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Community structure and seasonal changes in the population structure of pelagic polychaetes were studied based on zooplankton samples collected by sediment traps moored at 200 m depth in the subarctic and subtropical western North Pacific throughout the year. Eight species belonging to seven genera and seven families occurred at the subarctic station, while twelve species belonging to ten genera and seven families were identified at the subtropical station. Polychaete abundance was 5.37 ± 0.44 ind. m-2 day-1 (annual mean ± standard error) at the subarctic station, and 1.36 ± 0.15 ind. m-2 day-1 at the subtropical station. Polychaete abundance at the subarctic station was high from May to August, but no seasonal patterns were observed at the subtropical station. The dominant species in the subarctic was Tomopteris septentrionalis, which accounted for 62.9% of annual mean abundance; at the subtropical station, the dominant species was Pelagobia sp. (22.8%). In the subarctic, small specimens of T. septentrionalis (

In high latitude coastal regions, benthic scavenger communities are largely composed of invertebrates that play a key role in the cycling of organic matter. Factors including temperature and depth can structure Arctic and Subarctic fjord benthic communities, but the response of scavenging communities to these factors is poorly known. To address this, we compared scavenging fauna in eight fjords with different physical characteristics in Svalbard and northern Norway using time-lapse imagery of scavengers consuming Atlantic herring (Clupea harengus) bait. Fjords influenced by relatively warm Atlantic waters, both in Norway and Svalbard, had high scavenger richness. However, Svalbard fjords with negative bottom temperatures had the lowest species richness and were dominated by lysianassoid amphipods and ophiuroids. In these cold Svalbard fjords, the mean carrion removal rates were almost 20 times higher than mean values noted elsewhere, except in the warm Norwegian fjord Kaldfjorden. Amphipods and ophiuroids quickly reduced the bait to bones (207.6–304.7 g removed per hour (g h−1); mean 290.6 ± 7.3 g h−1, n = 4) in cold Svalbard fjords. In the warmer Svalbard fjords, carrion removal rates were low (0–51.5 g h−1; mean 14.6 ± 9.0 g h−1, n = 5). Carrion removal rates in Kaldfjorden were higher than other Atlantic Water influenced fjords (132.1 and 372.5 g h−1, n = 2) owing to the scavenging activity of Atlantic cod (Gadus morhua). The results demonstrate potential ecosystem responses to warming in Arctic and Subarctic fjords, particularly effects related to range expansion of boreal species. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Consecutive landscape-scale disturbances are known to influence boreal forest regeneration, yet few published data exist on the compounding effects of natural and anthropogenic disturbance on regeneration in subarctic forests. We conducted a dendroecological study of eastern coastal boreal forest regeneration two decades after fire at three subarctic forest stands that are important sources of fuelwood for the people of Nunatsiavut (Labrador, Canada). We quantified spruce (Picea spp.) and balsam fir (Abies balsamea (L.) Mill.) seedling regeneration, standing dead tree density, trees harvested within burned forests, and aged proximal unburned stands. Age of unburned forest varied with site; however, each exhibited continuous regeneration over several decades. Despite low seedling regeneration at each site (stems·m−2; less than 35% of pre-fire stem density), model results indicated harvesting post-fire did not impact seedling regeneration. Findings suggest a negative pressure on seedling abundance from increased presence of tall multi-stemmed shrubs, yet we argue that because stands exhibit a range in tree age, shrubs may be a set of early successional species rather than indicating a change in successional trajectory. Examination of a larger chronosequence within coastal forest stands of Nunatsiavut is warranted to further understand forest regeneration in the eastern subarctic under changing disturbance regimes.

AVISO satellite data on the speeds of geostrophic currents from 2004 to 2018 are used to associate a substantial reduction in the saury catch in recent years with a change in the oceanographic situation in the Russian fishing grounds off the coast of the southern and middle Kuril Islands and Hokkaido Island. Lagrangian maps of the origin of water masses, calculated for this period of time on the basis of the AVISO field, and with overlaid positions of fishing vessels of Russia, Japan and Korea, show that this catastrophic reduction is due to a change in the pathways of the nutrient-rich subarctic waters of the Oyashio current in recent years. The greatest changes in the hydrological regime since 2015 were caused by intensification of the third branch of the Oyashio, which transports the waters of this current to the open ocean. At the same time, traditional fishing grounds off the eastern coasts of Hokkaido and southern Kurils have been reduced, while good fishing grounds have appeared in the open ocean.

AIM: To better understand how climate change drives altitudinal treeline dynamics at large spatial scales. LOCATION: Northern Hemisphere. TIME PERIOD: 1901–2018. MAJOR TAXA STUDIED: Tree species that constitute alpine treelines. METHODS: We conducted a meta‐analysis of annual treeline shift rates at 143 sites from 38 published studies. For each site, we calculated current change rates in annual or seasonal temperatures, precipitation and drought (standardized precipitation evapotranspiration index). We then evaluated relationships between treeline shift rates, and site characteristics and climate using standard and partial correlation analyses, as well as generalized linear models. These analyses were conducted at the hemispheric scale and for two geographic subsets of subarctic (north of 60° N) and temperate regions (south of 60° N). RESULTS: Treelines ascended at 88.8%, remained stable at 10.5% and descended at 0.7% of the sites. The mean hemispheric shift rate (0.354 m/year) was half of what would be expected from climate warming alone. Treeline shifts were significantly faster in subarctic than temperate regions. The precipitation effect was more important than temperature for predicting treeline shift rate. In the subarctic regions, autumn precipitation mostly determined treeline shift rates. In the temperate region, warmer temperatures and higher autumn precipitation accelerated shift rates, whereas wetter springs reduced them. Autumn precipitation and winter mean minimum temperature best explained the treeline shift rates across the Northern Hemisphere. MAIN CONCLUSIONS: A combination of thermal and hydrological factors drives treeline shift rates across the Northern Hemisphere, with precipitation assuming an important modifying role of the general temperature‐driven treeline ascent. Regional treeline shift rates, therefore, co‐depend on drying and wetting trends, which should be considered in future estimates of global change impacts on alpine ecosystems.

The eastern Canadian Subarctic and Arctic are experiencing significant environmental change with widespread implications for the people, plants, and animals living there. In this study, we integrate 10 years of research at the Nakvak Brook watershed in Torngat Mountains National Park of Canada, northern Labrador, to assess the sensitivity of ecological and geomorphological systems to regional climate warming. A time series of the Normalized Difference Vegetation Index indicates that the area has undergone a significant greening trend over the past four decades. Analyses of shrub cross sections suggest that greening has been caused by a combination of rapid establishment and growth that began in the late 1990’s and coincided with warmer growing season temperatures. Recent (2010–2015) vegetation change has been subtle and heavily moderated by soil moisture status. Plant canopy height is greater in wet areas and has an insulating effect on ground surface temperatures during the winter, a consequence of snow trapping by shrub canopies. Observations of subsurface conditions indicate that the study site is best characterized as having discontinuous near-surface permafrost. The importance of subsurface conditions for above-ground vegetation depends on the geomorphological context, with plants in wet areas underlain by fine materials being the most likely to be growth-limited by permafrost, thus being potential hot-spots for future change. With the expectation of sustained climate change, loss of adjacent sea ice, and proximity to the forest-tundra ecotone, it is likely that the Torngat Mountains will continue to be an area of rapid environmental change in the coming decades.

The climate change is significantly changing the hydro-thermal state of active layer at Qinghai–Tibet Plateau (QTP), which endangers permafrost environment. The degradation of permafrost would damage the linear engineering in cold regions; furthermore, the alternation of soil hydro-thermal state in the area of rugged terrain would lead to geo-hazards and then threaten the safety of local people. Global warming is widely accepted as a big threat to the ecological environment of arctic, subarctic and alpine regions, while the changing trend of precipitation around the world is still in dispute. Furthermore, the role of precipitation accompanied with global warming is unknown. Hence, in this study, the localized monitoring data from Beiluhe permafrost monitoring station at QTP, including atmospheric and soil hydro-thermal data, were utilized for further processing and comparative analysis. Firstly, the changing trend of precipitation here was investigated through the atmospheric data from 2003 to 2013. Thereafter, the hydro-thermal change of active layer was analyzed combined with precipitation events during this period. However, the raining pattern in QTP is characterized with continuity, short duration and small amount, basically referring to thawed season. The hydro-thermal change affected by corresponding raining event could be influenced by temporally nearby event in timescale. To differentiate the effect, the characteristic precipitation event (CPE) was selected through an elaborate algorithm. Subsequently, the hydro-thermal changes of active layer were reanalyzed in response to CPEs. Representative outcomes were chosen for the specific analysis under the influence from CPEs. Hence, under the circumstance of global warming, the effect from precipitation on the hydro-thermal properties of active layer was also obtained, and the possible harmful consequence induced by that was also discussed.

Only two species of boreal Holarctic frogs (genus Rana Linnaeus, 1758) can survive freezing and overwinter on land; they are found in the subarctic and cold regions of North America (Wood Frog, Rana sylvatica LeConte, 1825) and Eurasia (Moor Frog, Rana arvalis Nilsson, 1842) and are an example of an unusual adaptive strategy of overwintering. Freeze tolerance (down to –16 °C) of R. sylvatica has been thoroughly studied; however, little is known about cold resistance of R. arvalis in cold regions. We found that R. arvalis from European Russia and from West Siberia tolerate freezing down to –12 or –16 °C, whereas frogs from the Danish population survived freezing only to –4 °C (Y. Voituron et al. 2009b; J. Comp. Physiol. B, 179: 223–230). All of these populations, according to mitochondrial DNA markers, are closely related. We suggest that the observed differences in cold tolerance (–4 °C vs. –12 or –16 °C) could be caused either by adaptations to climatic factors or by differences in experimental protocols. The northeastern boundary of the geographic range of R. arvalis in Yakutia coincides with the transitional area between discontinuous and continuous permafrost; beyond this area, winter soil temperature sharply declines. The lower lethal temperature and overwintering ecology of R. arvalis in Siberia are similar to those of the North American R. sylvatica.

Aleutian eddies are anticyclonic vortices on scale of 100–200 kilometers that transport the Alaskan Stream warm water originating in the Gulf of Alaska to the western Subarctic Pacific (WSP). We present an analysis of satellite, Argo floats and ship borne observations of Aleutian eddies, revealing the influence of the wind forcing on the eddy formation and shedding. We demonstrate that the eastern winds promote the Aleutian eddy formation south of Near Islands. Positive (cyclonic) wind stress curl in late fall- winter results in the SSH decrease and the mesoscale cyclones formation at the Aleutian eddy boundaries and thereby leads to the eddy shedding from the Alaskan Stream. An appearance of the Aleutian eddies in the central part of the WSP is accompanied by the deepening of the isopycnals and an increase of the temperature and dissolved oxygen (DO) concentration in 150–400 m layer. The eddies decrease the DO concentration on 26.7σθ and 26.8σθ surfaces in the upper intermediate layer but enrich the 27.0σθ surface by DO. The extent to which eddies modulate the temperature and DO concentration in the WSP is related to the SSH amplitude of eddies.

Formation of the surface structure mechanism of the South Kuril waters in the last two years has undergone significant changes. Therefore, the “cold” type of hydrological conditions prevailed in the South Kuril area during August-November 2017. The surface water temperature was below the norm by 1–2 °C. On the contrary, the “warm” type of hydrological conditions prevailed in the South Kuril area during August-November 2018 and the water temperature in the area under consideration was 1–3 °C higher than the average for many years. Saury fishing in 2018, as in 2017, began in the second decade of August on the peripheral fronts of the Ask eddy and continued here until the second decade of September. At the end of September, the fishing area formed in the southwestern part of the EEZ of the Russian Federation and, unlike last year, it remained until the beginning of the third decade of October. The “warm” type of hydrological conditions causes this duration of the fishery. Saury moved outside the EEZ in late October. Fishing for sardines and mackerel began in mid-July 2018 and was carried out on the northern periphery of the eddy A’. However, at the end of October, unlike in 2017, fishing here practically stopped due to a decrease in the temperature drops at the peripheral fronts of the eddy caused by the high temperature of the surface waters of the Oyasio current. In late October — the first half of November in 2018, mackerel and sardine fished in high-gradient areas of the Northern Subarctic Front (NSAF) close to the eastern and southern borders of the Russian EEZ. During fishing season 2018, in contrast to the previous year, schools of sardines and mackerel remained much longer in the economic zone of Russia.

This study examined the effects of temperature and irradiance on photosynthetic characteristics of the macroscopic sporophyte (SPO) and microscopic gametophyte (GAM) stages of a subarctic brown alga, Saccharina japonica var. japonica (Laminariales) from Hokkaido, Japan. In vitro measurements under short- and long-term exposures were carried out by using optical dissolved oxygen sensors and the pulse amplitude modulation (PAM)-chlorophyll fluorometer, respectively. The heteromorphic life history stages of S. japonica showed photosynthetic optima at 23–23.3 °C, derived from the gross photosynthesis–temperature model. Maximum quantum yields (Fv/Fm) of SPO and GAM after 72 h of temperature exposures in the dark were reduced to near zero above 24 °C, indicating PSII inactivation. Such similarity in their temperature characteristics suggests the co-occurrence of both generations in the habitat despite the seasonal growth and reproduction of the species. Net photosynthesis–irradiance experiments in the two life history stages at 8, 16, and 24 °C revealed similarity in their light-saturated photosynthetic rates (NPmax = 3.02–4.41 μg O2 gww−1 min−1, SPO; 2.87–3.73 μg O2 gww−1 min−1, GAM), but saturation irradiances of SPO (Ek = 81–102 μmol photons m−2 s−1) were higher than those of GAM (48–69 μmol photons m−2 s−1). A slight decrease in net photosynthetic rates of GAM above 500 μmol photons m−2 s−1 was likewise observed. This difference may be related to the light regime of their natural habitat, suggesting the low irradiance adaptation of the microscopic stage that settles on rock crevices beneath algal canopies.

Forest fires are becoming more frequent and larger in the subarctic Canadian Shield, so understanding the effect of fire on catchment scale water budgets is becoming increasingly important. The objective of this study was to determine the water budget impact of a forest fire that partially burned a ~450 km2 subarctic Canadian Shield basin. Water budget components were measured in a pair of catchments; one burnt and another unburnt. Burnt and unburnt areas had comparable net radiation, but ground thaw was deeper in burned areas. Snowpacks were deeper in burns. Differences in streamflow between the catchments were within measurement uncertainty. Enhanced winter streamflow from the burned watershed was evident by icing growth at the streamflow gauge location, which was not observed in the unburned catchment. A new framework to assess hydrological resilience to forest fire across the region revealed that watersheds with higher bedrock and open water fractions are more resilient to hydrological change after fire in the subarctic shield, and resilience decreases with increasingly wet conditions.

Kola nuclear power plant, which discharges warm water into one of the bays of sub-arctic Lake Imandra, significantly changes the fish habitat, creating temperature gradient from 2 to 8°C compared to water temperature in the other part of the lake. The permeation, metabolism and bioaccumulation of elements in the stenothermal cold-water species (Coregonus lavaretus L.) in warm water impact zone are characterized. One of the main adaptation mechanisms of ionic regulation is the intense metabolism of Na due to the high respiratory activity of whitefish in warmer water. This feature is associated with elevated accumulation of Rb and loss of Se, Mo, and Si. At elevated temperatures, the main metabolic need is caused by Se deficiency. An extensive metabolism of selenoproteins involves risks of toxic effects and bioaccumulation of Hg, As and Cu with an increase of existing stressor or appearance of new ones.

Beluga whales (Delphinapterus leucas) occur broadly throughout the polar and subpolar regions of the Northern Hemisphere, and as a whole, the species is of low conservation concern. However, some populations, including Alaska’s Cook Inlet beluga whales (CIBW), are in decline for reasons that remain poorly understood. Currently, information on population-specific reproductive parameters of CIBW is non-existent. To address this data gap, we examined long-term photo-identification data of CIBW for insight into the reproductive natural history of this endangered subarctic population. Data are from 438 photo-ID surveys conducted 2005–2017 and over 400 identified individuals, augmented with data from strandings, biopsies, and tagging. During the April–October ice-free field season, we observed neonates July–October but never April-June. We photo-documented three suspected births during July–September. Neonates were present in 30% of groups and encountered and comprised 2% of all belugas observed. Over the course of the 13-year study, the number of calves seen with an individual mother ranged from 1 to 5, with inter-birth intervals ranging from 2 to 13 years. This corresponds to rates of 0.08–0.38 calves per year per mother. Known-aged mothers ranged in age from 13 to 31 years. Skin color was not a reliable indicator of sexual maturity. Calves photographed alongside their mothers were estimated to be 1–8 years old, although most were 1–4 years old. Some mothers (6%) were accompanied by a neonate and an older calf. These summaries of observational data provide critical insight into CIBW reproductive natural history that will inform future population modeling and management decision-making.

A compilation of surface water nutrient (phosphate, nitrate, and silicate) and partial pressure of CO2 (pCO2) observations from 1961 to 2016 reveals seasonal and interannual variability in the North Pacific. Nutrients and calculated dissolved inorganic carbon (DIC) reach maximum concentrations in March and minimum in August. Nutrient and DIC variability is in-phase (anti-phase) with changes in the mixed layer depth (sea surface temperature) north of 30 °N, and it is anti-phase (in-phase) with changes in Chl-a north of 40 °N (in 30 °N–40 °N). Seasonal drawdown of nutrients and DIC is larger toward the northwest and shows a local maximum in the boundary region between the subarctic and subtropics. Stoichiometric ratios of seasonal drawdown show that, compared to nitrate, silicate drawdown is large in the northwestern subarctic including the Bering and Okhotsk seas, and drawdown of carbon is larger toward the south. Net community production in mixed layer from March to July is estimated to be more than 6 gC/m2/mo in the boundary region between the subarctic and subtropics, the western subarctic, the Gulf of Alaska, and the Bering Sea. Nutrient and DIC concentrations vary with the Pacific Decadal Oscillation and the North Pacific Gyre Oscillation which cause changes in horizontal advection and vertical mixing. The DIC trend is positive in all analysis area and large in the western subtropics (> 1.0 μmol/l/yr). Averaged over the analysis area, it is increasing by 0.77 ± 0.03 μmol/l/yr (0.75 ± 0.02 μmol/kg/yr).

Vegetation communities in the subarctic are at risk of change due to climate-driven tree and shrub encroachment. Vegetation change may lead to unsuitable habitat for arctic-breeding birds, many of whom are declining. Although many possible factors are contributing to their decline, loss of breeding habitat could be a major contributor. We examined nest-site selection in Dunlin (Calidris alpina hudsonia (Todd, 1953)), a shorebird that nests in open fen habitats in the Churchill, Manitoba, Canada, region. Our objective was to determine whether this species avoids treed habitats and the possible fitness consequences for this. We examined the role of vegetative horizontal and vertical concealments on nest-site selection and nest fate. Dunlin selected nest sites with lower densities of trees than present at unused sites (40 m radius). Both horizontal and vertical concealments were significantly greater at nests than at unused sites, and horizontal concealment was greatest in the north. No measure of tree density or height, or concealment, significantly predicted nest fate. Although Dunlin appear to select nest sites that may minimize exposure to northerly winds and that may provide cover against potential predators, the current nest-site characteristics are not reinforced by contemporary selection.

Warmer climatic conditions have been associated with numerous hydrologic changes that may impact riverbank erosion in cold regions, but the net effect is not well understood. We used regression and correlation analyses to examine the relationships among subarctic riverbank erosion and seasonal hydrology, the impact of climate change and variability, and the societal implications. Geomorphic change (loss and gain of vegetated land) was mapped along several river reaches in the Yukon River Basin, Alaska, throughout 1984 and 2017 using Landsat satellite imagery. Annual erosion rates were estimated from these spatial data. At most study sites, erosion rates (km2/year) were either positively correlated (r = 0.68–0.84, p = 0.0085–0.061) with monthly mean discharge within the cold season or inversely correlated (r = − 0.74 – −0.62, p

We investigated the seasonal occurrence and vertical distribution/migration of larval and juvenile northern smoothtongue,Leuroglossus schmidti(Pisces, Bathylagidae), in oceanic areas of the western subarctic Pacific. This species was the most abundant larval fish and one of the most abundant juvenile/adult fish at the study site. Larval recruitment of this species occurred in early March to mid-October. Larvae were found, however, throughout all seasons, suggesting that some had overwintered. The highest abundance (5.8 individuals m–2) of larvae was in summer. During summer and autumn, hatching mainly occurred at 100–150-m depth and larvae migrated toward the surface with growth. Once larvae reached about 20 mm in length, they moved below 100 m, and larger larvae (over 24 mm) exhibited diel vertical migration. The abundance of juveniles integrated through the water column was relatively constant (0.3 individuals m–2) throughout the study period. They were collected from below 300 m during the day, and part of the population (13–38%) swam into the epipelagic layer at night. The information on early stages ofL. schmidtipresented here provides a basis for future investigations of mesopelagic fish ecology in oceanic areas of the western subarctic North Pacific Ocean.

Global warming-related changes to freshwater ecosystems in Arctic and Subarctic regions have been magnified by nutrient input from increasing waterfowl populations. To gain insight into how these changes might affect ecosystem function, we conducted a mesocosm experiment in the Subarctic by enriching N and P (1 ×, 10 ×, and 20 × treatments) and increasing mean water temperatures ≤ 3°C. We measured responses of two species of larval amphibians, periphyton, and phytoplankton. Wood frog (Rana sylvatica) larvae developed quicker (odds ratio [OR] for 1°C increase = 0.903, 95% CI 0.892–0.912) and were more likely to metamorphose (OR 1.076, 95% CI 0.022–14.73) in warmer waters. Boreal chorus frogs (Pseudacris maculata) also developed quicker with warmer temperatures (OR 0.880, 95% CI 0.860–0.900), despite a non-significant trend toward reduced survival (OR 0.853, 95% CI 0.696–1.039). Periphyton and phytoplankton concentrations increased with nutrient additions, as did size of wood frog metamorphs. Periphyton and phytoplankton did not vary with temperature, but periphyton was limited by tadpole abundance. Our results highlight the potential for non-linear responses to ecosystem change, with species-specific consumer and ecosystem responses that depend on the magnitude of changes.

Diversity and composition of benthic diatom algae and ciliates were studied at several beaches along the White and Barents seas: from highly exposed, reflective beaches with coarse-grained sands to sheltered, dissipative silty-sandy flats. For diatoms, the epipelic to epipsammic species abundance ratio was significantly correlated with the beach index and mean particle size, while neither α-diversity measures nor mean cell length were related to beach properties. In contrast, most of the characteristics of ciliate assemblages (diversity, total abundance and biomass, mean individual weight and percentage of karyorelictids) demonstrated a strong correlation to beach properties, remaining low at exposed beaches but increasing sharply in more sheltered conditions. β-diversity did not correlate with beach properties for either diatoms or ciliates. We suggest that wave action and sediment properties are the main drivers controlling the diversity and composition of the intertidal microbenthos. Diatoms and ciliates, however, demonstrated divergent response to these factors. Epipelic and epipsammic diatoms exhibited 2 different strategies to adapt to their environments and therefore were complementarily distributed along the environmental gradient and compensated for each other in diversity. Most ciliates demonstrated a similar mode of habitat selection but differed in their degree of tolerance. Euryporal (including mesoporal) species were relatively tolerant to wave action and therefore occurred under a wide range of beach conditions, though their abundance and diversity were highest in fine, relatively stable sediments on sheltered beaches, whereas the specific interstitial (i.e. genuine microporal) species were mostly restricted to only these habitats.

Root membrane lipids are important biomolecules determining plant's ability to adapt to different growing environmental or climatic conditions. Herein, we demonstrate the potential use of root membrane lipids as biomarkers to discriminate silage-corn genotypes based on herbicide and insect/pest resistance genetic traits when cultivated on podzolic soils under short growing and moderately warm summer season in boreal climate. Lipids in root membranes of field grown silage-corn genotypes were previously quantified at crop maturity by ultra-high-performance liquid chromatography-hydrophilic interaction chromatography-heated electrospray ionization mass spectrometry. The lipid identified and quantified in silage-corn roots were phospholipids, glycolipids and sphingolipids. Following hierarchical cluster analysis, three groups of membrane lipids were observed to be very effective in segregating the five silage-corn genotypes. The first group consisted of hexosylceramide (HexCer), phosphatidylcholine (PC) and phosphatidylinositol (PI). The second group consisted of lysophosphatidic acid (LPA16:0) and lysophosphatidylcholine (LPC16:0), while the third group consisted of 37 molecular species from observed lipids (phospholipids, glycolipids, sphingolipids). Partial least squares-discriminant analysis (PLS-DA) based on 37 membrane lipid species, as well as principal component analysis using the variables important in projection derived from the PLS-DA segregated the five silage-corn genotypes into three groups according to their pesticide/herbicide resistant traits. This study is second to none using root lipidomics in discriminating different silage-corn genotypes based on their herbicide and insect/pest resistance genetic traits for cultivation in boreal climates. The segregated genotypes possess three different genetic traits for herbicide and insect/pest resistance including VT Double Pro (VT2P), VT Triple Pro Roundup Ready (VT3P/RR) and Roundup Ready-2 corn (RR2). These findings demonstrate that root membrane lipids could serve as appropriate chemical biosignatures to identify silage-corn genotypes based on herbicide and insect/pest resistance genetic traits suitable for cultivation in boreal climates.

It is necessary for air–sea interaction and climate research to evaluate heat and salinity transport between the mixed layer (ML) and the permanent pycnocline and its contribution to the ML properties. The authors have calculated the obduction and subduction rates with the Eulerian definition using a 1°-grid Argo dataset and incorporated the obduction rate into the ML budget analysis in order to assess the impact of the entrained permanent pycnocline water on the ML temperature and salinity. They have successfully separated the effect of obduction on the ML from the entrainment of the seasonal pycnocline, and specified the regions where the obduction impact is noticeable. The ML heating rate due to obduction was smaller than ± 0.1 K/yr on average over most of the domain, but it was larger than − 0.5 K/yr in places around the Circumpolar Current, in the northeastern tropical Pacific, the southwestern tropical Indian Ocean, and the northeastern North Atlantic. The salinizing rate due to obduction exceeded ± 0.02 psu/yr in these areas, and in the subarctic North Pacific and the eastern South Pacific. The waters entrained from the permanent pycnocline warm and salinize the ML in the high latitudes due to the dichothermal structure. The method applied in this study also enabled us to assess the residence time and route of obducted and subducted water parcels below the ML. Furthermore, the authors examined the changes of obduction and subduction related with the marine heatwave that occurred in the northeastern North Pacific around 2014.

This paper analyzes detached residential buildings with a sunspace and a thermal storage wall made of 20 cm thick concrete and either containing or not containing a phase-change material (PCM). Four building models are considered: P0, P1, P2, and P3. Model P0 has a 0.2 m thick thermal storage wall without PCM, while the other models contain PCM in the wall (PCM 1-M182/Q21, PCM 2-M182/Q25, and PCM 3-M182/Q29). The study focuses on the buildings’ performance in terms of heating and cooling energy consumption over one year at five locations in Serbia (Nis, Belgrade, Novi Sad, Kopaonik, and Zlatibor), depending on the type and position of PCM within the wall. The observed locations are found either in urban areas with moderately warm and humid climate or in mountain tourist centers with a humid boreal climate. The analysis of annual heating and cooling energy requirements of the building models in all locations with different climates (Koppen classification Cfa, Dfc, and Dfb), revealed model P3, with PCM 3-M182/Q29 within its wall to be the most efficient. Less heating and cooling energy is required for model P3 than for the other models. The total energy requirement for P3 is lower than P0 by: 1.90% for the Nis climate, 1.79% for the Belgrade climate, 1.77% for the Novi Sad climate, 0.91% for the Kopaonik climate, and 1.27% for the Zlatibor climate. Since model P3 was shown to be the best in terms of heating and cooling energy requirements, the positions of PCM within its wall were analyzed for each location, namely the PCM positions just beneath the exterior wall portion, in the middle of the wall, and just beneath the interior wall portion. The results showed that the mid-wall PCM position was the most efficient for each location. Compared to P0, the total energy requirement for P3 with a mid-wall PCM position is 2.37% lower in Nis, 2.41% lower in Belgrade, 2.14% lower in Novi Sad, 1.06% lower on Kopaonik, and 1.77% lower on Zlatibor.

Monitoring distributional shifts in Arctic and subarctic fish species as environmental conditions change can be difficult due to sparse or infrequent surveys. Pacific halibut (Hippoglossus stenolepis) are found as far north as the Bering Strait, and future changes in sea temperatures and prey distribution may lead to an expanded range. For this and other species, it is therefore important to use as much survey data as is available when estimating density indices and other quantities of interest. Setline and trawl surveys in the eastern Bering Sea provide partial coverage each year, but the two gear types capture different size distributions of fish. We apply a calibration method to data from the setline and trawl surveys to produce consistent, spatially indexed estimates of indices of local density. The resulting estimates are then combined through spatiotemporal models that can incorporate environmental covariates to provide reliable density indices and to map the dynamic distribution of Pacific halibut. Such approaches may become increasingly important as climate change affects species distribution relative to historical survey footprints, and scientists must adapt to the use of new and variable data sources.

The reproductive status of walleye (Sander vitreus) and lake whitefish (Coregonus clupeaformis) is largely unstudied in the northern extent of their ranges. Tathlina Lake and Kakisa Lake are large, shallow lakes in the Northwest Territories, Canada, supporting important commercial and subsistence fisheries for these species while being threatened by climate change. Fish were sampled in both lakes across multiple years in the spring and autumn to assess differences in reproductive status in the pre- and post-spawning periods for both species. Condition factor (K), gonadosomatic index (GSI), liversomatic index (LSI), and fecundity were calculated, and plasma samples were also taken from each fish to determine levels of reproductive hormones, specifically 17β-estradiol in females, and 11-ketotestosterone in males. Significant temporal (intra- and interannual) and spatial (between lakes) variation was found for both species and both sexes for all metrics. Expected differences in hormones and indices of reproductive success between pre- and post- spawning periods were demonstrated. When compared with previously published data, a latitudinal gradient for LSI, GSI and fecundity was evident for walleye, but not for lake whitefish. The differences in the reproductive biology of lake whitefish and walleye in these two neighbouring lakes highlights limitations in the use of a reference lake approach in biomonitoring studies. The data in this study can be used and expanded upon to provide information for the sustainable management of these fish stocks for the future.

The aim of the paper is to present the results obtained from scientific literature on the characteristics of gestation course and the mechanisms of its failure in HIV-infected women of the Subarctic region. Materials and Methods. The authors conducted a literary search in the CyberLeninka, PubMed, Medline, Scopus, and HAC journals. They also studied statistical HIV indicators in the world, in Russia and in the Khanty-Mansi Autonomous Area – Yugra. Literary sources are no older than 10 tears. Results. Long-term residence in a Subarctic region cannot but affect the course of a chronic viral infection in pregnant women. Besides the prevention of vertical HIV transmission from a woman to her child, highly active antiviral therapy is an additional factor contributing to the development of premature birth, anemia and other gestation complications in pregnant women. Keywords: HIV infection, leukocyte indices, adaptation, antiviral therapy, premature birth. Цель – представить данные научной литературы об особенностях течения беременности и механизмах формирования ее патологии у ВИЧ-инфицированных жительниц субарктического региона. Материалы и методы. Проведен литературный поиск в базах «КиберЛенинка», PubMed, Medline, журналах Scopus, ВАК, а также изучены статистические показатели ВИЧ в мире, России и ХМАО – Югре. Глубина исследования в основном не превышала 10 лет. Результаты. Длительное проживание в условиях субарктического региона не может не отразиться на течении хронической вирусной инфекции у беременной. Высокоактивная антивирусная терапия, несмотря на профилактику вертикальной передачи ВИЧ от матери ребенку, является дополнительным фактором развития преждевременных родов, анемии беременных и других осложнений гестации. Ключевые слова: ВИЧ-инфекция, лейкоцитарные индексы, адаптация, антивирусная терапия, преждевременные роды.

Two decades (1997–2017) of blended satellite-retrieved phytoplankton chlorophyll a concentration (Chl-a) data were used to assess the interannual variation and recent trends of phytoplankton biomas...

The article presents the results of studies of the environmental properties of organochlorines which differ in properties and origin, in the lake ecosystems of the Bolshezemelskaya tundra (Nenets Autonomous Okrug, Russia). The purpose of this study was to evaluate and assess the levels, distribution characteristics and composition of organochlorines in the bottom sediments of small lakes located in the Adzva river basin in Pymvashor natural boundary (the northernmost location of the exit of thermal-mineral springs of the continental Europe) and in the adjacent area, outside this unique subarctic hydrothermal zone.In order to meet this goal, multi-method (hydrochemical, geochemical, etc.) research was carried out using standard generally approved laboratory practices with their adaptation to the study goals. The quantitative content and composition of the target individual organochlorines were determined by gas chromatographic method with electron-capture detection.The presence of chlorophenol compounds and polychlorinated benzenes (including persistent organic pollutants) was shown in the lakes sediments. The influence of specific microclimatic conditions of subarctic hydrothermal system on the composition and distribution of chlorophenol compounds in lake sediments was considered. In the small lake sediment core in Pymvashor natural boundary a reducing trend in the levels of organochlorines with depth has been recorded (conditioned among other things by the lithological features of bottom sediments). The chlorophenol compounds were found at highest concentrations (619.3–765.5 ng/g) in the sediment upper layers, rich in organic matter; chlorophenol composition was represented mainly by chlorinated phenols, most likely of biotic origin. A lower concentration (185.0 ng/g) of chlorophenol compounds of predominantly abiogenic origin was determined in the lake sediments outside hydrothermal system. The presence and levels of persistent organochlorine pollutants (pentachlorophenol 0.1–2.4 ng/g; hexa- and pentachlorobenzenes 0.4–3.6 ng/g) in the lake sediments were associated with long-range atmospheric transport from various origin sources in nearby regions and low-latitude territories.

Here, we investigate the seasonal variability in the dissolved inorganic carbon (DIC) cycle in the Northwest Pacific using a high-resolution biogeochemical and carbon model coupled with an operational ocean model. Results show that the contribution to DIC from air–sea CO2exchange is generally offset by vertical mixing at the surface at all latitudes, with some seasonal variation. Biological processes in subarctic regions are evident at the surface, whereas in the subtropical region these processes take place within the euphotic layer and then DIC consumption deepens southward with latitude. Such latitudinal differences in biological processes lead to marked horizontal and vertical contrasts in the distribution of DIC, with modulation by horizontal and vertical advection–diffusion processes.

According to the data collected in the second half of summer for the period from 1954 to 2016 in the flat and mountainous parts of Western Siberia, the distribution and number of the narrow-headed vole in the zonal and provincial aspects were analyzed. Based on the cluster analysis of the matrix of similarity coefficients of abundance indicators obtained by averaging the initial data by years and groups of geobotanical maps units, the classification of habitats according to the favorable environmental conditions degree for the vole is made. The averaged samples are divided into five types of favorability: from optimal, where the abundance of the species is highest in the whole studied area, to extreme, where it is not encountered. In the South of the West Siberian plain narrow-headed vole prefers steppes, and in the subarctic tundras – communities of river valleys. In the Altai and Kuznetsk-Salair mountain regions it is most common in the subalpine light forests, tundras and tundra-steppe of the North-Western and SouthEastern Altai. On average, this vole prefers open habitats in Western Siberia. According to the classification and the structural graph, the dependence of the vole abundance on a number of factors and their inseparable combinations (enviromental and anthropogenic regimes) was revealed. The greatest connection with its distribution in the habitats of Western Siberia is traced for heat and water availability. On the plain, the number of this vole increases from the middle taiga, where it is found only once, to the subzone of the subarctic tundras in the North and to the forest-steppe and steppe zones in the South. In the mountains its more in the South-Eastern Altai, where a relatively high proportion of the most favorable for narrow-headed vole habitats.

Korosi JB, Thienpont JR, Eickmeyer DC, Kimpe LE, Blais JM. 2020. A paleolimnological approach for interpreting aquatic effects monitoring at the Diavik Diamond Mine (Lac de Gras, Northwest Territor...

Graphical abstract, The average fatty acid (FA) composition of canola oil is made up of 62% oleic acid (C18:1n9), 19% linoleic acid (C18:2n6), 9% linolenic acid (C18:3n3) and 7% saturated FA (SFA). We investigated whether boreal climate (7.5-17.2 °C) favorably altered the FA composition of canola. Results indicate that canola cultivated in boreal climatic conditions had approximately twice the levels of omega-3 FA (17-20%) compared to canola from other growing areas (9%). The presence of monoacetyldiacylglycerol (MAcDG), a unique class of triglyceride, is reported for the first time in canola cultivated in a boreal climate, and has the potential to reduce the risk of obesity and other health related diseases. We further demonstrated that a non-solvent based extraction method retained the novel lipid composition without reducing the quality of oil being produced. Our results contribute significantly to the understanding of lipid accumulation in the world's second most important oil crop when cultivated in a boreal or northern climate.

Genetic and linguistic evidence suggests that, after living in the Subarctic for thousands of years, Northern Athabascans began migrating to the American Southwest around 1,000 years ago. Anthropologists have proposed that this partial out-migration and several associated in situ behavioral changes were the result of a massive volcanic eruption that decimated regional caribou herds. However, regional populations appear to increase around the time of these changes, a demographic shift that may have led to increased territoriality, resource stress, and specialization. Building on existing syntheses of cultural dynamics in the region, analyses of excavated materials, and landscape data from Alaska and Yukon, this research shows that the Athabascan transition represented a gradual shift toward resource specialization in both salmon and caribou with an overall increase in diet breadth, indicating a behavioral transition that is more consistent with gradual demographic change. Further, this behavioral shift was already in motion at the time of the volcanic eruption circa 1150 cal BP and suggests that the ultimate migration from the area was the result of demographic pressures. In sum, this research elaborates on the complex dynamics of resilience and adaptation in hunter-gatherer groups and provides a testable model for explaining past migrations.

Many wetlands have been drained due to urbanization, agriculture, forestry or other purposes, which has resulted in a loss of their ecosystem services. To protect receiving waters and to achieve services such as flood control and storm water quality mitigation, new wetlands are created in urbanized areas. However, our knowledge of greenhouse gas exchange in newly created wetlands in urban areas is currently limited. In this paper we present measurements carried out at a created urban wetland in Southern Finland in the boreal climate. We conducted measurements of ecosystem CO2 flux and CH4 flux (FCH4) at the created storm water wetland Gateway in Nummela, Vihti, Southern Finland, using the eddy covariance (EC) technique. The measurements were commenced the fourth year after construction and lasted for 1 full year and two subsequent growing seasons. Besides ecosystem-scale fluxes measured by the EC tower, the diffusive CO2 and CH4 fluxes from the open-water areas (FwCO2 and FwCH4, respectively) were modelled based on measurements of CO2 and CH4 concentration in the water. Fluxes from the vegetated areas were estimated by applying a simple mixing model using the above-mentioned fluxes and the footprint-weighted fractional area. The half-hourly footprint-weighted contribution of diffusive fluxes from open water ranged from 0 % to 25.5 % in 2013. The annual net ecosystem exchange (NEE) of the studied wetland was 8.0 g C-CO2 m−2 yr−1, with the 95 % confidence interval between −18.9 and 34.9 g C-CO2 m−2 yr−1, and FCH4 was 3.9 g C-CH4 m−2 yr−1, with the 95 % confidence interval between 3.75 and 4.07 g C-CH4 m−2 yr−1. The ecosystem sequestered CO2 during summer months (June–August), while the rest of the year it was a CO2 source. CH4 displayed strong seasonal dynamics, higher in summer and lower in winter, with a sporadic emission episode in the end of May 2013. Both CH4 and CO2 fluxes, especially those obtained from vegetated areas, exhibited strong diurnal cycles during summer with synchronized peaks around noon. The annual FwCO2 was 297.5 g C-CO2 m−2 yr−1 and FwCH4 was 1.73 g C-CH4 m−2 yr−1. The peak diffusive CH4 flux was 137.6 nmol C-CH4 m−2 s−1, which was synchronized with the FCH4. Overall, during the monitored time period, the established storm water wetland had a climate-warming effect with 0.263 kg CO2-eq m−2 yr−1 of which 89 % was contributed by CH4. The radiative forcing of the open-water areas exceeded that of the vegetation areas (1.194 and 0.111 kg CO2-eq m−2 yr−1, respectively), which implies that, when considering solely the climate impact of a created wetland over a 100-year horizon, it would be more beneficial to design and establish wetlands with large patches of emergent vegetation and to limit the areas of open water to the minimum necessitated by other desired ecosystem services.

Alpine headwaters in subarctic regions are particularly sensitive to climate change, yet there is little information on stream thermal regimes in these areas and how they might respond to global warming. In this paper, we characterize and compare the hydrological and thermal regimes of two subarctic headwater alpine streams within an empirical framework. The streams investigated are located within two adjacent catchments with similar geology, size, elevation and landscape, Granger Creek (GC) and Buckbrush Creek (BB), which are part of the Wolf Creek Research Basin in the Yukon Territory, Canada. Hydrometeorological and high‐resolution stream temperature data were collected throughout summer 2016. Both sites exhibited a flow regime typical of cold alpine headwater catchments influenced by frozen ground and permafrost. Comparatively, GC was characterized by a flashier response with more extreme flows, than BB. In both sites, stream temperature was highly variable and very responsive to short‐term changes in climatic conditions. On average, stream temperature in BB was slightly higher than in GC (respectively 5.8 and 5.7°C), but less variable (average difference between 75th and 25th quantiles of 1.6 and 2.0°C). Regression analysis between mean daily air and stream temperature suggested that a greater relative (to stream flow) groundwater contribution in BB could more effectively buffer atmospheric fluctuations. Heat fluxes were derived and utilized to assess their relative contribution to the energy balance. Overall, non‐advective fluxes followed a daily pattern highly correlated to short‐wave radiation. G1enerally, solar radiation and latent heat were respectively the most important heat source and sink, while air–water interface processes were major factors driving nighttime stream temperature fluctuations.

Mortality rate in the Russian Federation in 2018 exceeded the birth rate again. At the same time, a stable and high frequency of early reproductive losses was noted. Every fifth wanted pregnancy terminates spontaneously before the due date. Living in the subarctic zone is associated with several unfavorable climatic factors. Implementation of the reproductive function in these conditions is influenced by region-specific factors, which have multiple effects on the mechanisms of recurrent pregnancy loss. The literature search was performed using PubMed, Medline, Cyberleninka, Scopus and HAC databases. Assessing the degree of adaptation of women of reproductive age living in the subarctic zone of the Russian Federation helps to assess their psychosomatic status and heart rate variability. Taking into account the adaptation parameters, certain patterns were revealed for women of reproductive age, as well as for each trimester of a normal and pathologically ongoing pregnancy. Particular attention in the assessment of adaptive resources of the body deserve leukocyte indices, by changing the parameters of which it is possible to make a forecast of the ongoing pregnancy. The results of this review are of interest to the clinicians working in the subarctic zone of Russia from the standpoint of personalized approach to prevention and prediction of recurrent pregnancy loss.

We investigated an alkenone-based sea surface temperature (SST) and the hydrographic change records of the subarctic Northwestern (NW) Pacific from the last glacial to interglacial. The core we investigated is a piston core (LV 63-41-2, 52.56° N, 160.00° E; water depth 1924 m) retrieved from the southern offshore east coast of the Kamchatka Peninsula, which is a location of high sedimentation rate, with highly dynamic interactions with the cold/warm water masses of the Bering Sea/the NW Pacific. Based on our alkenone analysis with a previously well-established chronology of the core, we found high glacial C37:4 contents suggesting larger freshwater influences prior to the last deglacial in approximately 27–16 ka BP. The most significant features of what we found are alkenone indicative of “warming” intervals with minimum alkenone productions that occurred prior to the stadial Heinrich event 1 and the Younger Dryas. In contrast, for the interval corresponding to the Bølling–Allerød period, our alkenone analysis shows relatively “colder” but maximum alkenone productions. We conclude that this particular subarctic alkenone SST proxy record is mainly masked by non-thermal environmental influences, such as strong shifts of timing and duration of the sea ice retreat and/or salinity changes in surface water at this site, which could cause changes in water stratification that affect nutrient supplies of the upper ocean that modulate growth durations of phytoplankton/coccolithophore productions. Our studies suggest that this subarctic alkenone “SST” proxy record is indicative of the changes of seasonality that control the timing and duration of the blooming seasons of coccolithophores. The alkenone “SST” proxy is also dominantly driven by water stratification effects that, instead of SSTs, reflect most likely a combination of the following local to regional climate and ocean current patterns: (1) the amount of meltwater inputs from high mountain glaciers at Kamchatka; (2) less saline, nutrient-rich Alaskan Stream waters from the Cordilleran Ice Sheet in the Gulf of Alaska; (3) downwelling waters associated with the interactions between the southward Eastern Kamchatka Current and the spinning-up of the North Pacific Subarctic Gyre; and (4) the strength of the Kuroshio Current since the last glacial.

Foraging by hyperabundant Arctic-nesting geese has significant impacts on vegetation of Arctic and subarctic coastal lowlands, but long-term data sets documenting these changes are rare. We undertook intensive surveys of plant communities at East Bay and South Bay, Southampton Island, Nunavut, Canada, in July 2010. Lesser Snow Geese, Ross’s Geese, Cackling Geese, and Brant nest and rear young at these sites; the first three have experienced up to 10-fold increases since the 1970s. At East Bay, we found significant declines in graminoids over the 31-year span, as well as significant declines in lichen and willow cover, and significant increases in rock cover. Transect data indicated graminoids were present at only 15%–36% of points at East Bay, whereas at South Bay, graminoids were present at 28%–90% of points. Moss was more prominent in transects at South Bay than at East Bay (40%–85% vs. 19%–42%), but quadrat data indicated much more of the moss cover at South Bay apparently was dead than at East Bay. Puccinellia phryganodes (Trin.) Scribn. & Merr. exceeded 1% in only two transects. Our data demonstrate a striking decline of preferred forage species and increases in non-forage cover, consistent with the hypothesis that changes resulted from persistent long-term foraging by the four species of breeding geese between spring arrival and late summer departure.

Eutrophication is one of the most important drivers of change in coastal marine ecosystems worldwide. Given their slow growth, rhodoliths and the biodiverse communities they support are regarded as non-renewable resources threatened by human activity. Consequences of nutrient enrichment on growth and calcification in crustose coralline algae are equivocal, and even more so in cold-water rhodoliths. We paired a 183 d laboratory mesocosm experiment with a 193 d field experiment on Newfoundland (Canada) rhodoliths (Lithothamnion glaciale) to test the hypothesis that nutrient (nitrate, ammonia, and phosphate) enrichment and biofouling reduce rhodolith growth. Rhodoliths in the laboratory were exposed to 1 of 3 nutrient concentrations (ambient, intermediate, or high) and either of 2 levels of manual cleaning (cleaned or uncleaned) to control biofouling. We exposed rhodoliths in the field to 1 of 2 nutrient concentrations (ambient or elevated). Eutrophication in the laboratory did not affect biofouling; however, manual cleaning reduced biofouling by ~4 times relative to uncleaned rhodoliths. Rhodoliths grew 2 times slower at elevated than ambient nutrient concentrations, and ~27% more in cleaned than uncleaned rhodoliths at all concentrations. Rhodoliths in the field also grew significantly slower under elevated than ambient phosphate concentrations, but only during the first 6 wk, indicating some capacity for long-term recovery. We conclude that despite some growth resilience to low and infrequent increases in nutrient concentrations, subarctic L. glaciale rhodoliths cannot cope with prolonged exposure to modest eutrophication.

Significance A correct understanding of the iron and macronutrient dynamics at the termination of the global ocean conveyor belt circulation is critical for understanding the global carbon cycle and its changes in geological timescale. Newly obtained and compiled datasets of iron and macronutrients with the vertical mixing magnitude in the subarctic Pacific and marginal seas indicate the processes that determine the nutritional status of intermediate waters and the mechanisms by which subpolar marginal seas fuel the North Pacific Ocean through the intermediate water. The intermediate water formation processes play a major role in the connection of nutrients between the deep water and the surface water above it, and sustain biological production, at the termination of the global nutrient circulation., The mechanism by which nutrients in the deep ocean are uplifted to maintain nutrient-rich surface waters in the subarctic Pacific has not been properly described. The iron (Fe) supply processes that control biological production in the nutrient-rich waters are also still under debate. Here, we report the processes that determine the chemical properties of intermediate water and the uplift of Fe and nutrients to the main thermocline, which eventually maintains surface biological productivity. Extremely nutrient-rich water is pooled in intermediate water (26.8 to 27.6 σθ) in the western subarctic area, especially in the Bering Sea basin. Increases of two to four orders in the upward turbulent fluxes of nutrients were observed around the marginal sea island chains, indicating that nutrients are uplifted to the surface and are returned to the subarctic intermediate nutrient pool as sinking particles through the biological production and microbial degradation of organic substances. This nutrient circulation coupled with the dissolved Fe in upper-intermediate water (26.6 to 27.0 σθ) derived from the Okhotsk Sea evidently constructs an area that has one of the largest biological CO2 drawdowns in the world ocean. These results highlight the pivotal roles of the marginal seas and the formation of intermediate water at the end of the ocean conveyor belt.

The vital infrastructure of Russia’s Arctic and Subarctic, in view of severe nature and climate, consumes much energy sources, mostly, coal shipped from central Russia by water transport via the Northern Sea Route (2-3 thousand kilometers) in summer. This raises the cost 3-4 times. A good alternative to the imported fuel is local peat. The principal consumer of peat as a fuel can be the Verkhoyansk Region in the Republic of Sakha (Yakutia), which is the subject of research. This article describes the promising deposits of peat in this region, peat occurrence conditions and possible production output. The scope of the discussion embraces the most popular methods of peat production: milling, hydraulic, dredging, scraper-elevator, cutting, milling-and-forming, shoveling, etc., with field curing and harvesting. However, because of high bogginess of the tundra zone, the listed methods of peat production are unusable. In this regard, the most promising approach is winter production of frozen peat with preliminary monitoring of the frozen thickness by ground penetrating radar. The earlier studies into the temperature conditions of the active soil layers, including peat beds, are presented. The chosen technology will ensure maximum preservation of landscape and ecological safety.

Vertical profiles of radiocesium (134Cs and 137Cs) were measured in the western subarctic area of the North Pacific in 2017. The highest concentration of 134Cs, which was derived from the accident of the Fukushima Dai-ichi Nuclear Power Plant in 2011, was 0.14 Bq m−3 (or 1.19 Bq m−3 after the decay correction to the accident date). Although the vertical inventory of 134Cs decreased between 2014 and 2017, the inventory in 2017 was larger than that expected. That was probably arose from the return of some portion of the high-concentration water mass along with the anticlockwise subarctic gyre current.

Although nitrogen (N) fixation by moss-associated bacteria is the main source of new N in N-limited ecosystems like arctic tundra, we do not know which nutrient, molybdenum (Mo) or phosphorus (P), is rate-limiting for sustaining this process in the long-term. Further, how moss-associated N2 fixation impacts the belowground microbial regulation of decomposition remains unresolved. Moss-associated N2 fixation and soil microbial process rates, abundance and community structure were assessed in long-term P and Mo field additions in the Subarctic during three years. We found tendencies for stimulation of moss-associated N2 fixation by Mo in the short term, by P in the long-term, and tendencies for a stimulation of soil microbial activity by P. However, large variation in microbial activity within and below the moss exceeded any systematic variation induced by the field treatments. Our findings suggest that soil microbial activity is not limited by N at our site, and that Mo and P only occasionally limit N2 fixation during a growing season. Since increasing CO2 concentrations can induce nutrient limitation, the here reported transient limitation can easily shift into a chronic one with significant implications for ecosystem productivity and biogeochemistry.