Mercury (Hg) is one of the primary contaminants of concern in the Arctic marine ecosystem. Methyl Hg (MeHg) is known to biomagnify in food webs. During the International Polar Year - Circumpolar Flaw Lead study, sea ice, seawater, bottom ice algae, phytoplankton and the herbivorous copepods were collected from the Amundsen Gulf to test whether ice algae and phytoplankton assimilate Hg from their habitat, and whether Hg bioaccumulates from the seawater to the primary consumers. Sea ice algae were found to accumulate Hg primarily from the bulk bottom ice, and the sea ice algae bloom depleted Hg stored within the bottom section of the ice. Furthermore, biodilution of Hg was observed to occur in sea ice algae. Higher concentrations of Hg were also found in phytoplankton and in grazing copepods. A positive correlation between MeHg and trophic level suggests the occurrence of MeHg biomagnification even at these low trophic positions.

Accelerated warming of high latitude systems of the northern hemisphere is expected to cause significant changes to the hydro-ecology of Arctic lakes. To record comprehensive and meaningful baseline hydrological, limnological, and ecological conditions to which future change can be compared, all available environmental information generated on Noell Lake, NWT was compiled and synthesized. Data included: physical and geographical characteristics (bathymetric and drainage basin attributes); general regional climatology; water quality (nutrients, major anions/cations, dissolved oxygen, dissolved organic carbon); biological composition (fish community, macrophyte, phytoplankton, epiphyton and epipelon surveys) and seasonal patterns in primary productivity (as measured by chlorophyll-a (Chl-a)). A field-monitoring study was conducted from September 2010 to July 2013 assessing the application, reliability, and quality control/quality assurance of a newly developed automated buoy-based Arctic Lake Monitoring System (ALMS). The ALMS continuously measured a range of lake limnological and water quality parameters under both open-water and under-ice conditions. Overall, the ALMS provided a usable, uninterrupted record of changes in measured environmental, hydrological, and limnological parameters in both the epilimnion and hypolimnion. Noell Lake was determined to be spatially homogeneous with respect to the limnological measurements taken and, thus, the data recorded by the instrument arrays were determined to be representative of the lake as a whole. In addition to the measurements made by environmental sensors mounted on the buoy and mooring components, an augmentary array of in-situ sampling campaigns and controlled experiments were conducted to produce a continuous and comprehensive description of daily and seasonal changes to the hydrological and limnological conditions of Noell Lake. The continuous data series confirmed that Noell Lake is dimictic, with mixing events occurring in August and June, and hypoxic oxygen conditions occurring in March. Nutrient limitation experiments revealed that autotrophic productivity in Noell Lake was nitrogen-limited. Compiling data from existing literature involved >700 northern, high-latitude lakes; patterns in temporal and latitudinal changes in Arctic lake primary productivity (as measured by open-water, epilimnion Chl-a) and geochemistry were assessed. The key hypothesis tested was whether Arctic lakes are showing increased primary productivity (i.e., “greening”), through time and by latitude, similar to that documented for Arctic terrestrial systems. In general, significant decreases in lake Chl-a was observed in Arctic and sub-Arctic lakes over a ≈50 year time span. Separation of lakes by latitudinal bands revealed that trends in the lower Arctic region (60.00-69.99 Degrees North) showed a significant decreasing time trend, while high Arctic lakes displayed no trends. Corresponding temporal trends of total phosphorous (TP), total nitrogen (TN), and dissolved organic carbon (DOC) differed depending on the latitude of the lakes. Re-evaluation of the original northern-lake productivity models developed by Flanagan et al. (2003) through the use of the new, independent datasets (>700 lakes) as well as the addition of other environmental variables (DOC, dissolved inorganic carbon, lake depth, conductivity, and ice-cover) showed that the original models were valid and the most parsimonious in predicting variation in algal biomass in northern latitude lakes. Only measures of dissolved nutrients (TP, TN) and latitude are required to predict autotrophic water column productivity. / Graduate

The spring freshet is the dominant annual hydrologic event occurring on largely nival Arctic river systems. It provides the greatest proportion of freshwater influx to the Arctic Ocean, amongst all other atmospheric input sources. To assess whether any shift in the seasonality of spring freshets has occurred, and how climatic drivers and flow regulation govern trends in sub-basin freshets and their contribution to outlet flow, a temporal and spatial analysis of 106 hydrometric stations located across four major Arctic-draining river systems is performed to extract information regarding the timing, magnitude and volume of the spring freshet of the four largest Arctic-draining rivers; namely, the Mackenzie River in Canada, and the Ob, Yenisei and Lena rivers in Eurasia. Total annual freshwater influx to the Arctic Ocean from these basins increased by 14% during 1980-2009. Despite freshet volume displaying a net increase, its proportional contribution to annual flow has decreased. In fact, rising winter, spring and fall discharge proportions, combined with lower peak freshet magnitudes, potentially increased freshet durations, and lower summer proportions indicate a shift towards flatter, more gradual annual hydrographs with earlier pulse onsets. Discharge assessed on a sub-basin level during 1962-2000 and 1980-2000 reveals regional differences in trends, with higher-relief drainage areas displaying the strongest trends. Sub-basin trends generally agree with those at the outlets, particularly in sub-basins without upstream flow regulation. Flow regulation has had a greater impact on observed trends in freshet volume compared to peak freshet magnitude. Timing measures are found to be strongly linked to spring temperatures. Volume relationships are also apparent with winter precipitation, however, these are less distinct. Moreover, flow regulation appears to suppress climatic drivers of freshet volume but has a lesser effect on timing measures. Significant relationships are found with several major atmospheric and oceanic teleconnections indices. This study provides valuable information regarding the dominant controls of freshet generation, whilst highlighting potential impacts of freshet variability on the freshwater balance of the Arctic Ocean. / Graduate / 0388 / 0368 / roxannea@uvic.ca

Sporadic reports of significant under-ice phytoplankton production indicate a critical knowledge gap of a key component of the Arctic ecosystem. In this thesis I examine the following research objectives in an effort to improve the understanding of under-ice phytoplankton production: (1) to determine the biophysical processes controlling the timing of under-ice phytoplankton production, and (2) to compare and contrast both the timing of the under-ice bloom and the controlling processes between multiple years of data. Data for objective (1) were collected during the three-year Arctic-ICE field campaign (2010-2012) near Resolute Bay, NU in the central Canadian Arctic. Additional data from the region were collected from open source databases and peer-reviewed literature for a dataset that spanned from early 1960 to the present, supporting the analysis to meet objective (2). Two separate under-ice phytoplankton blooms were observed during the three-year Arctic-ICE campaign. It was found that phytoplankton blooms conformed well to the critical depth hypothesis in the Canadian Archipelago under first-year ice, where snow and ice melt both increased light transmission and shoaled the surface mixed layer which, in turn, placed phytoplankton within a favourable light environment for positive net production underneath the ice cover. Factors such as timing of melt water drainage and water column mixing greatly affected bloom onset. From the historical analyses, I was able to show that under-ice phytoplankton blooms have regularly occurred under landfast ice from at least the 1960’s. Significant correlations between the timing of bloom onset with melt onset related variables (i.e., air temperature reaching 0 ºC and complete snow melt) suggested a strong link to climate change. In fact, the ii analysis supported that since the mid 1990s bloom onset has been occurring earlier, and is likely related to decreasing trends in day of complete snow melt, maximum ice thickness, and snow depth. Overall, this thesis has helped improve our understanding of the under-ice spring phytoplankton bloom, showing that under-ice production has been a regular occurrence in the Canadian Arctic. The results also support that timing of the spring phytoplankton blooms could be shifting earlier in response to the warming Arctic and its changing icescape. Such a shift could also have important consequences on the Arctic marine food web, influencing the transfer of energy through the food chain. Therefore, it is of utmost importance to continue future observational programs of the under-ice pelagic environment focussed on the late spring melt period to better understand how the system could change with further perturbations.

Since humans began to permanently settle locations for extended periods of time there has been the challenge to safely dispose of, or treat human effluent. In specific to the communities of Nunavut and Arctic Canada, the treatment of wastewater has been particularly challenging. The harsh climate, remote nature and socio-economic factors are a few of the aspects which make the treatment of wastewater problematic in Canadian Arctic communities. In the past several decades a number of conventional and alternative wastewater treatment systems (e.g. lagoons and tundra wetlands) have been proposed and implemented in Nunavut and other remote Arctic communities. Knowledge of performance of these systems is limited, as little research has been conducted and regulatory monitoring has been poorly documented or not observed at all. Also, in the past, the rational design process of treatment systems in Arctic communities has not acknowledged cultural and socio-economic aspects, which are important for the long-term management and performance of the treatment facilities in Arctic communities. From 2008 to 2010 I characterized and studied the performance of several tundra wastewater treatment wetlands in the Kivalliq Region of Nunavut, as well as two in the Inuvaliat Region of the Northwest Territories. Performance testing occurred weekly throughout the summer of 2008. Characterization included surveys of plant communities in the tundra wetlands, specifically analyzing the relationship between Carex aquatilis and various nutrient contaminants in wastewater. Through their characterization I was able to provide greater insight into primary treatment zones within the wetland, and identify the main potential mechanisms for the treatment wastewater in the Arctic. I also studied the performance of a horizontal subsurface flow (HSSF) constructed wetland in Baker Lake Nunavut; the first system of its kind in the Canadian Arctic. The weekly performance study showed average weekly percent reduction in all parameters, with small deviations immediately after snow-melt and at the beginning of freeze-up. For the six parameters monitored I observed reductions of 47-94% cBOD5, 57-96% COD, 39-98% TSS, >99% TC, >99% E. coli, 84-99% NH3-Nand 80-99% TP for the six tundra treatment wetlands. Whereas, the wetland characterization study through the use of spatial interpolations on each of the wetlands and their water quality showed that concentrations of the wastewater parameters decreased the most in the first 100m of the wetland in all three treatment wetlands used in this portion of the analysis (Chesterfield Inlet, Paulatuk and Ulukhaktok). Areas of greatest concentration where shown to follow preferential flow paths with concentrations decreasing in a latitudinal and longitudinal direction away from the wastewater source. The Paulatuk and Ulukhaktok treatment wetlands were observed to effectively polish pre-treated wastewater from the facultative lake and engineered lagoon, with removals of key wastewater constituents of cBOD5, TSS and NH3-N to near background concentrations. And despite the absence of pre-treatment in Chesterfield Inlet, the wetland was also observed to effectively treat wastewater to near background concentrations. Further characterization on the composition of the sedge C. aquatilis, showed a high percent cover of the species corresponded with areas of high concentration of NH3-N in the wastewater. A principal components analysis verified the spatial results showing correlation between C. aquatilis cover and NH3-N concentrations. Analysis also showed strong positive relationship between sites closer to the source of wastewater and C. aquatilis. No correlation was found between the other parameters analyzed and C. aquatilis. The first year of study of the HSSF constructed wetland showed promising mean removals in cBOD5, COD, TSS, E. coli, Total Coliforms, and TP throughout the summer of 2009; removals of 25%, 31%, 52%, 99.3%, 99.3%, and 5% were observed respectively. However, the second year of study in 2010 the system did not perform as expected, and concentrations of effluent actually increased. I concluded that a high organic loading during the first year of study saturated the system with organics. Finally, a review of planning process and regulatory measures for wastewater in Arctic communities and the impending municipal wastewater standards effluent resulted in the following recommendations; i) wastewater effluent standards should reflect the diverse arctic climate, and socio-economic environment of the northern communities, ii) effluent standards should be region or even community specific in the Arctic, and iii) for planning and management of wastewater incorporation of Inuit understanding of planning and consultation needs to be incorporated in the future. This research has several major implications for wastewater treatment and planning for Nunavut and other Arctic Regions. The performance and characterization of tundra treatment wetlands fills significant gaps in our understanding of their performance and potential mechanisms of treatment, and treatment period in the Kivalliq Region. Although the HSSF constructed wetland failed, further research into engineered/augmented treatment wetlands should be considered as they provide low-cost low maintenance solutions for remote communities. Finally, the data collected in this study will provide significant insight into the development of new municipal wastewater effluent standards for northern communities, which will be reflected in the Fisheries Act.

This study aimed to gain an understanding of changing active layer dynamics in the High Arctic, specifically in terms of understanding the spatial distribution of mudboils to identify climatic and landscape controls, and active layer processes driving their formation. Systematic mapping of mudboils and sediment and water sampling was undertaken at the Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, Nunavut in 2012 and 2013. Based on borehole stratigraphic profiles taken at CBAWO, three primary soil units were determined: mudboils at surface; overburden (soil) material; and a grey, fine-grained layer at approximately 80cm depth. These soil classes were used for comparison to gain an understanding of the properties and origins of the mudboil materials. Results indicate that these features only occur late in the melt season during exceptionally warm years (2007, 2011, and 2012) and in some cases closely follow major rainfall events. High-resolution satellite imagery was analyzed to determine landscape controls over mudboil formation. Notably, mudboils were significantly associated with bare soil and polar semi-desert vegetation settings, corresponding to increased active layer depth and rate of thaw when compared to more vegetated areas. Further, localized occurrence of mudboils appears to be related to differential soil moisture retention and spatially heterogeneous soil water pressurization due to thaw into the ice-rich transient layer in warm years. We hypothesize that the locally drier locations develop soil ped structures that contribute to diapir development and mud ejection when seasonal melt and hydraulic conditions pressurize soil water. Geotechnical and geochemical analysis of soil samples indicates that mudboils at surface do not significantly differ in terms of composition and physical properties from the undisturbed overburden material. This is consistent with a fine-grained slurry likely being generated in situ from a parent bed and subsequently ejected to surface. This research provides insights into the processes and landscape controls over mudboil formation to aid in understanding localized soil water response to deep summer thaw, with implications for surface water quality and predictions and potential mitigation of permafrost-related degradation and disturbance. / Thesis (Master, Geography) -- Queen's University, 2014-05-22 13:56:49.078

This study examined the impact of active layer detachments (ALDs) on seasonal dissolved nitrogen (N) export from continuous permafrost headwater catchments at the Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, Nunavut. Runoff samples collected throughout the summer of 2012 from an undisturbed catchment (Goose; GS) and from one that was disturbed by ALDs (Ptarmigan; PT) were analyzed for dissolved inorganic ions and species of total dissolved N (TDN), including dissolved organic N (DON) and dissolved inorganic N (DIN; ammonium (NH4+), nitrite (NO2-), and nitrate (NO3-)). Rainfall samples were also collected for dissolved ions analyses. Select runoff and rainfall samples were analyzed for stable isotopes of nitrogen and oxygen in NO3- (δ15N-NO3- and δ18O-NO3-, respectively) to determine its origin streamwater. Data from 2012 were compared to predisturbance data to assess the long-term effects of ALDs on N export. ALDs increased the proportion of DIN/TDN in PT from 4% (predisturbance) to 37% in 2012. The increase in DIN/TDN in PT largely resulted from significantly higher NO3- in runoff. Values of δ18O and δ15N-NO3- as well as correlations between NO3- and major ions indicated that the higher NO3- in PT was due to the exposure of mineral soils in ALDs, which likely reduced NO3- sinks (e.g. plant uptake) and increased inputs of nitrified-NO3-. Values of δ18O-NO3- during initial runoff showed that NO3- supplied from the snowpack overwhelmed NO3- sinks in PT, leading to a twelve-fold higher peak NO3- concentration relative to GS. Low δ18O-NO3- values in runoff during stormflow indicated that inputs of DIN from rainfall (1545 ± 148 and 1838 ± 174 g N-DIN to GS and PT, respectively) supplied less than 30% of the NO3- in both streams, and that exceptionally high NO3- concentrations in PT resulted from flushing of mineralized-NO3- from the mineral soils. Seasonal DIN flux was 95% higher in PT relative to GS, because NO3- export from PT was 27 times that of GS. This is the first study to show that ALDs can have persistent impacts on DIN export from High Arctic watersheds, and that this results from enhanced export of mineralized-NO3-. / Thesis (Master, Geography) -- Queen's University, 2014-05-27 10:30:38.874

This thesis investigates the relationships between mercury (Hg) and stable isotope of carbon (δ13C) in marine pelagic zooplankton (Calanus spp., Themisto spp. and Euchaeta spp.) with water mass characteristics in the North Water Polynya (NOW) and in the Mackenzie shelf – Amundsen Gulf area. Two ship based sampling field expeditions were carried out in late summer of 2005 and 2006 in both regions on board the CCGS Amundsen. In the North Water (NOW) polynya, higher levels of water Hg, depleted δ18O, lower salinity and lower nitrate levels were measured at sampling locations near the Prince of Wales glacier (POW) on the eastern coast of Ellesmere Island in the Smith Sound area. These results suggest that the glacier may be a source of Hg to this region which, in turn, is responsible for the correspondingly high concentrations of THg and MMHg measured in Calanus spp. and Euchaeta spp. at the same locations. The Mackenzie shelf – Amundsen Gulf region was characterized by fresher surface water properties (low salinity and depleted δ18O) in the western part and was strongly linked to the influence of the Mackenzie River. Higher THg concentrations in zooplankton were associated with larger fractions of both meteoric water and sea-ice melt. These findings suggest that in the western Arctic, inorganic Hg uptake in zooplankton via-absorption near surface water was highly driven by freshwater inputs into the system. Based on the analysis of three main genus Calanus spp. (mostly adult females Calanus hyperboreus), Euchaeta spp. and Themisto spp. (mostly adult Themisto libellula), THg and MMHg concentrations were the highest in the carnivorous copepod Euchaeta spp. in the North Water polynya followed by the omnivorous hyperiid amphipod Themisto spp. The herbivorous copepod Calanus spp. had both the lowest THg and MMHg concentrations in the Eastern and the Western Arctic. In addition, the Western Arctic is the area in which each zooplankton genus had the most depleted carbon and the most enriched nitrogen. The highest concentrations of THg in Calanus spp., Euchaeta spp. and Themisto spp. were measured in the Western Arctic as well as the highest MMHg in Calanus spp. and Themisto spp. The highest %MMHg was calculated in the Archipelago for Themisto spp., in the Eastern Arctic for Euchaeta spp. and in the Western Arctic for Calanus spp. The relationships observed between THg, MMHg, %MMHg and δ13C in all three major zooplankton taxa and water mass properties were in agreement with what have been previously described in the literature. Our findings suggested that both Hg and δ13C can be used as tracers to help understand zooplankton vertical distribution, feeding ecology and ultimately to predict climate changes impact at lower trophic level in the pelagic food web. The implications for marine mammals foraging in these regions are also discussed.

Mercury (Hg) is one of the primary contaminants of concern in the Arctic marine ecosystem. Methyl Hg (MeHg) is known to biomagnify in food webs. During the International Polar Year - Circumpolar Flaw Lead study, sea ice, seawater, bottom ice algae, phytoplankton and the herbivorous copepods were collected from the Amundsen Gulf to test whether ice algae and phytoplankton assimilate Hg from their habitat, and whether Hg bioaccumulates from the seawater to the primary consumers. Sea ice algae were found to accumulate Hg primarily from the bulk bottom ice, and the sea ice algae bloom depleted Hg stored within the bottom section of the ice. Furthermore, biodilution of Hg was observed to occur in sea ice algae. Higher concentrations of Hg were also found in phytoplankton and in grazing copepods. A positive correlation between MeHg and trophic level suggests the occurrence of MeHg biomagnification even at these low trophic positions.

During the last 20 years studies of various mammals and birds have shown that social organization is highly variable between and within species, and that such variation can frequently be explained on the basis of variation in food habits and food dispersion. This study is an attempt to discover the major ecological pressures affecting social organization and reproductive fitness of Arctic foxes in Iceland. Foxes were both studied at an individual level, by monitoring movements of radio-tagged foxes and observation of fox behaviour in demarcated study areas, and at the population level, by analysis of available foxhunting records, as well as material and information provided by foxhunters. The most common form of social organization was found to be a breeding pair, while social groups of 3-4 individuals also occur, particularly in coastal habitat, which is more productive and spatially more heterogenous with respect to food dispersion, than inland habitat. The Arctic foxes were found to occupy well defined, but fairly flexible group territories, whose borders were advertised by olfactory, auditory and visual signals. In one coastal region, three such territories ranged in size from 8.6 km² to 18.5 km², while there was an indication that territories were larger in inland habitats. In coastal habitats, foxes feed mainly on oceanic prey and do not show cycles in abundance. In inland habitat, foxes show a functional response to the 10 year population cycle of ptarmigan (Lagopus mutus), their main prey in winter. Litter sizes remain stable, however, due to little interannual variation in the foxes' summer diet, which consists mostly of migrant birds. Mean litter size at birth is 5-3 ± 1.7 S.D. and mortality from factors other than foxhunting is about 15% up to the age of weaning. Annual mortality in adults is about 50%, mostly due to foxhunting. Most vixens breed already as yearlings, while dog-foxes are more likely to show delayed breeding. In inland habitats there is balanced polymorphism with regard to colour morph, but in coastal habitats blue foxes have an overall selective advantage. Inland foxes are smaller than coastal foxes. Both size and colour affect reproductive fitness.