Canadian Arctic Region Research Articles

Living under Arctic kelp forests: linking soft-bottom communities to kelp cover in the Canadian Arctic

Kelp forests are dominant habitats along Canadian Arctic coastlines. While their extent and productivity are expected to change dramatically due to global warming, their role in supporting Arctic coastal biodiversity remains poorly explored. Leveraging an extensive data set encompassing core samples, video transects, and environmental data, this study explores the patterns and drivers of benthic diversity, particularly focusing on kelp cover, across 4 Eastern Canadian Arctic regions. We show that the widespread soft bottoms in many subtidal coastal Arctic areas are associated with high densities of the kelp Saccharina latissima, often growing in mixed stands with Laminaria solidungula and Alaria esculenta. These kelps enhance the diversity of invertebrate communities thriving in the sediment below, increasing densities in specific groups and promoting subsurface feeding activity. Interregional comparisons indicate that high turbidity conditions typically lead to low macroalgal cover and low invertebrate richness, whereas extensive sea ice cover can favor high macroalgal abundance and unique diverse communities. Conditions of intermediate open-water duration and high water clarity support tall kelp forests, hosting approximately 70% of local rare taxa. Based on these surveys, we provide a list of Arctic invertebrate taxa according to their level of selectivity for kelp forests as habitats. Despite variation among regions, kelp forests enhance biodiversity and drive unique benthic communities in the Canadian Arctic. Due to their ecological significance and potential vulnerability, we recommend efforts to integrate kelp forests into marine protected areas and minimize human-induced damaging activities within or near these habitats.

Combining Landsat TIR‐imagery data and ERA5 reanalysis information with different calibration strategies to improve simulations of streamflow and river temperature in the Canadian Subarctic

AbstractArctic and Subarctic environments are among the most vulnerable regions to climate change. Increases in liquid precipitation and changes in snowmelt onset are cited as the main drivers of change in streamflow and water temperature patterns in some of the largest rivers of the Canadian Arctic. However, in spite of this evidence, there is still a lack of research on water temperature, particularly in the eastern Canadian Arctic. In this paper, we use the CEQUEAU hydrological‐water temperature model to derive consistent long‐term daily flow and stream temperature time series in Aux Mélèzes River, a non‐regulated basin (41 297 km2) in the eastern Canadian subarctic. The model was forced using reanalysis data from the fifth‐generation ECMWF atmospheric reanalyses (ERA5) from 1979 to 2020. We used water temperature derived from thermal infrared (TIR) images as reference data to calibrate CEQUEAU's water temperature model, with calibration performed using single‐site, multi‐site, and upscaling factors approaches. Our results indicate that the CEQUEAU model can simulate streamflow patterns in the river and shows excellent spatiotemporal performance with Kling‐Gupta Efficiency (KGE) metric >0.8. Using the best‐performing flow simulation as one of the inputs allowed us to produce synthetic daily water temperature time series throughout the basin, with the multi‐site calibration approach being the most accurate with root mean square errors (RMSE) <2.0°C. The validation of the water temperature simulations with a three‐year in situ data logger dataset yielded an RMSE = 1.38°C for the summer temperatures, highlighting the robustness of the calibrated parameters and the chosen calibration strategy. This research demonstrates the reliability of TIR imagery and ERA5 as sources of model calibration data in data‐sparse environments and underlines the CEQUEAU model as an assessment tool, opening the door to its use to assess climate change impact on the arctic regions of Canada.

Brief communication: Identification of tundra topsoil frozen/thawed state from SMAP and GCOM-W1 radiometer measurements using the spectral gradient method

Abstract. From 2015 to 2020, using the spectral gradient radiometric method, the possibility of the frozen/thawed (FT) state identification of tundra soil was investigated based on Soil Moisture Active Passive (SMAP) and Global Change Observation Mission – Water Satellite 1 (GCOM-W1) satellite observations of 10 test sites located in the Arctic regions of Canada, Finland, Russia, and the USA. It is shown that the spectral gradients of brightness temperature and reflectivity (measured in the frequency range from 1.4 to 36.5 GHz with horizontal polarization, a determination coefficient from 0.775 to 0.834, a root-mean-square error from 6.6 to 10.7 d and a bias from −3.4 to +6.5 d) make it possible to identify the FT state of the tundra topsoil. The spectral gradient method has a higher accuracy with respect to the identification of the FT state of tundra soils than single-frequency methods based on the calculation of polarization index.

Socio-economic impacts of shipping along the Northwest Passage: The cost to locals

This paper presents a novel approach to assessing the cost of container liner shipping through the Northwest Passage (NWP) on northern local communities. Based on some representative communities, concerns of the residents of these Canadian Arctic regions were assessed. Two essential factors to the well-being of the community members—air pollution and oil spills—are considered in our model. The approach was therefore used to evaluate the socio-economic impact of Arctic container liner shipping in Canadian Arctic regions. More specifically, the approach adopted a) uses a logit model to estimate the market share of NWP for commercial liner shipping; b) investigates different scenarios to evaluate the feasibility of commercial liner shipping through the NWP; c) incorporating concerns from the local communities, conducts a socio-economic analysis for the communities. With the analysis of the socio-economic impacts on local communities, the study would help guide governments on how to evaluate and calculate transit fees for transiting NWP. The study is imperative in supporting decision-making to shape Arctic policy. Furthermore, it gives stakeholders an idea of the market dynamics of shipping in the Arctic area.

Multi-Year Sea Ice Conditions in the Northwest Passage: 1968–2020

ABSTRACT The Northwest Passage is often referred to as the “Holy Grail” of ship navigation as it provides a shorter route connecting the Atlantic and Pacific Oceans compared to the Northern Sea Route, Panama Canal, Suez Canal, and transiting around Cape Horn. Here, we summarize 52 years of observed multi-year ice (MYI) conditions from 1968 to 2020 in the western Canadian Arctic regions of the Northwest Passage updating a previous study that considered 1968–2006. Results indicate that on average, MYI area anomalies during the shipping season were +28% from 1968 to 2006 but −33% from 2007 to 2020 relative to the 1991–2020 climatology. The frequency of negative MYI area anomalies from 2007 to 2020 was unprecedented over the 52-year record. 13 of the past 14 years were negative in the Beaufort Sea, Franklin, and the Western Arctic Waterway; 10 of the past 14 years were negative in Western Parry Channel and Queen Elizabeth Islands; and 9 of the past 14 years were negative in the M’Clintock Channel. Despite strong and frequent negative MYI anomalies from 2007 to 2020, MYI recovery from first-year ice (FYI) aging and MYI dynamic import continued, but was reduced by 47% and 22%, respectively compared to 1968–2006. We demonstrate that from 2007 to 2020 (i) MYI dynamic recovery decreased because Arctic Ocean MYI has been primarily flowing into the Canadian Arctic via the smaller apertures in the Queen Elizabeth Islands and not from the Beaufort Sea via the M’Clure Strait and (ii) FYI aging decreased because recent changes in thermodynamic forcing have contributed to more melt. Overall, our results re-affirm that light MYI years in the Northwest Passage may occur more frequently as the Arctic continues to warm, but MYI recovery will continue to present a significant hazard to navigation for the foreseeable future.

Early successional changes in biological soil crust community assembly and nutrient capture in mining impacted landscapes

Biological soil crusts (BSCs) are communities of bryophytes, lichens, bacteria, and fungi and are the primary colonizing communities in early successional landscapes. In early ecosystem development BSCs often improve the physical and chemical conditions while also promoting soil microbial communities. Although BSCs are considered ecosystem engineers in many early successional environments, the links between BSC functional processes and their developmental stage are unclear, especially in landscapes recovering from anthropogenic disturbances. In this study we examined natural BSC development over a 30-year chronosequence on two mining impacted landscapes in both boreal and arctic regions of Canada. Using High Throughput Sequencing (HTS), we found similar ubiquitous ruderal bryophytes and bacteria species common at both study areas, but significant differences in lichen and fungal community structure between the two locations. In addition, community assembly of BSC macro (bryophytes and lichens) and micro (bacteria and fungi)-phyla changed over the first 30 years of recovery at both mine sites, however, these changes were unique to each study location. We observed nutrient accumulation in the crust layer but did not find clear trends in available nutrients or gas flux over time. Instead, changes in our functional measurements were associated with colonization by specific BSC species. Further, the bacterial community at both mines seemed to be responding to changes in the bryophyte communities as they developed over time. This suggests that the establishment of bryophyte communities in early succession may be driving micro-phyla BSC community composition. A holistic view of BSCs as they develop over time in relation to their functional abilities needs further investigation, and this study provides insight into these interactions. This knowledge will improve both our understanding of early stage BSC development and our ability to develop restoration techniques to effectively restore landscapes disturbed by anthropogenic activities.

Comparison of Early-Twentieth-Century Arctic Warming and Contemporary Arctic Warming in the Light of Daily and Subdaily Data

AbstractA review of many studies published since the late 1920s reveals that the main driving mechanisms responsible for the early-twentieth-century Arctic warming (ETCAW) are not fully recognized. The main obstacle seems to be our limited knowledge about the climate of this period and some forcings. A deeper knowledge based on greater spatial and temporal resolution data is needed. The article provides new (or improved) knowledge about surface air temperature (SAT) conditions (including their extreme states) in the Arctic during the ETCAW. Daily and subdaily data have been used (mean daily air temperature, maximum and minimum daily temperature, and diurnal temperature range). These were taken from 10 individual years (selected from the period 1934–50) for six meteorological stations representing parts of five Arctic climatic regions. Standard SAT characteristics were analyzed (monthly, seasonal, and yearly means), as were rarely investigated aspects of SAT characteristics (e.g., number of characteristic days, day-to-day temperature variability, and the onset, end, and duration of thermal seasons). The results were compared with analogical calculations done for data taken from the contemporary Arctic warming (CAW) period (2007–16). The Arctic experienced warming between the ETCAW and the CAW. The magnitude of warming was greatest in the Pacific (2.7°C) and Canadian Arctic (1.9°C) regions. A shortening of winter and lengthening of summer were noted. Furthermore, the climate was also a little more continental (except the Russian Arctic) and less stable (greater day-to-day variability and diurnal temperature range) during the ETCAW than during the CAW.Significance StatementIt is well established that human activity (particularly increased greenhouse gas emissions) is the primary driving mechanism of the recent dramatic warming in the Arctic. However, the causes of a similar warming here in the first half of the twentieth century remain uncertain. The limited knowledge about the climate of that period—which mainly results from the low resolution of data—is a significant obstacle to a definitive determination of the forcing mechanisms. Therefore, the main aim of our paper is to improve our understanding of specific aspects of weather and climate (including extremes) using long-term series of daily and subdaily data that have rarely been applied for this purpose. This new, more comprehensive knowledge about the historical Arctic climate should allow the scientific community (particularly climate modelers) to better validate both climate models and reanalysis products and, consequently, to more precisely identify the causes of the early-twentieth-century Arctic warming.

Canadian Arctic Neogene Temperatures Reconstructed From Hydrogen Isotopes of Lignin‐Methoxy Groups From Sub‐Fossil Wood

AbstractProxy‐based reconstructions of Neogene warm climates are a valuable data source for helping to understand what a future, warmer world may look like. Such insights are especially critical in the Arctic where the fastest rates of warming are underway and likely to continue. In this study, hydrogen isotopes of lignin‐methoxy groups (δ2HLM) from Miocene and Pliocene sub‐fossil wood samples (N = 43) at six high‐latitude sites (73–80°N) in the Canadian Arctic Archipelago were used to estimate mean δ2H values of precipitation and temperature anomalies (ΔT) relative to present. The ΔT estimates ranged from +9.7 to +16.7°C depending on site and epoch and are corroborated by a suite of independent proxy data for most sites, and for one site (Prince Patrick Island) this study provides the first quantitative ΔT estimates. These are conservative estimates as they do not account for the more negative δ2Hseawater values during the Neogene. These ΔT estimates, along with independent proxy and vegetation data, depict a dramatically warmer version of the Arctic. Some of this warming was likely driven by global atmospheric change and feedbacks that are possible in the modern‐day Arctic. However, transformation of the once‐contiguous Arctic landmass into a dissected archipelago has undoubtedly changed the nature and future warming potential of the Canadian Arctic region. Investigations aimed at disentangling the relative contribution of global versus regional boundary conditions to Neogene Arctic climate warming are needed to understand the extent to which these reconstructions may foreshadow conditions in the future.

ПРОБЛЕМЫ ЭКОНОМИЧЕСКОЙ УСТОЙЧИВОСТИ АРКТИЧЕСКИХ РЕГИОНОВ КАНАДЫ

The article examines the key issues and risks of the governing and socio-economic development of the Canadian Arctic regions. The relevance of this subject is determined by scientific and practical interest in adapting in Russia the most effective approaches and practices for realizing the economic potential of circumpolar regions in foreign countries. With regard to areas of the Arctic zone of the Russian Federation (characterized by low population density of vast areas, the absence of large urban settlements with scientific and cultural centers, undeveloped ground transport infrastructure, extreme climatic and geological conditions, the absence of large industrial and energy facilities) special interest represents the relevant Canadian experience. The article shows that in the 2000s, Canada did not come close to turning industry into a leading factor in the economy of the Arctic territories. At the same time, a series of federal programs for the modernization of social and transport infrastructure also did not become a significant incentive for the development of the northern regions. As federal statistics shows, the largest share of their GRP is still formed in the public sector, and the degree of diversification of the regional economy remains extremely low. The modern economy of the circumpolar Canada is based on the dominance of the state in investments and stimulating consumer demand. The consequence of this is an increase in wages, provoking an increase in the cost of all goods and the cost of living in general. Small businesses are unable to compete with the public sector for labor, which constrains private entrepreneurship. For Canada, the Arctic has not yet become the driver of national economic growth, and the lack of infrastructure is a serious obstacle to large-scale investment.

Ecology of Arctic rabies: 60 years of disease surveillance in the warming climate of northern Canada.

Rabies occurs throughout the Arctic, representing an ongoing public health concern for residents of northern communities. The Arctic fox (Vulpes lagopus) is the main reservoir of the Arctic rabies virus variant, yet little is known about the epidemiology of Arctic rabies, such as the ecological mechanisms driving where and when epizootics in fox populations occur. In this study, we provide the first portrait of the spatio-temporal spread of rabies across northern Canada. We also explore the impact of seasonal and multiannual dynamics in Arctic fox populations and climatic factors on rabies transmission dynamics. We analysed data on rabies cases collected through passive surveillance systems in the Yukon, Northwest Territories, Nunavut, Nunavik and Labrador from 1953 to 2014. In addition, we analysed a large and unique database of trapped foxes tested for rabies in the Northwest Territories and Nunavut from 1974 to 1984 as part of active surveillance studies. Rabies cases occurred in all Arctic regions of Canada and were relatively synchronous among foxes and dogs (Canis familiaris). This study highlights the spread of Arctic rabies virus variant across northern Canada, with contrasting rabies dynamics between different yet connected areas. Population fluctuations of Arctic fox populations could drive rabies transmission dynamics in a complex way across northern Canada. Furthermore, this study suggests different impacts of climate and sea ice cover on the onset of rabies epizootics in northern Canada. These results lay the groundwork for the development of epidemiological models to better predict the spatio-temporal dynamics of rabies occurrence in both wild and domestic carnivores, leading to better estimates of human exposure and transmission risk.

Effect of shipping activity on warming trends in the Canadian Arctic

This paper presents a detailed account of the effect of shipping activity on the increasing trends of air temperatures in the Canadian Arctic region for the period of 1980–2018. Increasing trend of temperature has gained significant attention with respect to shipping activities and sea ice area in the Canadian Arctic. Temperature, sea ice area and shipping traffic datasets were investigated, and simple linear regression analyses were conducted to predict the rate of change (per decade) of the average temperature, considering winter (January) and summer (July) seasons. The results indicate that temperature generally increased over the studied region. Significant warming trend was observed during July, with an increase of up to 1°C, for the Canadian Arctic region. Such increasing trend of temperature was observed during July from the lower to higher latitudes. The increase in temperature during July is speculated to increase the melting of ice. Results also show a decline in sea ice area has a significant positive effect on the shipping traffic, and the numbers of marine vessel continue to increase in the region. The increase in temperature causes the breaking of sea ice due to shipping activities over northern Arctic Canada.

The role of extractive industries in developing peripheral Arctic regions of Russia and Canada

Russian Federation and Canada are the largest arctic powers that have similar features in evolving their Arctic zones. In the mid-1920s both countries formalized their rights to the northern territories. Russian and Canadian arctic regions are located in harsh climatic zones,geographically distant from national political and business centers, poorly populated, and rich in natural resources. At the same time, there are obvious differences in political institutions,“core-periphery” relationships, business organization, and social activities of aboriginal people and newcomers. The purpose of this study is a comparative evaluation how the rich resource base and industrial production impact on the socio-economic development of the Arctic regions of Russia and Canada. To reach the goal authors use the official statistical sources of the Russian Federation and Canada. Case study method, comparative analysis, and econometric calculations are applied. As a result similar and distinctive features of the industrial development of the Arctic regions of these countries were identified. It can be explained, first of all, by the institutional characteristics of Russia and Canada. Comparing an evidence of the leading extractive companies completed the empirical analysis. Authors concluded that the regions under consideration are characterized by a high or medium share of the extractive industry in the regional economy. Specialization in natural resources extraction and primary processing does not have a negative impact on the economic development of the territories. However, outer companies are engaged in this business that increases the dependence of the regional economy on the conjuncture of world markets. The article investigates in empirical studying common features of the extractive industry in the peripheral Russian and Canadian Arctic territories and its impact on the socio-economic development of these regions.

Socio-Environmental Impacts of Mobility on Inuit People and Its Consequences in the High Arctic Region of Canada

This study examines the socio-environmental impacts of mobility on Inuit people and its consequences in the High Arctic region of Canada. Mobility is the part of Inuit culture, the Inuit people moved for hunting on familiar distances and sites that is the part of their life through generations. These patterns of mobility represent an admirable appreciation and familiar knowledge of the environment in the aboriginal people. The system of mobility as social change is related to the environmental stress, food shortage, fur-trade, construction of military bases, state policies, forced resettlement and non-renewable resources development projects in the Arctic region. Since 1950s, the Inuit of Canadian Arctic region have experience forcefully the mobilities in form of relocation, new-settlements, medical moves and residential schools as well as environmental mobility. The effects of relocation from their original lands have sustained through generations. There is another sad story of the DEW-line (Distance Early Warning) construction. The construction was started without any consent or notification to the local communities. Inuit people were displaced into other places with non-respectable way from their indigenous land. The residential school system was another a misfortune form of mobility which removed Aboriginal children from their parents and forcefully teach them ‘white manners’. This unfair treatment to the Inuit becomes big debate in the country from the several decades ago. Experience of mobility either it was due to relocation, displacement, individual or residential schools and mobility due to climate change are common story of Inuit people in the Arctic region of Canada. A number of families are still dealing with this intergenerational distresses.

Synoptic climatological approach associated with three recent summer heatwaves in the Canadian Arctic

Abstract The observed unusually high temperatures in the Arctic during recent decades can be related to the Arctic sea ice declines in summer 2007, 2012 and 2016. Arctic dipole formation has been associated with all three heatwaves of 2007, 2012 and 2016 in the Canadian Arctic. Here, the differences in weather patterns are investigated and compared with normal climatological mean (1981–2010) structures. This study examines the high-resolution datasets from the North American Regional Reanalysis model. During the study periods, the north of Alaska has been affected by the low-pressure tongue. The maximum difference between Greenland high-pressure centre and Alaska low-pressure tongue for the summers of 2012, 2016 and 2007 are 8 hPa, 7 hPa and 6 hPa, respectively, corresponding and matching to the maximum summer surface Canadian Arctic temperature records. During anomalous summer heatwaves, low-level wind, temperatures, total clouds (%) and downward radiation flux at the surface are dramatically changed. This study shows the surface albedo has been reduced over most parts of the Canadian Arctic Ocean during the mentioned heatwaves (∼5–40%), with a higher change (specifically in the eastern Canadian Arctic region) during summer 2012 in comparison with summer 2016 and summer 2007, agreeing with the maximum surface temperature and sea ice decline records.

North Atlantic killer whaleOrcinus orcapopulations: a review of current knowledge and threats to conservation

AbstractThe first comprehensive review on North Atlantic killer whalesOrcinus orcawas published in 1988. Since then, a significant increase in published studies has substantially improved our understanding of occurrence patterns, major food sources, abundance and population structuring in the North‐east Atlantic. Dedicated studies on killer whales in the Mid‐ and West Atlantic were undertaken beginning in 2006, mainly following an increase in their presence due to rapidly changing environmental conditions in the Arctic regions of Canada and Greenland.Compiling 111 scientific articles and reports published from 1957 to date, this review assesses the current state of knowledge of North Atlantic killer whale populations. We reviewed distribution, abundance, movements, genetic structure, acoustics, population parameters, and threats, whilst highlighting the connection among regions from east to west.Our results indicated that, while North Atlantic killer whales should be recovering following the end of the harvest, culling and live captures in the 1980s, new emerging threats including chemical pollution, anthropogenic noise and increasing unregulated subsistence harvest in Greenland could be hampering this rebound.There is an urgent need to collect data on the abundance and population structure of killer whales in Greenland and Eastern Canada. A lack of information across most regions of the North Atlantic Ocean has prevented regional status assessments from being conducted. Ongoing and future studies should be aimed at collecting relevant data to undertake these assessments, particularly genetic samples and photo‐identification.

Correcting Tmax Suppression: A Numerical Model for Removing Adsorbed Heavy Oil and Bitumen from Upper Ordovician Source Rocks, Arctic Canada

A Rock-Eval 6 dataset of 66 samples from the Cape Phillips Formation in the Canadian Arctic region was studied to investigate source rock characteristics and petroleum generation potential. Bulk geochemical characteristics and thermal decomposition behavior of the samples indicate an initial generation potential close to 700 mg HC/g TOC and show an unusually low onset Tₘₐₓ temperature for petroleum generation. This led to an examination of possible Tₘₐₓ suppression due to a large amount of high-molecular-weight heavy oil and bitumen derived from the early breakdown of kerogen in the samples. Application of a numerical method based on kerogen decomposition kinetics allows for the numerical removal of thermal evaporative products of oil and bitumen adsorbed in the sample without requiring additional pyrolysis experiments or solvent extraction treatments of sample replicates. The removal of the adsorbed hydrocarbon from samples increases the Tₘₐₓ value up to 17 °C. The estimated petroleum in the sorption phase varies from 1 to about 9 mg HC/g rock, depending on the total organic content (TOC) and maturity, and is the main form of the total oil yield in this area. The corrected Tₘₐₓ–HI cross-plot suggests an onset of petroleum generation around 435 °C of Tₘₐₓ, consistent with the general consensus for a normal marine source rock in this region. The constructed kinetic model shows a maximum of 75% transformation ratio (TR), and most samples show TR ranging from 10 to 50% in the early oil generation window on Cornwallis Island. This reconstructed source rock thermal decomposition model in a geological time scale indicates the onset of massive petroleum generation at a temperature of 120 °C, and the maximum transformation ratio of 75% corresponds to a temperature of 140 °C over geological time.

Assessing the impact of shipping emissions on air pollution in the Canadian Arctic and northern regions: current and future modelled scenarios

Abstract. A first regional assessment of the impact of shipping emissions on air pollution in the Canadian Arctic and northern regions was conducted in this study. Model simulations were carried out on a limited-area domain (at 15 km horizontal resolution) centred over the Canadian Arctic, using the Environment and Climate Change Canada's on-line air quality forecast model, GEM-MACH (Global Environmental Multi-scale – Modelling Air quality and CHemistry), to investigate the contribution from the marine shipping emissions over the Canadian Arctic waters (at both present and projected future levels) to ambient concentrations of criteria pollutants (O3, PM2.5, NO2, and SO2), atmospheric deposition of sulfur (S) and nitrogen (N), and atmospheric loading and deposition of black carbon (BC) in the Arctic. Several model upgrades were introduced for this study, including the treatment of sea ice in the dry deposition parameterization, chemical lateral boundary conditions, and the inclusion of North American wildfire emissions. The model is shown to have similar skills in predicting ambient O3 and PM2.5 concentrations in the Canadian Arctic and northern regions, as the current operational air quality forecast models in North America and Europe. In particular, the model is able to simulate the observed O3 and PM components well at the Canadian high Arctic site, Alert. The model assessment shows that, at the current (2010) level, Arctic shipping emissions contribute to less than 1 % of ambient O3 concentration over the eastern Canadian Arctic and between 1 and 5 % of ambient PM2.5 concentration over the shipping channels. Arctic shipping emissions make a much greater contributions to the ambient NO2 and SO2 concentrations, at 10 %–50 % and 20 %–100 %, respectively. At the projected 2030 business-as-usual (BAU) level, the impact of Arctic shipping emissions is predicted to increase to up to 5 % in ambient O3 concentration over a broad region of the Canadian Arctic and to 5 %–20 % in ambient PM2.5 concentration over the shipping channels. In contrast, if emission controls such as the ones implemented in the current North American Emission Control Area (NA ECA) are to be put in place over the Canadian Arctic waters, the impact of shipping to ambient criteria pollutants would be significantly reduced. For example, with NA-ECA-like controls, the shipping contributions to the population-weighted concentrations of SO2 and PM2.5 would be brought down to below the current level. The contribution of Canadian Arctic shipping to the atmospheric deposition of sulfur and nitrogen is small at the current level, < 5 %, but is expected to increase to up to 20 % for sulfur and 50 % for nitrogen under the 2030 BAU scenario. At the current level, Canadian Arctic shipping also makes only small contributions to BC column loading and BC deposition, with < 0.1 % on average and up to 2 % locally over the eastern Canadian Arctic for the former, and between 0.1 % and 0.5 % over the shipping channels for the latter. The impacts are again predicted to increase at the projected 2030 BAU level, particularly over the Baffin Island and Baffin Bay area in response to the projected increase in ship traffic there, e.g., up to 15 % on BC column loading and locally exceeding 30 % on BC deposition. Overall, the study indicates that shipping-induced changes in atmospheric composition and deposition are at regional to local scales (particularly in the Arctic). Climate feedbacks are thus likely to act at these scales, so climate impact assessments will require modelling undertaken at much finer resolutions than those used in the existing radiative forcing and climate impact assessments.

Semi volatile organic compounds in the snow of Russian Arctic islands: Archipelago Novaya Zemlya

Environmental contamination of the Arctic has widely been used as a worldwide pollution marker. Various classes of organic pollutants such as pesticides, personal care products, PAHs, flame retardants, biomass burning markers, and many others emerging contaminants have been regularly detected in Arctic samples. Although numerous papers have been published reporting data from the Canadian, Danish, and Norwegian Arctic regions, the environmental situation in Russian Arctic remains mostly underreported. Snow analysis is known to be used for monitoring air pollution in the regions with cold climate in both short-term and long-term studies. This paper presents the results of a nontargeted study on the semivolatile organic compounds detected and identified in snow samples collected at the Russian Artic Archipelago Novaya Zemlya in June 2016. Gas chromatography coupled to a high-resolution time-of-flight mass spectrometer enabled the simultaneous detection and quantification of a variety of pollutants including those from the US Environmental Protection Agency (EPA) priority pollutants list, emerging contaminants (plasticizers, flame retardants-only detection), as well as the identification of novel Arctic organic pollutants, (e.g., fatty acid amides and polyoxyalkanes). The possible sources of these novel pollutants are also discussed.GC-HRMS enabled the detection and identification of emerging contaminants and novel organic pollutants in the Arctic, e.g., fatty amides and polyoxyalkanes.

Elevated Potential Instability in the Comma Head: Distribution and Development

The development of elevated potential instability within the comma head of a continental winter cyclone over the north-central United States is examined using a 63-h Weather Research and Forecasting (WRF) Model simulation. The simulation is first compared to the observed cyclone. The distribution of most unstable convective available potential energy (MUCAPE) within the comma head is then analyzed. The region with positive MUCAPE was based from 2- to 4-km altitude with MUCAPE values up to 93 J kg−1. Backward trajectories from five sublayers within the region of elevated convection in the comma head were calculated to investigate how elevated potential instability developed. Air in the lowest sublayer, the source air for convective cells, originated 63 h earlier near Baja California at elevations between 2.25- and 2.75-km altitude. Air atop the layer where convection occurred originated at altitudes between 9.25 and 9.75 km in the Arctic, 5000 km away from the origin of air in the lowest sublayer. All air in the layer in which convection occurred originated over the Pacific coast of Mexico, the Pacific Ocean, or arctic regions of Canada. Diabatic processes strongly influenced air properties during transit to the comma head. Air underwent radiative cooling, was affected by mixing during passage over mountains, and underwent interactions with clouds and precipitation. Notably, no trajectory followed an isentropic surface during the transit. The changes in thermodynamic properties along the trajectories led to an arrangement of air masses in the comma head that promoted the development of potential instability and elevated convection.

Glucosinolates in Draba borealis DC. (Brassicaceae) in a taxonomic perspective

Draba borealis DC. is a perennial wild plant from the Arctic regions of Canada and USA. The seed and a whole plant of D. borealis were extracted and analysed by LC-MS for intact glucosinolates (GLs). Several identifications were confirmed by isolation. The identification of eleven compounds is reported in the seed and in the whole plant, including 3-methylsulfinylpropyl- (1), 4-methylsulfinylbutyl- (2), 5-methylsulfinylpentyl- (3), 3-methylsulfanylpropyl- (5), 6-methylsulfinylhexyl- (6), 5-methylsulfanylpentyl- (7), 6-methylsulfanylhexyl- (8), 4-methylsulfanylbutyl- (9), 8-methylsulfinyloctyl- (10), 9-methylsulfinylnonyl- (11), and 7-methylsulfanylheptyl- (12). Two additional GLs, 1-methylpropyl- (4) and 7-methylsulfinylheptyl- (13) GLs, were also proposed. This is the first report of occurrence of GLs 1–3, 5–9 and 12–13 from the genus Draba. Finally, the taxonomic perspective of the GL side chains in Draba genus was also discussed.