Siberian Sea Research Articles

Optimal Assimilation Number of Phytoplankton in the Siberian Seas: Spatiotemporal Variability, Environmental Control and Estimation Using a Region-Specific Model

The maximal value of the chlorophyll-specific carbon fixation rate in the water column or the optimal assimilation number (Pbopt) is an important parameter used to estimate water column integrated primary production (IPP) using models and satellite-derived data. The spatiotemporal variability in the Pbopt of the total and size-fractionated phytoplankton in the Siberian Seas (SSs) and its links with environmental factors were studied based on long-term (1993–2020) field and satellite-derived (MODIS-Aqua) observations. The average value of Pbopt in the SSs was equal to 1.38 ± 0.76 mgC (mg Chl a)–1 h–1. The monthly average values of Pbopt decreased during the growing season from 1.95 mgC (mg Chl a)–1 h–1 in July to 0.64 mgC (mg Chl a)–1 h–1 in October. The average value of Pbopt for small (<3 μm) phytoplankton 1.6-fold exceeded that for large (>3 μm) phytoplankton. The values of Pbopt depend mainly on incident photosynthetically available radiation (PAR). Based on the relationship between Pbopt and PAR, the empirical region-specific algorithm (E0reg) was developed. The E0reg algorithm performed better than commonly used temperature-based models. The application of E0reg for the calculation of Pbopt will make it possible to more precisely estimate IPP in the SSs.

Increasing Nutrient Fluxes and Mixing Regime Changes in the Eastern Arctic Ocean

AbstractPrimary productivity in the Arctic Ocean is experiencing dramatic changes linked to the receding sea ice cover. The vertical transport of nutrients from deeper water layers is the limiting factor for primary production. Here, we compare coincident profiles of turbulence and nutrients from the Siberian Seas in 2007, 2008, and 2018. In all years, the water column structure in the upstream region of the Arctic Boundary Current promotes upward nutrient transport, in contrast to the regions further downstream, and there are first indications for an eastward progression of these conditions. In summer 2018, strongly enhanced vertical nitrate flux and primary production above the continental slope were observed, likely related to a remote storm. The estimated contribution of these elevated fluxes above the slope to the Pan‐Arctic vertical nitrate supply is comparable with the basin‐wide transport, and is predicted to increase with declining sea ice cover in the future.

Process of Postglacial Transgression on the Coasts of the East Siberian and Laptev Seas

Process of Postglacial Transgression on the Coasts of the East Siberian and Laptev Seas

A linear mixed effects model for seasonal forecasts of Arctic sea ice retreat

ABSTRACT With sea ice cover declining in recent years, access to open Arctic waters has become a growing interest to numerous stakeholders. Access requires time for planning and preparation, which creates the need for accurate seasonal forecasts of summer sea ice characteristics. One important attribute is the timing of sea ice retreat, of which current statistical and dynamic sea ice models struggle to make accurate seasonal forecasts. We develop a linear mixed effects model to provide forecast of sea ice retreat over five major regions of the Arctic – Beaufort, Chukchi, East Siberian, Laptev, and Kara Seas. In this, the fixed effect – i.e. the mean influence of the atmosphere on sea ice retreat – is modeled using predictors that directly influence the dynamics or thermodynamics of sea ice, and random effects are grouped regionally to capture the local-scale effects on sea ice. The model exhibits very good skill in forecast of sea ice retreat at lead times of up to half a year over these regions.

Исследование загрязнения микропластиком морей российской Арктики и Дальнего Востока

The pollution of the seas in the Russian Arctic zone with micro-plastic particles is poorly studied in comparison with other areas of the World Ocean. The rapidly developing economic activity in the Arctic region threats to pollute the marine environment with plastic wastes. Arctic marine ecosystems are particularly vulnerable due to changes occurring in them under climate warming, as well as a large number of filter-feeder species in some coastal areas. The lack of observation data on the level of micro-plastic pollution in the region and methodological support for sampling requires the development of methods and approaches using the existing international experience. The paper presents preliminary results of the study carried out within the framework of the 4th stage of the TRANSARCTICA-2019 program in the Far Eastern and Arctic seas from Vladivostok to Murmansk. The authors present the analysis of existing approaches to sampling in seawaters and the possibility of their application in Russian expeditionary conditions. They describe in detail their method of sampling from a subsurface level (4—5 m) showing the advantage of using the proposed method for sampling when the vessel is moving and under adverse weather conditions. The studied quantitative and qualitative composition of the detected micro-plastic particles show that the East Siberian and Laptev seas have the lowest concentrations of micro-plastics. The largest amount of micro-plastic particles is found in the areas of intensive shipping in the Sea of Okhotsk and the Barents Sea. Comparison with existing international studies shows that the sampling method for micro-plastics strongly depends on the type of water body, its biological productivity, the level of pollution, as well as the technical capabilities of field research. All this indicates the need for intercalibration of sampling methods and further research for a more accurate quantitative and qualitative assessment of the micro-plastic pollution in the Arctic seas.

Trophic Dynamics of Calanus hyperboreus in the Pacific Arctic Ocean

AbstractThe zooplankton community composition in the Pacific Arctic Ocean depends heavily on the sea ice and hydrodynamic conditions. The calanoid copepod Calanus hyperboreus is a dominant Arctic zooplankton, but its diet sources in the Pacific Arctic are unclear. C. hyperboreus individuals were collected in the northern Chukchi Sea (NCS) and the northern‐East Siberian Sea (NESS), which display contrasting chlorophyll abundance and sea ice concentration in summer 2018. Nitrogen isotopes of individual amino acid and fatty acid compositions were measured to determine its trophic level (TL) and dominant diet. C. hyperboreus collected in the NCS had higher TL values (3.0 ± 0.2) and a relatively low proportion of C20:5(n‐3). In the NESS, C. hyperboreus had lower TL values (2.7 ± 0.2) and a larger percentage of C20:5(n‐3), suggesting a greater proportion of diatoms in its diet. Spatial TL variations of C. hyperboreus between the NCS and NESS may be caused by variations in phytoplankton composition (micro‐phytoplankton vs. nano‐ and picophytoplankton) as a result of surface seawater stratification triggered by the inflow of sea ice meltwater as well as summer Bering Sea water through the Bering Strait. These results suggest that the filter‐feeding copepod C. hyperboreus could be a useful indicator to understand trophic dynamics in zooplankton food web.

Age of volcanic-sedimentary complex from Сape Svyatoi Nos (Eastern Arctic)

Geological structure and age of the volcanogenic-sedimentary complex of the Cape Svyatoi Nos (Svyatonosskaya formation) are presented. The rocks of Cape Svyatoi Nos are located on the border of the Novosibirsk-Chukotka and Verkhoyansk–Kolyma fold belts, on the coast of the Laptev and East- Siberian Seas. Field studies indicate that the rocks belong to a single volcanogenic-sedimentary complex. The maximum thickness of individual sections reaches up 700 m. Coarse-grained pyroclastic rocks with rare lava flows prevail on the north (on the coast of Laptev Sea). The proportion and dimension of volcanics and pyroclastic rocks decrease in the south, terrigenous rocks appear. In the modern structure, the rocks are deformed.Zircons of several populations were separated from the flow of basalts. Two, the most representative zircon populations are characterized by close subconcordant ages. The structure and U-Pb ages of zircons from the first population suggest their formation during magmatic crystallization with a superimposed postmagmatic thermal event. Zircons of the second population have a xenomorphic appearance, which is typical of zircons formed at the late or postmagmatic phases. The weighted average age (MSWD = 3) of the first two populations is 149.3 ± 1.2 Ma (Tithonian age). It corresponds to the age of crystallization of basalts and the superimposed (close in time) postmagmatic thermal event.The third population of zircons is represented by two rounded grains with Archean U-Pb ages. It is assumed that these grains were trapped by magmatic melt from pre-Jurassic clastic rocks.Late Jurassic-Early Cretaceous radiolarians were identified from different horizons of tuff-terrigenous and terrigenous rocks. This is confirm the obtained U-Pb ages and the coeval of all the studied sections. The Titonian age of volcanic-sedimentary rocks allows us to classify them as suprasubduction complexes of the Late Jurassic - Early Cretaceous, widespread in the Verkhoyansk-Chukotka Mesozoids.

Sea ice conditions and navigability through the Northeast Passage in the past 40 years based on remote-sensing data

ABSTRACT Sea ice conditions and navigability along four typical routes of the Northeast Passage (NEP) are analysed using remote-sensing data from 1979 to 2019. The influence of air temperature (T air) and surface wind on the sea ice concentration (SIC) and the navigability of routes is determined. It is found that the annually averaged SICs of the different routes have decreased over the past 41 years. The fastest rate of decrease occurred in the Kara Sea (∼−1% per year), while the slowest rates of decrease occurred in the Laptev/East Siberian Sea (∼−0.42% per year). The number of navigable days for the Kara Sea has become ∼1–2 months longer than the Laptev/East Siberian Sea route as a result. The effect of T air on SIC, quantified by ΔSIC/ΔT air in the routes through the eastern Kara Sea and Laptev/East Siberian Sea in 2010s was ∼−0.04/°C, two to three times that seen during the 1980s. Air temperature is becoming a significant driving force of melting ice in these routes. Surface winds are also a crucial factor for the navigability of the Vilkitsky Strait and Long Strait, as they drive ice drift, and affect the navigability of the Kara Strait by introducing warm air.

Autumn Arctic Pacific Sea Ice Dipole as a Source of Predictability for Subsequent Spring Barents Sea Ice Condition

AbstractThis study uses observational and reanalysis datasets in 1980–2016 to show a close connection between a boreal autumn sea ice dipole in the Arctic Pacific sector and sea ice anomalies in the Barents Sea (BS) during the following spring. The September–October Arctic Pacific sea ice dipole variations are highly correlated with the subsequent April–May BS sea ice variations (r = 0.71). The strong connection between the regional sea ice variabilities across the Arctic uncovers a new source of predictability for spring BS sea ice prediction at 7-month lead time. A cross-validated linear regression prediction model using the Arctic Pacific sea ice dipole with 7-month lead time is demonstrated to have significant prediction skills with 0.54–0.85 anomaly correlation coefficients. The autumn sea ice dipole, manifested as sea ice retreat in the Beaufort and Chukchi Seas and expansion in the East Siberian and Laptev Seas, is primarily forced by preceding atmospheric shortwave anomalies from late spring to early autumn. The spring BS sea ice increases are mostly driven by an ocean-to-sea ice heat flux reduction in preceding months, associated with reduced horizontal ocean heat transport into the BS. The dynamical linkage between the two regional sea ice anomalies is suggested to involve positive stratospheric polar cap anomalies during autumn and winter, with its center slowly moving toward Greenland. The migration of the stratospheric anomalies is followed in midwinter by a negative North Atlantic Oscillation–like pattern in the troposphere, leading to reduced ocean heat transport into the BS and sea ice extent increase.

Ice sheet controls on fine-grained deposition at the southern Mendeleev Ridge since the penultimate interglacial

Clay minerals deposited at the southern Mendeleev Ridge in the Arctic Ocean have a unique provenance, which can be used to reconstruct changes in the local sedimentary environment. We show that sediments in core ARC7-E23 record high-frequency changes in clay minerals since the penultimate interglacial. The clay minerals, grain size, and ice-rafted debris indicate the extent of the East Siberia Ice Sheet (ESIS). During the glacial periods of Marine Isotope Stage 2 (MIS2) and MIS4, the southern Mendeleev Ridge was likely covered by an ESIS-extended ice shelf, blocking almost all sediment input from the Canadian Arctic and Laptev Sea, but allowing transport of fine-grained sediments from the East Siberian and Chukchi Sea shelves. After ESIS retreat, the Beaufort Gyre and Transpolar Drift became the primary transport mechanism for the distally sourced sediments. Climate conditions in MIS3 enhanced both the oceanic circulation and sediment transport.

A review of the genus Anatoma in the Eurasian Arctic seas (Gastropoda: Vetigastropoda: Anatomidae)

A taxonomic review of the genus Anatoma Woodward, 1859 in the Eurasian Arctic seas is presented. The new species A. golikovi sp. nov. is described from the northwestern part of the Barents Sea. The species differs from all other Arctic and North Atlantic Anatoma in having a flat spire. We consider Anatoma schioettei Høisæter et Geiger, 2011, syn. nov., a junior synonym of A. crispata (Fleming, 1828). Anatoma schanderi Høisæter et Geiger, 2011 is recorded for the first time from the Siberian seas.

Data on distribution, demographic structure and grazing of the dominant mesozooplankton species in the Yenisei estuary and adjacent shelf in early summer.

The data article refers to the paper “Distribution and grazing of the dominant mesozooplankton species in the Yenisei estuary and adjacent shelf in early summer (July 2016)” (Drits et al., 2020). The data were collected along quasi-longitudinal transect “Yenisei estuary – Kara Sea shelf” on 24–28 July 2016. Here we present data on the spatial and vertical distribution, demographic structure and gut pigment content of the dominant zooplankton species as well as the grazing impact on autotrophic phytoplankton in the three distinguished zones: freshwater zone, frontal zone of the Yenisei plume and marine shelf zone. The related article (Drits et al., 2020) considers the structure and functioning of zooplankton community in relation to environmental characteristics such as temperature, salinity, phytoplankton abundance, timing of ice retreat. Information presented in this article can be used by marine biologists for studies of structure and functioning of estuarine pelagic communities, ecology of zooplankton in the Siberian seas. Besides the data could provide a baseline for the assessment of the ecological role played by climate change events (e.g., increased precipitation, permafrost thawing, elevated river discharge) on the Arctic ecosystems.

Геологическое строение и сейсмогеологическая характеристика континентальной окраины Сибирской платформы и шельфа моря Лаптевых

The work is devoted to the analysis of the geological structure of the northern continental margin of the Siberian Platform and the western part of the Laptev Sea. In terms petroleum geological zoning, the study area covers the Anabar-Khatanga and Lena-Anabar petroleum bearing areas of the Lena-Tunguska petroleum province and the West Laptev Sea promising petroleum province. Seismogeological models of sedimentary stratum on the continent and in the water area are considered; the conclusion was made that the Northern Siberian and Laptev Sea basins are separated by a large basement high that extends from the Taimyr Peninsula along the coastline to the Lena River issue. A complex analysis of geological and geophysical data made it possible to conclude that the most probable model is that the western part of the Laptev Sea is a continuation of the Siberian Platform with an Archaean-Proterozoic basement and an Upper Proterozoic-Phanerozoic sedimentary cover.

Climatic Changes in Thermal Conditions of Sea Areas in the Eastern Arctic at the Turn of the 20th and 21st Centuries

The interannual variability of sea surface temperature and air temperature in the coastal zone and adjacent areas of the East Siberian and Chukchi seas and the Arctic Ocean at the modern stage of the climate warming is analyzed. The analysis is based on data of routine observations at hydrometeorological stations obtained in 1980–2016, global meteorological network data and NOAA reanalysis data. The analysis of the spatiotemporal pattern of temperature variations and the zoning of water areas based on the features of modern climate changes are carried out using the EOF (Empirical Orthogonal Functions), cluster, and correlation analyses. The possible cause-effect relationships between these changes and variations in wind field components and climate indices are considered. The studies revealed, specified, and quantified the modern trends and regional features of interannual variability of thermal conditions in the selected areas.

Taxonomic Status of the Okhotsk Lumpsucker Eumicrotremus ochotonensis (Cyclopteridae, Cottoidei) with Redescription of E. derjugini

The species status is justified for the Okhotsk lumpsucker Eumicrotremus ochotonensis based on the morphological characters. The differences from the closely related species E. derjugini inhabiting the Arctic Ocean are given. Two species were redescribed basing on type series, their diagnoses were clarified, and the lectotypes were designated. Intraspecific variability is discussed using new materials from the Barents, Kara, Laptev, and Okhotsk seas. The two species differ markedly in a complex of morphological features (shape of the submerged dorsal fin, proportions of the body, number and location of bony plaques) and characteristics of biology (spawning season). The modern disjunction of the ranges of E. ochotonensis and E. derjugini covers the Bering, East Siberian, and Chukchi seas. Sequence analysis of the cytochrome oxidase (COI) gene fragment of mtDNA revealed differences in the haplotypic diversity of the two species. Weak genetic divergence between species indicates a relatively recent isolation of E. derjugini and confirms its status of the evolutionary young species.

Redescription of Admete sadko Gorbunov, 1946 (Gastropoda: Cancellariidae).

Five species of the family Cancellariidae are currently known from Arctic seas: Admete contabulata Friele, 1879, A. clivicola Høisæter, 2011, A. solida (Aurivillius, 1885), A. viridula (Fabricius, 1780) and Iphinopsis inflata (Friele, 1879) (Golikov et al. 2001; Kantor Sysoev 2006; Høisæter 2011). Admete contabulata, A. clivicola and Iphinopsis inflata are only known from the Atlantic part of the Arctic, i.e. Norwegian and southwestern Barents seas (Høisæter 2011; Nekhaev 2014). Admete solida has been rarely reported since its first description from the Bering Strait (Sysoev Kantor 2002), however Nekhaev Krol (2017) recently reported a specimen from the eastern region of the Barents Sea that is similar in morphology to the holotype of this species. Admete viridula is the only representative of Admete reported from Siberian seas (Golikov et al. 2001; Lyubin 2003; Kantor Sysoev, 2006).

Arctic Sea Ice Melt Onset Timing From Passive Microwave‐Based and Surface Air Temperature‐Based Methods

AbstractMelt onset (MO) on Arctic sea ice has been monitored using satellite‐based passive microwave (PMW) observations since 1979. In this work, surface air temperatures from the International Arctic Buoy Programme/Polar Exchange at the Sea Surface and NASA's Atmospheric Infrared Sounder are used to derive MO date estimates using three threshold methods which are then compared with a record of PMW‐based MO dates. Results from the PMW data indicate a shift toward increasingly early MO timing, with significant trends as large as −9.45 days/decade in the E. Siberian Sea and −5.69 days/decade for the entire Arctic, consistent with other studies highlighting the overall decline of Arctic sea ice. Results indicate that the surface air temperature‐based MO date estimates produced using a −1 °C threshold are ~11 days later than the PMW‐based MO date estimates Arctic wide. A statistical comparison of the Polar Exchange at the Sea Surface and PMW‐based MO dates indicate that despite the ~11‐day bias, correlations between the MO date time series are generally good (≥0.6) for most of the Arctic Ocean while the Atmospheric Infrared Sounder and PMW‐based MO dates are generally better at capturing the statistically similar long‐term trends in MO dates for the Arctic and several Arctic subregions. Application of these results can contribute to the development of new methods to monitor the sea ice melting state.

Composition of Harpacticoida (Crustacea, Copepoda) of the Laptev Sea in comparison with faunas of adjacent Arctic seas

The invertebrate fauna of the Laptev Sea is one of the least investigated in the Arctic. In particular, little is known about the Harpacticoida (Copepoda, Crustacea)—one of the main components of marine meiofauna. Major objectives of our study were (1) to describe harpacticoid composition obtained from three sublittoral stations, (2) to compile the check-list of the Laptev Sea harpacticoids, and (3) to perform a comparative analysis of the Laptev Sea harpacticoid fauna with faunas of other Arctic seas. Of 38 species found in our material, 25 are new for the sea, and four species are likely new to science. A total list for the Laptev Sea includes 76 species from 18 families. Interstitial and phytal forms are poorly represented, due to the rarity of suitable biotopes and/or undersampling. The majority of the provisional endemics were found in the bathyal and abyssal zones of the sea, while widely distributed species, except for the plankton, belong to the fauna of the soft sediments of the littoral zone. Comparative analysis of harpacticoids from the Arctic region (the Laptev, White, Barents, Kara, East Siberian and Beaufort Seas and the Greenland area) shows the considerable distinction between the Eastern (Siberian) and Western sub-regions. Further investigations are necessary to reveal a more detailed pattern in Harpacticoida distribution and to evaluate possible vectors of dispersal and biogeographic relationships in the high Arctic.

Polymastiidae (Porifera: Demospongiae) of the Nordic and Siberian Seas

Polymastiidae (Porifera: Demospongiae) of the Nordic and Siberian Seas are revised and compared with the related species of the North Atlantic based on the morphological data from the type and comparative material and the molecular data from fresh samples. Twenty species from six polymastiid genera are recorded. Two species,Polymastia svensenifrom Western Norway andSpinularia njordifrom the Norwegian Sea, are new to science. One species,Polymastia andrica, is new to the Nordic Seas and two species,Polymastiacf.bartlettiandP. penicillus, are new to the Scandinavian Coast. Distribution of the polymastiids in the North Atlantic and Arctic is discussed and the allegedly wide distribution ofSpinularia sarsiiandS. spinulariais questioned.

The footprints of 16 year trends of Arctic springtime cloud and radiation properties on September sea ice retreat

AbstractThe most prominent September Arctic sea ice decline over the period of 2000–2015 occurs over the Siberian Sea, Laptev Sea, and Kara Sea. The satellite observed and retrieved sea ice concentration (SIC) and cloud/radiation properties over the Arctic (70°–90°N) have been used to investigate the impact of springtime cloud and radiation properties on September SIC variation. Positive trends of cloud fractions, cloud water paths, and surface downward longwave flux at the surface over the September sea ice retreat areas are found over the period of 1 March to 14 May, while negative trends are found over the period of 15 May to 28 June. The spatial distributions of correlations between springtime cloud/radiation properties and September SIC have been calculated, indicating that increasing cloud fractions and downward longwave flux during springtime tend to enhance sea ice melting due to strong cloud warming effect. Surface downward and upward shortwave fluxes play an important role from May to June when the onset of sea ice melting occurs. The comparison between linearly detrended and nondetrended of each parameter indicates that significant impact of cloud and radiation properties on September sea ice retreat occurs over the Chukchi/Beaufort Sea at interannual time scale, especially over the period of 31 March to 29 April, while strongest climatological trends are found over the Laptev/Siberian Sea.