Academic literature on the topic 'NW Barents Sea'

Palaeomagnetic data from the 337 Ma Magerøy dykes (northern Norway) are of exceptionally high quality, and a positive contact test along with an existing regional result from the Silurian Honningsvåg Igneous Suite attests to a primary Early Carboniferous magnetic signature. The palaeomagnetic pole (S14.8°, E320.1°, dp/dm=4.4/8.6°) is the first Early Carboniferous pole from Baltica, and implies that northernmost Norway–Greenland, the Barents Sea and Svalbard were located at tropical to low northerly latitudes at this time. Northward drift during Carboniferous times (5–6 cm/yr) as demonstrated from palaeomagnetic data is also reflected in the sedimentary facies in the Barents Sea realm, that is, a change from tropical (Early Carboniferous) to subtropical (20–30° N) carbonates and evaporites in the Late Carboniferous. The Magerøy dykes are continental tholeiites which intruded into a set of NW–SE-trending normal faults parallel to the Trollfjorden–Komagelva Fault Zone and the Magerøysundet Fault immediately to the north and south of Magerøya, respectively. These, and many other NW–SE-trending faults (onshore and offshore), were active during Late Palaeozoic extension, and the dykes were probably contemporaneous with the earliest syn-rift sedimentation in the Barents Sea (for example, the Nordkapp Basin).

Abstract. The Barents Sea and Kara Sea region as part of the European Arctic shelf, is geologically situated between the Proterozoic East-European Craton in the south and early Cenozoic passive margins in the north and the west. Proven and inferred hydrocarbon resources encouraged numerous industrial and academic studies in the last decades which brought along a wide spectrum of geological and geophysical data. By evaluating all available interpreted seismic refraction and reflection data, geological maps and previously published 3-D-models, we were able to develop a new lithosphere-scale 3-D-structural model for the greater Barents Sea and Kara Sea region. The sedimentary part of the model resolves four major megasequence boundaries (earliest Eocene, mid-Cretaceous, mid-Jurassic and mid-Permian). Downwards, the 3-D-structural model is complemented by the top crystalline crust, the Moho and a newly calculated lithosphere-asthenosphere boundary (LAB). The thickness distribution of the main megasequences delineates five major subdomains differentiating the region (the northern Kara Sea, the southern Kara Sea, the eastern Barents Sea, the western Barents Sea and the oceanic domain comprising the Norwegian-Greenland Sea and the Eurasia Basin). The vertical resolution of five sedimentary megasequences allows comparing for the first time the subsidence history of these domains directly. Relating the sedimentary structures with the deeper crustal/lithospheric configuration sheds some light on possible causative basin forming mechanisms that we discuss. The newly calculated LAB deepens from the typically shallow oceanic domain in three major steps beneath the Barents and Kara shelves towards the West-Siberian Basin in the east. Thereby, we relate the shallow continental LAB and slow/hot mantle beneath the southwestern Barents Sea with the formation of deep Paleozoic/Mesozoic rift basins. Thinnest continental lithosphere is observed beneath Svalbard and the NW Barents Sea where no Mesozoic/early Cenozoic rifting has occurred but strongest Cenozoic uplift and volcanism since Miocene times. The East Barents Sea Basin is underlain by a LAB at moderate depths and a high-density anomaly in the lithospheric mantle which follows the basin geometry and a domain where the least amount of late Cenozoic uplift/erosion is observed. Strikingly, this high-density anomaly is not present beneath the adjacent southern Kara Sea. Both basins share a strong Mesozoic subsidence phase whereby the main subsidence phase is younger in the South Kara Sea Basin.

AbstractA comprehensive dataset is collated in a study on sediment transport, timing and basin physiography during the Early Cretaceous Period in the Boreal Basin (Barents Sea), one of the world’s largest and longest active epicontinental basins. Long-wavelength tectonic tilt related to the Early Cretaceous High Arctic Large Igneous Province (HALIP) set up a fluvial system that developed from a sediment source area in the NW, which flowed SE across the Svalbard archipelago, terminating in a low-accommodation shallow sea within the Bjarmeland Platform area of the present-day Barents Sea. The basin deepened to the SE with a ramp-like basin floor with gentle dip. Seismic data show sedimentary lobes with internal clinoform geometry that advanced from the NW. These lobes interfingered with, and were overlain by, another younger depositional system with similar lobes sourced from the NE. The integrated data allow mapping of architectural patterns that provide information on basin physiography and control factors on source-to-sink transport and depositional patterns within the giant epicontinental basin. The results highlight how low-gradient, low-accommodation sediment transport and deposition has taken place along proximal to distal profiles for several hundred kilometres, in response to subtle changes in base level and by intra-basinal highs and troughs. Long-distance correlation along depositional dip is therefore possible, but should be treated with caution to avoid misidentification of timelines for diachronous surfaces.

Dons described several new ciliates on the gribble Limnoria lignorum in Norway, including Platycola circularis Dons, 1941. My samples of wood borers on Murmansk coast of Barents sea, in White and Black seas and in NW Pacific from Vladivostok to Bering island had only Lagenophrys on pleopods. L. circularis (Dons, 1941) comb. nov. is redescribed using samples made on Murmansk coast not far from its type locality (Trondheimsfjord). Previous descriptions of this species under 3 different names are analysed.

Abstract Benthos plays a significant role as substrate, refuge from predation and food for a wide variety of fish and invertebrates of all life stages and should therefore be considered in the ecosystem approach (EA) to management. Epibenthos from trawl catches, used in annual assessments of commercial fish stocks, was identified and measured on-board. The 2011 dataset present the baseline mapping for monitoring and included 354 taxa (218 to species level) analysed with multivariate statistical methods. This revealed four main megafaunal regions: southwestern (SW), banks/slopes in southeast and west (SEW), northwestern (NW), and northeastern (NE) which were significantly related to depth, temperature, salinity, and number of ice-days. The SW region was dominated by filter-feeders (sponges) in the inflow area of warm Atlantic water while the deeper trenches had a detritivorous fauna (echinoderms). In the SEW region, predators (sea stars, anemones and snow crabs) prevailed together with filtrating species (sea cucumber and bivalves) within a mosaic of banks and slopes. Plankton-feeding brittlestars were common in the NW and NE region, but with increasing snow crab population in NE. Climate change, potentially expanding trawling activity, and increasing snow and king crab populations might all have impacts on the benthos. Benthos should therefore be a part of an integrated assessment of a changing sea, and national agencies might consider adding benthic taxonomic expertise on-board scientific research vessels to identify the invertebrate “by-catch” as part of routine trawl surveys.

The Arctic Ocean plays a key role in sequestrating the carbon dioxide (the greenhouse gas mainly responsible of global climate change) from the atmosphere. However, the melting of sea ice and the release of the huge amounts of methane stored in Arctic marine sediments and permafrost have uncertain feedbacks on the Arctic marine carbon cycle. Therefore, in order to refine the future climate modelling, it is of primary importance to promote regional studies on carbon dynamics in the Arctic areas. In following this approach, studies on the interaction of carbon with chemical elements like nitrogen and sulphur in marine sediments are fundamental to the understanding of the biogeochemical cycling of these elements. This research is focused on better defining the carbon-related biogeochemical processes occurring in post-glacial sediments collected from the Kveithola trough, a glacigenic depression located at the boundary of the NW Barents Sea’s continental margin. The Kveithola trough is influenced by strong marine bottom currents, but its inner part, where active methane seepages have been recently detected, appears today as an apparently stagnant and possibly chemosynthetic environment. Thus, in order to give a contribution in clarifying what can be the local and global impact of this kind of environment in terms of carbon cycle, the aim of this PhD project was to investigate past and active dynamics of sedimentary carbon, nitrogen and sulphur in this depositional system.

Per la prima volta, abbiamo documentato la struttura della comunità bentonica artica nel Kveithola Trough (NW Mare di Barents), per migliorare i gaps conoscitivi esistenti. Il Kveithola è caratterizzato da particolari condizioni morfo-deposizionali e idrografiche che permettono di distinguere tre aree principali (esterna, interna e il canale settentrionale). Nell'area esterna, l’elevato idrodinamismo contrasta l'accumulo di materia organica e la bassa biodisponibilità di carbonio organico nei sedimenti supporta una comunità con bassa richiesta di ossigeno. L’area interna e il canale settentrionale sono ambienti eutrofici, dominati da una comunità di detritivori (policheti subsurface-feeding Maldane sarsi e surface-feeding Lenvisenia gracilis, bivalvi lamellibranchia subsurface Mendicula cf. pigmea, protobranchia subsurface del genere Yoldiella), predatori appartenenti al phylum Nemertea, foraminiferi calcarei Nonionellina labradorica e Globobulimina auriculata, e agglutinanti Lagenammina difflugiformis. Questi taxa, delineano un ambiente con elevate concentrazioni di materia organica nel sedimento e impoverito di ossigeno (probabilmente legati alla presenza di cold seep) inoltre, sono anche responsabili di attività di bioturbazione. Interessante notare, in tutti i siti, l’elevata densità di morfotipi di foraminiferi monotalamici (Micrometula e Cylindrogullmia) che popolano tipicamente lo strato detritico dei fiordi artici e ambienti estremi poveri di ossigeno. Inoltre, i risultati della megafauna mostrano come nel sito 21, caratterizzato da un ambiente eterogeneo con strutture carbonatiche, tappeti microbici e vermi chemiosintetici, le emissioni di metano possano creare un hotspot di biomassa e diversità. Per concludere, le diverse caratteristiche geomorfologiche e ambientali, l'apporto di materia organica e la presenza di cold seep in questa area, rappresentano i fattori chiave della struttura della fauna bentonica e della loro distribuzione eterogenea.
For the first time, we have documented the Arctic benthic faunal structure in the Kveithola Trough (NW Barents Sea), to improve knowledge gaps existing in this area. The Kveithola is characterized by peculiar morpho-depositional and hydrographic conditions, which allow to distinguish three main areas (the outer, the inner area and Northern channel). In the outer area, high hydrodynamic does not favour the accumulation of the organic matter and low sediment organic carbon bioavailability supports a poorly sediment community oxygen consumption. The inner part and Northern channel represent an eutrophic area, dominated by a detritivores community (subsurface-feeding polychaeta Maldane sarsi, the surface-feeding polychaeta Lenvisenia gracilis, the subsurface lamellibranch bivalve Mendicula cf. pigmea, the subsurface protobranch bivalve genus Yoldiella), predators belonging to Nemertea and foraminifera as calcareous Nonionellina labradorica, Globobulimina auriculata and agglutinated Lagenammina difflugiformis. These taxa indicate the presence of an organic-rich sediment and oxygen-depleted environment possibly linked to a cold seep system and are also responsible for the bioturbation activity. Interestingly, delicate foraminifera monothalamous morphotypes (Micrometula and Cylindrogullmia) were reported from all sites with high abundance percentage, they inhabit typically the detritus layer of Arctic fjords and live in an extremely oxygen-deficient environment. Meanwhile, megafauna results suggest the possibility of the methane emission creating a biomass and diversity hotspot on the site 21 seafloor, characterized by heterogeneous environment with carbonate structures, microbial mats and chemosynthetic worm tufts. To conclude, the distinct geomorphological and environmental feature, supply of organic matter and seep activity of this area, are key drivers of benthic faunal structure and their heterogeneity distribution.

Abstract The wind field at sea is of considerable interest to identify suitable sites and for designing offshore wind energy production facility. However, the reliability of wind information suffers from the relative scarcity of offshore wind measurements to validate the wind models used in assessments. This paper presents a comparison of the publicly available NOAA-CFSR global re-analysis data set against offshore wind measurement collected in West Africa, Mediterranean Sea, Barents Sea and NW Australia, with the goal to investigate — in widely different meteorological conditions — the overall model reliability, in term of statistical indices of performance: Moreover, an attempt has been made to ascertain the representative averaging duration of model wind and the reliability of engineering formulas used to correlate wind of different averaging durations.