Notes on the fishes of the Severnaya Zemlya archipelago and the spawning area of polar cod Boreogadus saida (Gadidae)

Data on the fishes of the high-latitude Severnaya Zemlya archipelago (the North Land) is presented. The archipelago is located in the Arctic on the border between the Kara Sea and the Laptev Sea. The ichthyofauna of the archipelago has not been studied; therefore, even small collections are of interest. Fish samples were obtained during the expedition “Open Ocean: Arctic Archipelagos – 2019: Severnaya Zemlya”. In addition, the samples from this area in the collections of the Zoological Institute (ZIN) were studied, which have been received from polar expeditions to the Kara and Laptev seas during the entire era of polar research. The most significant fact is the discovery of mass accumulation of polar cod Boreogadus saida (Lepechin, 1774) larvae in Mikoyan Bay (Bolshevik Island), which gives evidence of important spawning grounds near Severnaya Zemlya. Indirect evidence of this can be found in the publications of polar explorers who overwintered on Severnaya Zemlya in the 1930s–1950s and have reported that the polar cod approaches the shores for spawning in August, in huge schools. The waters of Severnaya Zemlya represent the spawning area of polar cod in the central part of the Eurasian shelf, which is not mentioned in current literature. In addition to polar cod, a few more species are registered in samples from the coastal waters of the archipelago (depths to 38 m), rough hookear sculpin Artediellus scaber Knipowitsch, 1907, twohorn sculpin Icelus bicornis (Reinhardt, 1840) (family Cottidae), Liparis tunicatus Reinhardt, 1836, black-bellied snailfish L. cf. fabricii (Liparidae), Knipowich eelpout Gymnelus knipowitschi Chernova, 1999 (Zoarcidae) and three-spined stickleback Gasterosteus aculeatus (Linnaeus, 1758) (Gasterosteidae). In the deepwater straits, snailfish Careproctus sp. (174–234 m) and pale eelpout Lycodes pallidus Collett, 1879 (105–348 m) were found. The Arctic charr Salvelinus alpinus (Linnaeus, 1758) (Salmonidae) inhabits some lakes of the archipelago. This is the first finding of a three-spined stickleback in the east of the Kara Sea.

Morphological description and DNA barcoding of some Diamesinae (Diptera, Chironomidae) from the Severnaya Zemlya Archipelago and the Vaigach Island (Russian Arctic)

Chironomids of the Diamesinae subfamily from the Russian Arctic were studied using both morphological characters and molecular data. Adult males of Diamesa urvantsevi sp. nov., D. amplexivirilia Hansen, Arctodiamesa appendiculata (Lundström) from Severnaya Zemlya Archipelago and D. arctica (Boheman), Pseudokiefferiella sp. from Vaigach Island were described, redescribed, annotated and figured. A reference 658 bp barcode sequence from a fragment of the mitochondrial gene cytochrome oxidase I (COI) was used as a tool for species delimitation. For D. arctica (Boheman) and Pseudokiefferiella sp. close DNA barcodes from Norway were performed, which allowed to relate these specimens to the described species. Comparisons with corresponding regions of COI between each described species and close related congeneric species produced K2P genetic distances of 0.11–0.16, values well associated with interspecific variation. Phylogenetic relationships for genera Arctodiamesa Makarchenko and Pseudokiefferiella Zavřel were reconstructed for the first time.

Energy exchange between surface and atmosphere on the Severnaya Zemlya archipelago in 2013 – 2019 years

<p>Based on the data of meteorological observations, executed in 2013-2019 at Research Station “Ice base Cape Baranova” (RS) and original algorithm, taken into account accuracy of measurements and footprints, the components of surface heat budget are calculated. It is shown that in winter due to radiation cooling turbulent sensible heat flux (H) directs to underlying surface. In summer H due to radiation heating of surface with low albedo directs to atmosphere and reaches 25% of the incoming short-wave radiation. The turbulent latent heat flux (LE) in winter directs to atmosphere. Its value is not more than 10% of H. During summer LE has no predominant direction. </p><p>Comprehensive monitoring carried out at RS since 2013 allowed to examine the role of large-scale processes in the polar atmosphere and hydrosphere on the formation of local climate in the region. In 2016, 2018 and 2019 sea ice cover of the Barents and Kara Seas in October, the month of active freezing of active soil layer, occupied the minimal area starting 1978 year (http://wdc.aari.ru/datasets/d0042/). This circumstance along with peculiarities of circulation processes in the atmosphere had led to anomalous of temperature and humidity regimes of lower troposphere. These years monthly mean air temperature up to 700 hPa was about -4 °C compared to -7 - -11 °C in 2013 - 2015 and 2017. In 2016 the lower troposphere was warmer by 2 - 3 °C  and specific humidity in atmospheric boundary layer was 30–60% higher its values in 2013–2015 and 2017. Even in 2018, when the area of open water adjacent to the Severnaya Zemlya archipelago was significantly larger than in 2016, specific humidity at altitudes up to 3 km was 4-12 percents less.</p><p>In 2016 monthly mean wind speed, mainly of southwestern direction, reached maximum value, more than 7 m/s. It led to weakening of atmospheric surface layer stratification (z/L <0.2). The air specific humidity  significantly increased also, up to 3.0 and 2.7 g /kg at 2 meters and at z<sub>0</sub> . Long-wave radiation fluxes increased by more than 15 – 20 W/m<sup>2</sup>. Same time due to increase of underlying surface temperature, its long-wave radiation cooling, which was not compensated by the increase of incoming long-wave radiation increased up to -27 W/m<sup>2</sup>. H, directed to the underlying surface, increased to 10 W/m<sup>2  </sup>and LE, directed to atmosphere, increased almost 2 times, up to 12 W/m<sup>2</sup>. As a result of multidirectional changes of heat fluxes, defining surface heat balance, its value in October 2016 (-31.6 W/m<sup>2</sup>) was comparable to calculated for other years.</p><p>The most probable explanation of the revealed features of atmospheric boundary and surface layers in October 2016 are the absence of sea ice cover in the waters, adjacent to the archipelago, prevented cooling of atmosphere, and strong zonal component of the wind velocity, caused the transfer of warm and moist air masses of Atlantic origin into the study area.</p><p>The work had been done under financial support of the Ministry of Science and Higher Education of the Russian Federation (project no. RFMEFI61619X0108).</p>

Modern benthic diatom taxocenes of loose grounds of the coast of the Severnaya Zemlya archipelago and adjacent sea areas

Modern taxocenes of benthic diatoms of coastal aquatic habitats of the Severnaya Zemlya archipelago were studied for the first time based on the materials of the expedition in summer 2019. The following habitats were studied: sublittoral, littoral, as well as semi-enclosed coastal water bodies. In the entire set of communities, a total of 180 species and subspecies (IST) of diatoms were noted. The local α-diversity of communities in the sublittoral was 6–26 species and IST (on average – 14.8), and for coastal locations, including the littoral – 12–51 species and IST (on average – 33). The floristic groups and coenotic groups of diatoms have been identified for sublittoral and coastal habitats. Significant differences were noted both among coastal taxocenes (average similarity of 23.41% in species composition and 9.78% in structure) and among sublittoral communities (19.51% and 34.54%, respectively). The entire spectrum of the noted on permanent slides species are photodocumented.

U–Pb Age and Hf Isotope Geochemistry of Detrital Zircons from Cambrian Sandstones of the Severnaya Zemlya Archipelago and Northern Taimyr (Russian High Arctic)

U–Pb and Lu–Hf isotope analyses of detrital zircons collected from metasedimentary rocks from the southern part of Kara Terrane (northern Taimyr and Severnaya Zemlya archipelago) provide vital information about the paleogeographic and tectonic evolution of the Russian High Arctic. The detrital zircon signatures of the seven dated samples are very similar, suggesting a common provenance for the clastic detritus. The majority of the dated grains belong to the late Neoproterozoic to Cambrian ages, which suggests the maximum depositional age of the enclosing sedimentary units to be Cambrian. The εHf(t) values indicate that juvenile magma mixed with evolved continental crust and the zircons crystallized within a continental magmatic arc setting. Our data strongly suggest that the main provenance for the studied clastics was located within the Timanian Orogen. A review of the available detrital zircon ages from late Neoproterozoic to Cambrian strata across the wider Arctic strongly suggests that Kara Terrane, Novaya Zemlya, Seward Peninsula (Arctic Alaska), Alexander Terrane, De Long Islands, and Scandinavian Caledonides all formed a single tectonic domain during the Cambrian age, with clastics predominantly sourced from the Timanian Orogen.

Glacier Flow Dynamics of the Severnaya Zemlya Archipelago in Russian High Arctic Using the Differential SAR Interferometry (DInSAR) Technique

Glacier velocity is one of the most important parameters to understand glacier dynamics. The Severnaya Zemlya archipelago is host to many glaciers of which four major ice caps encompassing these glaciers are studied, namely, Academy of Sciences, Rusanov, Karpinsky, and University. In this study, we adopted the differential interferometric synthetic aperture radar (DInSAR) method utilizing ALOS-2/PALSAR-2 datasets, with a temporal resolution of 14 days. The observed maximum velocity for one of the marine-terminating glaciers in the Academy of Sciences Ice Cap was 72.24 cm/day (≈263 m/a). For the same glacier, an increment of 3.75 times the flow rate was observed in 23 years, compared to a previous study. This has been attributed to deformation in the bed topography of the glacier. Glaciers in other ice caps showed a comparatively lower surface velocity, ranging from 7.43 to 32.12 cm/day. For estimating the error value in velocity, we selected three ice-free regions and calculated the average value of their observed movement rates by considering the fact that there is zero movement for ice-free areas. The average value observed for the ice-free area was 0.09 cm/day, and we added this value in our uncertainty analysis. Further, it was observed that marine-terminating glaciers have a higher velocity than land-terminating glaciers. Such important observations were identified in this research, which are expected to facilitate future glacier velocity studies.

Ice ridges in landfast ice of Shokal'skogo Strait

Three first-year ice ridges have been examined with respect to geometry and morphology in landfast ice of Shokal'skogo Strait (Severnaya Zemlya Archipelago) in May 2018. Two of the studied ice ridges were located on the edge of the ridged field and were part of it, because their keels extended for a long distance deep into this field. Ice ridges characteristics are discussed in the paper. These studies were conducted using hot water thermal drilling with computer recording of the penetration rate. Boreholes were drilled along the cross-section of the ridge crest at 0.25 m intervals. Cross-sectional profiles of ice ridges are illustrated. The maximal sail height varied from 2.9 up to 3.2 m, the maximal keel depth varied from 8.5 up to 9.6 m. The average keel depth to sail height ratio varied from 2.8 to 3.3, and the thickness of the consolidated layer was 2.5-3.5 m. The porosity of the non-consolidated part of the keel was about 23-27%. The distributions of porosity versus depth for all ice ridges are presented.