The evolution of permafrost in the taiga and in the forest–tundra, western Quebec–Labrador Peninsula

1976 ◽  
Vol 6 (2) ◽  
pp. 203-220 ◽  
Author(s):  
Serge Payette ◽  
Hélène Samson ◽  
Daniel Lagarec
Keyword(s):  
Developmental Stages ◽  
Hudson Bay ◽  
James Bay ◽  
Forest Tundra ◽  
Discontinuous Permafrost ◽  
Latitudinal Shift ◽  
Shrub Tundra ◽  
Forest Microclimate ◽  
Southern Section ◽  
Peat Plateaus

Major permafrost landforms of the discontinuous permafrost zone of Hudson Bay and James Bay, Quebec–Labrador Peninsula, are described and interpreted within an ecological perspective. These landforms are not fossil permafrost bodies; they are presently evolving under aggrading and degrading developmental stages. Permafrost peat complexes and permafrost mineral complexes are differentially distributed in the midtaiga, the forest–tundra, and the shrub–tundra zones of the study area. The wooded palsa complex is the most obvious permafrost complex in the midtaiga, and the palsa complex in the forest–tundra: The wooded palsa complex is related to the forest chronosequence, whereas the palsa complex, farther north, occurs where there is a suitable macroclimate for permafrost aggradation without the influence of cool forest microclimate. The wooded cryogenic mound complex in mineral landform is mainly distributed in the southern section of the forest–tundra and near the Hudson Bay shore; the cryogenic mineral mound complex is found in the northern section. The latitudinal shift of the northern complex is necessary for permafrost initiation in open sites. Degrading stages associated with thermokarst activity are similar for all these landforms and it is suggested that palsa complex is made of incipient, mature, and residual palsas whether they belong to palsa mounds or to peat plateaus. Similar conclusions are valid for cryogenic mineral mound complex.

The Holocene evolution of permafrost near the tree line, on the eastern coast of Hudson Bay (northern Quebec)

1987 ◽  
Vol 24 (11) ◽  
pp. 2206-2222 ◽  
Author(s):  
Michel Allard ◽  
Maurice K. Seguin
Keyword(s):  
Climatic Conditions ◽  
Snow Accumulation ◽  
Eastern Coast ◽  
Permafrost Degradation ◽  
Tree Line ◽  
Stratigraphic Sequence ◽  
Forest Tundra ◽  
Discontinuous Permafrost ◽  
Shrub Tundra ◽  
Peat Plateaus

Permafrost evolution in postglacial marine silts near the tree line was reconstructed using landform analysis, 14C dating, and palynostratigraphic analysis of peat sections. In the forest–tundra, below the tree line, four sites in peat plateaus have a stratigraphic sequence indicating an alluvial plain environment from 6000 to 4800 BP followed by a wetland supporting trees and shrubs with deep snow accumulation and without permafrost. Ground heave occurred between 1900 and 1200 BP as peat plateaus and palsas were formed. In the shrub–tundra, above the tree line, three permafrost sites with buried peat beds suggest that climatic conditions were cold enough for discontinuous permafrost in the surrounding landscape starting from land emergence, about 5800 BP; however, fen expansion and sedge peat accumulation continued over unfrozen ground until 2300, 1560, and 1400 BP. At these dates, the sites were buried with silt, probably as a result of mass wasting on nearby permafrost mounds and then permafrost aggraded under the sites. Generally, the palynostratigraphic data reflect a marked cooling of climate starting by 3200–2700 BP and culminating in a major period of permafrost aggradation between 1900 and 1200 BP. Permafrost degradation has been dominant since then despite other possible cold intervals. Nowadays, the permafrost in marine silts is twice as thick and three times more widespread in the shrub–tundra than in the forest–tundra.

Palsas and Peat Plateaus in Central Manitoba and Saskatchewan

1972 ◽  
Vol 2 (3) ◽  
pp. 291-302 ◽  
Author(s):  
S. C. Zoltai
Keyword(s):  
Volume Change ◽  
Developmental Stages ◽  
Present Climate ◽  
Southern Limit ◽  
Discontinuous Permafrost ◽  
Flin Flon ◽  
Peat Plateaus

Twenty-six peat plateaus and eight palsas were examined near Flin Flon, Manitoba at the southern limit of discontinuous permafrost. Peat plateaus in different developmental stages were identified on the basis of their morphology. The permafrost is entirely within the peat in all peat plateaus within the study area, but extends into mineral subsoil under all palsas examined. Doming in peat plateaus is largely explained by volume change due to change from unfrozen to frozen stage, and by buoyancy of the frozen mass floating on unfrozen peat. The occurrence of aggrading and degrading peat plateaus in the same area indicates that all developmental stages are permitted by the present climate.

Morphological and isozyme variation in Salicornia europaea (s.l.) (Chenopodiaceae) in northeastern North America

1987 ◽  
Vol 65 (7) ◽  
pp. 1410-1419 ◽  
Author(s):  
S. L. Wolff ◽  
R. L. Jefferies
Keyword(s):  
North America ◽  
Atlantic Coast ◽  
Hudson Bay ◽  
Salicornia Europaea ◽  
Electrophoretic Variation ◽  
James Bay ◽  
Northeastern North America ◽  
Electrophoretic Patterns ◽  
Anther Length ◽  
Vegetative Characters

Morphological and electrophoretic variation has been documented within and among populations of Salicornia europaea L. (s.l.) in northeastern North America. Univariate and multivariate analyses (discriminant analyses) of measurements of floral and vegetative characters delimited three morphologically distinct groups of populations: Atlantic coast tetraploids (2n = 36), Hudson Bay diploids, and Atlantic coast and James Bay diploids (2n = 18). The two diploid groups were morphologically distinct from the midwestern diploid, S. rubra Nels., based on anther length, width of the scarious border of the fertile segment, and the overall width of the fertile segment. Electrophoretic evidence supported the delimitation of the three distinct morphological groups of populations of S. europaea with the exception of the population from James Bay, which had electrophoretic patterns identical with those of plants from Hudson Bay but resembled the Atlantic coast diploids morphologically. Most enzyme systems assayed were monomorphic. Only homozygous banding patterns were detected in diploid plants and electrophoretic variation was not observed within populations of S. europaea or S. rubra but was detected between groups of populations. Four multilocus phenotypes were evident; these corresponded to the major groups recognized on the basis of ploidy level and morphology. Reasons that may account for the paucity of isozymic variation are discussed.

Ecology of the Forest-Tundra Ecotone on the East Coast of Hudson Bay

1948 ◽  
Vol 18 (1) ◽  
pp. 117-144 ◽  
Author(s):  
John W. Marr
Keyword(s):  
East Coast ◽  
Hudson Bay ◽  
Forest Tundra

Chapter 18 Marine and Coastal Birds of James Bay, Hudson Bay and Foxe Basin

1986 ◽  
pp. 355-386 ◽  
Author(s):  
R.I.G. Morrison ◽  
A.J. Gaston
Keyword(s):  
Hudson Bay ◽  
James Bay ◽  
Foxe Basin ◽  
Coastal Birds

BIOLOGICAL AND OCEANOGRAPHIC CONDITIONS IN HUDSON BAY: 6. THE GENERAL HYDROGRAPHY AND HYDRODYNAMICS OF THE WATERS OF THE HUDSON BAY REGION

1932 ◽  
Vol 7 (1) ◽  
pp. 91-118 ◽  
Author(s):  
H. B. HACHEY
Keyword(s):  
Fresh Water ◽  
Water Movement ◽  
Open Ocean ◽  
Hudson Bay ◽  
Water Drainage ◽  
James Bay ◽  
Bay Area ◽  
Hydrographic Conditions ◽  
The Many ◽  
Oceanographic Conditions

The waters of Hudson bay differ markedly from the waters of Hudson strait and the waters of the open ocean. Intense stratification in the upper twenty-five metres, decreasing as the waters of the open ocean are approached, gives Hudson bay the character of a large estuary. Below fifty metres the waters are for all purposes dynamically dead, thus resulting in a cold saline body of water which probably undergoes very little change from season to season. The movements of the waters at various levels are dealt with to show that the inflow of waters from Fox channel and the many fresh-water drainage areas control the hydrographic conditions as found. The main water movement is from the James bay area to Hudson strait and thence to the open ocean.

Contribution palynostratigraphique (dinokystes, pollen et spores) à la connaissance de la mer de Champlain: coupe de Saint-Césaire, Québec

1989 ◽  
Vol 26 (12) ◽  
pp. 2450-2464 ◽  
Author(s):  
Anne de Vernal ◽  
Claire Goyette ◽  
Cyril G. Rodrigues
Keyword(s):  
High Resolution ◽  
Relative Abundance ◽  
Surface Waters ◽  
Dinoflagellate Cysts ◽  
Site Location ◽  
Morphological Variations ◽  
Forest Tundra ◽  
Arctic Conditions ◽  
Shrub Tundra ◽  
Pollen And Spores

High-resolution continental (pollen and spores) and marine (dinoflagellate cysts) microfloral records were obtained from a section consisting of about 0.5 m of glaciolacustrine and 2.5 m of Champlain Sea deposits at the Saint-Césaire site. The pollen and spore assemblages indicate the existence of a regional open vegetation of shrub tundra to forest tundra. Fluctuations in the percentages of Picea and shrub and herb taxa are related to regional afforestation and paleogeographical evolution of the basin. The Champlain Sea sediments contain an abundant dinocyst flora dominated by Operculodinium centrocarpum, Brigantedinium spp., and Algidasphaeridium? minutum, which indicate cold Arctic conditions in surface waters. Fluctuations in concentration (102–104∙cm−3) and relative abundance of dinocyst species are attributed to changes in dinoflagellate productivity and paleoceanographic conditions, notably paleosalinity. Morphological variations of Operculodinium centrocarpum and Algidasphaeridium? minutum led to this description of the varieties, named "cezare" after the site location.

The Food Habits of Polar Bears of James Bay and Southwest Hudson Bay in Summer and Autumn

ARCTIC ◽  
1975 ◽  
Vol 28 (2) ◽  
Author(s):  
Richard H. Russell
Keyword(s):  
Food Habits ◽  
Hudson Bay ◽  
Polar Bears ◽  
James Bay
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