New paper in Biogeosciences: Nonlinear thermal and moisture response of ice-wedge polygons to permafrost disturbance increases heterogeneity of high Arctic wetland

March 10, 2016 in Article, post

The floor of the Qalikturvik valley (Bylot Island, NU) is a mosaic ice-wedges polygons. A subtype of polygons named wet polygons are bowl like shaped, which enable moisture from snowmelt and precipitation to concentrate in their centers. These fields of wet polygons can support productive ecological environments, particularly when considering the usually arid nature of the High-Arctic.

Thermal erosion gullying erode and breach the contour (rims) of the bowl-shaped polygons, therefore affecting their capacity to retain moisture and possibly changing the near-surface thermal regime. One gully can breach the rims of hundreds of polygons: at the study site, three dozen gullies were located.

Nearby polygons located near a gully were identified and instrumented; reference and intact polygon characteristics were compared against eroded polygons during 2012-2013. The intact polygon center was saturated following snowmelt and during precipitation events later in summer. The moisture diminished following the thickening of the active-layer and its overall moisture was significantly higher than any disturbed polygons. The thermal regime during 2012-13 for this polygon was similar to another intact polygon. The vegetation in its center was well distributed and relatively uniform (ex: Carex sp.).

On the other hand, disturbed polygons were characterized by varying state for their moisture, ground temperature and vegetation cover. A disturbed polygon could simultaneously be partially dry, partially wet, depending on the severity of the rims breach. The active layer evolution could be similar to an intact polygon or could be significantly thinner. Dry tussocks were present in the centers, underlining the changing moisture state of the polygon, where plants better adapted to the new conditions settled. Therefore in the eroded polygon centers, there was an intra-polygonal variability as there was an heterogeneity in the moisture levels and plant distributions and an inter-polygonal variability (as in not all disturbed polygon were affected in the same way), depending on the severity of the breach, the recharge capability and proximity to the gully.

At the scale of the decade, gullying cause heterogeneity in the landscape with a tendency toward a dryer environment than pre-gullying. Further, gullying affect polygons rims thus the area affected by the erosion exceeds the gully as it affects an entire disturbed polygon.

The paper is available here:

Godin, E.; Fortier, D. & Lévesque, E.
Nonlinear thermal and moisture response of ice-wedge polygons to permafrost disturbance increases heterogeneity of high Arctic wetland
Biogeosciences, 2016, 13, 1439-1452

 

 

M.Sc. thesis successfully completed for Gautier Davesne!

March 5, 2016 in post

Congratulation to Gautier Davesne who successfully completed his M.Sc.’s thesis under the supervision of Daniel Fortier! His research project deals with the spatio-temporal evolution of the marginal mountain permafrost on the summit of Mont Jacques-Cartier. This work has been a basis to write a paper entitled “The thermal regime of mountain permafrost at the summit of Mont Jacques Cartier in the Gaspé Peninsula, Québec, Canada: a 37-year record of fluctuations showing an overall warming trend” (authors: J. Gray; G. Davesne; D. Fortier; E. Godin) submitted to the journal Permafrost and Periglacial Processes and accepted with minor corrections. A second paper entitled “Snow conditions control the occurrence of contemporary marginal mountain permafrost of the Chic-Chocs mountains, south-eastern Canada – a case study from Mont Jacques-Cartier” (authors: G. Davesne; D. Fortier; J. Gray) is presently in the process of writing and will be soon submitted to the journal The Cryosphere.

To consult his M.Sc. thesis, please click here!

Talk of Gautier Davesne at the annual meeting of the Centre for Northern Studies!

February 18, 2016 in Conference, post

Gautier Davesne presented some results of his M.Sc. researches at the annual meeting of the Centre for Northern Studies on Thursday 11th February. Its presentation, entitled « The thermal regime of mountain permafrost at the summit of Mont Jacques Cartier in the Gaspé Peninsula, Québec, Canada: a 37-year record showing an overall warming trend », showed that mountain permafrost at the Mont Jacques-Cartier summit responded very quickly to the warming of the air temperature since the end of 1970s. Its internal temperature is presently close to the melting point. The disappearance of the permafrost body is expected to occur around 2040 if the warming trend continue in the future, inducing major impacts on the local alpine geosystem.

Présentation PowerPoint

Evolution (5-year running mean to filter inter-annual variability) of the modelled mean annual air temperature (MAAT) and measured mean ground annual temperature (MAGT) at the Mont Jacques-Cartier summit.

GHG emissions from Canadian Arctic aquatic systems dated for the first time

December 22, 2015 in Article

Bylot Island ponds and lakes: Carbon sinks or GHG emitters?

*all credits: http://www.inrs.ca/english/actualites/ghg-emissions-canadian-arctic-aquatic-systems-dated-first-time by Gisèle Bolduc*

For the first time, researchers have successfully dated the carbon dioxide (CO2) and methane (CH4) emitted by ponds and lakes on Bylot Island, Nunavut. The research team observed significant variability in age and emission rates of greenhouse gases (GHG) from aquatic systems located in a continuous permafrost zone. The study, whose lead author is Frédéric Bouchard affiliated to the INRS Eau Terre Environnement Research Centre and the Geography Department of Université de Montréal, appeared in the international journal Biogeosciences.

 

Gas samples taken over the summer showed strikingly different ages and emission rates depending on the size and depth of the water bodies. Carbon-14 dating revealed that gas emitted by shallow ponds was a few centuries old, making it relatively “young”. Certain ponds, covered by cyanobacterial mats, were identified as CO2 sinks and sources of CH4; others, with eroded banks, were significant emitters of both GHG. Compared to ponds, arctic lakes were found to release much older GHG—up to 3,500 years old in the case of CH4—but at a much slower rate, at least in summer.

“This study demonstrates the significant impact of the combined geomorphological, limnological, and hydrological properties of aquatic systems on CO2 and CH4 emissions caused by thawing permafrost,” noted Professor Isabelle Laurion.”

The research team approach enabled an estimation of GHG emissions caused by two distinct processes: diffusion and ebullition. Researchers found that diffusion can be a significant mode of emission, especially from ponds. Until now, ebullition had been considered the predominant mode of CH4 emissions in lake systems.

 


“This study on the age of GHG emitted in the Canadian Arctic is one of very few using data from lakes outside of Siberia or Alaska. It sheds light on the specific role played by aquatic systems on carbon dynamics associated with thawing permafrost, and their potential impact on future climate change,” stated researcher Frédéric Bouchard

This work sets the scene for further research that must not only measure gas exchange rates, but also account for the age of carbon emitted, since this will impact the systems’ potential positive feedback effect on climate.

About the publication

This research was conducted by Frédéric Bouchard, Isabelle Laurion, and Vilmantas Prėskienis, of the INRS Eau Terre Environnement Research Centre, along with Daniel Fortier of Université de Montréal, Xiaomei Xu of University of California, and Michael J. Whiticar of University of Victoria. The resulting article, “Modern to millennium‐old greenhouse gases emitted from ponds and lakes of the Eastern Canadian Arctic (Bylot Island, Nunavut),” was recently published in the international journal Biogeosciences (DOI: 10.5194/bg-12-7279-2015). Financial support for the research team was provided by ArcticNet, the Natural Sciences and Engineering Research Council of Canada (NSERC), Natural Resources Canada’s Polar Continental Shelf Program, NSERC’s Discovery Frontiers and EnviroNorth programs, and the W. Garfield Weston Foundation. 

C-Degel Project : web page now online

October 30, 2015 in @en

The C-Degel project summary and team presentation webpage is now online: click here to visit the page!

 

Nunavummiut, Parks Canada and Science

September 8, 2015 in post

The 22nd of June 2015, Bylot Island, Nunavut.

Around mid June 2015, we heard from our bi-daily radio communication with the outside world that visitors were interested in visiting Goose Camp. Parks Canada’s rangers and manager (Sirmilik Park) visiting us is a regular event,  we know each other by name,  appearance or project (yeah that guy working in the gully) after all these years. Rangers visit us about twice a year to check that everything is well done at the camp, that the site is well kept, that everyone is healthy and happy and to share a lunch with  the camp staff (coffee and chocolate chips cookies is usually a winner). While lunching we share the latest news : animal observations regional news, hockey playoff, project advancements and other important things.

But this time a special visitor would join the group: a MP from the Nunavut government. He would like to see what we are doing and the camp. It is unusual, but not exceptional. The last person from a government instance visiting us (as best as I can remember) was sometime in 2009-2010. He was wishing to visit the nearby fossil forest which Alexandre Guertin was working on at the moment.

camp 1

Figure 1: Everything was in order at the camp, as usual. June 2015.

All that is quite interesting, I like surprises! When the day came, everything was perfect at the camp (as usual, Figure 1). Visitors were visiting the camp under the wing of Yannick Seyer and Dom Fauteux – followed by a break for lunch-cookies-hockey-coffee. Our special guest, M. Joe Enook, is a member of the Legislative Assembly of Nunavut (Constituency: Tununiq), who heard among other things that there was an ongoing project on ‘permafrost erosion  and gullying’ and was willing to take a hike to see what it looks like.

 

Soon, we were leaving toward the gully with M. Enook and Parks Canada staff. A bizarre thought crossed my head while guiding the group: I was finding quite convenient to have this gully very nearby the camp : perfect to show visitors ! But simultaneously, I was wondering that I am probably one of the few to find anything positive about having a very active gully nearby any kind of infrastructure. Oh well – all depend on the context.

Visite du Ravin 2015

Figure 2: From left to right: Yannick Sayer, Dominic Fauteux, M. Joe Enook and Etienne Godin, and the gully in background. The 22nd of  June 2015.

When we arrived on site, M. Enook and Carey (Manager from Parks Canada) told me they heard and knew about gullying. But further they told me that pictures, describing the gully orally or even looking at it while flying over by helicopter was not as real as standing right on it. When standing a meter from the gully, they realized first hand how fast it occurred, how wide and big and how the tundra changed following the erosion. Gully channels, retrogressive thaw slumps, all around slumping or tundra denudation, it was quite obvious to the visitors what could be wrong with the permafrost terrain
when ice-wedges are disturbed. M. Enook, a scholar and a well informed person about climate change related problems told us that many people from the community have no solid ideas about what are the dynamics of such a gully on the landscape, and that he would have this as a topic in his next broadcast at the public radio channel !

This made me all realize one thing : considering our effort for science outreach in a classical way, such as presenting kiosks, making posters, conferences and discussions with peoples from the community, disturbed permafrost can be a concept which could be hard to relate. I think that this time with M. Enook for whom the communication with his people is quite a natural thing, permafrost erosion will get to people in a way I did not expected. In the future, it is quite important to consider how community members interested by science and who are good speakers are among the best people to broadcast knowledge using an approach which can be simultaneously interesting and accessible for the people from the community.

M. Enook, in any case, thank you for coming !

Michel Paquette, back from Cape Bounty

September 7, 2015 in post

Geocryolab has now set foot on the western Canadian High Arctic! Back from Cape Bounty Arctic Watershed Observatory, on Melville Island, Michel Paquette just inaugurated the collaborative effort between host researchers from Queen’s University and the Geocryolab. The short stay allowed the discovery of an at least 2m thick layer of buried massive ice near the top of permafrost under one of the most studied sub-watershed of the research site. Geocryolab will analyze more than 4m of frozen permafrost cores retrieved from the coring sites, with crystallographic, cryostratigraphic and ice content related analysis. The FaBRECC laboratory will analyse isotopic composition, geochemistry and nutrient chemistry in the frozen soil, and we hope that our complementary expertise will lead to a greater understanding of mass transfer through near-surface water movement, and of permafrost-related disturbances affecting the evolution of the watershed and its hydrology. A big thank you to Prof. Scott Lamoureux, Prof. Melissa Lafrenière and the Cape Bounty research team for their great hospitality!

Michel Paquette - Melville 2015

Michel Paquette – Melville 2015

Yukon fieldwork : finding ice-wedges

September 4, 2015 in post

Our Geocryolab colleagues Lyna Lapointe, Benoit Loranger and Manuel Verpaelst are currently in their way for the last fieldtrip of the season to westernmost village of Canada (Beaver Creek, Yukon).

The snow is already waiting for their one-week mission. On the menu: ground penetrating radar, gravity meter, drilling and environmental monitoring for this final part of the ice-wedges detection project. Have a nice fieldtrip!

Map Yukon Besver Creek

Beaver Creek – Yukon – located at the red star on the map

New paper from N. Perreault et al. about vegetation transition following gullying

August 6, 2015 in Article, post

New paper by Godin et al. on near surface dynamics in permafrost wetland following gully erosion

July 29, 2015 in Article, post