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Conducting assessments to understand the effects of changing environmental conditions on polar bear (Ursus maritimus) demography has become increasingly important to inform management and conservation. Here, we combined physical (2005–2007) and genetic (2017–2018) mark‐recapture with harvest recovery data (2005–2018) to estimate demographic rates of the Davis Strait polar bear subpopulation and examine the possible effects of climate, dynamic ice habitat, and prey resources on survival. Large sample sizes (e.g., 2,513 marked animals) allowed us to estimate temporal variation in annual survival rates using multistate mark‐recapture‐recovery models. We did not detect statistically significant effects of climate, ice habitat, and prey during the 13‐year study. Estimated total abundance in 2006 was 2,190, credible interval (CRI) [1,954, 2,454] and 1,944, CRI [1,593, 2,366] in 2018. Geometric mean population growth rate (0.99, 95% CRI [0.97, 1.01]) indicated the subpopulation may have declined slightly between 2006 and 2018. However, we did not detect a declining trend in survival or substantial change in reproductive metrics over this period. Given forecasts of major environmental change we emphasize the need to review monitoring programs for this subpopulation. [ABSTRACT FROM AUTHOR]

This paper analyzes the origins of two 1946 sightings of Soviet submarines in the Davis Strait, placing the various reports about them into an international and interservice framework. It shows how the Davis Strait and the surrounding area (Greenland, the Canadian Arctic, and Newfoundland and Labrador) fit into early post-World War II war plans for strategic deterrence. The Davis Strait sightings combined with American and British appreciations to spur Canada to endorse postwar joint defense plans with the Americans; to pursue trilateral intelligence, research, and defense work; and to agree to defense preparations in the north, including supporting American plans to establish strategic air forces in Goose Bay, Labrador. [ABSTRACT FROM AUTHOR]

In conditions of rapid development of trade and transport communications, the issue of navigation through ice regime zones became of greater importance. In particular, reduction of the area of ice cover in the Canadian Arctic because of global warming opens up favourable prospects for further development of maritime shipping in this zone. Considering that the routes through the Northwest Passage are the shortest ones of all the routes connecting the Atlantic and Pacific oceans, it is clear that all aspects of this topic are of great importance and relevance. This especially applies to the aspects dedicated to studying the characteristics of appearance, formation, concentration, physical characteristics, trajectory of ice movement and forecasting the area of the ice cover in a given zone, i.e. the characteristics affecting the conditions of ice navigation and serving as determining factors in terms of navigation safety. The research examines some of these issues, namely the spread of the ice cover during the period of its maximum formation across Davis Strait and the Labrador Sea (where the routes through the Northwest Passage start) and the establishment of statistical relations between the ice spread and the temperatures of surface water and surface air. The research method to be used: synoptic-climatic and statistical analysis of numerical series of ice cover deviations from its average limit as of April 15 over the period of 1979-2023 within the zone in study. Based on the set goal, the study processed raw data on distribution of ice cover across Davis Strait and the Labrador Sea for the period of 1979-2023 and completed its statistical analysis. The results of the analysis showed presence of a statistically significant negative trend and cyclical fluctuations with periods of 3-6, 9, 10 and 13 years in relation to the interannual variability of ice cover distribution for the studied period. Positive trends are also observed in the interannual variability of surface water temperature and surface air temperature. After bringing the original series to a quasi-stationary form, a correlation analysis of the relationships between the ice cover distribution and the temperature of water and air was carried out. The results of the analysis determined zones and points with statistically significant correlation coefficients between them during the year. It turned out that the highest values of coefficients are observed from December to March, and the maximum one occurs in March. Systematization and analysis of the ice field across Davis Strait and the Labrador Sea during the period of maximum development made it possible to establish that the spread of ice between 60° and 55° north parallels was the most stable during the studied period, and the least stable was observed in the area below 55° north parallel. The results of the conducted research open up prospects for development of methods for forecasting the distribution of ice cover across Davis Strait and the Labrador Sea. This will make ice navigation in this area safer.

Baffin Bay exports Arctic Water to the North Atlantic while receiving northward flowing Atlantic Water. Warm Atlantic Water has impacted the retreat of tidewater glaciers draining the Greenland Ice Sheet. Periods of enhanced Atlantic Water transport into Baffin Bay have been observed, but the oceanic processes are still not fully explained. At the end of 2010 the net transport at Davis Strait, the southern gateway to Baffin Bay, reversed from southward to northward for a month, leading to significant northward oceanic heat transport into Baffin Bay. This was associated with an extreme high in the Greenland Blocking Index and a stormtrack path that shifted away from Baffin Bay. Thus fewer cyclones in the Irminger Sea resulted in less frequent northerly winds along the western coast of Greenland, allowing anomalous northward penetration of warm waters, reversing the volume and heat transport at Davis Strait. Plain Language Summary: Baffin Bay exports cold and fresh Arctic Water to the North Atlantic while receiving northward flowing warm and saline Atlantic Water. This warm Atlantic Water has been shown to drive the retreat of tidewater glaciers. Periods of enhanced Atlantic Water transport into Baffin Bay have been observed. The oceanic processes that led to the enhanced transport of these warm waters into Baffin Bay are still not fully explained. Here we show from a combination of observational and model studies that at the end of 2010 the net transport at Davis Strait, the southern gateway to Baffin Bay, reversed from southward to northward for around a month, leading to significant northward oceanic heat transport into Baffin Bay. Anomalous winter winds kept the Atlantic Water on the West Greenland shelf, to propagate north into Baffin Bay instead of entering the interior Labrador Sea. At the same time, a mid‐level high pressure system sat over Greenland, efficiently preventing storms from reaching Baffin Bay. Anomalous winds also generated a positive transport signal that propagated cyclonically around Greenland, trapping warm waters on the West Greenland shelf, while also reversing the flow from the Arctic Ocean at Nares Strait. Key Points: Net transport through Davis and Nares Strait reversed from southward, in December 2010 to northward back toward the Arctic OceanThe transport reversal was driven by anomalous winter winds over the Labrador SeaThe anomalous winds were associated with a record high of the Greenland Blocking Index and a change in the storm track [ABSTRACT FROM AUTHOR]

A cyclone is an intensive synoptic activity that occurs frequently over Baffin Bay. By modifying the large‐scale distribution pattern of sea level pressure, a passing cyclone can serve as an important regulator of sea ice outflow via the Davis Strait. We obtain a nearly 40‐year‐long record (1979/1980–2017/2018) of the sea ice area flux (SIAF) through the Davis Strait and Arctic cyclone activities in winter. A case study and statistical results indicate that the sea ice concentration and motion fields can be greatly altered by the occurrence of cyclones, thereby contributing to changes in sea ice export. Moreover, the effects of cyclones on sea ice export in Baffin Bay are dependent on the spatial distribution pattern of the storms. In terms of the cyclone center count and intensity, the key regions with significant impacts on sea ice export out of Baffin Bay are identified, one around Baffin Island (80°W–60°W, 60°N–70°N) and the other over the southern Labrador Peninsula (70°W–50°W, 40°N–60°N). A robust correlation exists between the winter‐accumulated SIAF via the Davis Strait and the average winter cyclone intensity (center count) in the critical regions with R = −0.57 (+0.49), affirming the vital role of cyclone activity in modulating the interannual variability of sea ice export in Baffin Bay. Key Points: The wintertime sea ice area flux through the Davis Strait and cyclone activities nearby over the period 1979/1980–2017/2018 are acquiredStrong winds induced by cyclones can change the characteristics of sea ice and thus can impact sea ice export through the Davis StraitThe effects of cyclones on sea ice export through the Davis Strait are spatially dependent, and the key regions are identified [ABSTRACT FROM AUTHOR]

The North Atlantic subpolar gyre influences the climate in many different ways. Here, we identified that it is also responsible for a recent extreme event of Arctic Ocean freshwater export west of Greenland. A shift in climate regimes occurred in the mid-2000s, with a significant negative trend in the dynamic sea level in the subpolar gyre since then. We found that the dynamic sea level drop induced a strong increase in freshwater export west of Greenland, in particular from 2015 to 2017, when the sea level was close to the minimum. Sea ice melting and atmospheric variability in the Arctic had only a small contribution to this event. As the exported water from the Arctic Ocean has low salinity and constituents of chemical tracers very different from those in the North Atlantic, such events might have impacts on the North Atlantic ecosystem and the climate as well. Our study suggests that such events might be predictable if the subpolar gyre sea level has certain predictability.

Continental breakup between Greenland and North America produced the small oceanic basins of the Labrador Sea and Baffin Bay, which are connected via the Davis Strait, a region mostly comprised of continental crust. This study contributes to the debate regarding the role of pre-existing structures on rift development in this region using seismic reflection data from the Davis Strait data to produce a series of seismic surfaces, isochrons and a new offshore fault map from which three normal fault sets were identified as (i) NE-SW, (ii) NNW-SSE and (iii) NW-SE. These results were then integrated with plate reconstructions and onshore structural data allowing us to build a two-stage conceptual model for the offshore fault evolution in which basin formation was primarily controlled by rejuvenation of various types of pre-existing structures. During the first phase of rifting between at least Chron 27 (ca. 62 Ma; Palaeocene), but potentially earlier, and Chron 24 (ca. 54 Ma; Eocene) faulting was primarily controlled by pre-existing structures with oblique normal reactivation of both the NESW and NW-SE structural sets in addition to possible normal reactivation of the NNW-SSE structural set. In the second rifting stage between Chron 24 (ca. 54 Ma; Eocene) and Chron 13 (ca. 35 Ma; Oligocene), the sinistral Ungava transform fault system developed due to the lateral offset between the Labrador Sea and Baffin Bay. This lateral offset was established in the first rift stage possibly due to the presence of the Nagssugtoqidian and Torngat terranes being less susceptible to rift propagation. Without the influence of pre-existing structures the manifestation of deformation cannot be easily explained during either of the rifting phases. Although basement control diminished into the post-rift, the syn-rift basins from both rift stages continued to influence the location of sedimentation possibly due to differential compaction effects. Variable lithospheric strength through the rifting cycle may provide an explanation for the observed diminishing role of basement structures through time. [ABSTRACT FROM AUTHOR]

An efficient approach to ocean–iceberg modelling provides a means for assessing prospects for seasonal forecasting of iceberg distributions in the northwest Atlantic, where icebergs present a hazard to mariners each spring. The stand-alone surface (SAS) module that is part of the Nucleus for European Modelling of the Ocean (NEMO) is coupled with the NEMO iceberg module (ICB) in a “SAS-ICB” configuration with horizontal resolution of 0.25°. Iceberg conditions are investigated for three recent years, 2013–2015, characterized by widely varying iceberg distributions. The relative simplicity of SAS-ICB facilitates efficient investigation of sensitivity to iceberg fluxes and prevailing environmental conditions. SAS-ICB is provided with daily surface ocean analysis fields from the global Forecasting Ocean Assimilation Model (FOAM) of the Met Office. Surface currents, temperatures and height together determine iceberg advection and melting rates. Iceberg drift is further governed by surface winds, which are updated every 3 h. The flux of icebergs from the Greenland ice sheet is determined from engineering control theory and specified as an upstream flux in the vicinity of Davis Strait for January or February. Simulated iceberg distributions are evaluated alongside observations reported and archived by the International Ice Patrol. The best agreement with observations is obtained when variability in both upstream iceberg flux and oceanographic/atmospheric conditions is taken into account. Including interactive icebergs in an ocean–atmosphere model with sufficient seasonal forecast skill, and provided with accurate winter iceberg fluxes, it is concluded that seasonal forecasts of spring/summer iceberg conditions for the northwest Atlantic are now a realistic prospect. [ABSTRACT FROM AUTHOR]

Cascading of dense water from the shelf to deeper layers of the adjacent ocean basin has been observed in several locations around the world. The West Greenland Shelf (WGS), however, is a region where this process has never been documented. In this study, we use a numerical model with a 1/4° resolution to determine (i) if cascading could happen from the WGS; (ii) where and when it could take place; (iii) the forcings that induce or halt this process; and (iv) the path of the dense plume. Results show cascading happening off the WGS at Davis Strait. Dense waters form there due to brine rejection and slide down the slope during spring. Once the dense plume leaves the shelf, it gradually mixes with waters of similar density and moves northward into Baffin Bay. Our simulation showed events happening between 2003-2006 and during 2014; but no plume was observed in the simulation between 2007 and 2013. We suggest that the reason why cascading was halted in this period is related to: the increased freshwater transport from the Arctic Ocean through Fram Strait; the additional sea ice melting in the region; and the reduced presence of Irminger Water at Davis Strait during fall/early winter. Although observations at Davis Strait show that our simulation usually overestimates the seasonal range of temperature and salinity, they agree with the overall variability captured by the model. This suggests that cascades have the potential to develop on the WGS, albeit less dense than the ones estimated by the simulation. [ABSTRACT FROM AUTHOR]

Satellite-derived sea-ice concentration (SIC) and re-analysed atmospheric data are used to analyse the potential feedback of the North Atlantic Oscillation (NAO)-driven sea-ice anomalies in winter onto the atmosphere during 1979-2013. A maximum covariance analysis shows that this feedback can be detected with monthly data. When SIC leads, the covariability between Atlantic SIC and the Euro-Atlantic atmospheric circulation in February is statistically significant, but shows intra-seasonal differences: the December SIC influence is dominated by anomalies east of Greenland, with maximum amplitude in the Greenland Sea (GS); while the January SIC influence is dominated by anomalies west of Greenland, in the Davis Strait-Labrador Sea (DL) region. The lagged atmospheric anomalies are likewise different. A reduction of SIC over GS in December is followed in February by a negative NAO-like pattern near the surface and a hemispheric signature in the upper-troposphere, thus acting as a negative feedback. On the other hand, a reduction of SIC over DL in January is followed by an atmospheric anomaly over the North Atlantic that projects on the positive phase of the East Atlantic pattern. The dynamics associated with these atmospheric anomalies is described, indicating that transient-eddy activity is likely at work in settling the large-scale patterns. The role of concomitant North Atlantic sea surface temperature anomalies is discussed. [ABSTRACT FROM AUTHOR]

Assessing changes in sea surface conditions due to the effects of past freshwater outflow through Baffin Bay and Davis Strait to the Labrador Sea, hereafter referred to as the Baffin Bay corridor, is relevant in understanding the variability in Labrador Sea Water (LSW) formation. Here, regional changes in oceanographic circulation and sea surface conditions are reconstructed based on organic-walled dinoflagellate cyst (dinocyst) assemblages from four cores collected from deep, central sites of the Baffin Bay corridor. All cores exhibit a major shift in dinocyst assemblages since the late glacial period. This shift consists of a change from a polar–subpolar heterotrophic species assemblage tolerating cold and near permanent ice-covered conditions, to assemblages characterized by a higher diversity and the occurrence of phototrophic taxa associated with mild conditions. Sea surface reconstructions from the modern analogue technique display a shift from harsh, quasi-perennial ice cover to warmer summer sea surface temperatures and a seasonal sea ice. South of the Davis Strait sill, this regime shift occurred at ca. 11.9 cal ka BP due to the influence of North Atlantic waters. Baffin Bay, however, remained densely sea ice covered until about 7.4 cal ka BP, when these warmer waters penetrated into Baffin Bay and mixed with the West Greenland Current (WGC). This mixing was facilitated by the retreat of the Greenland and Laurentide Ice Sheet (LIS) margins. A major change in Labrador Sea surface conditions occurred nearly at about the same time (~7.6 cal ka BP) when the strong stratification of surface waters weakened because of the reduction in meltwater supplies from the LIS that allowed winter convection and the inception of LSW formation. All these new records demonstrate large amplitude fluctuations in sea surface conditions tightly controlled by the relative strengths and shifts of the warmer WGC and colder Baffin Island Current. [ABSTRACT FROM AUTHOR]

The Greenland ice sheet (GrIS) advanced onto the continental shelf during the last glacial period. While deglacial records for when the GrIS withdrew onto the modern coastline are relatively abundant, the timing of early GrIS retreat on the shelf is poorly constrained. Here we use planktic foraminiferal δ 18 O, sediment grain size, sedimentation rates, and 14 C ages in southeastern Davis Strait core HU87033-008 to develop an early deglaciation chronology of the southwestern GrIS while on the continental shelf. Sedimentation rates, and especially silt and clay fractions, are high between ∼20.5 and ∼17.1 ka, suggesting that the southwestern GrIS margin was near or at the shelf break, where it released subglacially derived sediment-laden meltwater. A peak in sedimentation rates of ∼110 cm ka −1 between ∼19.3 ka and ∼18.6 ka, combined with an initial decrease in planktic δ 18 O of ∼0.5 per mil, suggests an early deglacial pull back of the GrIS margin from the shelf break with a concurrent increase in surface ocean meltwater discharge. A subsequent planktic δ 18 O decrease of ∼1.0 per mil combined with a drop in silt and clay sedimentation rates at 18–17 ka likely record further GrIS retreat inland from the shelf break. Terrestrial 10 Be surface exposure ages indicate that the GrIS margin remained on the continental shelf until ∼11 ka, yet the cause of this subsequent ice-margin stability on the inner shelf is not known. Our new records provide the first evidence that the southwestern GrIS margin may have begun to deglaciate at the same time as other Northern Hemisphere ice sheets. As Labrador Sea water temperatures likely remained near glacial values until ∼15 ka, we suggest that initial southwestern GrIS retreat was in response to rising global sea level from retreat of other ice sheets and/or the initial deglacial rise in boreal summer insolation. [ABSTRACT FROM AUTHOR]

Abstract: Depth profiles of dissolved methane were measured along three transects of Davis Strait and the northern Labrador Sea in October 2011. Concentrations ranged from 0.2nmolL−1 (6% saturation) in the remarkably methane depleted Baffin Bay Deep Water to 38.8nmolL−1 (1057% saturation) in localised subsurface anomalies near the Baffin Island Shelf. These anomalies may be the result of natural gas seepage and this hypothesis is supported by the distribution of potential sea surface oil slicks detected by satellite radar backscatter. In contrast, methane concentrations within the Baffin Island Current 200km to the south of these anomalies were only slightly above atmospheric equilibrium. Methane was moderately supersaturated in West Greenland Shelf Water (<200%) with a distribution consistent with a sediment source. These measurements represent the first detailed baseline study of the vertical distribution of dissolved methane in an important Canadian Arctic Archipelago outflow region. [Copyright &y& Elsevier]

Davis Strait is a primary gateway for freshwater exchange between the Arctic and North Atlantic Oceans including freshwater contributions from west Greenland and Canadian Arctic Archipelago glacial melt. Data from six years (2004-10) of continuous measurements collected by a full-strait moored array and concurrent high-resolution Seaglider surveys are used to estimate volume and liquid freshwater transports through Davis Strait, with respective annual averages of −1.6 ± 0.5 Sverdrups (Sv; 1 Sv ≡ 106 m3 s−1) and −93 ± 6 mSv (negative sign indicates southward transport). Sea ice export contributes an additional −10 ± 1 mSv of freshwater transport, estimated using satellite ice area transport and moored upward-looking sonar ice thickness measurements. Interannual and annual variability of the net transports are large, with average annual volume and liquid freshwater transport standard deviations of 0.7 Sv and 17 mSv and with interannual standard deviations of 0.3 Sv and 15 mSv. Moreover, there are no clear trends in the net transports over the 6-yr period. However, salinity in the upper 250 m between Baffin Island and midstrait decreases starting in September 2009 and remains below average through August 2010, but appears to return to normal by the end of 2010. This freshening event, likely caused by changes in arctic freshwater storage, is not apparent in the liquid freshwater transport time series due to a reduction in southward volume transport in 2009-10. Reanalysis of Davis Strait mooring data from the period 1987-90, compared to the 2004-10 measurements, reveals less arctic outflow and warmer, more saline North Atlantic inflow during the most recent period. [ABSTRACT FROM AUTHOR]

Reconstructing the opening of the Labrador Sea and Baffin Bay between Greenland and North America remains controversial. Recent seismic data suggest that magnetic lineations along the margins of the Labrador Sea, originally interpreted as seafloor spreading anomalies, may lie within the crust of the continent-ocean transition. These data also suggest a more seaward extent of continental crust within the Greenland margin near Davis Strait than assumed in previous full-fit reconstructions. Our study focuses on reconstructing the full-fit configuration of Greenland and North America using an approach that considers continental deformation in a quantitative manner. We use gravity inversion to map crustal thickness across the conjugate margins, and assimilate observations from available seismic profiles and potential field data to constrain the likely extent of different crustal types. We derive end-member continental margin restorations following alternative interpretations of published seismic profiles. The boundaries between continental and oceanic crust (COB) are restored to their pre-stretching locations along small circle motion paths across the region of Cretaceous extension. Restored COBs are fitted quantitatively to compute alternative total-fit reconstructions. A preferred full-fit model is chosen based on the strongest compatibility with geological and geophysical data. Our preferred model suggests that (i) the COB lies oceanward of magnetic lineations interpreted as magnetic anomaly 31 (70 Ma) in the Labrador Sea, (ii) all previously identified magnetic lineations landward of anomaly 27 reflect intrusions into continental crust and (iii) the Ungava fault zone in Davis Strait acted as a leaky transform fault during rifting. This robust plate reconstruction reduces gaps and overlaps in Davis Strait and suggests that there is no need for alternative models proposed for reconstructions of this area including additional plate boundaries in North America or Greenland. Our favoured model implies that break-up and formation of continent-ocean transition (COT) first started in the southern Labrador Sea and Davis Strait around 88Ma and then propagated north and southwards up to the onset of real seafloor spreading at 63 Ma in the Labrador Sea. In Baffin Bay, continental stretching lasted longer and actual break-up and seafloor spreading started around 61 Ma (chron 26). [ABSTRACT FROM AUTHOR]

The Davis Strait is located between Canada and Greenland and connects the Labrador Sea and the Baffin Bay basins. Both basins formed in Cretaceous to Eocene time and were connected by a transform fault system in the Davis Strait. Whether the crust in the central Davis Strait is oceanic or continental has been disputed. This information is needed to understand the evolution of this transform margin during the separation of the North American plate and Greenland. We here present a 315-km-long east–west-oriented profile that crosses the Davis Strait and two major transform fault systems—the Ungava Fault Complex and the Hudson Fracture Zone. By forward modelling of data from 12 ocean bottom seismographs, we develop a P-wave velocity model. We compare this model with a density model from ship-borne gravity data. Seismic reflection and magnetic anomaly data support and complement the interpretation. Most of the crust is covered by basalt flows that indicate extensive volcanism in the Davis Strait. While the upper crust is uniform, the middle and lower crust are characterized by higher P-wave velocities and densities at the location of the Ungava Fault Complex. Here, P-wave velocities of the middle crust are 6.6 km s−1 and of the lower crust are 7.1 km s−1 compared to 6.3 and 6.8 km s−1 outside this area; densities are 2850 and 3050 kg m−3 compared to 2800 and 2900 kg m−3. We here interpret a 45-km-long section as stretched and intruded crust or as new igneous crust that correlates with oceanic crust in the southern Davis Strait. A high-velocity lower crust (6.9–7.3 km s−1) indicates a high content of mafic material. This mantle-derived material gradually intruded the lower crust of the adjacent continental crust and can be related to the Iceland mantle plume. With plate kinematic modelling, we can demonstrate the importance of two transform fault systems in the Davis Strait: the Ungava Fault Complex with transpression and the Hudson Fracture Zone with pure strike-slip motion. We show that with recent poles of rotation, most of the relative motion between the North American plate and Greenland took place along the Hudson Fracture Zone. [ABSTRACT FROM AUTHOR]

The Arctic Ocean is increasingly becoming accessible to international shipping as a result of the reduction in Arctic sea ice. Commercial shipping may seek to transit the Arctic Ocean from either the Pacific or Atlantic Ocean and, as a result, the legal regime of straits has significance for trans-Arctic navigation. In this article, current developments in Arctic shipping are assessed and consideration is given to certain Arctic straits that could prove to be pivotal in future Arctic navigation and shipping. These straits include the Bering Strait, Nares Strait, Davis Strait, Fram Strait, and Denmark Strait. [ABSTRACT FROM PUBLISHER]

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Davis Strait volume [[−−2.3 ±± 0.7 Sv (1 Sv ≡≡ 106 m3 s−−1); negative sign indicates southward transport]], freshwater (−−116 ±± 41 mSv), and heat (20 ±± 9 TW) fluxes estimated from objectively mapped 2004--05 moored array data do not differ significantly from values based on a 1987--90 array but are distributed differently across the strait. The 2004--05 array provided the first year-long measurements in the upper 100 m and over the shelves. The upper 100 m accounts for 39%% (−−0.9 Sv) of the net volume and 59%% (−−69 mSv) of the net freshwater fluxes. Shelf contributions are small: 0.4 Sv (volume), 15 mSv (freshwater), and 3 TW (heat) from the West Greenland shelf and −−0.1 Sv, −−7 mSv, and 1 TW from the Baffin Island shelf. Contemporaneous measurements of the Baffin Bay inflows and outflows indicate that volume and freshwater budgets balance to within 26%% and 4%%, respectively, of the net Davis Strait outflow. Davis Strait volume and freshwater fluxes nearly equal those from Fram Strait, indicating that both are significant Arctic freshwater pathways. [ABSTRACT FROM AUTHOR]

Most baleen whales undertake migrations between low-latitude breeding grounds and high-latitude feeding grounds. Though little is known about the timing of their migration from the Arctic, fin whales are assumed to undertake a similar migratory pattern. To address questions about habitat use and migrations, the acoustic activity of fin whales in Davis Strait, between Greenland and Canada, was monitored continuously for two years using three bottom-moored acoustic recorders. The acoustic power in the fin whale call frequencies peaked in November-December, showing that fin whales are present in Davis Strait much later in the year than previously expected. The closely timed peaks in song activity and conception time imply that not all fin whales migrate south to mate, but rather start mating at high latitudes rather than or before migrating. Singing activity was strongly linked to daylight hours, suggesting that fin whales might feed during the few daylight hours of the late fall and early Arctic winter. A negative correlation between the advancing sea ice front and power in fin whale frequencies indicates that future changes in sea ice conditions from global warming might change the distribution and migratory patterns of fin whales near the poles. [ABSTRACT FROM AUTHOR]

Nine specimens belonging to four separate species and two genera from Davis Strait and Hudson Strait exceeded the known maximum recorded sizes for their associated species. New size records are given for Bathypolypus pugniger, B. bairdii, B. arcticus and Cirroteuthis muelleri. All individuals were found within the same basin (532 to 1453 m) within Davis Strait with the exception of B. arcticus which was found along the trench (284 to 388 m) that runs through the middle of Hudson Strait. Six large sized Gonatus fabricii were also found in the same region of Davis Strait, but did not exceed the maximum size of 385 mm, a female caught in the Norwegian Sea. Since these two regions are the only areas where such large individuals were found, we speculate that these areas are of particular interest as potential spawning sites and are oceanographically and biologically favourable for the maintenance of large individuals. [ABSTRACT FROM AUTHOR]

We investigate some aspects of the variability of the Arctic freshwater content during the 1965–2002 period using the DRAKKAR eddy admitting global ocean/sea-ice model (12 km resolution in the Arctic). A comparison with recent mooring sections shows that the model realistically represents the major advective exchanges with the Arctic basin, through Bering, Fram and Davis Straits, and the Barents Sea. This allows the separate contributions of the inflows and outflows across each section to be quantified. In the model, the Arctic freshwater content variability is explained by the sea-ice flux at Fram and the combined variations of ocean freshwater inflow (at Bering) and outflow (at Fram and Davis). At all routes, except trough Fram Strait, the freshwater transport variability is mainly accounted for by the liquid component, with small contributions from the sea-ice flux. The ocean freshwater transport variability through both Davis and Fram is controlled by the variability of the export branch (Baffin Island Current and East Greenland Current, respectively), the variability of the inflow branches playing a minor role. We examine the respective role of velocity and salinity fluctuations in the variability of the ocean freshwater transport. Fram and Davis Straits offer a striking contrast in this regard. Freshwater transport variations across Davis Strait are completely determined by the variations of the total volume flux (0.91 correlation). On the other hand, the freshwater transport through Fram Strait depends both on variations of volume transport and salinity. As a result, there is no significant correlation between the variability of freshwater flux at Fram and Davis, although the volume transports on each side of Greenland are strongly anti-correlated (−0.84). Contrary to Davis Strait, the salinity of water carried by the East Greenland Current through Fram Strait varies strongly due to the ice-ocean flux north of Greenland. [ABSTRACT FROM AUTHOR]

The crustal structure in the southern Davis Strait and the adjacent ocean–continent transition zone in NE Labrador Sea was determined along a 185-km-long refraction/wide-angle reflection seismic transect to study the impact of the Iceland mantle plume to this region. A P-wave velocity model was developed from forward and inverse modelling of dense airgun shots recorded by ocean bottom seismographs. A coincident industry multichannel reflection seismic profile was used to guide the modelling as reflectivity could be identified down to Moho. The model displays a marked lateral change of velocity structure. The sedimentary cover (velocities 1.8–3.9 km s−1) is up to 4 km thick in the north and thins to 1 km in the south. The segment of the line within southern Davis Strait is interpreted to be of continental character with a two-layered 13-km-thick crust with P-wave velocities of 5.6–5.8 and 6.4–6.7 km s−1 in the upper and lower crust, respectively. The crust is underlain by a 2- to 4-km-thick high-velocity layer (7.5 km s−1). This layer we interpret as underplated material related to the Iceland plume. The southern segment of the line in Labrador Sea displays a 2-km-thick layer with a velocity of 4.5 km s−1. This layer can be correlated to a well about 100 km to the west of the line, where Palaeocene basalts and interbedded sediments were drilled. Underneath is a 12-km-thick crust with a 2-km-thick upper layer (5.8–6.6 km s−1) and a 10-km-thick lower layer (6.8–7.2 km s−1). This crust is interpreted to be of oceanic character. S-wave modelling yields a Poisson's ratio of 0.28 for the lower crust, compatible with a gabbroic composition. The igneous crust is 5 km thicker than normal oceanic crust. We suggest that the increased magma production was created by buoyancy-driving flow. We propose a model in which initial seafloor spreading occurred between Labrador and West Greenland, when the Iceland plume arrived in the area at ∼62 Ma and caused enhanced magma production. Shortly afterwards (chron 27–26), plume material was channelled southward underplating part of Davis Strait and forming basaltic flows interbedded with sediment. [ABSTRACT FROM AUTHOR]

Twenty-one narwhals tagged in 2003 and 2004 in Admiralty Inlet showed a different summer distributional pattern than previous narwhal-tracking studies from Somerset Island, Eclipse Sound and Melville Bay. The migration of the narwhals tracked from Admiralty Inlet moved out through Lancaster Sound 15 days earlier ( P < 0.0001) than the narwhals summering around Eclipse Sound, whereas the Admiralty Inlet narwhals reached the mouths of Eclipse Sound 18 days later ( P < 0.0001) than the Eclipse Sound summering population. The winter range of the Admiralty Inlet narwhals overlapped with the winter range of narwhals from Melville Bay and Eclipse Sound in central southern Baffin Bay and Northern Davis Strait, but not with the winter range of narwhals from Somerset Island that wintered further north. Distribution size of range, and population size did not appear to be related. An example of considerable year to year variation between area of summer and winter distribution in the 2 years was believed to be related to the sample size and number of pods of whales tagged, rather than to differences in sex or age classes. [ABSTRACT FROM AUTHOR]

Abstract: A small population of endangered northern bottlenose whales (Hyperoodon ampullatus) inhabits “The Gully” a Marine Protected Area on the Scotian Shelf, eastern Canada. Amid concerns regarding nearby oil and gas development, we took 36 skin and blubber biopsy samples in 1996–1997 (prior to major development) and 2002–2003 (five years after development began), and three samples from a population in the Davis Strait, Labrador in 2003. These were analysed for cytochrome P4501A1 (CYP1A1) protein expression (n =36), and for persistent contaminants (n =23). CYP1A1 showed generally low expression in whales from The Gully, but higher levels during 2003, potentially coincident with recorded oil spills, and higher levels in Davis Strait whales. A range of PCB congeners and organochlorine compounds were detected, with concentrations similar to other North Atlantic odontocetes. Concentrations were higher in whales from The Gully than from the Davis Strait, with significant increases in 4,4′-DDE and trans-nonachlor in 2002–2003 relative to 1996–1997. [Copyright &y& Elsevier]

Abstract: Sea ice concentration derived from satellite data were used to quantify sea ice characteristics in the Baffin Bay–Davis Strait–Labrador Sea area. The ice edge in Davis Strait extends from Disko Bay in West Greenland 2500 km south to Newfoundland. The mean intercept at the West Greenland coast between 1979 and 2002 was located at 66.9°N, assuming the ice edge was 85% ice concentration. The shallow banks of West Greenland (>200 m) had, on average, an ice extent covering 30 to 100% of the bank area during March for the 24 year time series. This extent varied in concentration between 39 and 100%. However, intermediate ice concentrations (39–85% ice concentration) covered on average 25% of the banks. The Davis Strait ice edge showed considerable interannual variation correlated with the winter index of the North Atlantic Oscillation and the Arctic Oscillation. No temporal trend in ice extent could be detected over the 24 years. In addition to the ice production on the banks of West Greenland, sea ice produced further north in Baffin Bay was advected to the banks as shown by satellite tracked drifting buoys. Both the local sea ice production and the advected sea ice contributed significantly to sea temperatures and salinities measured during summer on the banks. No correlation between sea ice concentration and plankton abundance could be detected but the recruitment of the offshore cod (Gadus morhua) component in South Greenland was negatively correlated to the amount of sea ice in Baffin Bay. [Copyright &y& Elsevier]

Abstract: The continental margin of Baffin Island was interpreted from a compilation of seismic reflection and potential field data. Based on these data, it was divided into volcanic and non-volcanic segments. In the northernmost area, coast-parallel grabens and continental basement highs are superseded beneath the slope by irregular basement topography. In combination with the velocities from refraction data and the lack of a magnetic slope anomaly, we propose a non-volcanic margin. In the central region, the seismic data show a limited region with a seaward dipping reflector sequence that may be intercalated with a sedimentary section. Both north and south of Cape Dyer extensive volcanic rocks are interpreted at and below seabed consistent with a volcanic margin. In the southern region, the depth to basement drops rapidly offshore. A thick prograding sedimentary wedge produces a high-amplitude long-wavelength free-air gravity anomaly that was previously confused with the continent–ocean boundary. Although some volcanic rocks are mapped in the region, this area is adjacent to the non-volcanic Labrador Sea margin and is interpreted to be of similar structure. Segmentation of the margin by major faults can explain the abrupt transitions from volcanic to non-volcanic margin segments. The continent–ocean boundary for the region is determined based on the potential field and seismic data. Along the Greenland plate in Davis Strait the continent–ocean boundary coincides with the Ungava Fault Zone. The continent–ocean boundary is used in conjunction with published poles of rotation to evaluate plate reconstructions at chrons 33n and 27n. The earlier reconstruction produces an extensive overlap of boundaries in the north. The later reconstruction shows a gap in the southern region. Thus, additional information is required to refine the reconstructions. [Copyright &y& Elsevier]

The bathymetry of Baffin Bay, with shallow sills both to the north and south, creates a relatively isolated body of deep polar water, unique among the Arctic Seas. During 263 trawl hauls completed during October 1999 and September to November 2001, 116 fish species were collected in Davis Strait and the southern Baffin Bay (61°44.1′ N–73°52.8′ N, depths of 145–1484 m). The abundance data for the 80 benthic species were used for analyses of the fish fauna diversity and fish assemblages. As a first step, seven assemblages were found by a standard type of cluster analysis. A Bayesian multinomial logit model was then applied to calculate vectors of probabilities defining the likelihood of each haul belonging to each of the seven clusters. The spatial distribution of the conditional probabilities for each cluster (assemblage) was mapped by means of a geostatistical tool. Each assemblage was further defined by indicator species, depth, and temperature. Four of the assemblages were found in Baffin Bay, two in Davis Strait and one mainly in Davis Strait but scattered into Baffin Bay. [ABSTRACT FROM AUTHOR]

Abstract: Volume, freshwater and heat transport through Davis Strait, the northern boundary of the Labrador Basin, are computed using a mooring array deployed for three consecutive years. The net volume, freshwater and heat transports are , , . Both southward and northward volume and freshwater transports are maximum in November. The seasonal variability is dictated by the variability in the main water mass transports: Irminger Sea Water, West Greenland shelf water, surface meltwater, and a cold intermediate layer (CIL) originating from Lancaster Sound. The southward freshwater transport seasonal amplitude is dominated by the CIL transport rather than the surface meltwater layer. Sea-ice transport through Davis Strait deduced from remote sensing data is equal to which is much smaller than equivalent estimates for Fram Strait. Using these new estimates, we attempt to close the Arctic Ocean volume and freshwater budget. [Copyright &y& Elsevier]

Abstract: The oceanographic, meteorological and sea-ice conditions in Baffin Bay are studied using historical hydrographic, satellite and meteorological data, and a set of current meter data from a mooring program of the Bedford Institute of Oceanography. Baffin Bay is partially covered by sea-ice all year except August and September. The interannual variation of the ice extent is shown to be correlated with winter air temperature. Available hydrographic data were used to study the water masses and the horizontal and vertical distribution of temperature/salinity. Three water masses can be identified – Arctic Water in the upper 100–300m of all regions except the southeast, West Greenland Intermediate Water at 300–800m in most of the interior of Baffin Bay, and Deep Baffin Bay Water in all regions below 1200m. The temperature and salinity in Baffin Bay have limited seasonal variability except in the upper 300 m of eastern Davis Strait, northern Baffin Bay and the mouth of Lancaster Sound. Summer data have a temperature minimum at ∼100m, which suggests winter convection does not penetrate deeper than this depth. Current meter data and results of a circulation model indicate that the mean circulation is cyclonic. The seasonal variation of the currents is complex. Overall, summer and fall tend to have stronger currents than winter and spring at all depths. Among the different regions, the largest seasonal variation occurs at the mouth of Lancaster Sound and the Baffin Island slope. Model generated velocity fields show a basic agreement with the observed currents, and indicate strong topographic control in the vicinity of Davis Strait and on the Greenland shelves. The model also produces a southward counter current on the Greenland slope, which may explain the observed high horizontal shears over the Greenland slope. Estimates of the volume and fresh water transports through Lancaster, Jones and Smith Sounds are reviewed. Transports through Davis Strait are computed from the current meter data. The balance of freshwater budget and sensitivity of the thermohaline circulation to freshwater transport are discussed. [Copyright &y& Elsevier]

This paper presents a bio economic analysis determining the resource rent and optimum effort of the shrimp (Pandalus borealis) fishery in the Davis Strait, taking into account the discard behaviour of the fleet. It is demonstrated that, from an economic point of view, the shrimp stock in the Davis Strait is substantially overfished. In order to obtain the maximum economic yield, the effort must be reduced by at least 40% compared to the effort level of 1991. The gain in resource rent by reducing effort is estimated to be at least 20% compared to the resource rent of 1991. [ABSTRACT FROM AUTHOR]

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The article discusses eighteenth and nineteenth-century whaling of the North Atlantic Greenland Right whale, Balaena mysticetus, in the Davis Strait focusing on season environmental factors facing whalers in the area, using historical sources from Scottish whaling operations such as journals, diaries, and ships' logs. The whale fishery of the strait used ice edge operations and thus information regarding wind, currents, and temperatures were important features in deciding the outcome of whaling ventures. Topics include the Baffin land current, the Labrador Current, and charts of whale sightings and whale captures for the period.

Vertebral counts of Greenland halibut collected from West Greenland in 1995 were compared to samples from the same areas for the period 1987–1989. The 1995 samples, obtained in Davis Strait, Baffin Bay, and two North-west Greenland fjords, showed no significant differences in mean vertebral numbers. Previous studies in 1987–1989, however, showed significant differences in mean vertebral counts between some of the same areas. Inter-annual variation in vertebral numbers is therefore suggested to be greater than the variation between sample areas. Despite the protracted egg and larval stage of Greenland halibut, the currents along the West Coast of Greenland are unlikely to transport juveniles in any significant amount from the Davis Strait spawning grounds to the North-west Greenland fjords. The origin of the northernmost populations therefore remains unknown. As single cohorts in the material seem to affect the total average counts per area significantly it is suggested that a change in the distribution of Greenland halibut might have occurred during the period studied. The results also emphasize the importance of relying on data based on more than one year and question the suitability of vertebral counts in stock delineation studies of Greenland halibut. [ABSTRACT FROM PUBLISHER]

Voluminous, subaerial, ultra-depleted, 62 Ma, primary picritic lavas lie on conjugate volcanic margins on both sides of Davis Strait separating Baffin Island and West Greenland. Temporally, these picrites erupted just prior to, and coeval with, the initiation of sea-floor spreading in Labrador Sea and Baffin Bay. Petrogenetically, the chemical characteristics of these picrites (MgO = 18–21 wt%; K 2 O = 0.01–0.20 wt%; 87Sr/86Sr i ≈ 0.7030; εNd i ≈ +5.2–8.6; 3He/4He ≤ 49.5R A) are those of D-MORBs that demand derivation only by partial melting of highly incompatible-element depleted subcontinental lithospheric mantle (SCLM) at a pressure of ~ 4 GPa, followed by rapid ascent to the surface, but do not necessarily require high temperatures or high degrees of partial melting. Tectonically, these picrites formed near Paleoproterozoic suture zones in the SCLM of thick Paleoproterozoic cratonic terranes during Paleogene rifting between Greenland and North America. Structurally, the picrites are related to the major intersection of a NNW-trending lithospheric thinning under Baffin Bay and the ~E-W-trending thickened lithosphere of the Paleoproterozoic Nagssugtoqidian Fold Belt. During the late Mesozoic, ENE extension that thinned the mantle lithosphere and created normal-faulted basins. Elastic finite-element models and present-day studies of crustal extension show that the thicker Nagssugtoqidian Fold Belt underwent less thinning and extension than the Baffin Bay lithosphere. These extensional disparities occurred at the orthogonal intersection of pre-existing ~E-W-trending strike-slip faults in the thicker Nagssugtoqidian Fold Belt with the incipient spreading under Baffin Bay, and likely resulted in the formation of one or more pull-apart basins. Because the strike-slip faults are ancient suture zones, trans-tension within these suture zones easily reached depths of ~120 km, not only creating adiabatic decompression melting in the SCLM, but also forming an open pathway for the picritic melts to rapidly reach the surface. This purely tectonic model requires no spatially or temporally improbable deep mantle plume for generation of the Paleocene picrites of Davis Strait. [ABSTRACT FROM AUTHOR]