David Olefeldt
@olefeldt.bsky.social
Professor in Catchment and Wetland Sciences at University of Alberta. Research on impacts of disturbances on function of northern peatlands, with focus on carbon cycling, greenhouse gas emissions, and on downstream water quality.
New Study in ES&T! Permafrost peatlands accumulate mercury from distant sources, but thaw causes collapse into wetter bogs and fens. Lauren Thompson shows that these bogs, and especially fens, become hotspots for mercury methylation, and potential downstream transport.
pubs.acs.org/doi/10.1021/...
pubs.acs.org/doi/10.1021/...
September 4, 2025 at 2:26 PM
New Study in ES&T! Permafrost peatlands accumulate mercury from distant sources, but thaw causes collapse into wetter bogs and fens. Lauren Thompson shows that these bogs, and especially fens, become hotspots for mercury methylation, and potential downstream transport.
pubs.acs.org/doi/10.1021/...
pubs.acs.org/doi/10.1021/...
Our analysis also reveals where effort should be placed to further improve estimates of boreal-Arctic wetland and lake methane emissions, including wintertime methane studies from wetlands, studies of lake methane ebullition, and further refined land cover maps.
August 28, 2025 at 4:05 PM
Our analysis also reveals where effort should be placed to further improve estimates of boreal-Arctic wetland and lake methane emissions, including wintertime methane studies from wetlands, studies of lake methane ebullition, and further refined land cover maps.
Our estimate of current-day methane emissions is ~20-40% lower than many prior studies, partly because of a bias where prior studies were more likely to target sites with relatively higher emissions. Having new land cover maps with different wetland and lake types reduces this bias.
August 28, 2025 at 4:05 PM
Our estimate of current-day methane emissions is ~20-40% lower than many prior studies, partly because of a bias where prior studies were more likely to target sites with relatively higher emissions. Having new land cover maps with different wetland and lake types reduces this bias.
This study uses data from almost 200 studies going back to the 1970s, with data from almost 2000 unique sites. Knowing what it takes to collect this data and publish these individual studies, it is humbling to be able to use their findings in a joint analysis – standing on the shoulder of giants.
August 28, 2025 at 4:05 PM
This study uses data from almost 200 studies going back to the 1970s, with data from almost 2000 unique sites. Knowing what it takes to collect this data and publish these individual studies, it is humbling to be able to use their findings in a joint analysis – standing on the shoulder of giants.
Our modelling of future methane emissions account for both climate warming (through a space-for-time framework) and permafrost thaw (through landscape transitions caused by thaw), and we find that these effects have important interactions – although the direct effect of warming dominates.
August 28, 2025 at 4:05 PM
Our modelling of future methane emissions account for both climate warming (through a space-for-time framework) and permafrost thaw (through landscape transitions caused by thaw), and we find that these effects have important interactions – although the direct effect of warming dominates.
Perfect day for measuring carbon dioxide and methane emissions from our thawed (former permafrost) fen in northern Alberta. 20 deg C, light breeze and almost no mosquitoes.
August 14, 2025 at 4:29 PM
Perfect day for measuring carbon dioxide and methane emissions from our thawed (former permafrost) fen in northern Alberta. 20 deg C, light breeze and almost no mosquitoes.
The black lines are the roads which we collect water samples along - shown with the historical fire map you can see that ~half of this large region has burned in the last few years. There are community concerns about impacts of wildfires and permafrost thaw on water and traditional land use.
July 17, 2025 at 11:29 PM
The black lines are the roads which we collect water samples along - shown with the historical fire map you can see that ~half of this large region has burned in the last few years. There are community concerns about impacts of wildfires and permafrost thaw on water and traditional land use.
I spent this week collecting river samples in northwestern Canada (Dehcho, Hay, and South Slave regions), an area the size of England with ~4,000 km of driving.
And so much of the landscape is burned - we drove hours and hours through charred forests. The last decade has been unprecedented.
And so much of the landscape is burned - we drove hours and hours through charred forests. The last decade has been unprecedented.
July 17, 2025 at 11:29 PM
I spent this week collecting river samples in northwestern Canada (Dehcho, Hay, and South Slave regions), an area the size of England with ~4,000 km of driving.
And so much of the landscape is burned - we drove hours and hours through charred forests. The last decade has been unprecedented.
And so much of the landscape is burned - we drove hours and hours through charred forests. The last decade has been unprecedented.
The bog gives and the bog takes. Liam Heffernan's PhD site, the Lutose thermokarst big - photos from 2015 and today 10 years later... Note the trees dying in the background due to permafrost thaw, and the growth of Sphagnum mosses covering our once proud boardwalk!
July 11, 2025 at 8:59 PM
The bog gives and the bog takes. Liam Heffernan's PhD site, the Lutose thermokarst big - photos from 2015 and today 10 years later... Note the trees dying in the background due to permafrost thaw, and the growth of Sphagnum mosses covering our once proud boardwalk!
I have a fully funded PhD position open for start in Jan or May 2026. Field work in peatlands of the Northwest Territories, with lab work to understand potential downstream mobilization of carbon, nutrients, mercury after thaw or wildfire. Reach out for more information, and please send on!
July 7, 2025 at 8:56 PM
I have a fully funded PhD position open for start in Jan or May 2026. Field work in peatlands of the Northwest Territories, with lab work to understand potential downstream mobilization of carbon, nutrients, mercury after thaw or wildfire. Reach out for more information, and please send on!
When the Arctic burns, the soils thaw. How much and for how long? Anna Talucci compiled depth of thaw measurements from 157 sites, now published in ESSD. Main impact occurs 4-10 years after fire, but effects remain 20+ years. Key information to estimate losses of soil C!
doi.org/10.5194/essd...
doi.org/10.5194/essd...
June 26, 2025 at 2:59 PM
When the Arctic burns, the soils thaw. How much and for how long? Anna Talucci compiled depth of thaw measurements from 157 sites, now published in ESSD. Main impact occurs 4-10 years after fire, but effects remain 20+ years. Key information to estimate losses of soil C!
doi.org/10.5194/essd...
doi.org/10.5194/essd...
I run a mid-size research group (7 graduate students / staff, 3 field assistants) which focuses on field-based research in northern Canada. Last year (2024-2025) our total expenses were ~CAD$370,000, provided in grants from federal/provincial/industry agencies, and it was spent as shown below.
March 20, 2025 at 9:26 PM
I run a mid-size research group (7 graduate students / staff, 3 field assistants) which focuses on field-based research in northern Canada. Last year (2024-2025) our total expenses were ~CAD$370,000, provided in grants from federal/provincial/industry agencies, and it was spent as shown below.
Winter field work at a thermokarst fen in northern Alberta by PhD student Finn Kurylowicz this week - chilly but very successful. The first winter for the eddy covariance set-up and it had collected data on almost all days since late November.
February 7, 2025 at 5:57 PM
Winter field work at a thermokarst fen in northern Alberta by PhD student Finn Kurylowicz this week - chilly but very successful. The first winter for the eddy covariance set-up and it had collected data on almost all days since late November.
Patchy permafrost adds to patterning in colder climates, often raising the surface 1-2 m above its surroundings and causing abrupt shifts in vegetation compared to adjacent non-permafrost. Rapid current permafrost thaw is causing collapse - seen here as bright green patches along permafrost edges
January 26, 2025 at 4:31 AM
Patchy permafrost adds to patterning in colder climates, often raising the surface 1-2 m above its surroundings and causing abrupt shifts in vegetation compared to adjacent non-permafrost. Rapid current permafrost thaw is causing collapse - seen here as bright green patches along permafrost edges
Different species of mosses prefer wetter or drier microhabitats, creating hummocks and hollows over time. Water movement will over time cause self-organization of hummocks into strings stretching perpendicular to the direction of flow.
January 26, 2025 at 4:31 AM
Different species of mosses prefer wetter or drier microhabitats, creating hummocks and hollows over time. Water movement will over time cause self-organization of hummocks into strings stretching perpendicular to the direction of flow.
The Hudson Bay Lowlands covers approximately ~350,000 km2 (i.e. similar to size of Germany), and it’s been rising out of the ocean since the end of the last glaciation to due isostatic rebound. The former ocean-bottom is very flat and has poor drainage – perfect for the development of peatlands.
January 26, 2025 at 4:31 AM
The Hudson Bay Lowlands covers approximately ~350,000 km2 (i.e. similar to size of Germany), and it’s been rising out of the ocean since the end of the last glaciation to due isostatic rebound. The former ocean-bottom is very flat and has poor drainage – perfect for the development of peatlands.
One of my favorite things about #peatlands is their patterning at different scales caused by millennia of interplay between hydrology and peat accumulation - mainly Sphagnum mosses. Spent my Saturday evening looking at satellite images of the Hudson Bay Lowlands - a perfectly reasonable activity…
January 26, 2025 at 4:31 AM
One of my favorite things about #peatlands is their patterning at different scales caused by millennia of interplay between hydrology and peat accumulation - mainly Sphagnum mosses. Spent my Saturday evening looking at satellite images of the Hudson Bay Lowlands - a perfectly reasonable activity…
First lecture of the semester, and a new course on Water Resource Management. Most of my winter "break" was used to prepare for the course. What are your best examples of Canadian water resource management issues that I should highlight?
January 7, 2025 at 9:21 PM
First lecture of the semester, and a new course on Water Resource Management. Most of my winter "break" was used to prepare for the course. What are your best examples of Canadian water resource management issues that I should highlight?
I'll be dammed! Next week Jessica Lagroix will present her MSc thesis on the influence of beaver ponds on water chemistry on the Taiga Plains, focusing on methylmercury. Two years of sampling, bushwacking to access sites and avoiding wildfires, but results are really cool TBA!
#FieldworkFriday
#FieldworkFriday
December 13, 2024 at 3:07 PM
I'll be dammed! Next week Jessica Lagroix will present her MSc thesis on the influence of beaver ponds on water chemistry on the Taiga Plains, focusing on methylmercury. Two years of sampling, bushwacking to access sites and avoiding wildfires, but results are really cool TBA!
#FieldworkFriday
#FieldworkFriday
Well done Edmonton - 7.30 am and last night's snow has been cleared from the bike path. Much appreciated!
December 11, 2024 at 3:03 PM
Well done Edmonton - 7.30 am and last night's snow has been cleared from the bike path. Much appreciated!
New truck for the CAWS research group - last truck lasted 7 years and we put 350,000 km on it. Will this one go further? What podcasts will be popular? Who will get it stuck on a muddy road? Also - infrastructure grants are slow, I budgeted for this truck in 2019 so needless to say I blew my budget!
December 7, 2024 at 2:55 PM
New truck for the CAWS research group - last truck lasted 7 years and we put 350,000 km on it. Will this one go further? What podcasts will be popular? Who will get it stuck on a muddy road? Also - infrastructure grants are slow, I budgeted for this truck in 2019 so needless to say I blew my budget!
For #FieldworkFriday I'm today reminiscing about a 2018 trip with McKenzie Kuhn (UBC) sampling greenhouse gas emissions from peatland ponds near Fort McPherson in northernmost Canada. It's a 3,500 km one-way drive from Edmonton (well worth the drive!). Note the permafrost thaw along pond edges!
November 29, 2024 at 4:30 PM
For #FieldworkFriday I'm today reminiscing about a 2018 trip with McKenzie Kuhn (UBC) sampling greenhouse gas emissions from peatland ponds near Fort McPherson in northernmost Canada. It's a 3,500 km one-way drive from Edmonton (well worth the drive!). Note the permafrost thaw along pond edges!
For #FieldworkFriday we're heading to northernmost Alberta and the Hay-Zama wetland, on Dene Tha' traditional lands. Our group is not all about peat, here Sarah and Fiona opportunistically took soil samples across the 35 x 20 km wetland basin during extreme drought to assess soil carbon storage.
November 22, 2024 at 5:23 PM
For #FieldworkFriday we're heading to northernmost Alberta and the Hay-Zama wetland, on Dene Tha' traditional lands. Our group is not all about peat, here Sarah and Fiona opportunistically took soil samples across the 35 x 20 km wetland basin during extreme drought to assess soil carbon storage.
Pancake ice forming on the North Saskatchewan River in Edmonton today. Also - I changed to studded tires on my bike for the commute, which was good timing.
November 20, 2024 at 3:39 PM
Pancake ice forming on the North Saskatchewan River in Edmonton today. Also - I changed to studded tires on my bike for the commute, which was good timing.
The Hay River in northwestern Canada (with Alexandra Falls in the pictures) is at the center of my groups' research. How will permafrost thaw, wildfires, warming, and droughts affect the mobilization of carbon, nutrients, and mercury from the widespread peatlands in its watershed?
November 17, 2024 at 10:34 PM
The Hay River in northwestern Canada (with Alexandra Falls in the pictures) is at the center of my groups' research. How will permafrost thaw, wildfires, warming, and droughts affect the mobilization of carbon, nutrients, and mercury from the widespread peatlands in its watershed?