scholarly journals Potential shifts in Canadian High Arctic sedimentary organic matter composition with permafrost active layer detachments

2015 ◽  
Vol 79 ◽  
pp. 1-13 ◽  
Author(s):  
David M. Grewer ◽  
Melissa J. Lafrenière ◽  
Scott F. Lamoureux ◽  
Myrna J. Simpson
2018 ◽  
Vol 52 (3) ◽  
pp. 1062-1071 ◽  
Author(s):  
Jun-Jian Wang ◽  
Melissa J. Lafrenière ◽  
Scott F. Lamoureux ◽  
André J. Simpson ◽  
Yves Gélinas ◽  
...  

2008 ◽  
Vol 156 (3) ◽  
pp. 928-935 ◽  
Author(s):  
Elizabeth Guthrie Nichols ◽  
Samuel T. Gregory ◽  
Jennifer S. Musella

2017 ◽  
Vol 3 (2) ◽  
pp. 378-405 ◽  
Author(s):  
J. Fouché ◽  
M. J. Lafrenière ◽  
K. Rutherford ◽  
S. Lamoureux

Arctic landscapes are experiencing intense warming and modification of precipitation regimes with climate change. Permafrost disturbances and climate change impacts on hydrology of Arctic watersheds are likely to modify the quantity and composition of exported dissolved organic matter (DOM). In July 2007, intense rainfall and active layer thickening caused widespread active layer detachments at Cape Bounty, Melville Island (Canada). This study investigates the impacts of seasonal hydrology and permafrost disturbance on DOM composition exported from High Arctic headwater catchments. In 2012, streams were sampled from three disturbed catchments and one undisturbed catchment. The composition of DOM was characterized using absorbance and fluorescence spectroscopy. DOM was mostly exported during the spring freshet. Throughout this period, the undisturbed catchment exported humified DOM with high humic-like fluorescence that likely originated from runoff through shallow organic rich soil. In contrast, DOM exported from disturbed catchments was fresher, less humified with a high proportion of low molecular weight humic acid. We demonstrate that disturbed catchments delivered likely more labile DOM derived from either thawed permafrost or enhanced microbial activity. If this labile DOM comes from an ancient pool, as indicated by other studies at this site, disturbances may strengthen the permafrost carbon feedback on climate change.


2016 ◽  
Vol 128 (3) ◽  
pp. 397-415 ◽  
Author(s):  
David M. Grewer ◽  
Melissa J. Lafrenière ◽  
Scott F. Lamoureux ◽  
Myrna J. Simpson

2017 ◽  
Vol 3 (2) ◽  
pp. 334-353 ◽  
Author(s):  
Michel Paquette ◽  
Daniel Fortier ◽  
Warwick F. Vincent

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.


2019 ◽  
Vol 8 (46) ◽  
Author(s):  
Calvin Rusley ◽  
Tullis C. Onstott ◽  
Tatiana A. Vishnivetskaya ◽  
Alice Layton ◽  
Archana Chauhan ◽  
...  

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.


2016 ◽  
Vol 164 ◽  
pp. 112-127 ◽  
Author(s):  
Solveig Bourgeois ◽  
Philippe Kerhervé ◽  
Maria Ll. Calleja ◽  
Gaël Many ◽  
Nathalie Morata

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