scholarly journals Water tracks in the High Arctic: a hydrological network dominated by rapid subsurface flow through patterned ground

2017 ◽  
Vol 3 (2) ◽  
pp. 334-353 ◽  
Author(s):  
Michel Paquette ◽  
Daniel Fortier ◽  
Warwick F. Vincent
Keyword(s):  
Active Layer ◽  
Cold Water ◽  
High Arctic ◽  
Canadian High Arctic ◽  
Patterned Ground ◽  
Arctic Water ◽  
Near Surface ◽  
Polar Desert ◽  
Flow Through

Water tracks play a major role in the headwater basin hydrology of permafrost landscapes in Alaska and Antarctica, but less is known about these features in the High Arctic. We examined the physical and hydrological properties of water tracks on Ward Hunt Island, a polar desert site in the Canadian High Arctic, to evaluate their formation process and to compare with water tracks reported elsewhere. These High Arctic water tracks flowed through soils that possessed higher near-surface organic carbon concentrations, higher water content, and coarser material than the surrounding soils. The water track morphology suggested they were initiated by a combination of sorting, differential frost heaving, and eluviation. The resultant network of soil conduits, comparable to soil pipes, dominated the hydrology of the slope. The flow of cold water through these conduits slowed down the progression of the thawing front during summer, making the active layer consistently shallower relative to adjacent soils. Water tracks on Ward Hunt Island, and in polar desert catchments with these features elsewhere in the High Arctic, strongly influence slope hydrology and active-layer properties while also affecting vegetation distribution and the quality of runoff to the downstream lake.

scholarly journals Geophysical imaging of permafrost in the SW Svalbard – the result of two high arctic expeditions to Spitsbergen

2020 ◽  
Author(s):  
Mariusz Majdanski ◽  
Artur Marciniak ◽  
Bartosz Owoc ◽  
Wojciech Dobiński ◽  
Tomasz Wawrzyniak ◽  
...  
Keyword(s):  
Surface Waves ◽  
Active Layer ◽  
High Arctic ◽  
The Arctic ◽  
Seismic Profiles ◽  
Frozen Ground ◽  
Near Surface ◽  
Seismic Processing ◽  
Reflection Seismic ◽  
Sea Coast

<p>The Arctic regions are the place of the fastest observed climate change. One of the indicators of such evolution are changes occurring in the glaciers and the subsurface in the permafrost. The active layer of the permafrost as the shallowest one is well measured by multiple geophysical techniques and in-situ measurements.</p><p>Two high arctic expeditions have been organized to use seismic methods to recognize the shape of the permafrost in two seasons: with the unfrozen ground (October 2017) and frozen ground (April 2018). Two seismic profiles have been designed to visualize the shape of permafrost between the sea coast and the slope of the mountain, and at the front of a retreating glacier. For measurements, a stand-alone seismic stations has been used with accelerated weight drop with in-house modifications and timing system. Seismic profiles were acquired in a time-lapse manner and were supported with GPR and ERT measurements, and continuous temperature monitoring in shallow boreholes.</p><p>Joint interpretation of seismic and auxiliary data using Multichannel analysis of surface waves, First arrival travel-time tomography and Reflection imaging show clear seasonal changes affecting the active layer where P-wave velocities are changing from 3500 to 5200 m/s. This confirms the laboratory measurements showing doubling the seismic velocity of water-filled high-porosity rocks when frozen. The same laboratory study shows significant (>10%) increase of velocity in frozen low porosity rocks, that should be easily visible in seismic.</p><p>In the reflection seismic processing, the most critical part was a detailed front mute to eliminate refracted arrivals spoiling wide-angle near-surface reflections. Those long offset refractions were however used to estimate near-surface velocities further used in reflection processing. In the reflection seismic image, a horizontal reflection was traced at the depth of 120 m at the sea coast deepening to the depth of 300 m near the mountain.</p><p>Additionally, an optimal set of seismic parameters has been established, clearly showing a significantly higher signal to noise ratio in case of frozen ground conditions even with the snow cover. Moreover, logistics in the frozen conditions are much easier and a lack of surface waves recorded in the snow buried geophones makes the seismic processing simpler.</p><p>Acknowledgements               </p><p>This research was funded by the National Science Centre, Poland (NCN) Grant UMO-2015/21/B/ST10/02509.</p>

scholarly journals A trajectory analysis of atmospheric transport of black carbon aerosols to Canadian High Arctic in winter and spring (1990–2005)

2010 ◽  
Vol 10 (2) ◽  
pp. 2221-2244 ◽  
Author(s):  
L. Huang ◽  
S. L. Gong ◽  
S. Sharma ◽  
D. Lavoué ◽  
C. Q. Jia
Keyword(s):  
Regression Model ◽  
Black Carbon ◽  
North American ◽  
Emission Intensity ◽  
Atmospheric Transport ◽  
High Arctic ◽  
The Arctic ◽  
Canadian High Arctic ◽  
Near Surface ◽  
Annual Variations

Abstract. Black carbon (BC) particles accumulated in the Arctic troposphere and deposited over snow have significant effects on radiative forcing of the Arctic regional climate. Applying cluster analysis technique on 10-day backward trajectories, transport pathways affecting Alert (82.5° N, 62.5° W), Nunavut in Canada are identified in this work, along with the associated transport frequency. Based on the atmospheric transport frequency and the estimated BC emission intensity from surrounding regions, a linear regression model is constructed to investigate the inter-annual variations of BC observed at Alert in January and April, representative of winter and spring respectively, between 1990 and 2005. Strong correlations are found between BC concentrations predicted with the regression model and measured at Alert for both seasons (R2 equals 0.77 and 0.81 for winter and spring, respectively). Results imply that atmospheric transport and BC emission are the major contributors to the inter-annual variations in BC concentrations observed at Alert in the cold seasons for the 16-year period. Based on the regression model the relative contributions of regional BC emissions affecting Alert are attributed to the Eurasian sector, composed of the European Union and the former USSR, and the North American sector. Considering both seasons, the model suggests that Eurasia is the major contributor to the near-surface BC levels at the Canadian High Arctic site with an average contribution of over 85% during the 16-year period. In winter, the atmospheric transport of BC aerosols from Eurasia is found to be even more predominant with a multi-year average of 94%. The model estimates smaller contribution from the Eurasian sector in spring (70%) than that in winter. It is also found that the change in Eurasian contributions depends mainly on the reduction of emission intensity, while the changes in both emission and atmospheric transport contributed to the inter-annual variation of North American contributions.

scholarly journals Metagenome-Assembled Genome of USCα AHI, a Potential High-Affinity Methanotroph from Axel Heiberg Island, Canadian High Arctic

2019 ◽  
Vol 8 (46) ◽  
Author(s):  
Calvin Rusley ◽  
Tullis C. Onstott ◽  
Tatiana A. Vishnivetskaya ◽  
Alice Layton ◽  
Archana Chauhan ◽  
...  
Keyword(s):  
Active Layer ◽  
Complete Genome ◽  
Carbon Assimilation ◽  
High Arctic ◽  
Metagenomic Sequencing ◽  
Canadian High Arctic ◽  
Upland Soil ◽  
High Affinity ◽  
Axel Heiberg Island

Metagenomic sequencing of active-layer cryosols from the Canadian High Arctic has yielded a nearly complete genome for an atmospheric CH4-oxidizing bacterium belonging to upland soil cluster α (USCα). This genome contains genes involved in CH4 metabolism, H2 metabolism, and multiple carbon assimilation pathways.

scholarly journals Thaumarchaea Genome Sequences from a High Arctic Active Layer

2020 ◽  
Vol 9 (21) ◽  
Author(s):  
Emily Wei-Hsin Sun ◽  
Sassan Hajirezaie ◽  
Mackenzie Dooner ◽  
Tatiana A. Vishnivetskaya ◽  
Alice Layton ◽  
...  
Keyword(s):  
Active Layer ◽  
High Arctic ◽  
Metagenomic Data ◽  
Data Sets ◽  
Ammonia Oxidizers ◽  
Canadian High Arctic ◽  
Genome Sequences ◽  
Terrestrial Environments

ABSTRACT The role of archaeal ammonia oxidizers often exceeds that of bacterial ammonia oxidizers in marine and terrestrial environments but has been understudied in permafrost, where thawing has the potential to release ammonia. Here, three thaumarchaea genomes were assembled and annotated from metagenomic data sets from carbon-poor Canadian High Arctic active-layer cryosols.

scholarly journals Arctic gypsum endoliths: a biogeochemical characterization of a viable and active microbial community

2013 ◽  
Vol 10 (11) ◽  
pp. 7661-7675 ◽  
Author(s):  
L. A. Ziolkowski ◽  
N. C. S. Mykytczuk ◽  
C. R. Omelon ◽  
H. Johnson ◽  
L. G. Whyte ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Microbial Community ◽  
Environmental Conditions ◽  
High Arctic ◽  
Molecular Techniques ◽  
23S Rrna ◽  
Small Scale ◽  
Canadian High Arctic ◽  
Polar Desert ◽  
Endolithic Community

Abstract. Extreme environmental conditions such as those found in the polar regions on Earth are thought to test the limits of life. Microorganisms living in these environments often seek protection from environmental stresses such as high UV exposure, desiccation and rapid temperature fluctuations, with one protective habitat found within rocks. Such endolithic microbial communities, which often consist of bacteria, fungi, algae and lichens, are small-scale ecosystems comprised of both producers and consumers. However, the harsh environmental conditions experienced by polar endolithic communities are thought to limit microbial diversity and therefore the rate at which they cycle carbon. In this study, we characterized the microbial community diversity, turnover rate and microbe–mineral interactions of a gypsum-based endolithic community in the polar desert of the Canadian high Arctic. 16S/18S/23S rRNA pyrotag sequencing demonstrated the presence of a diverse community of phototrophic and heterotrophic bacteria, archaea, algae and fungi. Stable carbon isotope analysis of the viable microbial membranes, as phospholipid fatty acids and glycolipid fatty acids, confirmed the diversity observed by molecular techniques and indicated that present-day atmospheric carbon is assimilated into the microbial community biomass. Uptake of radiocarbon from atmospheric nuclear weapons testing during the 1960s into microbial lipids was used as a pulse label to determine that the microbial community turns over carbon on the order of 10 yr, equivalent to 4.4 g C m−2 yr−1 gross primary productivity. Scanning electron microscopy (SEM) micrographs indicated that mechanical weathering of gypsum by freeze–thaw cycles leads to increased porosity, which ultimately increases the habitability of the rock. In addition, while bacteria were adhered to these mineral surfaces, chemical analysis by micro-X-ray fluorescence (μ-XRF) spectroscopy suggests little evidence for microbial alteration of minerals, which contrasts with other endolithic habitats. While it is possible that these communities turn over carbon quickly and leave little evidence of microbe–mineral interaction, an alternative hypothesis is that the soluble and friable nature of gypsum and harsh conditions lead to elevated erosion rates, limiting microbial residence times in this habitat. Regardless, this endolithic community represents a microbial system that does not rely on a nutrient pool from the host gypsum cap rock, instead receiving these elements from allochthonous debris to maintain a more diverse and active community than might have been predicted in the polar desert of the Canadian high Arctic.

Differences in Riverine and Pond Water Dissolved Organic Matter Composition and Sources in Canadian High Arctic Watersheds Affected by Active Layer Detachments

2018 ◽  
Vol 52 (3) ◽  
pp. 1062-1071 ◽  
Author(s):  
Jun-Jian Wang ◽  
Melissa J. Lafrenière ◽  
Scott F. Lamoureux ◽  
André J. Simpson ◽  
Yves Gélinas ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Active Layer ◽  
Pond Water ◽  
High Arctic ◽  
Canadian High Arctic ◽  
Organic Matter Composition
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