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 Geophysical mapping of palsa peatland permafrost

2015 ◽  
Vol 9 (2) ◽  
pp. 465-478 ◽  
Author(s):  
Y. Sjöberg ◽  
P. Marklund ◽  
R. Pettersson ◽  
S. W. Lyon
Keyword(s):  
Geophysical Methods ◽  
Permafrost Zone ◽  
Added Value ◽  
Spatial Distributions ◽  
Resistivity Tomography ◽  
Discontinuous Permafrost ◽  
Ice Content ◽  
Ground Penetrating ◽  
Biogeochemical Hotspots ◽  
Geophysical Mapping

Abstract. Permafrost peatlands are hydrological and biogeochemical hotspots in the discontinuous permafrost zone. Non-intrusive geophysical methods offer a possibility to map current permafrost spatial distributions in these environments. In this study, we estimate the depths to the permafrost table and base across a peatland in northern Sweden, using ground penetrating radar and electrical resistivity tomography. Seasonal thaw frost tables (at ~0.5 m depth), taliks (2.1–6.7 m deep), and the permafrost base (at ~16 m depth) could be detected. Higher occurrences of taliks were discovered at locations with a lower relative height of permafrost landforms, which is indicative of lower ground ice content at these locations. These results highlight the added value of combining geophysical techniques for assessing spatial distributions of permafrost within the rapidly changing sporadic permafrost zone. For example, based on a back-of-the-envelope calculation for the site considered here, we estimated that the permafrost could thaw completely within the next 3 centuries. Thus there is a clear need to benchmark current permafrost distributions and characteristics, particularly in under studied regions of the pan-Arctic.

Climate and ground temperature relations at sites across the continuous and discontinuous permafrost zones, northern Canada1This article is one of a series of papers published in this CJES Special Issue on the theme of Fundamental and applied research on permafrost in Canada.2Earth Science Sector (ESS) Contribution 20110128.

2012 ◽  
Vol 49 (8) ◽  
pp. 865-876 ◽  
Author(s):  
Jennifer Throop ◽  
Antoni G. Lewkowicz ◽  
Sharon L. Smith
Keyword(s):  
Active Layer ◽  
High Arctic ◽  
High Elevation ◽  
Climatic Conditions ◽  
Yukon Territory ◽  
Ground Temperature ◽  
Air Temperatures ◽  
Discontinuous Permafrost ◽  
Heat Effects ◽  
Ice Content

Climate – ground temperature relations are examined under a range of conditions for 10 sites across northern Canada. The sites are located between 60°N and 83°N and at elevations of 40 to 1840 m above sea level. They encompass various environmental and climatic conditions, with permafrost temperatures that range from just below 0 to –15 °C. The substrates range from bedrock to fine-grained sediment with high ice content, and vegetation types include coniferous forests in the Mackenzie Valley, shrub tundra at high elevation in the southern Yukon Territory, and polar desert in the High Arctic. Permafrost conditions at all of these sites are determined primarily by air temperature, followed by snow and substrate conditions. The apparent thermal diffusivity is relatively high at colder sites and in bedrock and is lower at sites in sediment with high ice content. Snow has a greater influence on air–ground temperature relations at sites where mean annual air temperatures and active-layer moisture contents are relatively high, leading to physically significant latent heat effects and a slower freeze-back of the active layer.

scholarly journals Soil Moisture but Not Warming Dominates Nitrous Oxide Emissions During Freeze–Thaw Cycles in a Qinghai–Tibetan Plateau Alpine Meadow With Discontinuous Permafrost

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhe Chen ◽  
Shidong Ge ◽  
Zhenhua Zhang ◽  
Yangong Du ◽  
Buqing Yao ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Soil Moisture ◽  
Tibetan Plateau ◽  
Active Layer ◽  
Alpine Meadow ◽  
Nitrous Oxide Emissions ◽  
Freeze Thaw ◽  
Discontinuous Permafrost ◽  
Significant Difference

Large quantities of organic matter are stored in frozen soils (permafrost) within the Qinghai–Tibetan Plateau (QTP). The most of QTP regions in particular have experienced significant warming and wetting over the past 50 years, and this warming trend is projected to intensify in the future. Such climate change will likely alter the soil freeze–thaw pattern in permafrost active layer and toward significant greenhouse gas nitrous oxide (N2O) release. However, the interaction effect of warming and altered soil moisture on N2O emission during freezing and thawing is unclear. Here, we used simulation experiments to test how changes in N2O flux relate to different thawing temperatures (T5–5°C, T10–10°C, and T20–20°C) and soil volumetric water contents (VWCs, W15–15%, W30–30%, and W45–45%) under 165 F–T cycles in topsoil (0–20 cm) of an alpine meadow with discontinuous permafrost in the QTP. First, in contrast to the prevailing view, soil moisture but not thawing temperature dominated the large N2O pulses during F–T events. The maximum emissions, 1,123.16–5,849.54 μg m–2 h–1, appeared in the range of soil VWC from 17% to 38%. However, the mean N2O fluxes had no significant difference between different thawing temperatures when soil was dry or waterlogged. Second, in medium soil moisture, low thawing temperature is more able to promote soil N2O emission than high temperature. For example, the peak value (5,849.54 μg m–2 h–1) and cumulative emissions (366.6 mg m–2) of W30T5 treatment were five times and two to four times higher than W30T10 and W30T20, respectively. Third, during long-term freeze–thaw cycles, the patterns of cumulative N2O emissions were related to soil moisture. treatments; on the contrary, the cumulative emissions of W45 treatments slowly increased until more than 80 cycles. Finally, long-term freeze–thaw cycles could improve nitrogen availability, prolong N2O release time, and increase N2O cumulative emission in permafrost active layer. Particularly, the high emission was concentrated in the first 27 and 48 cycles in W15 and W30, respectively. Overall, our study highlighted that large emissions of N2O in F–T events tend to occur in medium moisture soil at lower thawing temperature; the increased number of F–T cycles may enhance N2O emission and nitrogen mineralization in permafrost active layer.

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.

scholarly journals Geophysical mapping of palsa peatland permafrost

2014 ◽  
Vol 8 (5) ◽  
pp. 5137-5168 ◽  
Author(s):  
Y. Sjöberg ◽  
P. Marklund ◽  
R. Pettersson ◽  
S. W. Lyon
Keyword(s):  
Thought Experiment ◽  
Geophysical Methods ◽  
Permafrost Zone ◽  
Added Value ◽  
Resistivity Tomography ◽  
Discontinuous Permafrost ◽  
Ice Content ◽  
Ground Penetrating ◽  
Biogeochemical Hotspots ◽  
Geophysical Mapping

Abstract. Permafrost peatlands are hydrological and biogeochemical hotspots in the discontinuous permafrost zone. Non-intrusive geophysical methods offer possibility to map current permafrost spatial distributions in these environments. In this study, we estimate the depths to the permafrost table surface and base across a peatland in northern Sweden, using ground penetrating radar and electrical resistivity tomography. Seasonal thaw frost tables (at ~0.5 m depth), taliks (2.1–6.7 m deep), and the permafrost base (at ~16 m depth) could be detected. Higher occurrences of taliks were discovered at locations with a lower relative height of permafrost landforms indicative of lower ground ice content at these locations. These results highlight the added value of combining geophysical techniques for assessing spatial distribution of permafrost within the rapidly changing sporadic permafrost zone. For example, based on a simple thought experiment for the site considered here, we estimated that the thickest permafrost could thaw out completely within the next two centuries. There is a clear need, thus, to benchmark current permafrost distributions and characteristics particularly in under studied regions of the pan-arctic.

Comparative Study on Vit. E & Mefenamic acid vs Mefenamic acid alone on mean reduction in pain in Primary Dysmenorrhea

2021 ◽  
Vol 15 (12) ◽  
pp. 3195-3197
Author(s):  
Fariha Sadiqa ◽  
Mufakhara Fatimah ◽  
Abdul Mudabbir Rehan ◽  
Sidra Mushtaq ◽  
Asia Firdous ◽  
...  
Keyword(s):  
Vitamin E ◽  
Mefenamic Acid ◽  
Controlled Trial ◽  
Acid Group ◽  
P Value ◽  
Primary Dysmenorrhea ◽  
High Concentration ◽  
Randomized Controlled ◽  
Significant Difference ◽  
Menstrual Fluid

Background: Pelvic pain around the time of mensturation without any identifiable pathologic lesion present from menarche is called primary dysmenorrhea. The pain is believed to be related to prostaglandin (PG). Women with dysmenorrhoea have a relatively high concentration of PGF 2 alpha in menstrual fluid and suppression of PG synthesis has become the main treatment. Aim: To compare mean reduction in pain in patients presenting with primary dysmenorrhea given vitamin E & Mefenamic acid versus Mefenamic acid alone. Results: It was a randomized controlled trial which was conducted in Department of Obstetrics & Gynecology, THQ Raiwind Hospital, Lahore for 6 months duration w.e.f 01/02/2017 to 31/07/2017. In this study, 18(36%) in Vitamin-E group and 21(42%) in Mefenamic acid group were between 15-20 years while 32(64%) in Vitamin-E group and 29(58%) in Mefenamic acid group were between 21-25 years, mean±sd was calculated as 20.86±2.92 and 20.66±2.86 years respectively, mean dysmenorrheal pain at baseline was recorded as 50.06±10.27 in Vitamin-E group and 50.14±10.28 in Mefenamic acid group, p value < 0.754, showing that both groups are insignificant, mean dysmenorrheal pain after treatment was recorded as 20.50±10.04 in Vitamin-E group and 30.22±10.28 in Mefenamic acid group, p value was < 0.002 showing significant difference between the two group, comparison of mean reduction in dysmenorrheal pain after treatment was recorded as 20.56±0.91 in Vitamin-E group and 10.92±0.75 in Mefenamic acid group, p value was < 0.000, showing significant difference. Conclusion: We concluded that there is a significant mean reduction in dysmenorrhic pain in patients given Mefenamic Acid + Vitamen E as compared to patients given Mefenamic Acid alone. Keywords: Dysmenorrhic pain, Mefenamic Acid + Vitamen E, mean reduction in dysmenorrhic pain

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