Miniature Carvings in the Canadian Dorset Culture: the Paleo-Eskimo Belief System

En este estudio, intento resumir los debates relacionados con la última cultura paleoesquimal de Canadá Ártica y la de Groenlandia, y llamar la atención sobre las analogías culturales desde Asia, además de crear un cuadro complejo sobre el chamanismo y el culto al oso de los Dorset. Los temas como el origen del arte de los Dorset, la transición Pre-Dorset-Dorset, y los contactos entre los Dorset y los Thule son relevantes para reconstruir el sistema de creencias de los Dorset. Sin embargo, la totalidad del sistema de creencias de los paleoesquimales no se puede comprender sobre la base de los hallazgos arqueológicosy las analogías etnográficas remotas.

Foraging Habitat and Chick Diets of Roseate Tern, Sterna dougallii, Breeding on Country Island, Nova Scotia

Breeding seabirds are threatened by human activities that affect nesting and foraging habitat. In Canada, one of the seabirds most at risk of extirpation is the Roseate Tern, Sterna dougallii. Although critical nesting habitat has been identified for the Roseate Tern in Canada, its foraging locations and the diet of its chicks are unknown. Therefore, our goal was to determine the foraging locations and diet of chicks of Roseate Tern breeding on Country Island, Nova Scotia, which is one of Canada's two main breeding colonies. In 2003 and 2004, we radio-tracked the Roseate Tern by plane to locate foraging areas and conducted feeding watches to determine the diet of chicks. Roseate Tern foraged approximately 7 km from the breeding colony over shallow water < 5 m deep. In both years, sand lance, Ammodytes spp., was the most common prey item delivered to chicks, followed by hake, Urophycis spp. Our results are consistent with previous work at colonies in the northeastern United States, suggesting that throughout its range, this species may be restricted in both habitat use and prey selection. The reliance on a specific habitat type and narrow range of prey species makes the Roseate Tern generally susceptible to habitat perturbations and reductions in the availability of prey.

Linking Canadian Harvested Juvenile American Black Ducks to Their Natal Areas Using Stable Isotope (δD, δ13C, and δ15N) Methods

Understanding source-sink dynamics of game birds is essential to harvest and habitat management but acquiring this information is often logistically and financially challenging using traditional methods of population surveys and banding studies. This is especially true for species such as the American Black Duck (Anas rubripes), which have low breeding densities and extensive breeding ranges that necessitate extensive surveys and banding programs across eastern North America. Despite this effort, the contribution of birds fledged from various landscapes and habitat types within specific breeding ranges to regional harvest is largely unknown but remains an important consideration in adaptive harvest management and targeted habitat conservation strategies. We investigated if stable isotope (δD, δ13C, δ15N) could augment our present understanding of connectivity between breeding and harvest areas and so provide information relevant to the two main management strategies for black ducks, harvest and habitat management. We obtained specimens from 200 hatch-year Black Duck wings submitted to the Canadian Wildlife Service Species Composition Survey. Samples were obtained from birds harvested in Western, Central, and Eastern breeding/harvest subregions to provide a sample representative of the range and harvest rate of birds harvested in Canada. We sampled only hatch-year birds to provide an unambiguous and direct link between production and harvest areas. Marine origins were assigned to 12%, 7%, and 5% of birds harvested in the Eastern, Central, and Western subregions, respectively. In contrast, 32%, 9%, and 5% of birds were assigned, respectively, to agricultural origins. All remaining birds were assigned to nonagricultural origins. We portrayed probability of origin using a combination of Bayesian statistical and GIS methods. Placement of most eastern birds was western Nova Scotia, eastern New Brunswick, Prince Edward Island, and southern Newfoundland. Agricultural birds from the Central region were consistent with the Saguenay region of Québec and the eastern claybelt with nonagricultural birds originating in the boreal. Western nonagricultural birds were associated with broad boreal origins from southern James Bay to Lake of the Woods and east to Cochrane, Ontario. Our work shows that the geographic origins, landscape, and habitat associations of hatch-year Black Ducks can be inferred using this technique and we recommend that a broad-scale isotopic study using a large sample of Canadian and US harvested birds be implemented to provide a continental perspective of source-sink population dynamics.

Confocal imaging of pseudomonas syringae pv. phaseolicola colony development in bean reveals reduced multiplication of strains containing the genomic island PPHGI-1.

Pseudomonas syringae pv. phaseolicola is the seed borne causative agent of halo blight in the common bean Phaseolus vulgaris. Pseudomonas syringae pv. phaseolicola race 4 strain 1302A contains the avirulence gene hopAR1 (located on a 106-kb genomic island, PPHGI-1, and earlier named avrPphB), which matches resistance gene R3 in P. vulgaris cultivar Tendergreen (TG) and causes a rapid hypersensitive reaction (HR). Here, we have fluorescently labeled selected Pseudomonas syringae pv. phaseolicola 1302A and 1448A strains (with and without PPHGI-1) to enable confocal imaging of in-planta colony formation within the apoplast of resistant (TG) and susceptible (Canadian Wonder [CW]) P. vulgaris leaves. Temporal quantification of fluorescent Pseudomonas syringae pv. phaseolicola colony development correlated with in-planta bacterial multiplication (measured as CFU/ml) and is, therefore, an effective means of monitoring Pseudomonas syringae pv. phaseolicola endophytic colonization and survival in P. vulgaris. We present advances in the application of confocal microscopy for in-planta visualization of Pseudomonas syringae pv. phaseolicola colony development in the leaf mesophyll to show how the HR defense response greatly affects colony morphology and bacterial survival. Unexpectedly, the presence of PPHGI-1 was found to cause a reduction of colony development in susceptible P. vulgaris CW leaf tissue. We discuss the evolutionary consequences that the acquisition and retention of PPHGI-1 brings to Pseudomonas syringae pv. phaseolicola in planta.

Assimilation impacts on Arctic Ocean circulation, heat and freshwater

We investigate the Arctic basin circulation, freshwater content (FWC) and heat budget by using a high-resolution global coupled ice–ocean model implemented with a state-of-the-art data assimilation scheme. We demonstrate that, despite a very sparse dataset, by assimilating hydrographic data in and near the Arctic basin, the initial warm bias and drift in the control run is successfully corrected, reproducing a much more realistic vertical and horizontal structure to the cyclonic boundary current carrying the Atlantic Water (AW) along the Siberian shelves in the reanalysis run. The Beaufort Gyre structure and FWC and variability are also more accurately reproduced. Small but important changes in the strait exchange flows are found which lead to more balanced budgets in the reanalysis run. Assimilation fluxes dominate the basin budgets over the first 10 years (P1: 1987–1996) of the reanalysis for both heat and FWC, after which the drifting Arctic upper water properties have been restored to realistic values. For the later period (P2: 1997–2004), the Arctic heat budget is almost balanced without assimilation contributions, while the freshwater budget shows reduced assimilation contributions compensating largely for surface salinity damping, which was extremely strong in this run. A downward trend in freshwater export at the Canadian Straits and Fram Strait is found in period P2, associated with Beaufort Gyre recharge. A detailed comparison with observations and previous model studies at the individual Arctic straits is also included.

Past and future conditions for polar stratospheric cloud formation simulated by the Canadian Middle Atmosphere Model

We analyze here the polar stratospheric temperatures in an ensemble of three 150-year integrations of the Canadian Middle Atmosphere Model (CMAM), an interactive chemistry-climate model which simulates ozone depletion and recovery, as well as climate change. A key motivation is to understand possible mechanisms for the observed trend in the extent of conditions favourable for polar stratospheric cloud (PSC) formation in the Arctic winter lower stratosphere. We find that in the Antarctic winter lower stratosphere, the low temperature extremes required for PSC formation increase in the model as ozone is depleted, but remain steady through the twenty-first century as the warming from ozone recovery roughly balances the cooling from climate change. Thus, ozone depletion itself plays a major role in the Antarctic trends in low temperature extremes. The model trend in low temperature extremes in the Arctic through the latter half of the twentieth century is weaker and less statistically robust than the observed trend. It is not projected to continue into the future. Ozone depletion in the Arctic is weaker in the CMAM than in observations, which may account for the weak past trend in low temperature extremes. In the future, radiative cooling in the Arctic winter due to climate change is more than compensated by an increase in dynamically driven downwelling over the pole.

Statistical characterization of arctic polar-night jet oscillation events

A novel diagnostic tool is presented, based on polar-cap temperature anomalies, for visualizing daily variability of the Arctic stratospheric polar vortex over multiple decades. This visualization illustrates the ubiquity of extended-time-scale recoveries from stratospheric sudden warmings, termed here polar-night jet oscillation (PJO) events. These are characterized by an anomalously warm polar lower stratosphere that persists for several months. Following the initial warming, a cold anomaly forms in the middle stratosphere, as does an anomalously high stratopause, both of which descend while the lower-stratospheric anomaly persists. These events are characterized in four datasets: Microwave Limb Sounder (MLS) temperature observations; the 40-yr ECMWF Re-Analysis (ERA-40) and Modern Era Retrospective Analysis for Research and Applications (MERRA) reanalyses; and an ensemble of three 150-yr simulations from the Canadian Middle Atmosphere Model. The statistics of PJO events in the model are found to agree very closely with those of the observations and reanalyses. The time scale for the recovery of the polar vortex following sudden warmings correlates strongly with the depth to which the warming initially descends. PJO events occur following roughly half of all major sudden warmings and are associated with an extended period of suppressed wave-activity fluxes entering the polar vortex. They follow vortex splits more frequently than they do vortex displacements. They are also related to weak vortex events as identified by the northern annular mode; in particular, those weak vortex events followed by a PJO event show a stronger tropospheric response. The long time scales, predominantly radiative dynamics, and tropospheric influence of PJO events suggest that they represent an important source of conditional skill in seasonal forecasting.

Occurrence of organochlorine compounds in Euphausia superba and unhatched eggs of Pygoscelis genus penguins from Admiralty Bay (King George Island, Antarctica) and estimation of biomagnification factors

Polychlorinated biphenyls (PCBs) and organochlorine pesticides are compounds that do not occur naturally in the environment and are not easily degraded by chemical or microbiological action. In the present work, those compounds were analysed in unhatched penguin eggs and whole krill collected in Admiralty Bay, King George Island, Antarctica in the austral summers of 2004-2005 and 2005-2006. The compounds found in higher levels (in a wet weight basis) were, in most of the egg samples, the PCBs (2.53-78.7 ng g(-1)), DDTs (2.07-38.0 ng g(-1)) and HCB (4.99-39.1 ng g(-1)) and after Kruskal-Wallis ANOVA, the occurrence seemed to be species-specific for the Pygoscelis genus. In all of the cases, the levels found were not higher than the ones in Arctic birds in a similar trophic level. The krill samples analysis allowed estimating the biomagnification factors (which resulted in up to 363 for HCB, one order of magnitude higher than DDTs and chlordanes and two orders of magnitude higher than the other groups) of the compounds found in eggs, whose only source of contamination is the female-offspring transfer. (C) 2009 Elsevier Ltd. All rights reserved.

Retreat of top cliff of Kurungnakh Island, Lena Delta, Siberia, Russia, 2010-2014, with links to shapefiles

Thawing-induced cliff top retreat in permafrost landscapes is mainly due to thermo-erosion. Ground-ice-rich permafrost landscapes are specifically vulnerable to thermo-erosion and may show high degradation rates. Within the HGF Alliance Remote Sensing and the FP7 PAGE21 permafrost programs we investigated how SAR and optical remote sensing can contribute to the monitoring of erosion rates of ice-rich cliffs in Arctic Siberia (Lena Delta, Russia). We produced two different vector products: i) Intra-annual cliff top retreat based on TerraSAR-X (TSX) satellite data (2012-2014): High-temporal resolution time series of TSX satellite data allow the inter-annual and intra-annual monitoring of the upper cliff-line retreat also under bad weather conditions and continuous cloud coverage. This published SAR product contains the retreating upper cliff lines of a 1.5 km long part of eroding ice-rich coast of Kurungnakh Island in the central Lena Delta. The upper cliff line was mapped using a thresholding approach for images acquired in the years 2012, 2013 and 2014 for the months June (2013, 2014), July (2013, 2014), August (2012, 2013, 2014) and September (2013, 2014). The cliff top retreat vector product is called 'upper_cliff_TerraSAR-X'. While the 2014 cliff lines show a clear retreat of 2 to 3 m/month, the cliff top lines for 2012 and 2013 are not chronologically ordered. However, lines from the end of the season of a year are always close to the lines from the beginning of the next summer season, indicating low cliff retreat in winter. ii) 4-year cliff top retreat based on optical satellite data (2010-2014): Long-term cliff top retreat could be assessed with two high-spatial resolution optical satellite images (GeoEye-1, 2010-08-05 and Worldview-1, 2014-08-19). The cliff top retreat vector product is called 'upper_cliff_optical'. Results: The long-term cliff top retreat derived from optical satellite data are 35 m cliff retreat within 4 years. The higher-temporal resolution SAR data equivalently show long-term rates of 18 m within 2 years and nearly now degradation activities in winter but maximum erosion rates in summer months.The Intra-seasonal cliff top retreat lines from 2014 show a rate of 2 to 3 m per month.

Dissolved organic carbon (DOC) in Arctic ground ice, from northwest Canada, east Siberia, and Alaska

Thermal permafrost degradation and coastal erosion in the Arctic remobilize substantial amounts of organic carbon (OC) and nutrients which have accumulated in late Pleistocene and Holocene unconsolidated deposits. Permafrost vulnerability to thaw subsidence, collapsing coastlines and irreversible landscape change are largely due to the presence of large amounts of massive ground ice such as ice wedges. However, ground ice has not, until now, been considered to be a source of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC) and other elements which are important for ecosystems and carbon cycling. Here we show, using biogeochemical data from a large number of different ice bodies throughout the Arctic, that ice wedges have the greatest potential for DOC storage, with a maximum of 28.6 mg/L (mean: 9.6 mg/L). Variation in DOC concentration is positively correlated with and explained by the concentrations and relative amounts of typically terrestrial cations such as Mg2+ and K+. DOC sequestration into ground ice was more effective during the late Pleistocene than during the Holocene, which can be explained by rapid sediment and OC accumulation, the prevalence of more easily degradable vegetation and immediate incorporation into permafrost. We assume that pristine snowmelt is able to leach considerable amounts of well-preserved and highly bioavailable DOC as well as other elements from surface sediments, which are rapidly frozen and stored in ground ice, especially in ice wedges, even before further degradation. We found that ice wedges in the Yedoma region represent a significant DOC (45.2 Tg) and DIC (33.6 Tg) pool in permafrost areas and a freshwater reservoir of 4200 km**3. This study underlines the need to discriminate between particulate OC and DOC to assess the availability and vulnerability of the permafrost carbon pool for ecosystems and climate feedback upon mobilization.

Clay mineralogy and multi-element chemistry of surface sediments on the Aiberian-Arctic Shelf

Clay mineral and bulk chemical (Si, Al, K, Mg, Sr, La, Ce, Nd) analyses of terrigenous surface sediments on the Siberian-Arctic shelf indicate that there are five regions with distinct, or endmember, sedimentary compositions. The formation of these geochemical endmembers is controlled by sediment provenance and grain size sorting. (1) The shale endmember (Al, K and REE rich sediment) is eroded from fine-grained marine sedimentary rocks of the Verkhoyansk Mountains and Kolyma-Omolon superterrain, and discharged to the shelf by the Lena, Yana, Indigirka and Kolyma Rivers. (2) The basalt endmember (Mg rich) originates from NE Siberia's Okhotsk-Chukotsk volcanic belt and Bering Strait inflow, and is prevalent in Chukchi Sea Sediments. Concentrations of the volcanically derived clay mineral smectite are elevated in Chukchi fine-fraction sediments, corroborating the conclusion that Chukchi sediments are volcanic in origin. (3) The mature sandstone endmember (Si rich) is found proximal to Wrangel Island and sections of the Chukchi Sea's Siberian coast and is derived from the sedimentary Chukotka terrain that comprises these landmasses. (4) The immature sandstone endmember (Sr rich) is abundant in the New Siberian Island region and reflects inputs from sedimentary rocks that comprise the islands. (5) The immature sandstone endmember is also prevalent in the western Laptev Sea, where it is eroded from sedimentary deposits blanketing the Siberian platform that are compositionally similar to those on the New Siberian Islands. Western Laptev can be distinguished from New Siberian Island region sediments by their comparatively elevated smectite concentrations and the presence of the basalt endmember, which indicate Siberian platform flood basalts are also a source of western Laptev sediments. In certain locations grain size sorting noticeably affects shelf sediment chemistry. (1) Erosion of fines by currents and sediment ice rafting contributes to the formation of the coarse-grained sandstone endmembers. (2) Bathymetrically controlled grain size sorting, in which fines preferentially accumulate offshore in deeper, less energetic water, helps distribute the fine-grained shale and basalt endmembers. An important implication of these results is that the observed sedimentary geochemical endmembers provide new markers of sediment provenance, which can be used to track sediment transport, ice-rafted debris dispersal or the movement of particle-reactive contaminants.

Pollen record with radiocarbon datings from Faddeyevskiy Island, Laptev Sea

Pollen, plant macrofossil, loss-on-ignition and radiocarbon analyses of a 1.4-m section in thermokarst topography from Faddeyevskiy Island (75°20'N, 143°50'E, 30 m elevation) provides new information on Late Pleistocene interstadial environmental history of this high Arctic region. Conventional radiocarbon dates (25,700 ± 1000, 32,780 ± 500, 35,200 ± 650 yr BP) and two AMS dates (29,950 ± 660 and 42,990 ± 1280 yr BP) indicate that the deposits accumulated during the Kargian (Boutellier) interval. Numerous mammoth (Mammuthus primigenius) remains that have been collected in vicinity of the site in this study were radio-carbon dated to 36,700-18,500 yr BP. Rare bison (Bison priscus) bones were dated to 32,200 ± 600 and 33,100 ± 320 yr BP. Poaceae, Cyperaceae, and Artemisia pollen dominate the spectra with some Ranunculaceae, Caryophyllaceae, Rosaceae, and Asteraceae. The pollen spectra reflect steppe-like (tundra-steppe) vegetation, which was dominant on the exposed shelf of the Arctic Ocean. Numerous Carex macrofossils suggest that the summer climate was at least 2°C warmer than today. The productivity of the local vegetation during the Kargian interstadial was high enough to feed the population of grazing mammals.

Results of modelled Arctic river discharge trends since 7 ka BP

The Arctic hydrological cycle throughout the Holocene is analyzed based on the results of transient simulations with the coupled atmosphere-ocean circulation model ECHO-G. The results suggest a ~ 2 % increase of mid-Holocene to preindustrial Arctic river discharges for the Eurasian continent. However, rivers of the North America Arctic realm show a moderate runoff decline of approximately 4 to 5 % for the same period. The total river discharge into the Arctic Ocean has remained at an approximately constant preindustrial level since the mid Holocene. The positive discharge trend within Eurasia is caused by a more rapid decrease in local net evaporation compared to a smaller decline in advected moisture and hence precipitation. This effect is neither recognized within the North American Arctic domain nor in the far eastern part of the Eurasian Arctic realm. A detailed comparison of these model findings with a variety of proxy studies is conducted. The collected proxy records show trends of continental surface temperatures and precipitation rates that are consistent with the simulations. A continuation of the transient Holocene runs for the 19th and 20th century with increased greenhouse gases indicates an increase of the total river influx into the Arctic Ocean of up to 7.6 %. The Eurasian river discharges increase by 7.5 %, the North American discharges by up to 8.4 %. The most rapid increases have been detected since the beginning of the 20th century. These results are corroborated by the observed rising of Arctic river discharges during the last century which is attributed to anthropogenic warming. The acceleration of the Arctic hydrological cycle in the 20th century is without precedence in the Holocene.

Deep drilling of glaciers: Russian projects in the Arctic (1975-1995)

The data collection "Deep Drilling of Glaciers: Soviet-Russian projects in Arctic, 1975-1995" was collected by the following basic considerations: - compilation of deep (>100 m) drilling projects on Arctic glaciers, using data of (a) publications; (b) archives of IGRAN; (c) personal communication of project participants; - documentation of parameters, references. Accuracy of data and techniques applied to determine different parameters are not evaluated. The accuracy of some geochemical parameters (up to 1984 and heavy metalls) is uncertain. Most reconstructions of ice core age and of annual layer thickness are discussed; - digitizing of published diagrams (in case, when original numerical data were lost) and subsequent data conversion to equal range series and adjustment to the common units. Therefore, the equal-range series were calculated from original data or converted from digitized chart values as indicated in the metadata. For the methodological purpose, the equal-range series obtained from original and reconstructed data were compared repeatedly; the systematic difference was less then 5-7%. Special attention should be given to the fact, that the data for individual ice core parameters varies, because some parameters were originally measured or registered. Parameters were converted in equal-range series using 2 m steps; - two or more parameter values were determined, then the mean-weighted (i.e. accounting the sample length) value is assigned to the entire interval; - one parameter value was determined, measured or registered independently from the parameter values in depth intervals which over- and underlie it, then the value is assigned to the entire interval; - one parameter value was determined, measured or registered for two adjoining depth intervals, then the specific value is assigned to the depth interval, which represents >75% of sample length ; if each of adjoining depth intervals represents <75% of sample length, then the correspondent parameter value is assigned to both intervals of depth. This collection of ice core data (version 2000) was made available through the EU funded QUEEN project by S.M. Arkhipov, Moscow.