South Of Svalbard Research Articles

A late response of the sea-ice cover to Neoglacial cooling in the western Barents Sea

In high northern latitudes, the Middle to Late-Holocene was a time of orbitally-induced atmospheric cooling. This led to increased sea-ice production in the Arctic Ocean and its export southward, a decrease in sea surface temperatures (SST), and glacier advances at least since 5–4 ka BP. However, the response of the ocean-climate system to decreasing insolation was not uniform. Our research shows that the sea-ice cover in the northwestern Barents Sea experienced a late response to Neoglacial cooling. We analyzed dinoflagellate cyst assemblages from a sediment core from Storfjordrenna, south of Svalbard. We found that the area experienced ice-free conditions throughout most of the Mid- and Late-Holocene. It was only after 2.3 ka BP that the study site became covered with winter drift ice and primary productivity decreased subsequently. Other regional data support the decrease in SST, the expansion of the sea-ice cover, and the deterioration of the environmental conditions around that time. Our findings indicate that the sea-ice cover in the northwestern Barents Sea required a significant amount of time to respond to the general cooling trend in the region. These results have important implications for present-day environmental changes. Even if the current warming trend is revoked in the future, the observed sea-ice loss in the Barents Sea may be incredibly challenging to reverse.

CAGE16-5 Cruise Report: ROV-based Geological and Biological Investigations of Methane Seeps at Prins Karls Forland, Storfjordrenna Pingos and Bjørnøyrenna Craters

The cruise was an activity in of the Centre of Excellence for Gas Hydrate, Environment and Climate (CAGE) at UiT – The Arctic University of Norway. The overall aim of the cruise was to utilize the NTNU/AMOS SK30k ROV for seafloor mapping and targeted sample collection at selected CAGE sites, focusing on methane seepage areas west and south of Svalbard. More specific objectives of the cruise were to: Use an ROV-mounted multibeam system to acquire very high resolution (10cm) seabed bathymetry in areas of methane seepsConduct detailed visual seabed surveys for habitat mapping and photomosaicking at specific seep featuresCollect seabed samples of authigenic carbontate crusts, sediments, microbes, foraminifera and macro organisms associated with methane seeps from the ROV, and complimented with more traditional sampling methodsContinue time series investigations of water column measurements of methane concentrations, and of methane oxidizing microbes in the seawaterNet sampling for planktic forams at seeps Sampling activities were designed with a multi-disciplinary approach, with research groups from all CAGE work packages working together in the same locations to develop a holistic understanding of the geological, oceanographic and biological components at key methane seep sites. This cruise prioritized the acquisition of information for mapping seabed features and habitat characterizations (e.g. photomosaicking, visual information) combined with in-situ site sampling using ROV technologies, and complimented by our ‘traditional’ technologies (e.g. CTD, net, and coring devices). With these objectives in mind, the strategy for each of the selected locations is to first carry out visual survey work to acquire framework measurements and data to be of use for all groups within CAGE, followed by a consolidated sampling plan to satisfy the needs of individual researchers for sample material The cruise may be known as: CAGE16_5

Cetacean spatial trends from 2005 to 2019 in Svalbard, Norway

This study uses cetacean sighting data, acquired via a citizen science programme, to update distributions and spatial trends of whales and dolphins in waters around the Svalbard Archipelago during the period 2005–2019. Distributions, based on kernel density estimates, from an early period (2005–2019) and a recent period (2015–19) were compared to identify potential shifts in distribution in this area, which is experiencing rapid warming and concomitant sea-ice losses. Among the three Arctic endemic cetaceans, white whales (Delphinapterus leucas, also known as beluga) had a stable, coastal distribution throughout the study, whereas narwhals (Monodon monoceros) and bowhead whales (Balaena mysticetus) were observed only north of the archipelago, but with increasing frequency during the recent period. White-beaked dolphins (Lagenorhynchus albirostris) had a stable distribution along the continental shelf break, west and south of Svalbard. Sperm whale observations shifted from west of Bjørnøya during the early period to being concentrated around the north end of Prins Karls Forland, west of Spitsbergen during the recent period. The four summer-resident baleen whales—blue whales (Balaenoptera musculus), fin whales (Balaenoptera physalus), humpback whales (Megaptera novaeangliae) and minke whales (Balaenoptera acutorostrata)—have shifted their distributions from the continental shelf break west of Spitsbergen during the early period into fjords and coastal areas during the recent period. These changes coincide with increased inflows of Atlantic Water into the fjords along the west coast of Spitsbergen and across the north of the archipelago.

The short-term development of performance and aerobic endurance following prolonged low-intensity ski trekking in Svalbard: A case study

Abstract The purpose of this case study was to examine the short-term development of performance and aerobic endurance following prolonged low-intensity ski trekking (LIST) in an Arctic region. Two male recreational athletes (aged 24 and 26 years) with high aerobic fitness performed LIST 7 ± 2 h·day−1 for 23 consecutive days, while hauling sledges (∼80 kg initially) with supplies from the north to the south of Svalbard (∼640 km). Time to exhaustion, maximal oxygen uptake (V̇O2max), lactate threshold (LT) and work economy were evaluated at pre- and post-trek. The results showed that the absolute and relative exercise intensity during LIST were ∼3.9 km·h−1 and ∼60% of maximal heart rate, respectively. Time to exhaustion during a ∼4–6 min ramp walking test, and a >45 min stepwise walking test, while pulling 12.5 kg weights (simulation of ski trekking with loaded sledge), increased by 11–17% and 3–9%, respectively, following LIST. Body mass and V̇O2max relative to body mass (ml·kg−1·min−1) decreased by 5–8% and increased by 3–8%, respectively. Furthermore, the workload associated with LT and LT percentage of V̇O2max increased by 39–69% and 12–13%, respectively. No notable change in work economy was observed. The mean pace during LIST (∼3.9 km·h−1) corresponded to the treadmill walking speed (4 km·h−1) with the lowest oxygen cost (mL·kg−1·m−1) in both participants. It can be concluded that short-term prolonged LIST can improve ski trek-simulated performance and fractional utilisation of V̇O2max in recreational athletes with high aerobic fitness. Moreover, highly aerobically fit ski trekkers appear to instinctively choose the most energy-efficient pace during LIST.

A New Technique for Estimating the Lifetime of Bursts of Electron Precipitation From Sounding Rocket Measurements

AbstractAt 0735 UT on 13 December 2015, the Rocket Experiment for Neutral Upwelling‐2 experiment launched north toward the auroral cusp region from Andoya, Norway. The instrumented rocket included an electron spectrometer, photometers that measured the auroral redline and greenline, and an instrument that measured ionospheric thermal electron temperature. On the down leg, just south of Svalbard, the rocket entered a region of poleward moving auroral forms that were characterized by narrow structures due to a combination of spatial and temporal variations. A noticeable feature was that the redline to greenline brightness ratio was much smaller than expected. A model is developed that shows that these emissions can be used to estimate the lifetimes of bursty electron precipitation. This model is shown to be consistent with some poleward moving auroral form lifetimes being on the order of 100 ms. The correlation between the precipitation and temperature bursts suggest that some transport occurred.

Spatial distributions and seasonality of four Calanus species in the Northeast Atlantic

This paper analyses spatial and seasonal patterns for near-surface abundances of four Calanus species in the Northeast Atlantic based on monthly Continuous Plankton Recorder (CPR) Survey data collected during 2008–2016. C. finmarchicus, C. helgolandicus, C. hyperboreus and C. glacialis represent different ecosystems, and water masses with differing oceanographic properties and origins. Hence, these are considered as indicator species in climate change studies. A southern transect between Norway and the United Kingdom represented the northern North Sea, a central transect crossed the Norwegian and Iceland Seas, while a northern transect between Norway and Svalbard crossed the entrance to the Barents Sea. C. finmarchicus was prevalent everywhere, while C. helgolandicus was mainly confined to the northern North Sea though also documented downstream in the Norwegian Sea as far north as the entrance to the Barents Sea. The ratio of C. helgolandicus to C. finmarchicus abundances is expected to increase in the northern North Sea and southern Norwegian Sea given continued increases in seawater temperature. C. hyperboreus and C. glacialis were mainly associated with regions influenced by Arctic waters in the Iceland and Norwegian Seas, and south of Svalbard, respectively. Within Atlantic water masses in the central Norwegian Sea, a distinct second generation of C. finmarchicus with surprisingly high late-autumn concentrations of older stages were found. In Coastal water, two or more generations of C. finmarchicus occurred, while only one generation was evident in Arctic waters. Young C. finmarchicus of the first annual generation showed an earlier timing in Coastal than Atlantic and Arctic waters. The upper range of the temperature niche for both C. hyperboreus and C. glacialis was found to be around 7 °C. However, the peak occurrence within the study area was in 1–2 °C in Arctic water in the Iceland Sea in April for C. hyperboreus, while around 5 °C in Barents Sea Arctic water in July for C. glacialis. C. finmarchicus was present in all water masses with a peak occurrence in June at around 6 °C. C. finmarchicus generally dominated the Calanus-biomass, but C. hyperboreus in Arctic water in the Iceland and Norwegian Seas in spring, and C. helgolandicus in the northern North Sea, could match or exceed the biomass of C. finmarchicus.

Ice‐margin retreat and grounding‐zone dynamics during initial deglaciation of the Storfjordrenna Ice Stream, western Barents Sea

Processes occurring at the grounding zone of marine terminating ice streams are crucial to marginal stability, influencing ice discharge over the grounding‐line, and thereby regulating ice‐sheet mass balance. We present new marine geophysical data sets over a ~30×40 km area from a former ice‐stream grounding zone in Storfjordrenna, a large cross‐shelf trough in the western Barents Sea, south of Svalbard. Mapped ice‐marginal landforms on the outer shelf include a large accumulation of grounding‐zone deposits and a diverse population of iceberg ploughmarks. Published minimum ages of deglaciation in this region indicate that the deposits relate to the deglaciation of the Late Weichselian Storfjordrenna Ice Stream, a major outlet of the Barents Sea–Svalbard Ice Sheet. Sea‐floor geomorphology records initial ice‐stream retreat from the continental shelf break, and subsequent stabilization of the ice margin in outer‐Storfjordrenna. Clustering of distinct iceberg ploughmark sets suggests locally diverse controls on iceberg calving, producing multi‐keeled, tabular icebergs at the southern sector of the former ice margin, and deep‐drafted, single‐keeled icebergs in the northern sector. Retreat of the palaeo‐ice stream from the continental shelf break was characterized by ice‐margin break‐up via large calving events, evidenced by intensive iceberg scouring on the outer shelf. The retreating ice margin stabilized in outer‐Storfjordrenna, where the southern tip of Spitsbergen and underlying bedrock ridges provide lateral and basal pinning points. Ice‐proximal fans on the western flank of the grounding‐zone deposits document subglacial meltwater conduit and meltwater plume activity at the ice margin during deglaciation. Along the length of the former ice margin, key environmental parameters probably impacted ice‐margin stability and grounding‐zone deposition, and should be taken into consideration when reconstructing recent changes or predicting future changes to the margins of modern ice streams.

Paleomagnetism and rock magnetism from sediments along a continental shelf-to-slope transect in the NW Barents Sea: Implications for geomagnetic and depositional changes during the past 15 thousand years

Abstract Paleomagnetic and rock magnetic data were measured on glaciomarine silty-clay successions along an E-W sediment-core transect across the continental shelf and slope of the Kveithola paleo-ice stream system (south of Svalbard, north-western Barents Sea), representing a stratigraphic interval spanning the last deglaciation and the Holocene. The records indicate that magnetite is the main magnetic mineral and that magnetic minerals are distinctly less abundant on the shelf than at the continental slope. The paleomagnetic properties allow for the reconstruction of a well-defined characteristic remanent magnetization (ChRM) throughout the sedimentary successions. The stratigraphic trends of rock magnetic and paleomagnetic parameters are used for a shelf-slope core correlation and sediment facies analysis is applied for depositional processes reconstruction. The new paleomagnetic records compare to the PSV and RPI variation predicted for the core sites by a simulation using the global geomagnetic field variation models SHA.DIF.14k and CALS7K.2 and closest PSV and RPI regional stack curves. The elaborated dataset, corroborated by available 14C ages, provides a fundamental chronological framework to constrain the coupling of shelf-slope sedimentary processes and environmental changes in the NW Barents Sea region during and after deglaciation.

Palaeoclimatic changes in Kveithola, Svalbard, during the Late Pleistocene deglaciation and Holocene: Evidences from microfossil and sedimentary records

Climate changes are reflected in the Arctic ecosystem history over different timescales. We use a multi proxy-based approach for palaeoenvironmental and palaeoclimatic reconstructions, conducted on sediment cores, compared with summer insolation and Greenland ice core δ18O data in order to establish a framework for climate changes from Late Pleistocene to late Holocene. Our dataset includes the results compiled from a sediment core, collected on the middle slope of the Kveithola Trough Mouth Fan (South of Svalbard) during the CORIBAR cruise (2013). The studied core presents remarkable lithological and magnetic susceptibility similarities with cores recovered in the same area during the SVAIS (2007) and the OGS-EGLACOM cruise (2008), allowing the construction of the age model. The results indicate that during the last 14.5calkyBP advances and retreats of the Svalbard Barents Sea Ice Sheet were strictly linked to the interplay of Atlantic and Arctic water inflows to the study area. During the deglaciation, from the Last Glacial Maximum to the onset of the Holocene, the climate underwent a series of abrupt changes including the Bølling-Allerød warm interstadial and the Younger Dryas cold event. During the early Holocene, the investigated area was dominated by enhanced warm Atlantic water inflow, which was concomitant with summer insolation increase, characterizing the Holocene Thermal Maximum. Conversely, the late Holocene was governed by deteriorating climatic conditions, with predominant Arctic/Polar water inflow on the surface water masses off Western Svalbard, possibly associated with summer insolation decline due to orbital forcing.

Geomagnetic palaeosecular variation around 15 ka ago from NW Barents Sea cores (south of Svalbard)

Geomagnetic palaeosecular variation around 15 ka ago from NW Barents Sea cores (south of Svalbard)

Regional constraints of the Sørkapp Basin: A Carboniferous relic or a Cretaceous depression?

The Sørkapp Basin (NW Barents Shelf) contains a comprehensive sedimentary succession that provides insight into regional tectonics and depositional development of the shelf from the Devonian to the Cretaceous. With its location east of the mid-Atlantic spreading ridge and south of Svalbard, the Basin serves as an important link between the offshore and onshore realms.This study subdivides this sparsely studied basin into six main seismic units (three Paleozoic and three Mesozoic). A metamorphic basement together with assumed Devonian sedimentary deposits form the foundation for a chiefly Carboniferous basin. The Basin forms a syncline with infill showing limited fault-influence. Overlying the early infill are Late Carboniferous deposits which show less lateral variation in thickness but also active growth on the few faults showing significant displacement. The overlying platform deposits of the latest Carboniferous and Permian show a change in depositional geometry, with onlapping deposits towards the east probably resulting from uplift of the Stappen High and regional flooding. Subsequent, particularly Late, Triassic sedimentation shows a more distinctly progradational pattern with a dominantly southeastern source for sediments. During this shallow shelf-filling stage, the Sørkapp Basin is sheltered by the Gardarbanken High, blocking the Early Triassic clinoform development. The High was transgressed in the Middle Triassic and the platform-edge progressively approached the present Svalbard coastline.The youngest Mesozoic unit forms a separate saucer-shaped depocenter west of the Sørkapp Basin, where deposits are truncated by the seafloor in a mid-basin position and across the Gardarbanken High. The depositional pattern for this succession correlates with the outcrop pattern of the Adventdalen Group implying a post Middle Jurassic to Cretaceous age. The Sørkapp Basin has been referred to as a Cretaceous feature based in this depocenter. However, the foundations are much older and the Cretaceous depression is located west of the deeper basin. Accordingly, we propose the informal term Sørkapp Depression for the Cretaceous basin.

Characteristics of winter cyclone activity in the northern North Atlantic: Insights from observations and regional modeling

Fields from the NCEP/NCAR reanalysis are used in conjunction with simulations from Polar MM5 to examine regional processes contributing to cyclone development in the sub‐Arctic/Arctic sector of the North Atlantic. Strong deepening of systems (>6 hPa/6 hours) is especially common south of the tip of Greenland and in the vicinity of the mean Icelandic Low (IL). A secondary maximum is located just south of Svalbard. Composite analyses of strongly deepening systems in these areas point to the influence of pronounced preexisting low‐level temperature gradients linked to ocean currents, the sea ice margin and ocean‐land contrasts. The area of preferred deepening near Svalbard corresponds to the northernmost penetration of open water in the North Atlantic. Impacts of Greenland's orography are prominent in the synoptic complexity of the region. Typical synoptic situations, examined as case studies, include splitting, or “bifurcation” of cyclones at the southern tip of Greenland; orographic cyclogenesis in the lee of Greenland, at the location of the mean IL; and deepening of preexisting systems near the IL. Orographic influences are clearly captured in Polar MM5 simulations for which control runs of the three cases are compared to runs for which the orography of Greenland is removed.

Interpretation of depth to the magnetic basement in the northern Barents Sea (south of Svalbard)

Aeromagnetic data covering some 135,000 km 2 with 34,000 km of profiles in the northern Barents Sea (south of Svalbard) have been interpreted. The survey area is situated between 74° 30′ and 78°N, and 15° and 32°E. The main result of the study is a contour map of the depth to the top of the magnetic basement, indicating the thickness of the sedimentary rocks in the area. Three different graphical techniques and the autocorrelation method have been applied to determine the depths to magnetic sources from the profile data. The different methods yield errors which generally vary between 5% and 15%. Systematic errors will add to the spread shown by the different methods. Therefore, the inaccuracy of individual point estimates can sometimes be as large as 30%. The interpreted depths to the magnetic basement exceed 10 km in the Sørkapp Basin, in parts of Storfjorden, and towards the Olga Basin. The basement is located at depths of less than 2 to 3 km on the Bjørnøya-Sørkapp High and the Hopen High, and at depths of about 6 km on the Gardar-banken High. Depths in the area of the central platform vary smoothly and gradually from 6 to 9 km. It is suggested that in some areas pre-Permian sediments may constitute more than half of the total sedimentary column. The location of the continent-ocean transition zone has been interpreted from the aeromagnetic data. Strong gradients in the contour map of depth to magnetic basement coincide with the well-known Bjørnøya-Sørkapp Fault Zone. The strongest gradients seen elsewhere in the depth to basement map may therefore reveal major basement faults and/or flexures which define the margins of structural highs and troughs. In the Tertiary, the continental crust in the western part of the study area was deformed along NNW-SSE trending fault zones. These faults are sub-parallel to linear positive magnetic anomalies observed in the same area which reflect trends within the basement, and sub-parallel to major tectonic lines (including basement faults) mapped by geologists further to the north, on Spitsbergen. It is therefore inferred that (Precambrian?) basement fault or fracture zones have been reactivated in Phanerozoic times. East of a major tectonic line running N-S to NW-SE through the central part of the area, the basement map and the aeromagnetic map show variable trends, with NE-SW trends dominating. Comparison with deep seismic reflection data suggests that the interpreted discontinuity may represent a major Caledonian compressional structure (perhaps the Iapetus suture) which separates two different crustal terranes.

Aeromagnetic surveying at high latitudes, a case history from the northern Barents Sea

The need for geophysical data covering the northern Barents Sea (south of Svalbard) prompted the Geological Survey of Norway (NGU) and GECO a.s. to conduct an aeromagnetic survey for the oil industry, to identify the main structural features. The area lies between 15° and 32°E and between 74°30' and 78°N and is located within the auroral belt.