Four millennia of woodland structure and dynamics at the Arctic treeline of eastern Canada

A pair of Short-eared Owls was observed throughout the summer of 2008 showing territorial behavior more than 1000 km north of their known breeding range in north-eastern Canada. These observations might be related to high lemming densities and/or climate change occurring in the Arctic.

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Structure and dynamics of mesoscale eddies over the Laptev Sea continental slope in the Arctic Ocean

10.5194/os-2018-22 ◽

2018 ◽

Cited By ~ 1

Author(s):

Andrey Pnyushkov ◽

Igor V. Polyakov ◽

Laurie Padman ◽

An T. Nguyen

Keyword(s):

Arctic Ocean ◽

Continental Slope ◽

Mesoscale Eddies ◽

The Arctic ◽

Laptev Sea ◽

Surface Mixed Layer ◽

Fram Strait ◽

Structure And Dynamics ◽

The Arctic Ocean ◽

The Laptev Sea

Abstract. Heat fluxes steered by mesoscale eddies may be a significant (but still not quantified) source of heat to the surface mixed layer and sea ice cover in the Arctic Ocean, as well as a source of nutrients for enhancing seasonal productivity in the near-surface layers. Here we use four years (2007–2011) of velocity and hydrography records from a moored profiler over the Laptev Sea slope, and 15 months (2008–2009) of acoustic Doppler current profiler data from a nearby mooring, to investigate the structure and dynamics of eddies at the continental margin of the eastern Eurasian Basin. Typical eddy scales are radii of order of 10 km, heights of six hundred meters, and maximum velocities of ~ 0.1 m s −1. Eddies are approximately equally divided between cyclonic and anticyclonic polarizations, contrary to prior observations from the deep basins and along the Lomonosov Ridge. Eddies are present in the mooring records about 20–25 % of the time, taking about one week to pass through the mooring at an average frequency of about one eddy per month. We found the eddies observed are formed in two distinct regions–near Fram Strait, where the western branch of Atlantic Water (AW) enters the Arctic Ocean, and near Severnaya Zemlya, where the Fram Strait and Barents Sea branches of the AW inflow merge. These eddies, embedded in the Arctic Circumpolar Boundary Current, carry anomalous water properties along the eastern Arctic continental slope. The enhanced diapycnal mixing that we found within EB eddies suggests a potentially important role for eddies in the vertical redistribution of heat in the Arctic Ocean interior.

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Late Quaternary sedimentation in Baffin Bay

Canadian Journal of Earth Sciences ◽

10.1139/e87-174 ◽

1987 ◽

Vol 24 (9) ◽

pp. 1833-1846 ◽

Cited By ~ 51

Author(s):

A. E. Aksu ◽

David J. W. Piper

Keyword(s):

Debris Flow ◽

Late Quaternary ◽

Ocean Basin ◽

The Arctic ◽

Bottom Current ◽

Eastern Canada ◽

Baffin Bay ◽

Quaternary Glaciation ◽

Continental Slopes ◽

Channel Systems

Baffin Bay is a small ocean basin that connects the Arctic and Atlantic oceans. The adjacent continental shelves have been extensively reworked during Quaternary glaciation. The shelf break generally lies between 200 and 500 m. The continental slope passes directly into the abyssal plain of Baffin Bay basin without any major submarine canyon – deep-sea fan system being present, except for a large smooth sediment apron in northern Baffin Bay.On the basis of over 50 piston cores, six Quaternary sediment facies are distinguished from detrital mineralogy (reflected in colour) and sediment texture. Facies A, B, and C are predominantly ice-rafted or are debris flow deposits, each with a distinct mineralogy. Facies D is turbidites and bottom-current sorted sands, silts, and muds. Facies E is hemipelagic sediment. Facies F consists of sediments ranging from slumps, through debris flow deposits, to fine-grained turbidites, with a distinctive provenance in northern Baffin Bay.These sediment facies appear to be partly controlled by glacial conditions. Hemipelagic facies E predominates during the present interglacial. During glacial stages, facies D turbidites were deposited. They resulted from slumping of proglacial sediments on the continental slopes off Greenland and Baffin Island. Facies C and F occurred on the continental slopes at these times. Ice-rafted facies A and B predominate at several horizons, reflecting a rapid breakup of ice shelves in northern Baffin Bay and increased rates of iceberg melting within the Bay. Overall sedimentation rates are relatively low, reflecting dry-base ice sheets in source areas.Deep-sea channel systems floored by sorted coarse sediments and bounded by muddy levees are absent in Baffin Bay, in contrast to mid-latitude glaciated continental margins off eastern Canada. These channel systems are the result of melting of wet-base glaciers, which provide a localized supply of sediment that is sorted by ice margin processes. In Baffin Bay, most glacial sediments are derived by calving of icebergs, probably from dry-base glaciers. Sediments are gradually released over large areas as the bergs melt, and are subsequently redistributed by debris flows.

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The effects of isolation and colonization history on the genetic structure of marine-relict populations of Atlantic cod (Gadus morhua) in the Canadian Arctic

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f06-085 ◽

2006 ◽

Vol 63 (8) ◽

pp. 1830-1839 ◽

Cited By ~ 30

Author(s):

David C Hardie ◽

Roxanne M Gillett ◽

Jeffrey A Hutchings

Keyword(s):

Gadus Morhua ◽

Atlantic Cod ◽

Allelic Diversity ◽

Canadian Arctic ◽

Environmental Stochasticity ◽

Arctic Lakes ◽

The Arctic ◽

Effective Population ◽

Eastern Canada ◽

High Allelic Diversity

The genetic consequences of extended periods at low population size are fundamental to the conservation of depleted species such as the Atlantic cod (Gadus morhua). We compared microsatellite genetic variability among cod populations in Canadian Arctic lakes with that of Gilbert Bay resident and inshore cod from eastern Canada. The Arctic populations had the lowest genetic diversity and were the most strongly genetically structured and distinct. By contrast, eastern Canadian samples expressed high allelic diversity and were not significantly genetically structured or distinct relative to each other, whereas Gilbert Bay resident cod were intermediate to the Arctic and eastern Canadian groups. Our results are consistent with the hypothesis that the Arctic populations were colonized between 8000 and 5000 years ago and have experienced little or no gene flow since that time. Despite isolation at the extreme of the species' range, the Arctic populations have retained relatively high heterozygosities and high genetic effective population sizes relative to census sizes (Ne–Nc ratios). Potential explanations for this include the absence of fishing pressure, allowing for the persistence of large, highly fecund individuals, as well as biotic (e.g., absence of planktivores) and abiotic (e.g., low environmental stochasticity) factors in the Arctic lakes that minimize individual variance in reproductive success.

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Environmental Controls on Needle Gas Exchange and Growth of White Spruce (Picea glauca) on a Riverside Terrace near the Arctic Treeline

Arctic Antarctic and Alpine Research ◽

10.1657/1938-4246-43.2.279 ◽

2011 ◽

Vol 43 (2) ◽

pp. 279-288 ◽

Cited By ~ 13

Author(s):

Patrick F. Sullivan ◽

Bjartmar Sveinbjörnsson

Keyword(s):

Gas Exchange ◽

Picea Glauca ◽

White Spruce ◽

The Arctic ◽

Environmental Controls ◽

Arctic Treeline

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An Account of the Taxonomy of North American Wolves From Morphological and Genetic Analyses

North American Fauna ◽

10.3996/nafa.77.0001 ◽

2012 ◽

Vol 77 (1) ◽

pp. 1-67 ◽

Cited By ~ 38

Author(s):

Steven M. Chambers ◽

Steven R. Fain ◽

Bud Fazio ◽

Michael Amaral

Keyword(s):

North American ◽

Canis Lupus ◽

Microsatellite Dna ◽

Genetic Data ◽

Morphological Data ◽

The Arctic ◽

Gray Wolf ◽

Eastern Canada ◽

Canis Rufus ◽

Eastern Wolf

Abstract The available scientific literature was reviewed to assess the taxonomic standing of North American wolves, including subspecies of the gray wolf, Canis lupus. The recent scientific proposal that the eastern wolf, C. l. lycaon, is not a subspecies of gray wolf, but a full species, Canis lycaon, is well-supported by both morphological and genetic data. This species' range extends westward to Minnesota, and it hybridizes with gray wolves where the two species are in contact in eastern Canada and the Upper Peninsula of Michigan, Wisconsin, and Minnesota. Genetic data support a close relationship between eastern wolf and red wolf Canis rufus, but do not support the proposal that they are the same species; it is more likely that they evolved independently from different lineages of a common ancestor with coyotes. The genetic distinctiveness of the Mexican wolf Canis lupus baileyi supports its recognition as a subspecies. The available genetic and morphometric data do not provide clear support for the recognition of the Arctic wolf Canis lupus arctos, but the available genetic data are almost entirely limited to one group of genetic markers (microsatellite DNA) and are not definitive on this question. Recognition of the northern timber wolf Canis lupus occidentalis and the plains wolf Canis lupus nubilus as subspecies is supported by morphological data and extensive studies of microsatellite DNA variation where both subspecies are in contact in Canada. The wolves of coastal areas in southeastern Alaska and British Columbia should be assigned to C. lupus nubilus. There is scientific support for the taxa recognized here, but delineation of exact geographic boundaries presents challenges. Rather than sharp boundaries between taxa, boundaries should generally be thought of as intergrade zones of variable width.

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Variation in body size of ringed seals (Pusa hispida hispida) across the circumpolar Arctic: evidence of morphs, ecotypes or simply extreme plasticity?

Polar Research ◽

10.33265/polar.v40.5753 ◽

2021 ◽

Vol 40 ◽

Author(s):

Kit M. Kovacs ◽

John Citta ◽

Tanya Brown ◽

Rune Dietz ◽

Steve Ferguson ◽

...

Keyword(s):

Body Size ◽

The Arctic ◽

Age At Maturity ◽

Adaptation To Climate Change ◽

Eastern Canada ◽

Genetic Studies ◽

Ringed Seals ◽

Pusa Hispida ◽

Potential Adaptation ◽

Circumpolar Arctic

The ringed seal is a small phocid seal that has a northern circumpolar distribution. It has long been recognized that body size is variable in ringed seals, and it has been suggested that ecotypes that differ in size exist. This study explores patterns of body size (length and girth) and age-at-maturity across most of the Arctic subspecies’ range using morphometric data from 35 sites. Asymptotic lengths varied from 113 to 151 cm, with sites falling into five distinct size clusters (for each sex). Age-at-maturity ranged from 3.1 to 7.4 years, with sites that had early ages of sexual maturity generally having small length-at-maturity and small final body length. The sexes differed in length at some sites, but not in a consistent pattern of dimorphism. The largest ringed seals occurred in western Greenland and eastern Canada, and the smallest occurred in Alaska and the White Sea. Latitudinal trends occurred only within sites in the eastern Canadian Arctic. Girth (with length and season accounted for) was also highly variable but showed no notable spatial pattern; males tended to be more rotund than females. Genetic studies are needed, starting with the “giants” at Kangia (Greenland) and in northern Canada to determine whether they are genetically distinct ecotypes. Additional research is also needed to understand the ecological linkages that drive the significant regional size differences in ringed seals that were confirmed in this study, and also to understand their implications with respect to potential adaptation to climate change.

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