Lancaster Sound Research Articles

The Canadian Arctic Archipelago throughflow in a multiresolution global model: Model assessment and the driving mechanism of interannual variability

The volume and freshwater transports through the Canadian Arctic Archipelago (CAA) are assessed using the unstructured‐mesh Finite Element Sea ice‐Ocean Model (FESOM) in a global setup with the CAA resolved at 5 km scale. The hindcast simulation realistically represents fluxes through the main gates of the Arctic Ocean and the Arctic sea ice conditions. During the period 1968–2007, the mean volume transports through Lancaster Sound and Nares Strait amount to 0.86 and 0.91 Sv, respectively. The monthly mean volume transport through western Lancaster Sound is highly correlated with the observational estimate (r = 0.81). The seasonal variability of the Lancaster Sound transport is well represented in the model. The simulated mean CAA freshwater export rate is 123 mSv, slightly higher than the observational estimate. The interannual variability of CAA volume transports is determined by sea surface height (SSH) gradients between the Arctic Ocean and northern Baffin Bay. The sea level upstream of Lancaster Sound is mainly determined by that along the Beaufort Sea coast, which can be explained by changes in the wind regimes (cyclonic versus anticyclonic) associated with release or accumulation of freshwater in the Beaufort Gyre. Sea level variations downstream of Lancaster Sound and Nares Strait are connected to SSH variations in the eastern Baffin Bay and in the Labrador Sea, which can be attributed to the variability of ocean‐atmosphere heat fluxes. Both processes upstream and downstream of the CAA are linked with the North Atlantic Oscillation type of atmospheric variability. The local mesh refinement of ∼5 km allows us to investigate the contribution of individual narrow straits to the Parry Channel volume transport. The volume transports through these straits show a very similar variability.

Distribution and sources of organic matter in surface marine sediments across the North American Arctic margin

As part of the International Polar Year research program, we conducted a survey of surface marine sediments from box cores along a section extending from the Bering Sea to Davis Strait via the Canadian Archipelago. We used bulk elemental and isotopic compositions, together with biomarkers and principal components analysis, to elucidate the distribution of marine and terrestrial organic matter in different regions of the North American Arctic margin. Marked regional contrasts were observed in organic carbon loadings, with the highest values (≥1 mg C m−2 sediment) found in sites along Barrow Canyon and the Chukchi and Bering shelves, all of which were characterized by sediments with low oxygen exposure, as inferred from thin layers (<2 cm) of Mn oxihydroxides. We found strong regional differences in inorganic carbon concentrations, with sites from the Canadian Archipelago and Lancaster Sound displaying elevated values (2–7 wt %) and highly depleted 14C compositions consistent with inputs from bedrock carbonates. Organic carbon:nitrogen ratios, stable carbon isotopes, and terrigenous organic biomarkers (lignin phenols and cutin acids) all indicate marked regional differences in the proportions of marine and terrigenous organic matter present in surface sediments. Regions such as Barrow Canyon and the Mackenzie River shelf were characterized by the highest contributions of land‐derived organic matter, with compositional characteristics that suggested distinct sources and provenance. In contrast, sediments from the Canadian Archipelago and Davis Strait had the smallest contributions of terrigenous organic matter and the lowest organic carbon loadings indicative of a high degree of post‐depositional oxidation.

Distribution and abundance of killer whales (Orcinus orca) in Nunavut, Canada—an Inuit knowledge survey

Traditional ecological knowledge is being increasingly used in wildlife management in northern regions, and Inuit harvesters in Nunavut, Canada, have extensive knowledge about local wildlife species. We collected Inuit knowledge on killer whales (Orcinus orca) through 105 semi-directed interviews in 11 Nunavut communities from 2007 to 2010. Interviewees provided extensive information on killer whale movements, seasonal presence, distribution and abundance in the eastern Canadian Arctic. Observations from different communities were often complementary, and there was consistency in interview comments both within and among regions. Nearly all participants had seen killer whales at least once, and the whales were present every summer (July–September) in all regions, although movements depended on ice conditions. Relative abundance of killer whales varied by region, and they were reported more often in North Baffin communities than in other regions. Killer whales migrated through Hudson Strait and Lancaster Sound following their marine mammal prey. Estimates of local population sizes were variable, with suggested numbers that varied from tens to the low hundreds. Most interviewees in the Foxe Basin, Hudson Bay and north Baffin regions thought that killer whale presence was increasing. In contrast, half the South Baffin interviewees noted declines in past abundance due to the 1977 harvest of 14 whales that became trapped in a saltwater lake. Interviews provided information at a long temporal and wide spatial record. Inuit are reliable observers and continued killer whale research will be most effective if it integrates modern science approaches with the traditional skills, knowledge and experience of Inuit harvesters.

Prey assemblage isotopic variability as a tool for assessing diet and the spatial distribution of bowhead whale Balaena mysticetus foraging in the Canadian eastern Arctic

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 469:161-174 (2012) - DOI: https://doi.org/10.3354/meps10004 Prey assemblage isotopic variability as a tool for assessing diet and the spatial distribution of bowhead whale Balaena mysticetus foraging in the Canadian eastern Arctic C. Pomerleau1,6,*, V. Lesage2, S. H. Ferguson3, G. Winkler1, S. D. Petersen4, J. W. Higdon5 1Institut des Sciences de la Mer, Université du Québec à Rimouski, Rimouski, Quebec G5L 3A1, Canada 2Fisheries and Oceans Canada, Maurice Lamontagne Institute, Mont-Joli, Quebec G5H 3Z4, Canada 3Fisheries and Oceans Canada, Freshwater Institute, Winnipeg, Manitoba R3T 2N6, Canada 4Assiniboine Park Zoo, Winnipeg, Manitoba R3P 2N7, Canada 5Higdon Wildlife Consulting, Winnipeg, Manitoba R3G 3C9, Canada 6Present address: Fisheries and Oceans Canada, Institute of Ocean Sciences, Sidney, British Columbia V8L 4B2, Canada *Email: corinne.pomerleau@dfo-mpo.gc.ca ABSTRACT: The eastern Canada-West Greenland (EC-WG) bowhead whale Balaena mysticetus population is slowly recovering from the intensive commercial whaling of the 18th and 20th centuries. However, climate change, through effects on ice conditions and prey availability, is one of several threats that might affect bowhead whale recovery. In this study, we exploited the variability observed in isotopic signatures of prey assemblages across the eastern Arctic to examine variability in diet among bowhead whales (n = 202) and identify their potential foraging areas. We compared δ13C and δ15N isotope ratios of biopsied skin samples with those of potential zooplankton prey species collected across the Canadian eastern Arctic, and calculated the proportional contributions of various sources (zooplankton) to the diet of bowhead whales using a Bayesian stable isotope mixing model. A cluster analysis indicated some variability in isotopic composition among groups of individuals, but not between males and females or age classes. The isotopic model discounted Davis Strait and Disko Bay as potential foraging areas for bowhead whales, at least in spring and summer. Lancaster Sound, Baffin Bay and the Gulf of Boothia were the 3 main areas likely used for summer feeding, where bowhead whales fed primarily on large Arctic calanoid copepods (Calanus hyperboreus, C. glacialis, Metridia longa, and Paraeuchaeta spp.), mysids and euphausiids. While some inter-individual variability in diet was observed, the strong dependence of this endemic Arctic species on Arctic zooplankton may make them vulnerable to the predicted latitudinal shift in prey species composition caused by ongoing warming. KEY WORDS: Canadian Arctic · Bowhead whale · Diet · Foraging behaviour · Marine mammal · Zooplankton · Stable isotopes · Bayesian mixing model · SIAR · Trophic ecology Full text in pdf format PreviousNextCite this article as: Pomerleau C, Lesage V, Ferguson SH, Winkler G, Petersen SD, Higdon JW (2012) Prey assemblage isotopic variability as a tool for assessing diet and the spatial distribution of bowhead whale Balaena mysticetus foraging in the Canadian eastern Arctic. Mar Ecol Prog Ser 469:161-174. https://doi.org/10.3354/meps10004 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 469. Online publication date: November 26, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.

A New Record of Holocene Sea Levels from the Northwestern Gulf of Mexico Based on Paleo Algal Mats

A series of cores (box and piston) were collected at 2 key locations in Lancaster Sound (cores 2004-804-009 BC and PC) and Barrow Strait (cores 2005-804-004 BC and PC) in the Canadian Arctic Archipelago to document the evolution of sea-surface conditions in the main axis of the Northwest Passage during the Holocene time period. Reconstruction of sea-surface parameters (summer temperature and salinity, duration of sea-ice cover) were estimated based on transfer functions using dinoflagellate cyst assemblages as proxy indicators. The chronology of these cores is based on calibrated AMS-14C dates, 210Pb analyses, and correlations between paleomagnetic secular variations of the geomagnetic field and a predicted spherical harmonic model of the geomagnetic field (CALS7 K.2). Our age models for both cores indicate that 009 PC spans the last 11,100 cal BP, while 004 PC encompasses the last 10,800 cal BP. Calculated sedimentation rates are in the range of 43–140 cm/kyr for core 009 PC and 15–118 cm/kyr for core 004 PC, allowing for a millennial time scale resolution in each core. Our results indicate relatively harsh conditions in Lancaster Sound between 10,800 and 9000 cal BP (summer temperatures 2 °C cooler than at present), which we associate with the presence of active ice-streams in northernmost Baffin Bay and a weak West Greenland Current. This is followed by a warming trend (up to 3 °C higher than present) that took place between ∼8500 and 5500 cal BP, which we associate with the Holocene thermal maximum and to a large scale atmospheric pattern such as the Arctic Oscillation operating at the millennial time scale. This is concomitant with an increase in the relative abundance of phototrophic dinoflagellate cyst taxa. A gradual cooling of sea-surface temperature and increased sea-ice follow this from 5500 cal BP until the modern period. In Barrow Strait, harsh sea-surface conditions prevailed from 11,100 to 5500 cal BP, with summer temperatures as low as 4 °C cooler than at present. The warming trend occurred later in this region (between 5500 and ∼1000 cal BP), after which a gradual cooling is observed until the modern period. The apparent shift, or opposite warming trends, between Lancaster Sound and Barrow Strait after 5500 cal BP could be the result of a change in atmospheric circulation patterns related to a possible shift in the AO mode (from AO+ to AO−). Comparison of ice core δ18O record from Devon Island ice cap and the reconstructed sea-surface temperature from core 009 PC suggests a strong atmospheric-oceanic coupling throughout the Holocene in this area.

Wind‐forcing of volume transport through Lancaster Sound

Volume and freshwater transport through Lancaster Sound are estimated from mooring measurements collected in eastern Barrow Strait for 13 years between 1998 and 2011. Estimates from 2006 to 2011 confirm the relationship between surface wind and volume transport derived from data collected between 1998 and 2006. Volume transport through Barrow Strait along the Northwest Passage is significantly correlated with northeastward winds in the Beaufort Sea, parallel to the western coasts of the Canadian Arctic Archipelago, at monthly to interannual time scales. The location and wind direction for which there is maximum correlation are consistent with the flow being driven by a sea level difference between opposite ends of the Passage, and the difference being determined by setup caused by alongshore winds in the Beaufort Sea. Monthly alongshore wind anomalies account for 43% of the variance of the transport anomalies (p < 0.01). Examination of the residuals, after subtracting the volume transport driven by the Beaufort Sea winds from the total transport, showed that they are not significantly correlated with winds in Baffin Bay (p > 0.05). The annual cycles of the total volume transport and its part attributed to the Beaufort Sea wind both have peaks in the summer and are lowest in the autumn. Correlations of the volume transport anomaly with ice velocity anomalies are lower than with surface wind anomalies.

A new model for the Paleogene motion of Greenland relative to North America: Plate reconstructions of the Davis Strait and Nares Strait regions between Canada and Greenland

A simplified plate kinematic model for the Paleogene motion of Greenland relative to North America has been developed to provide a new framework for modeling the oceanic spreading system in Baffin Bay and the intraplate tectonic development of the Davis Strait and Nares Strait regions of the Arctic. A single Euler rotation pole was calculated for the C13N to C24N Eocene motion of the Greenland Plate relative to North America using spreading centers and fracture zones interpreted from satellite derived gravity data in Baffin Bay combined with fracture zones in Labrador Sea from published sources. A single stage pole is proposed for the C25N to C27N portion of the Paleocene and a short‐lived stage pole was found necessary to accommodate the C24N to C25N interval. This kinematic model has been used to reinterpret published shipborne magnetic profiles in central Baffin Bay to reveal a Paleocene spreading center and limits of both Eocene and Paleocene oceanic crust. Aeromagnetic data over northeastern Baffin Bay have been used to identify a new fracture zone in northern Baffin Bay. Plate reconstructions are presented incorporating constraints on plate boundaries from onshore and offshore geological and geophysical mapping. Within the Davis Strait, Paleocene oceanic crust was emplaced in an elongated rift that was subsequently inverted by approximately 300 km of Eocene transpression along the Ungava Fault Zone. In the Nares Strait Region, a “microplate” scenario is presented to explain the simultaneous formation of the Lancaster Sound Rift Basin and complex deformation within the Eurekan Orogenic Belt.

Nitrogen fixation and identification of potential diazotrophs in the Canadian Arctic

Global gaseous nitrogen (N2) fixation rates may be underestimated and data is lacking from many regions without conspicuous diazotrophic cyanobacteria, such as cold oceans. We estimated N2 fixation rates at diverse sites in the Canadian Arctic, including the mouth of the Mackenzie River, the offshore Beaufort Sea, Lancaster Sound, Baffin Bay and a river influenced fjord. We also identified potential diazotrophic communities using a targeted survey of the nifH gene. Nitrogen fixation rates ranged from 0.02 nmol N L−1 d−1 in Baffin Bay to 4.45 nmol N L−1 d−1 in the Mackenzie River plume. Sequences recovered from the nifH gene survey belonged mainly to Cluster III, a group of nifH sequences associated with diverse microorganisms, with some α‐ andγ‐proteobacterianifH genes at most sites. Cyanobacteria nifH genes with best matches to Nostocales, which are common in Arctic freshwaters, were recovered from the marine Beaufort Sea. The geographic pattern of N2 fixation rates and nifHgene identities suggest that the Mackenzie River is the source of a diazotrophic community that contributes new nitrogen to the nitrogen‐depleted surface waters of the Beaufort Sea. This first record of N2 fixation at high latitudes refines our understanding of the global nitrogen budget.

Flow Constraints on Pathways through the Canadian Arctic Archipelago

To identify flow pathways through the Canadian Arctic Archipelago, numerical model results were examined using two configurations of the Nucleus for European Modelling of the Ocean (NEMO). After correcting for shortwave radiation, the models captured much of the observed spatiotemporal structure of the sea-ice and ocean circulation in the Canadian Arctic Archipelago, especially the southward flow in M'Clintock Channel and the cyclonic circulation in eastern Lancaster Sound. The southward flow in M'Clintock Channel is driven by ageostrophic accelerations and is controlled by topography. Vorticity dynamics analysis showed that both stratification and bathymetry have a strong impact on the circulation in eastern Lancaster Sound. RÉSUMÉ Pour identifier les trajets d’écoulement à travers l'archipel Arctique canadien, nous avons examiné les résultats de modèles numériques en utilisant deux configurations du NEMO (Nucleus for European Modelling of the Ocean). Après avoir appliqué une correction visant à tenir compte du rayonnement de courtes longueurs d'onde, les modèles capturent la majeure partie de la structure spatiotemporelle de la glace de mer et de la circulation océanique dans l'archipel Arctique canadien, en particulier l’écoulement vers le sud dans le détroit de M'Clintock et la circulation cyclonique dans l'est du détroit de Lancaster. L’écoulement vers le sud dans le détroit de M'Clintock est dû à des accélérations agéostrophiques et est contrôlé par la topographie. L'analyse de la dynamique tourbillonnaire a montré que tant la stratification que la bathymétrie ont un effet marqué sur la circulation dans l'est du détroit de Lancaster.

Current state and trends in Canadian Arctic marine ecosystems: II. Heterotrophic food web, pelagic-benthic coupling, and biodiversity

As part of the Canadian contribution to the International Polar Year (IPY), several major international research programs have focused on offshore arctic marine ecosystems. The general goal of these projects was to improve our understanding of how the response of arctic marine ecosystems to climate warming will alter food web structure and ecosystem services provided to Northerners. At least four key findings from these projects relating to arctic heterotrophic food web, pelagic-benthic coupling and biodiversity have emerged: (1) Contrary to a long-standing paradigm of dormant ecosystems during the long arctic winter, major food web components showed relatively high level of winter activity, well before the spring release of ice algae and subsequent phytoplankton bloom. Such phenological plasticity among key secondary producers like zooplankton may thus narrow the risks of extreme mismatch between primary production and secondary production in an increasingly variable arctic environment. (2) Tight pelagic-benthic coupling and consequent recycling of nutrients at the seafloor characterize specific regions of the Canadian Arctic, such as the North Water polynya and Lancaster Sound. The latter constitute hot spots of benthic ecosystem functioning compared to regions where zooplankton-mediated processes weaken the pelagic-benthic coupling. (3) In contrast with another widely shared assumption of lower biodiversity, arctic marine biodiversity is comparable to that reported off Atlantic and Pacific coasts of Canada, albeit threatened by the potential colonization of subarctic species. (4) The rapid decrease of summer sea-ice cover allows increasing numbers of killer whales to use the Canadian High Arctic as a hunting ground. The stronger presence of this species, bound to become a new apex predator of arctic seas, will likely affect populations of endemic arctic marine mammals such as the narwhal, bowhead, and beluga whales.

Evaluation and control mechanisms of volume and freshwater export through the Canadian Arctic Archipelago in a high‐resolution pan‐Arctic ice‐ocean model

This study examined the 1979–2004 volume and freshwater fluxes through the Canadian Arctic Archipelago (CAA) and into the Labrador Sea using a high resolution (∼9 km) coupled ice‐ocean model of the pan‐Arctic region to provide a reference, compare with limited observational estimates, and investigate control mechanisms of this exchange. The 26‐year mean volume and freshwater fluxes through Nares Strait were 0.77 Sv ± 0.17 Sv and 10.38 mSv ± 1.67 mSv respectively, while those through Lancaster Sound amounted to 0.76 Sv ± 0.12 Sv and 48.45 mSv ± 7.83 mSv respectively. The 26‐year mean volume and freshwater fluxes through Davis Strait were 1.55 Sv ± 0.29 Sv and 62.66 mSv ± 11.67 mSv while the modeled Fram Strait branch provided very little (∼2%) freshwater into the Labrador Sea compared to the total CAA input. Compared to available observations, the model provides reasonable volume and freshwater fluxes, as well as sea ice thickness and concentration in the CAA. In Nares Strait and Lancaster Sound, volume flux anomalies were controlled by the sea surface height (SSH) gradient anomalies along the straits and freshwater anomalies were highly correlated with the volume anomalies. At least half of the variance in the time series of SSH gradient anomaly was due to SSH anomalies in northern Baffin Bay. The West Greenland Current (WGC) exhibits seasonality, with cross shelf flow (into the Labrador Sea) peaking in January/February/March, while reducing the northward flow across eastern Davis Strait. We hypothesize that the eddy‐reduced northward flow of WGC results in the lower volume and SSH in Baffin Bay. This maximizes the SSH gradients between the Arctic Ocean and Baffin Bay, leading to maximum winter volume fluxes through Nares Strait and Lancaster Sound. Model limitations include the insufficient spatial resolution of atmospheric forcing (especially to account for the effects of local topography), the representation of river runoff into Hudson Bay and coastal buoyancy currents, low mobility of modeled ice, and incomplete depiction of ice arching. Many of these issues are expected to be resolved with increased model grid cell resolution, improved sea ice and ocean models and more realistic atmospheric forcing.

Environmental forcing of phytoplankton community structure and function in the Canadian High Arctic: contrasting oligotrophic and eutrophic regions

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 442:37-57 (2011) - DOI: https://doi.org/10.3354/meps09378 Environmental forcing of phytoplankton community structure and function in the Canadian High Arctic: contrasting oligotrophic and eutrophic regions Mathieu Ardyna1,5,*, Michel Gosselin1, Christine Michel2, Michel Poulin3, Jean-Éric Tremblay4 1Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski, 310 Allée des Ursulines, Rimouski, Québec G5L 3A1, Canada 2Freshwater Institute, Fisheries and Oceans Canada, 501 University Crescent, Winnipeg, Manitoba R3T 2N6, Canada 3Research Division, Canadian Museum of Nature, PO Box 3443, Station D, Ottawa, Ontario K1P 6P4, Canada 4Département de biologie et Québec-Océan, Université Laval, Québec, Québec G1V 0A6, Canada 5Present address: Takuvik Joint International Laboratory, Laval University (Canada) - CNRS (France), Département de biologie et Québec-Océan, Université Laval, Québec, Québec G1V 0A6, Canada *Email: mathieu.ardyna@takuvik.ulaval.ca ABSTRACT: We assessed phytoplankton dynamics and its environmental control across the Canadian High Arctic (CHA). Environmental (hydrographic, atmospheric, sea ice conditions) and biological variables (phytoplankton production, biomass, composition) were measured along 3500 km transects across the Beaufort Sea, the Canadian Arctic Archipelago, and Baffin Bay during late summer 2005, early fall 2006 and fall 2007. Phytoplankton production and chlorophyll a (chl a) biomass were measured at 7 optical depths, including the depth of subsurface chl a maximum (ZSCM). Phytoplankton taxonomy, abundance, and size structure were determined at the ZSCM. Redundancy analyses and non-metric multidimensional scaling were used to assess relationships between phytoplankton composition in relation to biological and environmental variables. In late summer/fall, the CHA was characterized by (1) an oligotrophic flagellate-based system extending over the eastern Beaufort Sea, the peripheral Amundsen Gulf, and the central region of the Canadian Arctic Archipelago; and (2) a eutrophic diatom-based system located in Baffin Bay, Lancaster Sound, and in a hotspot in the central Amundsen Gulf. The oligotrophic regions were characterized by low production and biomass of large phytoplankton cells (>5 µm) and relatively high abundance of eukaryotic picophytoplankton (<2 µm) and unidentified nanoflagellates (2−20 µm). The eutrophic regions were characterized by high production and biomass of large cells and relatively high abundance of centric diatoms, mainly Chaetoceros spp. The distinction between the 2 regimes was explained by differences in stratification (density gradient) and nitrate concentrations at the ZSCM. This study demonstrates the key role of vertical mixing and nutrient input in shaping the structure and function of phytoplankton communities in the CHA, showing how ongoing environmental changes have the capacity to alter the diversity of biogeographic regions in the CHA. KEY WORDS: Primary production . Phytoplankton communities . Biogeographic regions . Sea ice cover . Stratification . Nutrients . Climate change . Canadian High Arctic Full text in pdf format PreviousNextCite this article as: Ardyna M, Gosselin M, Michel C, Poulin M, Tremblay JÉ (2011) Environmental forcing of phytoplankton community structure and function in the Canadian High Arctic: contrasting oligotrophic and eutrophic regions. Mar Ecol Prog Ser 442:37-57. https://doi.org/10.3354/meps09378 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 442. Online publication date: December 05, 2011 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2011 Inter-Research.

Arctic Shipping Routes

Fast-receding summer sea ice in the Arctic has been documented and making the headlines since 2007. The phenomenon, underlined by scientists and the media since about the turn of the century, has triggered speculation about the opening of much shorter sea routes linking Europe via the eastern North American coast to Asia. The prospect of growing shipping traffic in Arctic waters, especially through the Northwest Passage in the Canadian Arctic archipelago, or through the northeast passage north of Russia, has fuelled rhetoric on the status of these Arctic routes and controversy over the pace of such shipping growth. Few analysts question the common belief that it is only a matter of time before new sea lanes will be operational in the Arctic. This prospect is at the very heart of the ongoing debate on security in the Canadian Arctic, for it raises the issue of control of such navigation, and therefore of Canadian sovereignty over the Northwest Passage and the Canadian Arctic waters. It is this debate over control of navigation, often depicted as something bound to experience out-of-hand growth, that triggered the house of commons to vote in favour of a highly debatable resolution in December 2009, renaming the Northwest Passage the Canadian Northwest Passage, a move unlikely to attract any sympathy elsewhere in the world.But how much truth is there in the widely accepted notion that melting sea ice, opening up Arctic channels in the summer, will lead to greatly increased sea traffic in the region? Shorter distances seem to be the main factor considered by commentators, but shipping companies take many other questions into account before their managers decide to develop Arctic shipping. Indeed, shipping companies are in no rush to develop what they perceive to be a risky and not necessarily profitable route.FACTS: ARCTIC SEA ICE IS RECEDING IN THE SUMMERThe year 2007 saw a record low in the extent of summer sea ice, and the data show a trend towards an accelerated decline of the ice. Five years ago, climatologists talked about a possible ice-free Arctic Ocean in the summer by the year 2100, but models now suggest that this could happen as early as 2015.1 Ever since Arctic- wide data for the extent of sea ice were computed in 1979, a general declining trend has been observed. To be sure, there is an inter-annual variability and it is difficult from year to year to predict the extent of the ice the following year, but the general trend definitely points towards an accelerating decline.Regression trends for shorter periods follow a steeper slope as time goes by, indicating that the pace of melting has accelerated over the past years. This means that the ice is melting faster and faster, with the prospect of ice-free summers as early as 2015 in some models, underlining the real possibility of little ice remaining in the summertime.This receding sea ice opens up channels that were long sought by Europeans to reach Asia, across the fabled northwest or northeast passages. The Northwest Passage is generally understood as the sea stretch from Lancaster Sound to the Bering Strait, although many authors limit its scope to the Canadian archipelago. The northeast passage - also called the northern sea route by Russia - follows the Siberian Arctic coast and crosses Russian Arctic straits between the mainland and Russian Arctic archipelagos: Novaya Zemlya, Sevemaya Zemlya, the New Siberian Islands, and Wrangel Island. There is a difference here between the two passages: the Northwest Passage rests almost entirely in Canadian-claimed internal waters if it is defined as extending from Baffin Bay to the Beaufort Sea, whereas the northeast passage merely skips across Russian straits and thus Russian-claimed internal waters, but for the most part lies outside Russian territorial waters, except in a few places. The route lies rather in the Russian exclusive economic zone, which is not insignificant, since Russian regulations on shipping along the northern sea route, based upon article 234 of the UN law of the sea, oblige ships to respect Russian regulations within Russia's economic zone, particularly with regard to mandatory piloting and icebreaker escort. …

Volume and freshwater transports through the Canadian Arctic Archipelago–Baffin Bay system

[1] Baffin Bay connects the Arctic Ocean and the Labrador Sea. It receives Polar water through the Canadian Arctic Archipelago and by the West Greenland Current. The Polar water is, after transformation, exported through Davis Strait. With control sections both upstream and downstream Baffin Bay invites the use of an idealized geostrophic approach to estimate transports. The baroclinic transports, driven by the density differences between the Arctic Ocean and Baffin Bay, are first determined. The density and upper layer depth are assumed the same in Lancaster Sound, Nares Strait and the West Greenland Current. Once the baroclinic transports are estimated the sea level difference between the Arctic Ocean and Baffin Bay is computed. Next the upper layer depth in Nares Strait and the West Greenland Current is reduced, while the sea level difference is kept constant. This allows for deep inflows through Nares Strait and the West Greenland Current. To establish a deep outflow through Davis Strait a “barotropic” sea level slope between the Arctic Ocean and the Labrador Sea is estimated from two “ideal” water columns. The transports are computed for different salinities in the Polar water and the salinity giving mass balance in the deeper layers is determined. The effects of possible increased melting of the Greenland icecap are examined. If the meltwater is added directly to Baffin Bay the effects are small, but if it is incorporated in the East and West Greenland Current a significant reduction of the outflow through the Archipelago might occur.

The Effect of Climate Change on the Sea Ice and Hydrography in Nares Strait

A three-dimensional coupled ocean (Hybrid Coordinate Ocean Model; HYCOM) and sea-ice (Community Ice Code; CICE) model were used to simulate the ice cover and hydrography in the Lincoln Sea, Nares Strait and Baffin Bay for the period 1952 to 2080. The first eight years were used to spin up the model. The last 120 years were divided into four-year sub-periods, which have been evaluated and compared in order to estimate the simulated changes. The modelled oceanic volume flux and freshwater fluxes compare well with observations in the present day scenario. The annual volume flux varies, but the 10-year average is approximately 0.8 Sv (1 Sv = 106m3s−1) without any long-term trend. It should be noted that 5 cm were added to the sea surface height in Baffin Bay and Lancaster Sound during the entire simulation. This was done in order to control the volume flux of the control period without changing the variabillity. The freshwater flux increases from approximately 27 mSv in the control scenario to 73 mSv in the future scenario, mainly due to a fresher surface. The magnitude of the annual ice area flux through Nares Strait is higher than expected compared with results from satellite images. This is because the ice arch formed in the southern part of Kane Basin is less stable in the model simulation. The result is a sea-ice area flux of about 100 . This is approximately the same sea-ice area flux as observed in 2007 when the ice arch did not form. The sea-ice area flux from 2040 increases by around 50% because of a lowering of the sea-ice concentration which causes a large reduction in the internal sea-ice strength. The sea-ice volume flux is reduced during the entire period from approximately 200 to around 125 . The simulated sea-ice cover decreases throughout the entire period. The area is still fully ice covered during winter, but the duration of the sea-ice coverage becomes shorter. This leads to a fresher sea surface and a temperature increase of up to 0.5 °C at depths of approximately 200 m. The opening of the North Water Polynya in spring is limited by the reduced lifetime of the ice arch in Kane Basin. However, during some years when the ice arch is stable the polynya opens as expected both in time and place.

The Quaternary Lancaster Sound trough‐mouth fan, NW Baffin Bay

AbstractThe development of the Lancaster Sound Trough Mouth Fan (TMF) and glacial history in Arctic Canada were studied using a high‐resolution seismic profile across the entire fan and two piston cores. Stacked tills separated by erosion surfaces on the shelf pass seaward through till deltas into thick transparent glacigenic debris flow (GDF) deposits on the slope, separated by thin, well‐stratified glaciomarine layers. An age model was built by ties to the Ocean Drilling Program Site 645. The deepest GDF on the seismic profile was indicative of the onset of shelf‐crossing glaciation in the Early Pleistocene. The transition of the growth of Lancaster Sound TMF from an aggradational sequence (unit M) to an aggradational–progradational sequence (unit F) occurred at the Middle Pleistocene transition in glacial cyclicity. In the most recent glacial cycle, GDF sheets were deposited during Heinrich events 4 and 2 according to the correlation of the main detrital carbonate beds in two piston cores. The outmost till wedge reflects the maximum advance of the grounding glacier, far seaward of previously proposed Last Glacial Maximum ice extent. Copyright © 2011 John Wiley &amp; Sons, Ltd.

Atmospheric forcing on the Canadian Arctic Archipelago freshwater outflow and implications for the Labrador Sea variability

The variability of the freshwater export through the Canadian Arctic Archipelago (CAA) is analyzed using a hindcast simulation forced by surface atmospheric forcing from the ERA40 reanalysis (1958-2001). Although the two channels representing the archipelago in the model are both sensitive to the along-channel sea surface height (SSH) gradient, they appear to have very distinct behaviors. The outflow to Lancaster Sound is shown to be largely controlled by the magnitude of the upstream SSH gradient across McClure Strait. The gradient shows a close link to the wind stress curl in the western Arctic but also to a large-scale SSH anomaly pattern which has a strong signal over the shelf to the south of McClure Strait. The latter has, however, little statistical connection to the SSH variability in the Beaufort Gyre. By contrast, the outflow through Nares Strait responds preferentially to SSH variations in the northern Baffin Bay which are remotely forced by air-sea heat exchanges in the Labrador Sea. The variability is largely coherent between the two outflows and is controlled by a dipolar atmospheric pattern reminiscent of the North Atlantic/Arctic Oscillation. When entering the subpolar gyre, the CAA freshwater outflow remains confined to the Labrador shelf with little impact on the salinity of the interior Labrador Sea and potentially on the convection. The latter is represented by a distinct mode of salinity variability in the western subpolar gyre which is rather influenced by the variability of the sea ice export through Fram Strait.

Export of Pacific carbon through the Arctic Archipelago to the North Atlantic

During an east-to-west transect through the Canadian Arctic Archipelago, dissolved inorganic carbon (DIC) and total alkalinity (TA) were measured. The watermass composition throughout the Archipelago is determined using TA and the seawater oxygen isotope fractionation ( δ 18 O ) data, and the carbon characteristics of these waters are examined. The influence of the Mackenzie River is primarily limited to the upper water column in the western Archipelago while the fraction of sea-ice melt water in the surface waters increases eastward with maximum values at the outflows of Jones and Lancaster Sounds. The depth of Pacific-origin upper halocline waters increases eastward through the Archipelago. In the western Archipelago, non-conservative variations in deep water DIC are used to compute a subsurface carbon surplus, which appears to be fueled by organic matter produced in the surface layer and by benthic respiration. The eastward transport of carbon from the Pacific, via the Arctic Archipelago, to the North Atlantic is estimated, and the impact of increased export of sea-ice melt water to the North Atlantic is discussed.

Chapter 40 Baffin Fan and its inverted rift system of Arctic eastern Canada: stratigraphy, tectonics and petroleum resource potential

Abstract Baffin Fan is a 12 km-thick sedimentary wedge of Eocene to Pleistocene age in northwestern Baffin Bay, with size and resource potential comparable to Beaufort–Mackenzie Basin. A widespread Moho detachment originating in Mesoproterozoic strata may have influenced development of Cretaceous–Palaeogene horst blocks and half-grabens throughout the region, and their transformation by later phases of inversion. Reflection profiles indicate 12 depositional sequences in lower Palaeozoic and Cretaceous to Pleistocene strata. Notable is syntectonic sedimentation with possible volcanism and rifting in the Cretaceous–Danian. Sequences associated with inversion in the later Paleocene and Eocene display out-of-graben thrust anticlines formed over horst blocks in Lady Ann and Lancaster Sound basins. The Oligocene to mid-Miocene is associated with fluvial–deltaic systems, replaced since then by glacial–interglacial sequences including submarine canyons and deepwater fans. Exploration targets are located in Lancaster Sound, and a Baffin Bay fairway that runs 220 km northwestward to east of Coburg Island. Sixty-five per cent of prospects are located under Neogene cover. Fourteen are each greater than 70 km 2 , and five are between 334 and 592 km 2 . Based on drilling success rates elsewhere and the existence of a petroleum system, 12 of the 40 mapped structures may contain hydrocarbons in significant quantity.

Chapter 41 Geology and petroleum potential of the West Greenland–East Canada Province

Abstract The US Geological Survey (USGS) assessed the potential for undiscovered oil and gas resources of the West Greenland–East Canada Province as part of the USGS Circum-Arctic Resource Appraisal programme. The province lies in the offshore area between western Greenland and eastern Canada and includes Baffin Bay, Davis Strait, Lancaster Sound and Nares Strait west of and including part of Kane Basin. A series of major tectonic events led to the formation of several distinct structural domains that are the geological basis for defining five assessment units (AU) in the province, all of which are within the Mesozoic–Cenozoic Composite Petroleum System. Potential petroleum source rocks include strata of Ordovician, Lower and Upper Cretaceous, and Palaeogene ages. The five AUs defined for this study – the Eurekan Structures AU, NW Greenland Rifted Margin AU, NE Canada Rifted Margin AU, Baffin Bay Basin AU and the Greater Ungava Fault Zone AU – encompass the entire province and were assessed for undiscovered technically recoverable resources. The mean volumes of undiscovered resources for the West Greenland–East Canada Province are 10.7×10 9 barrels of oil, 75×10 12 cubic feet of gas, and 1.7×10 9 barrels of natural gas liquids. For the part of the province that is north of the Arctic Circle, the estimated mean volumes of these undiscovered resources are 7.3×10 9 barrels of oil, 52×10 12 cubic feet of natural gas, and 1.1×10 9 barrels of natural gas liquids. Supplementary material: Supplementary Appendices 1–5 are available at http://www.geolsoc.org.uk/SUP18476