EFFECTS OF ACTIVE LAYER REMOVAL FROM ORGANIC LANDFORMS IN THE DISCONTINUOUS PERMAFROST ZONE

1975 ◽  
Vol 55 (2) ◽  
pp. 235-238
Author(s):  
M. E. WALMSLEY ◽  
L. M. LAVKULICH
Keyword(s):  
Active Layer ◽  
Permafrost Zone ◽  
Layer Removal ◽  
Discontinuous Permafrost

not available

A Landscape Zonation for the Southern and Central Mackenzie River Valley based on Terrain Permafrost Characteristics

1973 ◽  
Vol 10 (12) ◽  
pp. 1843-1854 ◽  
Author(s):  
C. B. Crampton
Keyword(s):  
Active Layer ◽  
Relative Abundance ◽  
River Valley ◽  
Permafrost Zone ◽  
The Past ◽  
Discontinuous Permafrost ◽  
Mackenzie River

A landscape zonation is presented for the southern and central Mackenzie River valley, based on observed changes in permafrost characteristics of selected terrain types, with changing climatic implications. The relative abundance of lichen on specified terrain types suggests the thickness of the active layer within the discontinuous permafrost zone, and is a useful guide in air photograph interpretation for extensive mapping of landscape–permafrost realtionships between localities of ground inspection. Widespread, fossil, cryoturbated terrain supports the contention that today's climate in the study area is less severe than that in the past.

SOME CHARACTERISTICS OF CRYIC ORGANIC SOILS IN NORTHERN MANITOBA

1972 ◽  
Vol 52 (3) ◽  
pp. 485-496 ◽  
Author(s):  
C. TARNOCAI
Keyword(s):  
Active Layer ◽  
Black Spruce ◽  
Permafrost Zone ◽  
Organic Soils ◽  
High Concentration ◽  
Water Ice ◽  
Discontinuous Permafrost ◽  
Significant Difference ◽  
Exchangeable Magnesium ◽  
Ice Content

Two commonly occurring, perennially frozen, organic soils were studied, one from the south-west part of the Discontinuous Permafrost Zone and the other from the Continuous Permafrost Zone of the Hudson Bay Lowland in northern Manitoba. These soils had a characteristic domed or slightly elevated topography with a dense cover of black spruce (Picea mariana (Mill.) BSP.), Ledum groenlandicum Oeder, feathermoss, and sphagnum moss. The water content of the active layer was found to be much lower than the water (ice) content of the frozen layer. The exchangeable calcium and hydrogen and pH were higher in the frozen layer than in the active layer but no significant difference was found in the exchangeable magnesium, potassium, and sodium of the two layers. The high concentration of Ca in the frozen layer is likely due both to the transfer of soil moisture and nutrients along the thermal gradient and, as has been found previously, to the high selectivity of organic soils for calcium over magnesium and monovalent cations.

scholarly journals Effects of freezing on soil temperature, freezing front propagation and moisture redistribution in peat: laboratory investigations

2012 ◽  
Vol 16 (2) ◽  
pp. 501-515 ◽  
Author(s):  
R. M. Nagare ◽  
R. A. Schincariol ◽  
W. L. Quinton ◽  
M. Hayashi
Keyword(s):  
Water Content ◽  
Active Layer ◽  
Water Movement ◽  
Peat Soil ◽  
Soil Column ◽  
Initial Period ◽  
Soil Freezing ◽  
Permafrost Soil ◽  
Freezing Front ◽  
Discontinuous Permafrost

Abstract. There are not many studies that report water movement in freezing peat. Soil column studies under controlled laboratory settings can help isolate and understand the effects of different factors controlling freezing of the active layer in organic covered permafrost terrain. In this study, four peat Mesocosms were subjected to temperature gradients by bringing the Mesocosm tops in contact with sub-zero air temperature while maintaining a continuously frozen layer at the bottom (proxy permafrost). Soil water movement towards the freezing front (from warmer to colder regions) was inferred from soil freezing curves, liquid water content time series and from the total water content of frozen core samples collected at the end of freezing cycle. A substantial amount of water, enough to raise the upper surface of frozen saturated soil within 15 cm of the soil surface at the end of freezing period appeared to have moved upwards during freezing. Diffusion under moisture gradients and effects of temperature on soil matric potential, at least in the initial period, appear to drive such movement as seen from analysis of freezing curves. Freezing front (separation front between soil zones containing and free of ice) propagation is controlled by latent heat for a long time during freezing. A simple conceptual model describing freezing of an organic active layer initially resembling a variable moisture landscape is proposed based upon the results of this study. The results of this study will help in understanding, and ultimately forecasting, the hydrologic response of wetland-dominated terrain underlain by discontinuous permafrost.

scholarly journals Active layer thermal regime in two climatically contrasted sites of the Antarctic Peninsula region

2016 ◽  
Vol 42 (2) ◽  
pp. 457 ◽  
Author(s):  
F. Hrbáček ◽  
M. Oliva ◽  
K. Laska ◽  
J. Ruiz-Fernández ◽  
M. A. De Pablo ◽  
...  
Keyword(s):  
Active Layer ◽  
Antarctic Peninsula ◽  
Thermal Regime ◽  
Active Layer Thickness ◽  
Mean Annual Temperature ◽  
Climate Trends ◽  
Ground Temperatures ◽  
Air Temperatures ◽  
Discontinuous Permafrost ◽  
The Antarctic

Permafrost controls geomorphic processes in ice-free areas of the Antarctic Peninsula (AP) region. Future climate trends will promote significant changes of the active layer regime and permafrost distribution, and therefore a better characterization of present-day state is needed. With this purpose, this research focuses on Ulu Peninsula (James Ross Island) and Byers Peninsula (Livingston Island), located in the area of continuous and discontinuous permafrost in the eastern and western sides of the AP, respectively. Air and ground temperatures in as low as 80 cm below surface of the ground were monitored between January and December 2014. There is a high correlation between air temperatures on both sites (r=0.74). The mean annual temperature in Ulu Peninsula was -7.9 ºC, while in Byers Peninsula was -2.6 ºC. The lower air temperatures in Ulu Peninsula are also reflected in ground temperatures, which were between 4.9 (5 cm) and 5.9 ºC (75/80 cm) lower. The maximum active layer thickness observed during the study period was 52 cm in Ulu Peninsula and 85 cm in Byers Peninsula. Besides climate, soil characteristics, topography and snow cover are the main factors controlling the ground thermal regime in both areas.

scholarly journals Dissolved organic carbon and major and trace elements in peat porewater of sporadic, discontinuous, and continuous permafrost zones of western Siberia

2017 ◽  
Vol 14 (14) ◽  
pp. 3561-3584 ◽  
Author(s):  
Tatiana V. Raudina ◽  
Sergey V. Loiko ◽  
Artyom G. Lim ◽  
Ivan V. Krickov ◽  
Liudmila S. Shirokova ◽  
...  
Keyword(s):  
Trace Elements ◽  
Organic Carbon ◽  
Western Siberia ◽  
Peat Soil ◽  
Major And Trace Elements ◽  
Permafrost Zone ◽  
Discontinuous Permafrost ◽  
Latitudinal Transect ◽  
Soil Solutions ◽  
Continuous Permafrost

Abstract. Mobilization of dissolved organic carbon (DOC) and related trace elements (TEs) from the frozen peat to surface waters in the permafrost zone is expected to enhance under ongoing permafrost thaw and active layer thickness (ALT) deepening in high-latitude regions. The interstitial soil solutions are efficient tracers of ongoing bio-geochemical processes in the critical zone and can help to decipher the intensity of carbon and metals migration from the soil to the rivers and further to the ocean. To this end, we collected, across a 640 km latitudinal transect of the sporadic to continuous permafrost zone of western Siberia peatlands, soil porewaters from 30 cm depth using suction cups and we analyzed DOC, dissolved inorganic carbon (DIC), and 40 major elements and TEs in 0.45 µm filtered fraction of 80 soil porewaters. Despite an expected decrease in the intensity of DOC and TE mobilization from the soil and vegetation litter to the interstitial fluids with the increase in the permafrost coverage and a decrease in the annual temperature and ALT, the DOC and many major and trace elements did not exhibit any distinct decrease in concentration along the latitudinal transect from 62.2 to 67.4° N. The DOC demonstrated a maximum of concentration at 66° N, on the border of the discontinuous/continuous permafrost zone, whereas the DOC concentration in peat soil solutions from the continuous permafrost zone was equal to or higher than that in the sporadic/discontinuous permafrost zone. Moreover, a number of major (Ca, Mg) and trace (Al, Ti, Sr, Ga, rare earth elements (REEs), Zr, Hf, Th) elements exhibited an increasing, not decreasing, northward concentration trend. We hypothesize that the effects of temperature and thickness of the ALT are of secondary importance relative to the leaching capacity of peat, which is in turn controlled by the water saturation of the peat core. The water residence time in peat pores also plays a role in enriching the fluids in some elements: the DOC, V, Cu, Pb, REEs, and Th were a factor of 1.5 to 2.0 higher in mounds relative to hollows. As such, it is possible that the time of reaction between the peat and downward infiltrating waters essentially controls the degree of peat porewater enrichments in DOC and other solutes. A 2° northward shift in the position of the permafrost boundaries may bring about a factor of 1.3 ± 0.2 decrease in Ca, Mg, Sr, Al, Fe, Ti, Mn, Ni, Co, V, Zr, Hf, Th, and REE porewater concentration in continuous and discontinuous permafrost zones, and a possible decrease in DOC, specific ultraviolet absorbency (SUVA), Ca, Mg, Fe, and Sr will not exceed 20 % of their current values. The projected increase in ALT and vegetation density, northward migration of the permafrost boundary, or the change of hydrological regime is unlikely to modify chemical composition of peat porewater fluids larger than their natural variations within different micro-landscapes, i.e., within a factor of 2. The decrease in DOC and metal delivery to small rivers and lakes by peat soil leachate may also decrease the overall export of dissolved components from the continuous permafrost zone to the Arctic Ocean. This challenges the current paradigm on the increase in DOC export from the land to the ocean under climate warming in high latitudes.

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