions.

Trophic ecology is a key component in describing patterns of variation between and within populations, particularly in Arctic marine systems wherein climate change is impacting food webs. This thesis investigates the trophic ecology of Arctic char (Salvelinus alpinus) in the Cumberland Sound region using a multi-indicator approach. My data show trophic niche differences between resident and anadromous ecotypes and evidence for estuarine feeding by residents. I document a shift in the marine diet of Arctic char from zooplankton to capelin (Mallotus villosus) – a novel prey species in this region – that has occurred in less than a decade. Changes in Arctic char growth imply population-level effects of this shift; however, more research is required. Finally, I find lipid effects on δ13C and lipid-extraction effects on δ15N and δ34S for Arctic char muscle tissue. Lipid-correction models did not provide adequate δ13C estimates; thus, chemical extraction or ecotype-specific validation of models is recommended.

This dissertation investigates the domestic architecture produced by the Late Dorset, an Arctic-adapted hunter-gatherer society which occupied much of the Eastern North American Arctic between circa 1500 B.P. and 500 B.P. Architecture, like any artefact class, is a dynamic and socially constructed technology that is produced, maintained, and transmitted by its practitioners. It is replicated via series of learned actions or techniques; patterns accordingly result from adherence to cultural standards while differences represent instances of technological divergence. Such departures are typically ignored or suppressed in closed systems, although they can be tolerated or even widely adopted in more flexible ones. In order to identify and explore patterning, a methodological strategy using the chaîne opératoire is adopted. This approach is invaluable because, when properly implemented, it links the static archaeological record with the dynamic architect-agents whose meaning-laden technical acts are visible archaeologically. Viewed through the lens of chaîne opératoire, I examine domestic architecture as a conduit for informing on Late Dorset structure and social organisation. As part of this investigation, a multi-scalar research design was implemented. The first analytical scale examined architecture across the Eastern Arctic to determine regional patterns of behavioural variability. Large-scale behavioural trends were recognised and demonstrated the range of behaviours enacted by Dorset architects as they designed, reproduced, and altered dwellings. The second stage of analysis focused on the micro-scale analysis of dwellings from three locations, each presented as fully contextualised case studies. Analysis at this level allowed for the investigation of how idiosyncratic behaviours and localised knowledge (reflecting an agent’s awareness of local conditions) was manifested and ‘fit’ within the overall technology. This strategy, which combined structure-specific analysis with purposefully broad regional patterning, suggests that Late Dorset architectural technology was comparatively open and flexible and that architects could adapt technological practise to suit local conditions and housing needs. This flexibility contrasts with other aspects of Late Dorset culture that appear more constrained and standardised.

This dissertation investigates the domestic architecture produced by the Late Dorset, an Arctic-adapted hunter-gatherer society which occupied much of the Eastern North American Arctic between circa 1500 B.P. and 500 B.P. Architecture, like any artefact class, is a dynamic and socially constructed technology that is produced, maintained, and transmitted by its practitioners. It is replicated via series of learned actions or techniques; patterns accordingly result from adherence to cultural standards while differences represent instances of technological divergence. Such departures are typically ignored or suppressed in closed systems, although they can be tolerated or even widely adopted in more flexible ones. In order to identify and explore patterning, a methodological strategy using the chaîne opératoire is adopted. This approach is invaluable because, when properly implemented, it links the static archaeological record with the dynamic architect-agents whose meaning-laden technical acts are visible archaeologically. Viewed through the lens of chaîne opératoire, I examine domestic architecture as a conduit for informing on Late Dorset structure and social organisation. As part of this investigation, a multi-scalar research design was implemented. The first analytical scale examined architecture across the Eastern Arctic to determine regional patterns of behavioural variability. Large-scale behavioural trends were recognised and demonstrated the range of behaviours enacted by Dorset architects as they designed, reproduced, and altered dwellings. The second stage of analysis focused on the micro-scale analysis of dwellings from three locations, each presented as fully contextualised case studies. Analysis at this level allowed for the investigation of how idiosyncratic behaviours and localised knowledge (reflecting an agent’s awareness of local conditions) was manifested and ‘fit’ within the overall technology. This strategy, which combined structure-specific analysis with purposefully broad regional patterning, suggests that Late Dorset architectural technology was comparatively open and flexible and that architects could adapt technological practise to suit local conditions and housing needs. This flexibility contrasts with other aspects of Late Dorset culture that appear more constrained and standardised.

Mercury (Hg) is a known neurotoxin that is often found in concentrations exceeding safe consumption guidelines in aquatic biota. This is evident in northern Canada, where northerners consume significant amounts of animals such as beluga, seals and burbot. In the Mackenzie River Basin, recent increases in Hg concentration in many of these animals over the past 25 years have been observed. The warming climate, and with it, the changing carbon cycle, are hypothesised in this thesis to play a role in the increases. Within the context of the two major zones (mountainous and peatland), with distinct geomorphology, hydrology and geology, traditional fossil fuel exploration methods (Rock-Eval pyrolysis, organic petrography) have been employed in a novel manner on recent sediments to qualify and quantify the OM and several geochemical analyses have been used to determine the geochemical sources of Hg. The mountainous zone is composed mostly of refractory OM, from forest fire char and heavily reworked OM. It also contains, and fluxes, most of the Hg, which derives from oxidative weathering and erosion of widespread sulfide minerals. However, Hg from this zone is in chemical forms of limited bioavailability. The peatland zone has a greater proportion of labile OM, with higher concentrations of DOC and algal-derived OM. Lake-fed tributaries in this zone contain even higher proportions of labile OM. At one of these sites, the sediment core record shows that Hg has been increasingly associated with labile OM over time, due to increasing primary productivity accelerated by climate change, and is resulting in an increase in scavenged Hg. The temporal trend in algal-bound Hg in the sediment record matches very well with the temporal trend of Hg in burbot sampled from the area, providing one of the first and strongest lines of evidence for the climatic impact on Hg bioaccumulation in Arctic ecosystems.

An understanding of the adaptability of belugas (Delphinapterus leucas) to changing ice-conditions is required to interpret and predict possible changes in habitat selection in response to projected loss of sea ice throughout the circumpolar Arctic. Beluga spring distribution in the eastern Beaufort Sea was described by analyzing observations from aerial surveys conducted from 1975 to 1979. Repeated surveys along the Franklin Bay fast-ice edge in June 2008 were used to study the distribution and behaviour of belugas and bowheads. Despite inter-annual variability in ice extent, belugas consistently selected areas with water depths of 200-500 m, heavy ice concentrations (8/10 to 10/10) and seafloor slope ≥0.5 degrees in spring 1975 to 1979. While predator avoidance may partially explain the observed distribution, foraging success likely has more influence on beluga habitat selection in the spring. In ice-covered offshore regions, belugas may be engaged in under-ice and deep water foraging on Arctic cod (Boreogadus saida). In lighter ice years, belugas may expand their distribution and shift shoreward to take advantage of high prey densities along fast-ice edges. Both belugas and bowheads appeared to be feeding along the Franklin Bay ice edge in June 2008. More research is required to examine and compare possible changes in distribution since the late 1970s and to investigate the factors driving the patterns described.

The veracity of a Radiometric Microwave Profiling Radiometer (MWRP) while mounted onboard a ship in the Arctic marine environment was assessed. The MWRP was validated against radiosonde data by calculating the RMS and bias for simultaneous measurements taken for temperature and absolute humidity profiles. The vertical resolution of the MWRP was calculated using the inter-level covariance method. Based on the comparisons, the MWRP provided reliable measurements of both temperature and absolute humidity while mounted on the CCGS Amundsen. Satellites CloudSat and Calipso were assessed over the Arctic marine cryosphere. Temperature and absolute humidity from the ECMWF-aux data product was compared with profiles from the ship based MWRP. The cloud base heights measured by the ceilometer and MWRP were compared to CloudSat and Calipso's GeoProf-lidar. Due to a large number of possible false detections, the constraints used by the GeoProf-lidar data product for cloud detection may need to be further refined.