Subarctic Regions Research Articles

Northeast Pacific marine heatwaves associated with high-latitude atmospheric blocking

The Northeast Pacific Ocean (NEP) is one of the hotspots of marine heatwaves (MHWs) occurring in the global ocean. The causes of MHWs in this region have been widely investigated, but the physical processes underlying heatwaves and regional climate variability remain under debate. By analyzing interannual large-scale high-latitude atmospheric dynamics and oceanic physical conditions over the NEP, we show that winter-spring sea surface temperature (SST) anomalies are strongly correlated with winter-spring atmospheric blocking events over Alaska. The occurrence of weaker westerly wind over the subarctic region over the NEP during the period of the blocking, accompanies a shallower vertical mixed layer, less southward horizontal Ekman transport, and higher SST in the upper NEP. These findings establish a linkage between high-latitude atmospheric dynamics and subarctic oceanic conditions and reveal the physical mechanisms of this connection, providing new insight into the possible causes of MHW in the NEP.

Comparison of ocean deoxygenation between CMIP models and an observational dataset in the North Pacific from 1958 to 2005

This study investigated the relationship between the observed and simulated dissolved oxygen (O2) inventory changes in the North Pacific by analyzing an observational dataset and the outputs of Coupled Model Intercomparison Project Phase 5 and 6 (CMIP5/6) between 1958 and 2005. A total of 204 ensembles from 20 models were analyzed. Many of the models in the North Pacific subarctic region have higher climatological O2 concentrations than observed at deeper water depths. Therefore, the negative trend of O2 inventories tends to be larger, and in fact, several model ensemble members have a larger negative trend in O2 inventories than observed. The variability among model ensemble members is more influenced by the uncertainty due to internal variability than by the uncertainty resulting from model dependency. An inter-model empirical orthogonal function (EOF) analysis revealed that the different simulated magnitudes of the negative O2 trend is closely associated with the first EOF mode, and ensemble members with strong negative trends are characterized by large oxygen reduction in the subarctic North Pacific, especially around the boundaries between the North Pacific Ocean and the Sea of Okhotsk as well as the Bering Seas. The modeled strong O2 decrease in the subarctic North Pacific is consistent with the spatial pattern of the observed O2 trend. Further analysis of climate models indicated that the O2 decrease in the subarctic region was primarily caused by physical factors. This conclusion is supported by the significantly high correlation is present between the potential temperature and O2 inventory trend in the subarctic region, whereas an insignificant correlation coefficient is present between dissolved organic carbon and the O2 inventory trend. However, the observations have a larger ratio of O2 inventory trend to temperature trend than any of the ensembles, and thus the relationship between O2 and temperature change in the subarctic North Pacific seen in the CMIP5/6 simulations is not exact.

Estimation of morbidity of military personnel under contract in extreme living conditions

We analyzed the incidence of military personnel in the Arctic, subarctic (Arctic zone) and continental climatic zones for 2015–2020. In terms of the prevalence of diseases, the highest registration was determined in the Subarctic, respectively 3493.2 ± 12.7‰, 3692.6 ± 19.2‰ and 2610.1 ± 72.6‰. However, in the conditions of the Arctic, it is difficult to provide general medical or specialized medical care due to the duration of non-flying weather. The incidence of the class «Diseases of the genitourinary system» in the Arctic exceeded that in other climatic zones, 1.3–1.6 times. In the Subarctic, the most highly recorded pathology of the digestive system. For diseases of the respiratory and digestive organs, genitourinary, musculoskeletal, endocrine systems and blood circulation, the excess in the Arctic zone, compared with the continental climate, reached 1.3–2.0 times. Primary morbidity in different climatic zones did not differ. The first four ranking places were left for diseases of the respiratory, genitourinary, musculoskeletal and endocrine systems. In the conditions of the Arctic zone, traumatism was relevant, and in the conditions of the Subarctic and continental climates, diseases of the ear and its mastoid process. The prevalence of diseases in the Arctic zone proves the influence of weather and climate conditions on the health of servicemen. Differences in the prevalence of diseases in the Arctic and Subarctic regions were determined by the class «Diseases of the genitourinary system»: 2nd and 6th ranking places (excess by 1.3 times, p = 0.01). In the continental climate, indicators for diseases of the genitourinary, musculoskeletal and endocrine systems, the circulatory system and the digestive system did not differ. In the Arctic zone, data on diseases of the endocrine system did not differ and were less significant (by 1.3–1.4 times) than in the continental belt, but the injury rate was 1.5–2.1 times higher. The revealed features in the long-term dynamics of the incidence of military personnel allow us to adjust the directions of preventive activities.

Особенности организации изгородного содержания северных оленей в лесной зоне Тюменского Севера

Abstract. The purpose of the research is based on the analysis of historical and modern experience of hedge keeping of reindeer, to determine the possibilities and tasks of creating reindeer farms in the forest zone of the Tyumen North. Methods. During the study historical, expert and comparative analysis, structural analysis, monitoring, analogy, generalization were used. Results. The hedge keeping of reindeer in the Subarctic regions has been used for about a hundred years, but today it requires a new conceptual approach to the design of farms in the forest zone. Almost 700,000 domestic reindeer are grazed in the Tyumen region are the largest population in the Arctic and Subarctic. The pastures of the tundra zone are mainly used for grazing deer – 92% of the herds are located here in the summer. Due to the excess of the project reindeer capacity, pastures in the Yamal-Nenets Autonomous District have been in a state of long-term overgrazing for the last 30 years and require a reduction in pastoral load. One of the ways to optimize the tundra grazing of deer is to transfer some of the animals to free forest pastures. Since 2019 In the Yamalo-Nenets Autonomous District, a production experiment is being conducted on year-round grazing of reindeer herds in a forest area using hedges. A monitoring study of two hedge farms in the forest zone of the Yamalo-Nenets Autonomous District was conducted. The implementation of projects to create hedge farms for reindeer in the forest zone of the Tyumen North will not only relieve tundra pastures, but also solve a number of socio-economic, environmental, technological issues in the territories of traditional nature management in the Yamalo-Nenets Autonomous District and KhMAO-Yugra. The scientific novelty of the work lies in a comprehensive approach to the tasks and goals of designing forest farms for hedging reindeer, which includes not only the technological features of the projects, but also their social significance for the indigenous small population of the North.

Relationship between meteorological factors and the pituitary-thyroid axis in healthy men living in the Subarctic

BACKGROUND: The changing seasons in the subarctic region causes an adaptive restructuring of the inhabitants’ organisms. The most healthy individuals can adjust to the Northern climate without developing health disorders. However, a decrease in adaptive reserves may result in various pathological conditions. Extensive studies across different populations in various climatic zones have reported significant associations between meteorological factors and the fluctuations in thyroid hormones. AIM: To assess the influence of circannual dynamics of meteorological factors on the serum levels of thyroid hormones and thyroxin-binding globulin (TBG) in men living in subarctic environmental conditions. MATERIAL AND METHODS: An prospective analytical study was conducted in the city of Arkhangelsk (64°32´24.4˝ N). Twenty clinically healthy men comprised the sample. Blood samples were collected every 3 months over a 12-months period. Subjects with any factors affecting the hypothalamic-pituitary-thyroid axis were excluded. Circannual variation in the studied characteristics were analyzed using Wilcoxon signed-rank tests with Bonferroni correction. Associations between hormonal data and climatic data were assessed using Spearman’s correlation coefficients. RESULTS: The thyroid-stimulating hormone reached its peak, while T4 and TBG were at their lowest during the period of minimal daylight hours in December. This coincided with the highest values of relative humidity and atmospheric pressure. Furthermore, T4 and TBG positively correlated with the duration of daylight and outdoor temperature at the day of samples collection, while showing an inverse correlation with atmospheric pressure and average monthly relative humidity. Т3 and T4 inversely correlated with average monthly atmospheric pressure. T3 was positively associated with the duration of daylight. CONCLUSION: The key environmental factors affecting the health people living in Northern regions include are the duration of daylight, outdoor temperature, monthly atmospheric pressure, and relative humidity. It is important to note that the impact of these climatic conditions on human health varies across the regions. Thus, our findings cannot be generalized to other areas..

Оценка липидного спектра и C-Реактивного белка крови у работающих в Арктической зоне России

Adaptation to the extreme living conditions of the North causes dyslipidemia, a risk factor for cardiovascular diseases (CVD), in people working there. This study aimed to assess the level of lipids and C-reactive protein (CRP), a marker of inflammation in CVD cases, in the blood of men staying in the Arctic and Subarctic zones of Russia. Accordingly, the sample was divided into two group, Arctic and Subarctic, the former included 51 participants, aged 35.7 ± 0.6 years, the latter — 54 individuals, aged 34.2 ± 0.9 years (p = 0.167); the duration of their work/stay in the Arctic and Subarctic zones was 7.1 ± 0.2 and 6.4 ± 0.6 years (p = 0.447), respectively. We sampled blood of the participants and measured triglycerides, total cholesterol, low (LDL) and high (HDL) density lipoproteins, atherogenic index (AI), CRP content. Arctic group had higher levels of triglycerides (1.71 ± 0.03 and 1.38 ± 0.14 mmol/l, p = 0.021), total cholesterol (6.15 ± 0.08 and 5.47 ± 0.14 mmol/l, p =0.001), HDL (1.5 ± 0.06 and 1.1 ± 0.04 mmol/l, p = 0.001); the values of LDL did not differ significantly between the groups (4.07 ± 0.08 and 4.1 ± 0.15 mmol/l, p = 0.88), and AI and CRP values (3.41 ± 0.18 and 4.18 ± 0.2, p = 0.007; 3.41 ± 0.18 and 4.91 ± 0.22 mg/l, p = 0.006, respectively) were greater in the Subarctic group. By triglycerides, dyslipidemia was diagnosed in 49.0% and 18.4% of Arctic and Subarctic participants, respectively, by total cholesterol — in 98.0% and 57.8%, by LDL — in 94.1% and 88.0%. As for HDL, their level was lower than normal in 2.0% of the Arctic group subjects and 36.7% of the Subarctic group subjects, which means a higher risk of cardiovascular diseases in the Subarctic region. The level of CRP indicated that 90% of the Arctic group participants were at risk of CVD (moderate risk for 23.5%, high risk for 66.7%), and in the Subarctic group this number was 100% (moderate risk for 7.7%, high risk for 88.5%). The likely reasons behind this are the specifics of nutrition and living conditions. Program of prevention of CVD in the Arctic zone should include lipid profile and CRP tests as part of every periodic medical examination, regardless of age. It is necessary to implement dyslipidemia alimentary correction measures.

Description of the Family Argidae (Insecta: Hymenoptera)

Sawflies, horntails, and wood wasps Argidae sawflies Argidae occur in all tropical, temperate, and subarctic regions of the world. Even though worldwide in distribution, the fauna of the Neotropical Region is the most diverse. Representatives of all subfamilies, except the Australian Zenarginae, occur in the neotropics. In the number of genera (32) and numbers of species (over 350), the Neotropical fauna includes more than twice the number of genera and nearly half the species as the rest of the world’s regions. Adults of Argidae some species can be found on various types of flowers, especially the larger species belonging to the Arginae subfamily. In this case, the eggs are laid in groups on the surface of a leaf, and the female takes care of the eggs and young larvae. The larvae feed in groups, presenting defined feeding patterns, and, when they complete their development, weave cocoons in groups protected by a common cover. The purpose of the manuscript is to describe the Biology, Ecology, behavior, damage, and taxonomy of the family Argidae (Insecta, Hymenoptera, Symphita). The articles were published from 1979 to 2023 in indexed scientific research, book scientific chapters, theses banks, university dissertations, national and international scientific articles, scientific journals, documents, and even in general journals when considered of interest and digital platforms: Universidade de São Paulo, Scielo Universidade de Brasilia, WaspWeb, Biological Abstract, and ResearchGate. The main terms used were: Hymenoptera, Symphyta, Woodwasps, Horntails, Sawflies, and Tenthredinoidea. In summary, basically, the following steps of analysis were covered: · Exhaustive reading of each article aiming at a global understanding and discovery of the approach used by its authors; · Identification of the central ideas of each article; · Classification of ideas around nuclei of meaning; · Comparison between the different nuclei of meaning present in the studied articles; · Classification of the nuclei of meaning in broader axes (themes) around which the authors' discussions revolved and Writing of the interpretative syntheses of the theme.

Effects of heatwave events on the seagrass-dwelling crustacean Pandalus latirostris in a subarctic lagoon

Heatwaves often cause mass mortality of organisms in seagrass areas, and they eventually alter some ecological functions of seagrass ecosystems. In subarctic regions, however, the effects of heatwaves on seagrass areas are still unclear. In a subarctic lagoon of northern Japan, we examined the effects of heatwaves on the Hokkai shrimp, Pandalus latirostris, a commercially exploited species distributed in seagrass areas of northern Japan and eastern Russia. A long-term survey of the surface water temperature in the lagoon clarified a gradual increase in the frequency and intensity of heatwave events since 1999. Surveys of the water temperature at a seagrass area in the lagoon during summer have also demonstrated that the maximum water temperature had been exceeding 25 °C, unusually high for this location, regardless of water depth. These results indicate that the effects of heatwaves in seagrass areas in a subarctic region had become as severe as those in tropical and temperate regions. We also experimentally evaluated the effects of this unusually high water temperature (25 °C) on the survival of P. latirostris by changing the length of exposure time. Some individuals suffered damage to their intestinal mucosal structure after exposure for 12 h or longer, and all individuals died after exposure for 120 h. Our results suggest that heatwaves possibly cause mass mortality in P. latirostris in the following sequence: heat stress, damage to the intestinal epithelial mucosal structure, degradation of nutrient absorption and immunological function of the intestine, energy deficiency and disease infection, and finally mortality. This study, conducted in subarctic closed waters, concludes that it is essential to become familiar with not only trends in heatwaves but also the intermittent occurrence of unusually high water temperature in seagrass areas in order to better understand the process of mortality of organisms that inhabit these ecosystems.

Mesopelagic particulate nitrogen dynamics in the subarctic and subtropical regions of the western North Pacific

Recently, new spatiotemporal-scale particle observations by autonomous profiling floats equipped with bio-optical sensors have revealed that, in addition to gravitational particle sinking, the downward transport of surface particles by physical mixing events, which has been overlooked, contributes to particulate organic carbon export. However, the subsequent behavior of these exported particles in the mesopelagic zone (e.g., particle fragmentation and degradation) remains unclear, although it may influence the efficiency of carbon transport to further depths. This study successfully depicted the new annual mean mesopelagic particulate nitrogen (PN) dynamics with multi-layer, steady-state suspended PN pools by reanalyzing seasonal data on the stable nitrogen isotopic compositions of both suspended and sinking particles, each with different profiles, from subarctic station K2 and subtropical station S1 in the North Pacific, which are both CO2 sinks but in different oceanic settings. As analytical conditions, we assumed that the net loss of sinking PN was entirely due to abiotic fragmentation of particle aggregates to non-sinking particles and that the apparent 15N enrichment associated with heterotrophic degradation in the suspended PN pools was vertically constant. The 15N mass balance for the PN supply to the uppermost mesopelagic pool, derived from such constraints, allowed estimating the PN export by the mixed-layer pump, which was 1.6 times greater at K2 than at S1. However, its contribution to the total export (including gravitational PN sinking) from the surface layer was approximately 20% at both stations. Moreover, the ratio of PN supplied to the uppermost pool by the mixed-layer pump and by the fragmentation of particle aggregates was also similar at both stations, approximately 1:1. Using these ratios, together with separate observations of the mixed-layer pump-driven flux, it may be possible to estimate the efficiency of the particulate organic carbon transport due to the biological gravitational pump responsible for carbon sequestration in the deep sea.

Patterns and drivers for benthic algal biomass in sub-Arctic mountain ponds

This study investigated the spatial variation in total benthic algal biomass and within cyanobacteria, green algae, and diatoms in sub-Arctic ponds. Additionally to more widely used explanatory variables, snowmelt and ice duration were considered as their importance on algal communities is poorly understood. The data comprised algal biomasses from 45 sub-Arctic ponds in the Finnish Lapland. A generalized linear model and hierarchical partitioning were used to identify the significantly influential variables. Cyanobacteria were the most abundant algal group. Trace elements (e.g. Fe, Al, and Mn) were the most significant explanatory variable group in explaining algal biomasses. Macronutrients apart from K were found insignificant in all models. There were positive relationships between some algal biomasses indicating no strong competition between them. Snow and ice variables were found insignificant for all models, but they could have an important secondary role on algal communities. The results highlight the importance of trace elements in shaping algal biomasses in sub-Arctic ponds and thus their wider use in research can be advocated to better understand the productivity of nutrient poor and acidic waters in sub-Arctic regions. Focussing on benthic algal biomasses and the chemical composition of sub-Arctic freshwaters provides important information on the aquatic primary production.

Comparison of 210Pb Age Models of Peat Cores Derived from the Arkhangelsk Region

Dating young peatlands using the 210Pb dating procedure is a challenging task. The traditional 210Pb age models assume an exponential decline in radioactivity in line with depth in the peat profile. Lead exhibits considerable migratory capacity in Arctic peatlands; hence, to perform precise peat dating, existing models should be enhanced to remove the effects of migration. Independent isotope chronometers, such as 137Cs, can verify this. The Monte Carlo method and IP-CRS were utilised, together with several CA, CF/CS, PF, and CF models, to analyse the peat core samples acquired in the Arkhangelsk region. Data analysis revealed that the height partitioning of 137Cs and 210Pb is associated with physical characteristics, like the peat ash and the bulk density of the bog. Comparison between the natural activity of 210Pb in the peat and the radioactivity of 137Cs measured at depths of 19–21 cm in relation to the global fallout in 1963 indicated that the CF/CS, CF, and IP-CRS models (1965, 1962 and 1964, respectively) gave the closest age to the reference point given. IP-CRS was found to be the preferred model of these three options, as it gave a rather closer correlation with the 137Cs activity specific to the reference layer, allowing the error. The core dating of 210Pb showed an age of 1963 for a depth of 17–19 cm, which was in agreement with the reference horizon 137Cs and ash content, thus validating the accuracy and sufficiency of the selected model turf profile chronology. The maximum content of man-made radioisotopes in the peatlands corresponded to the formulation of the Partial Test Ban Treaty of 1963. The rates of accumulation of peat and atmospheric flux of 210Pb are in good agreement with the values available for the bogs of Northern Europe and those previously estimated by the authors in the subarctic region of European Russia. Although the problems of the complex migration-related distribution of 210Pb in the peat layer were considered, the dating methods used were effective in our study and can be adapted in following studies to perform the age determination of different peat deposits.

Exploring novel alkane-degradation pathways in uncultured bacteria from the North Atlantic Ocean.

Microbes play a significant role in the degradation of petroleum hydrocarbons in the oceans, yet little is known about the native bacteria that metabolize hydrocarbons before an oil spill. The Faroe-Shetland Channel (FSC) is a deepwater subarctic region of the North Atlantic with prominent oil production and a diverse microbial community associated with the degradation of petroleum. Here, we combine DNA-based stable-isotope probing (DNA-SIP) with metagenomics to elucidate the metabolic underpinnings of native alkane-degrading bacteria from the FSC. From two 13C n-hexadecane SIP experiments using seawater from 5 and 700 m depths in the FSC, we obtained 42 metagenome-assembled genomes (MAGs) belonging to 19 genera, including two previously overlooked hydrocarbon-degrading bacteria, Lentibacter (Alphaproteobacteria) and Dokdonia (Bacteroidetes). Diversity surveys indicated Lentibacter were dominant members of the FSC, constituting up to 17% of these communities. Many of the SIP-enriched MAGs (20/42) encoded a complete alkane oxidation pathway, including alkane monooxygenase (AlkB), rubredoxin reductase (AlkT), and rubredoxin-2 (AlkG). Fourteen Aphaproteobacteria MAGs lacked AlkG for electron transfer. Instead, they encoded novel disulfide isomerases with iron-binding cysteine motifs conserved across rubredoxins. Dokdonia lacked AlkT and AlkG, however, their central alkane-degradation catabolic pathways were complete. We describe previously unrecognized bacteria capable of hydrocarbon degradation, including the dominant genera Lentibacter, which may continuously purge hydrocarbons released from oil exploration activities in the FSC. This advances the understanding of the diversity and physiologies of alkane degradation in the North Atlantic and provides evidence of new mechanisms used to metabolize alkanes. IMPORTANCE Petroleum pollution in the ocean has increased because of rapid population growth and modernization, requiring urgent remediation. Our understanding of the metabolic response of native microbial communities to oil spills is not well understood. Here, we explored the baseline hydrocarbon-degrading communities of a subarctic Atlantic region to uncover the metabolic potential of the bacteria that inhabit the surface and subsurface water. We conducted enrichments with a 13C-labeled hydrocarbon to capture the fraction of the community actively using the hydrocarbon. We then combined this approach with metagenomics to identify the metabolic potential of this hydrocarbon-degrading community. This revealed previously undescribed uncultured bacteria with unique metabolic mechanisms involved in aerobic hydrocarbon degradation, indicating that temperature may be pivotal in structuring hydrocarbon-degrading baseline communities. Our findings highlight gaps in our understanding of the metabolic complexity of hydrocarbon degradation by native marine microbial communities.

Exploring light and colour patterns for remote biophilic northern architecture

This research explores the effects of light in terms of colour, surface colour configuration and finishes using simple and advanced methods in the development of biophilic lighting ambiances for remote northern architecture. Biophilic light and colour design can benefit inhabitants of subarctic regions, where drastic changes in the natural photoperiod can impact the mind and body. To predict the outcomes of light and colour, this research used reduced-scale models that replicate a north-oriented room and a specially designed mirror-box sky simulator, which emulates the lighting conditions and correlated colour temperature (CCT) of a northern sky. Physical models with distinct surface colour properties and the use of high dynamic range imagery (HDRi) techniques allow the recognition of quantitative effects and lighting attributes of main hue families such as red, green, blue and yellow. The results reveal that the colour and the surface colour configuration significantly modify the spectral properties of a lit ambiance measured in Equivalent Melanopic Lux (EML) and CCT. Surface colour configuration and finishes produce variations in the luminous attributes measured in intensity contrast. This combination of simple and innovative tools could predict light and colour effects in early design stages for responsive architecture in subarctic territories.

Фолатный статус у студентов из Индии, обучающихся в г. Архангельске

The harsh climatic conditions of the subarctic regions of Russia, followed by lifestyle and nutritional changes, put a strain on the adaptive self-regulation mechanisms of newcomers. Acclimatization of foreign students coming to these regions, along with a high mental load and significant lifestyle modifications as well as alimentary and behavioural habits, can lead to homeostatic failure, in particular, folate metabolism disorder. It is known that both genetic (alleles determining the characteristics of folate and homocysteine metabolism) and phenotypic (nutritional and behavioural) factors play an important role in regulating folate metabolism. The purpose of this study was to analyse the folate status of ethnic Indians living in a subarctic region of Russia. Materials and methods. A prospective cross-sectional population-based study was conducted on a sample of ethnic Indians (n = 117) studying at Northern State Medical University in the city of Arkhangelsk. An analysis was performed of the relationship between folate levels and the duration of living in the subarctic region of Russia, body mass index, tobacco smoking, alcohol intake and nutritional status. The results of the study showed that folate levels in Indian students living in Arkhangelsk decreased significantly (from 10.0 [9.325; 13.65] ng/ml in the first year to 4.00 [4.00; 6.00] ng/ml in the sixth year of study; р < 0.001). This can be associated with changes in their diet (less vegetables), smoking and alcohol consumption, which are risk factors for impaired homocysteine metabolism and, as a consequence, for adverse vascular events. The significant folate deficiency in Indian students during their residence in subarctic conditions requires taking a number of measures aimed to prevent maladjustment disorders of folate metabolism in foreign students, which include quality of life, health and nutritional status controls as well as maintaining a healthy lifestyle, including giving up bad habits.

Consistent imprints of elevation, soil temperature and moisture on plant and arthropod communities across two subarctic landscapes

Abstract Factors shaping arthropod and plant community structure at fine spatial scales are poorly understood. This includes microclimate, which likely plays a large role in shaping local community patterns, especially in heterogeneous landscapes characterised by high microclimatic variability in space and in time. We explored differences in local microclimatic conditions and regional species pools in two subarctic regions: Kilpisjärvi in north‐west Finland and Varanger in north‐east Norway. We then investigated the relationship between fine‐scale climatic variation and local community characteristics (species richness and abundance) among plants and arthropods, differentiating the latter into two groups: flying and ground‐dwelling arthropods collected by Malaise and pitfall traps, respectively. Arthropod taxa were identified through DNA metabarcoding. Finally, we examined if plant richness can be used to predict patterns in arthropod communities. Variation in soil temperature, moisture and snow depth proved similar between regions, despite differences in absolute elevation. For each group of organisms, we found that about half of the species were shared between Kilpisjärvi and Varanger, with a quarter unique to each region. Plants and arthropods responded largely to the same drivers. The richness and abundance of both groups decreased as elevation increased and were positively correlated with higher soil moisture and temperature values. Plant species richness was a poor predictor of local arthropod richness, in particular for ground‐dwelling arthropods. Our results reveal how microclimatic variation within each region carves pronounced, yet consistent patterns in local community richness and abundance out of a joint species pool.

History of vegetation and fires in the Arctic part of the Pur-Taz interfluve in the Holocene

The global climate change and significantly increased anthropogenic pressure on the Arctic and Subarctic regions require modern ecosystem monitoring and understanding of the past environmental changes. Vegetation history is reflected by pollen spectra recorded in peat deposits, investigation of which is one of the main methods in the research of long-term climatic changes. In order to reconstruct the vegetation and fire history of today’s south tundra in the lower reaches of the Taz river, we carried out palynological exploration of peat and underlying lake sediments covering the last 11.2 cal ka BP in the Tazovsky district of the Yamalo-Nenets Autonomous Okrug (Russia). In the course of the research, we found 31 pollen taxa, 4 taxa of spore plants, 2 types of fungal spores, one species of shell amoeba and green algae. We have identified several stages in the development of the local wetland biocenosis at the study site and reconstructed the history of changes in the vegetation cover of the region, including changes in the composition of the woody vegetation. Grasslands, with groups of trees among thickets of shrubs and lake-mire complexes dominated in the study area by 11.2 cal ka BP. The grasslands were gradually supplemented by wet grass communities, which were then replaced by swamps and tundra complexes in the mid-Holocene. The time periods of the local fires have been established. The fire that had the greatest effect on the vegetation at the study site was detected in the period of 8.1 cal ka BP. We have revealed periods of the least fire activity – 7.6–5.5 cal ka BP and the highest fire activity – 12.5–8 cal ka BP.

Groundwater discharge contribution to dissolved inorganic carbon and riverine carbon emissions in a subarctic region

Groundwater discharge contribution to dissolved inorganic carbon and riverine carbon emissions in a subarctic region

Surface energy balance on a polythermal glacier, Arctic, and the role of poleward atmospheric moisture transport

In recent years, increasing moisture over the Arctic and subarctic regions shows that the Arctic is experiencing wetting conditions, and poleward atmospheric moisture transport (PAMT) plays a vital role in the atmosphere-ice/snow interactions in the Arctic. To identify the effect of PAMT on the surface energy balance (SEB) for the Arctic glacier, meteorological data from an automatic weather station (AWS) at 377 m a.s.l. on the Austre Lovénbreen glacier, as well as the ERA5 reanalysis data from 30 April 2014 to 30 April 2015, were analyzed in this paper. Our results show that the net shortwave radiation (Snet) (18 W m−2, 55%), turbulent sensible (H) (14 W m−2, 43%) and subsurface heat flux (G) (1 W m−2, 2%) act as the energy sources, while the net longwave radiation (Lnet) (−19 W m−2, 56%), melt energy (Qm) (−12 W m−2, 35%) and turbulent latent heat flux (LE) (−3 W m−2, 9%) represent the heat sink. The development process of Atmospheric River (AR), primary form of PAMT, near the Svalbard in February 2015 was revealed according to the total column water vapor, 850 hPa winds and geopotential height fields. Compared to summer, the glacier SEB was more affected in winter by PAMT, leading to a frequent overcast and thus increasing air temperature, moisture, and wind speed, all of which are variables governing the SEB by decreasing H, LE and G less than increasing the Lnet. Our findings obtained here can help to better understand the diverse SEB change on the high Arctic glacier from the perspective of PAMT and large-scale atmospheric circulations anomalies.

Trees on the tundra: warmer climate might not favor prostrate Larix tree but Betula nana shrub growth in Siberian tundra (Lena River Delta)

Tundra is primarily a habitat for shrub growth, not trees, but growth of prostrate forms of trees has been reported occasionally from the subarctic tundra region. In the light of on-going climate change, climate sensitivity studies of these unique trees are essential to predict vegetation dynamics and potential northward expansion of boreal forest tree species into tundra. Here we studied one of the northernmost Larix Mill. trees and Betula nana L. shrubs (72°N) from the Siberian tundra for the common period 1980-2017. We took advantage of the discovery of a single cohort of prostrate Larix trees within a tundra ecosystem, i.e., ca. 60 km northwards from the northern treeline, and compared climate-growth relationships of the two species. Both woody plants were sensitive to the July temperature, however this relationship was stable across the entire study period (1980-2017) only for Betula nana chronology. Additionally, radial growth of Larix trees became negatively correlated to temperatures during the previous summer. In recent period moisture sensitivity between Larix trees and Betula nana shrubs was contrasting, with generally wetter soil conditions favoring Larix trees growth and dryer conditions promoting Betula nana growth. Our study indicates that Larix trees radial growth in recent years is more sensitive to moisture than to summer air temperatures, whereas temperature sensitivity of Betula nana shrub is stable over time. We provide first detailed insight into the annual resolution on Larix tree growth sensitivity to climate in the heart of the tundra. The potentially higher Betula nana shrub resistance to warmer and drier climate versus Larix trees on a tundra revealed in our study needs to be further examined across habitats of various soil, moisture and permafrost status.

A first look at megabenthic community responses to seasonal change using the new Holyrood Subsea Observatory in Conception Bay, NL

Sub-Arctic seafloor communities rely on seasonal phytoplankton blooms for food, revealing a tight benthic-pelagic coupling. To maximize resource availability for offspring, organisms such as snow crabs, sea stars, and sea cucumbers synchronize their reproductive and feeding behaviours with spring blooms. Due to climate change, spring blooms are occurring earlier in sub-Arctic regions, leading to a possible mismatch between timing of resource availability and important life-history behaviours. Here, we utilize high-frequency time-series observations from the Holyrood Subsea Observatory, a new cabled seafloor observatory deployed in Conception Bay, Newfoundland. We use hourly data collected from environmental sensors (Conductivity-Temperature-Depth, Acoustic Doppler Current Profiler, fluorometer), a near-surface mooring (fluorometer), and a video camera to identify and quantify abundance and diversity of benthic megafauna, and to determine how community composition changed from pre-bloom to full bloom conditions. Data analysis revealed striking temporal changes in benthic activity, with the notable emergence of Psolus cf. phantapus sea cucumbers (up to 289.9 indiv./m2) coinciding with increased chlorophyll-a concentration and seawater temperature. At least three dense schools of forage fish, two Atlantic herring (79 and 144 indiv. frame−1) and one capelin (91 indiv. frame−1), were observed during the main bloom between May 5 and June 16. This study provides the first high-frequency in situ observations of benthic community response to seasonal food input in the region. The high temporal resolution made it possible to record the precise timing of the of Psolus cf. phantapus emergence in relation to the timing of food input to the seafloor, which will provide a baseline to monitor phenology as climate change progresses. Changes to the timing of spring blooms have implications for sub-Arctic fisheries productivity and ecosystem functioning, making continuous long-term monitoring of seafloor communities essential.