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Based on the results of an analysis of 174 samples of bottom sediments collected at 48 stations in the Chaun Bay during the cruise 60 of the R/V Akademik Oparin (October 2020), it was found that their grain size distribution varies from poorly sorted silty clay to well sorted sand. The results of the study led to conclusion that the main sedimentation mechanisms in Chaun Bay are thermal abrasion, river runoff, and abrasion, as well as ice rafting and aeolian transport. The zoning of grain size types of bottom sediments is related to the bottom topography and consistent with areas affected by riverine runoff, abrasion, and thermal coastal abrasion, as well as with the direction of currents. The high occurrence of coarse clastic matter in sediments is evidence of abrasion of the coastal zone and active ice rafting of large (up to 15 cm) rock fragments. The vertical variability of the grain size parameters of the studied bottom sediments within the upper 20 cm layer reflects gradual Late Holocene intensification of terrigenous (fluvial and thermal abrasion) fluxes with the current effects of climate change in the Arctic. [ABSTRACT FROM AUTHOR]

Plastic pollution threatens many organisms around the world. In particular, the northern fulmar, Fulmarus glacialis , is known to ingest high quantities of plastics. Since data are sparse in the Eurasian Arctic, we investigated plastic burdens in the stomachs of fulmar fledglings from Kongsfjorden, Svalbard. Fifteen birds were collected and only particles larger than 1 mm were extracted, characterised and analysed with Fourier Transform InfraRed spectroscopy. All birds ingested plastic. In total, 683 plastic particles were found, with an average of 46 ± 40 SD items per bird. The most common shape, colour and polymer were hard fragment, white, and polyethylene, respectively. Microplastics (< 5 mm) were slightly more represented than mesoplastics (> 5 mm). This study confirms high numbers of ingested plastics in fulmar fledglings from Svalbard and suggests that fulmar fledglings may be suitable for temporal monitoring of plastic pollution, avoiding potential biases caused by age composition or breeding state. • In total, 683 plastic pieces were found, with an average of 46 items per bird. • Every fulmar fledgling (n = 15) had plastic in its stomach. • 80 % of the fulmars exceeded the EcoQO of 0.1 g. • This study confirms high numbers of plastic in fulmar fledglings in Svalbard. • Fulmar fledglings could be used for temporal monitoring in the Arctic [ABSTRACT FROM AUTHOR]

The world is dealing with the mismanaged plastic waste found even in the Arctic. The crisis is being tried to solve with the plastivor bugs or bio-plastics, and the marine pollution profiles become priority however, putative phytotoxicity on terrestrial farming have not received significant attention. Hence, morpho-physiological and molecular response in maize seedlings exposed to the most prevalent microplastic (MP) types (PP, PET, PVC, PS, PE) differing in their particle size (75–150 μm and 150–212 μm) and combinations (PP + PET + PVC + PS + PE mix) was analyzed here for a predictive holistic model. While POD1 regulating the oxidative defense showed a slight down-regulation, HSP1 abundance quantified in the 75–150 μm MP lead a significant up-regulation particularly for PET (2.2 fold) PVC (3.3 fold), and the MP mix (6.4 fold). Biochemical imbalance detected at lower sized (75–150 μm) MPs in particular at the MP mix, involved the cell membrane instability, lesser photosynthetic pigments and a conjectural restraint in the photosynthetic capacity along with the accumulated endogenous H 2 O 2 proved that the bigger the particle size the better the cells restore the damage under MP-caused xenobiotic stress. The determination of the impacts of MP pollution in in-vitro agricultural models might guide the development of policies in this direction and help ensure agricultural security by predicting the possible pollution damage. [Display omitted] • The physical nature and size of the MPs is of vast significance in plant stress response network. • Smaller MPs particle size leads to potential redox deregulation. • Larger MPs might help economizing the water budget. • The mix, PET and PS left the most hazardous signatures. • POD1 and HSP1 are hub elements in transduction of MPs caused ROS into gene transcript expression. The MP mix, PET, and PS left the most hazardous signatures on seedlings via ROS triggered by mechanical and/or xenobiotic damage. [ABSTRACT FROM AUTHOR]

An aerosol electrical mobility spectrum analyzer (AEMSA), developed at Hanyang University, was employed to investigate the particle charge characteristics in the Antarctic and Arctic regions. The particle charge characteristics in these areas were compared with the charging state in Ansan, South Korea, located in the midlatitude, where artificial factors, such as human activity, urbanization, and traffic, might result in a higher total concentration. Furthermore, in Ansan, South Korea, the charged-particle polarity ratio was very stable and was close to 1. However, notably different particle charge characteristics were obtained in the Antarctic and Arctic regions. The imbalance between the numbers of positively and negatively charged particles was evident, resulting in more positive charges on the atmospheric particles. On average, the positively charged particle concentrations in the Antarctic and Arctic areas were 1.4 and 2.8 times higher, respectively, compared with the negatively charged particles. The developed AEMSA system and the findings of this study provide useful information on the characteristics of atmospheric aerosols in the Antarctic and Arctic regions and can be further utilized to study particle formation mechanisms., (Copyright © 2021. Published by Elsevier B.V.)

The organic carbon produced in the ocean's surface by phytoplankton is either passed through the food web or exported to the ocean interior as marine snow. The rate and efficiency of such vertical export strongly depend on the size, structure and shape of individual particles, but apart from size, other morphological properties are still not quantitatively monitored. With the growing number of in situ imaging technologies, there is now a great possibility to analyze the morphology of individual marine snow. Thus, automated methods for their classification are urgently needed. Consequently, here we present a simple, objective categorization method of marine snow into a few ecologically meaningful functional morphotypes using field data from successive phases of the Arctic phytoplankton bloom. The proposed approach is a promising tool for future studies aiming to integrate the diversity, composition and morphology of marine snow into our understanding of the biological carbon pump.

The Arctic is rapidly transforming due to sea ice loss, increasing shipping activity, and oil and gas development. Associated marine and combustion emissions influence atmospheric aerosol composition, impacting complex aerosol-cloud-climate feedbacks. To improve understanding of the sources and processes determining Arctic aerosol composition, atmospheric particles were collected aboard the Korean icebreaker R/V Araon cruising within the Bering Strait and Chukchi Sea during August 2016. Offline analyses of individual particles by microspectroscopic techniques, including scanning electron microscopy with energy dispersive X-ray spectroscopy and atomic force microscopy with infrared spectroscopy, provided information on particle size, morphology, and chemical composition. The most commonly observed particle types were sea spray aerosol (SSA), comprising ∼60-90%, by number, of supermicron particles, and organic aerosol (OA), comprising ∼50-90%, by number, of submicron particles. Sulfate and nitrate were internally mixed within both SSA and OA particles, consistent with particle multiphase reactions during atmospheric transport. Within the Bering Strait, SSA and OA particles were more aged, with greater number fractions of particles containing sulfate and/or nitrate, compared to particles collected over the Chukchi Sea. This is indicative of greater pollution influence within the Bering Strait from coastal and inland sources, while the Chukchi Sea is primarily influenced by marine sources.

Atmospheric aerosols over polar regions have attracted considerable attention for their pivotal effects on climate change. In this study, temporospatial variations in single-particle-based depolarization ratios (δ: s -polarized component divided by the total backward scattering intensity) were studied over the Northwest Pacific and the Arctic Ocean using an optical particle counter with a depolarization module. The δ value of aerosols was 0.06 ± 0.01 for the entire observation period, 61 ± 10% lower than the observations for coastal Japan (0.12 ± 0.02) ( Pan et al. Atmos. Chem. Phys. 2016 , 16 , 9863 - 9873 ) and inland China (0.19 ± 0.02) ( Tian et al. Atmos. Chem. Phys. 2018 , 18 , 18203 - 18217 ) in summer. The volume concentration showed two dominant size modes at 0.9 and 2 μm. The supermicrometer particles were mostly related to sea-salt aerosols with a δ value of 0.09 over marine polar areas, ∼22% larger than in the low-latitude region because of differences in chemical composition and dry air conditions. The δ values for fine particles (<1 μm) were 0.05 ± 0.1, 50% lower than inland anthropogenic pollutants, mainly because of the complex mixtures of submicrometer sea salts. High particle concentrations in the Arctic Ocean could mostly be attributed to the strong marine emission of sea salt associated with deep oceanic cyclones, whereas long-range transport pollutants from the continent were among the primary causes of high particle concentrations in the Northwest Pacific region.

In this article, an analytical methodology to investigate the proteinaceous content in atmospheric size-resolved aerosols collected at the Zeppelin observatory (79 °N, 12 °E) at Ny Ålesund, Svalbard, from September to December 2015, is proposed. Quantitative determination was performed after acidic hydrolysis using ultrahigh-performance liquid chromatography in reversed-phase mode coupled to electrospray ionization tandem mass spectrometry. Chromatographic separation, as well as specificity in the identification, was achieved by derivatization of the amino acids with N-butyl nicotinic acid N-hydroxysuccinimide ester prior to the analysis. The chromatographic run was performed within 11 min and instrumental levels of detection (LODs) were between 0.2 and 8.1 pg injected on the column, except for arginine which exhibited an LOD of 37 pg. Corresponding method LODs were between 0.01 and 1.9 fmol/m 3 , based on the average air sampling volume of 57 m 3 . The sum of free amino acids and hydrolyzed polyamino acids was shown to vary within 6-2914 and 0.02-1417 pmol/m 3 for particles in sizes < 2 and 2-10 μm in equivalent aerodynamic diameter, respectively. Leucine, alanine, and valine were the most abundant among the amino acids in both aerosol size fractions. In an attempt to elucidate source areas of the collected aerosols, 5- to 10-day 3D backward trajectories reaching the sampling station were calculated. Overall, the method described here provides a first time estimate of the proteinaceous content, that is, the sum of free and polyamino acids, in size-resolved aerosols collected in the Arctic. Graphical Abstract ᅟ.

Knowledge of the past variability of climate at high northern latitudes during astronomical analogues of the present interglacial may help to inform our understanding of future climate change. Unfortunately, long-term continuous records of ice-sheet variability in the Northern Hemisphere only are scarce because records of benthic (18)O content represent an integrated signal of changes in ice volume in both polar regions. However, variations in Northern Hemisphere ice sheets influence the Siberian High (an atmospheric pressure system), so variations in the East Asian winter monsoon (EAWM)--as recorded in the aeolian dust deposits on the Chinese Loess Plateau--can serve as a useful proxy of Arctic climate variability before the ice-core record begins. Here we present an EAWM proxy record using grain-size variations in two parallel loess sections representative of sequences across the whole of the Chinese Loess Plateau over the past 900,000 years. The results show that during periods of low eccentricity and precessional variability at approximately 400,000-year intervals, the grain-size-inferred intensity of the EAWM remains weak for up to 20,000 years after the end of the interglacial episode of high summer monsoon activity and strong pedogenesis. In contrast, there is a rapid increase in the EAWM after the end of most other interglacials. We conclude that, for both the 400,000-year interglacials, the weak EAWM winds maintain a mild, non-glacial climate at high northern latitudes for much longer than expected from the conventional loess and marine oxygen isotope records. During these times, the less-severe summer insolation minima at 65° N (ref. 4) would have suppressed ice and snow accumulation, leading to a weak Siberian High and, consequently, weak EAWM winds.

Single-particle characterization of summertime Arctic aerosols is useful to understand the impact of air pollutants on the polar atmosphere. In the present study, a quantitative single particle analytical technique, low-Z particle electron probe X-ray microanalysis, was used to characterize 8100 individual particles overall in 16 sets of aerosol samples collected at Ny-Alesund, Svalbard, Norway on 25-31 July, 2007. Based on their X-ray spectral and secondary electron image data of individual particles, 13 particle types were identified, in which particles of marine origin were the most abundant, followed by carbonaceous and mineral dust particles. A number of aged (reacted) sea salt (and mixture) particles produced by the atmospheric reaction of genuine sea-salts, especially with NO(x) or HNO(3), were significantly encountered in almost all the aerosol samples. They greatly outnumbered genuine sea salt particles, implying that the summertime Arctic atmosphere, generally regarded as a clean background environment, is disturbed by anthropogenic air pollutants. The main sources of airborne NO(x) (or HNO(3)) are probably ship emissions around the Arctic Ocean, industry emission from northern Europe and northwestern Siberia, and renoxification of NO(3)(-) within or on the melting snow/ice surface.

Ruminants depend on efficient physical degradation of forage through chewing to increase the surface area of the food particles presented to the microflora. Fossil evidence suggests that increased molar height is an adaptation for wear tolerance in dry ecosystems with sparse vegetation, but no study has shown selection pressure for hypsodonty in contemporary ruminants. We explored the relationships between particle size in rumen, tooth wear (scanned molar occlusal topography), age and body mass of female Svalbard reindeer living in an arctic desert at 78 degrees latitude on Svalbard. We predicted that (H1) if the rumen particle size is determined mainly by constraints due to tooth wear, and if tooth wear is mainly a function of age, average particle size in rumen should increase with age. From allometric relations it is known that larger individuals can survive on a lower-quality diet, we therefore predicted (H2) larger particle sizes with increases in (ln) body mass, irrespective of age and wear. Lastly, if there is a trade-off between growth and tooth wear in dry ecosystems (a selection pressure for hypsodonty), we predicted (H3) that teeth of heavier animals should be more worn than those of lighter animals of the same age. The proportion of small particles (<1.0 mm) decreased rapidly with increasing age (consistent with H1). Heavier females within an age class had more worn teeth (consistent with H3) than lighter ones. A close-to-isometric relationship between particle size and body mass suggested that heavier animals partly compensated for reduced tooth efficiency by chewing more. We provide the first evidence of a trade-off between fast early growth and wear (a somatic cost) of a senescence-related trait--the structure and height of the molar--in a wild ruminant inhabiting an arctic desert where selection pressure for increased tooth height is expected. This suggests that foraging conditions are more extreme than the environment in which the species originally evolved.

Soil PCB contamination has been delineated at 18 of 21 Distant Early Warning Line (DEW-line) stations being cleaned up by the Canadian Department of National Defence (DND). As a result, detailed surface soil delineation data has been reported for contamination exceeding 1 microg/g (dw total Aroclor), which is the remedial criteria for PCB contaminated soil under the DEW-line cleanup project. The results of this delineation work has allowed us to estimate the mass of PCB contained in surface soil at these sites and to quantify the DEW-line as a source of PCBs to both local and Arctic wide contamination. Our analysis of DEW-line cleanup delineation reports suggests that pre-cleanup surface soils (top 10 cm) with over 1 microg/g PCB constituted a source of PCBs that ranged from 0.8 to 43 kg with a mean of 18 kg. The total mass of PCB at all 18 sites was 119 kg. Previous studies have described a "halo-effect" that surrounds DEW-line sites, whereby PCB signatures in soil and plants up to 10 km from source areas were attributed to the local source. At Cambridge Bay (CAM-M), Nunavut, our inventory of PCB sources and redistribution suggests that up to 3.4 kg of PCB were exported from the site to the surrounding tundra prior to cleanup. The primary mechanism of transportation appears to be wind borne particulate. Potential vapour phase emissions of PCB from contaminated soil at DEW-line sites appears to have been negligible.

Mean silver concentrations in weekly particle samples collected at Kevo, northern Finland, were determined for the period of October 1964-March 1978 by neutron activation analysis. Two distinct periods were observed in the silver concentration levels over this time frame. During 1964-1970, mean weekly silver concentration levels were found in the range of 0.01-190 ng/m3 with an arithmetic mean of 2.19 ng/m3. A few very high silver concentration levels (>10 ng/m3) were observed in this period, some of which simultaneously occurred with some of the highest bromine and iodine concentration levels. During 1971-1978, silver concentration levels were in the range of 0.02-0.89 ng/m3 with a mean value of 0.09 ng/m3. The observed concentration levels in the later period matched well the data from the early 1990s reported at Sevettijärvi, northern Finland, about 60 km east of Kevo. Data analysis, historical records for this region, and residence time analysis (RTA) using wind back-trajectories show that occasional smelting of silver-rich Norilsk ores at the Nikel smelter, Kola Peninsula, was probably a significant contributor to elevated mean silver concentration levels during 1964-1970. RTA alone was not able to unambiguously identify the most probable source region for highest silver impacts at Kevo due to the weekly integrated nature of the samples collected. Critical examination of wind back-trajectories (24 per day) for specific high silver, bromine, and iodine concentration weeks was carried out to supplement the ensemble RTA analysis (2 back-trajectories per day). The supplemental back-trajectory analysis revealed that deposition of the smelter component silver as well as the sea components (bromine and iodine) could occur together at Kevo during these weekly sampling periods. The study implies that data from weekly integrated samples are insufficiently time-resolved for RTA methods alone to unambiguously resolve the sources contributing to ambient atmospheric concentrations at Kevo, Finland.

New data on the levels and long-range transport of plutonium in the Arctic Ocean, recorded in the course of two expeditions to this zone in 1994 and 1996, are discussed in this paper. Specifically, approximately 100 plutonium measurements in surface and sub-surface water sampled at 58 separate stations throughout the Kara, Laptev and East Siberian Seas, as well as along latitudinal transects across the Lomonosov Ridge, are reported and interpreted in terms of the circulation pathways responsible for the transport of this element from the North Atlantic to the Arctic Shelf and into the Arctic interior. In addition, the behaviour of plutonium in its transit through the vast Arctic shelf seas to open waters under extreme environmental conditions is discussed in terms of the partitioning of plutonium between filtered (<0.45 microm) seawater and suspended particulate, and its association with colloidal matter. Finally, limited evidence of the presence of a colloidal plutonium component in Arctic waters subject to direct riverine input is adduced.

The sources of inorganic pollutants to the Arctic areas are reviewed using previously published results. The removal of particle-reactive pollutants is discussed using thorium scavenging as an analog. The scavenging of 234Th from the upper water column (approximately 100 m) and sediment inventory of 230Th from the deep Arctic waters is compared to different ocean basins in the subarctic areas. Such a comparison shows that 234Th is in equilibrium with its parent, 238U, in certain regions of the Canada Basin of the Arctic Ocean, while it is deficient in other regions of the arctic as well as in sub-polar ocean basins. This implies that the particle-reactive pollutants in the deep Arctic of the Canada Basin are less likely to be removed from the deep waters and will eventually be transported out of this area. We have utilized the 230Th inventory in sediments from the Arctic area to determine the removal rates of particle-reactive nuclides. The 230Th inventory in the deep Arctic Ocean of the Canada Basin is much lower than the Norwegian Sea and the Fram Strait of the Arctic as well as all other sub-polar world oceans. These observations suggest that any pollutants into the deep Arctic areas of the Canada Basin are less likely to be removed locally and may be transported out of this area. In those areas, the colloidal material could potentially play a major role in the removal of particle-reactive contaminants.