Impacts of Arctic Tundra
Wildfires on Carbon
Cycling
Mack MC, Bret-Harte MS, Hollingsworth TN, Jandt RR, Schuur EAG, Shaver
GR, Verbyla DL (2011) Carbon loss from an unprecedented Arctic tundra
wildfire. Nature 475:489-492.
by Catherine Deschenes
Overview
1.
Case
2. Methods
3. Results
4. Global Connection
5. Ecosystem Connection
6. Human Connection
7.
Take Home
ACIA (2004)
Anaktuvuk River Fire, Alaska
Bureau of Land Management, Alaska Fire Service (2007)
1039
2
km
Area burned during the fire, doubling the total burned area in the region since
1950
Suppl. Figure 1
(large)
Suppl. Figure 3
(small)
FOCUS:
➢2008 field campaign to evaluate C
and N released from plant and soil of
moist acidic tundra ecosystems during
the fire.
Methods
Tundra soil
profile
Typical soil profile in wet tundra. (2010)
State of Alaska Division of Spill Prevention
and Response.
Eriophorum vaginatum
Suppl. Fig. 4 C, D, B, A (clockwise from top left)
Field Sampling
Methods
20 burned sites
11 unburned
reference sites
Suppl. Fig. 5
Carbon Dating
Figure 1
Results
31%
(+/-3%)
loss of combustible C
5X the annual NPP of moist Arctic tundra
2.1 Tg C
released in atmosphere
→ Similar in magnitude to annual net C sink for entire Arctic tundra
biome (avg of last 25 years)
→ Extrapolation from MAT ecosystem (54% of burn area)
~21%
loss of combustible N
400 years of N accumulation
NASA Langley Research Center
M. Ewert
30%
(+/-3%)
decrease in soil organic
layer
Burning restricted to soil surface
So what? :
Global
Connection
Carbon
Arctic
100 Pg carbon
Native Americans: Arctic culture area. Britannica Online for Kids.
496 Pg
carbon
Wikipedia Commons
Removal of organic
layer:
1. Loss of permafrost
insulation
2. Thawing
3. Deep C release
4. Altered ecosystem C
Decreased
albedo by 50balance
Increased ground heat
71%
flux
+
+
→
Suppl. Fig. 4C, D
Lower
Albedo=
Permafrost
thawing=
methane+carbon dioxide
So what? :
Ecosystem Connection
Arctic fire VS
other climate-driven C loss
pathways
30-50X more rapid
(+amplification of pathways?)
Ground subsidence
Neil Shubin
Stimulation of microbial activity
Jenny E. Ross/Corbis (2009)
USGS Alaska Science Center
Stimulation of soil
decomposition
Net C transfer into
the atmosphere=
warming
➔ Young soil lost+high grass survivorship
= renewal of topsoil lost
➔ Shift to early-successional ecosystems
with low C storage
Recovery Scenario 1
Shorter
fire regime
(80-150 yrs)
Positive feedback
to climate warming
➔ Shrubs have lower albedo
Grasses die,
shrubs
prevail
➔ Shrubs have higher productivity and biomass, and lower soil C
stocks (inefficient C sinks)
Arctic fire
rapid offset
of greening
through
release of deep
permafrost C
pools
VS
Arctic greening
(-’ve feedback to global warming)
graminoid (grass) tundra → shrub tundra or boreal
forest
Scott Goetz, Pieter Beck, and Kevin Guay, Woods Hole Research Center
Who cares? :
Human
Connection
The global
community (all of us!)
Northern communities
(some Canadians)
➔ Air quality
➔ Physical danger
➔ Local economy
➔ Ecosystem imbalance
➔ Local climate warming
➔ Subsidence amplification(?)
➔ Global climate
warming
amplification
(impacts on economy,
populations, food
supply, ecosystem
imbalances, etc.)
Take Home
➢The Anaktuvuk River Fire is a manifestation of an increasing fire regime
in the Arctic tundra.
➢Arctic tundra wildfires release significant amounts of young topsoil
carbon and nitrogen, decrease tundra albedo while increasing
ground heat flux and facilitating permafrost thawing (which releases
CH4 and CO2).
➢Impact: Rapid C loss in the Arctic ground goes into the atmosphere, causing
positive feedback for local and global climate warming.
Thank you!
Questions?
Photo Sources
ACIA. (2004) Carbon cycle in the Arctic. Retrieved from
http://www.xplora.org/downloads/Knoppix/ESPERE/ESPEREdez05/ESPEREde/www.atmosphere.mpg.de/enid/0,55a304092d09/Zukunft_der_Arktis/Leben_in_der_Arktis_3
w0.html.
Britannica Online for Kids. Native Americans: Arctic culture area. [Map/Still]. Retrieved from http://kids.britannica.com/elementary/art-192332.
Bureau of Land Management, Alaska Fire Service. (2007) Anaktuvuk River Fire. Retrieved from http://hermes.mbl.edu/news/features/anaktuvuk.html.
Compass: http://www.clipartbest.com/cliparts/ncX/8oo/ncX8ooecB.png
Ecocem Ireland Ltd. Albedo diagram [graphic]. Retrieved from http://www.ecocem.ie/index.php?p=environmental&q=albedo.
Jenny E. Ross/Corbis. (2009) Thawing permafrost on the tundra of Wrangel Island. Retrieved from https://www.newscientist.com/article/dn27420-microbes-play-villainousrole-in-arctic-climate-change/.
M. Ewert. Tundra. Retrieved from https://www.flickr.com/photos/mewerts/4680757869/sizes/l/in/photostream/.
NASA Langley Research Center. Boreal Forest Fire. Retrieved from http://www.colorado.edu/geography/blanken/GEOG%206181%20Fall%202003/rech/pages/fire2.gif.
Native Americans: Arctic culture area. [Map/Still]. In Britannica Online for Kids. Retrieved from http://kids.britannica.com/elementary/art-192332
Neil Shubin (photographer). Arctic Bone Nurseries. Retrieved from
http://static1.squarespace.com/static/544591e6e4b0135285aeb5b6/t/566aee0240667acc25b71f0c/1449848323270/.
Scott Goetz, Pieter Beck, and Kevin Guay, Woods Hole Research Center[data graphic]. Greening of the Arctic. Retrieved from http://www.amnh.org/explore/sciencebulletins/bio/visualizations/greening-of-the-arctic/dataset-information.
State of Alaska Division of Spill Prevention and Response. (2010) Typical soil profile in wet tundra. Retrieved from https://dec.alaska.gov/spar/ppr/r_d/ttman/images/P-2-webimages/soil_profile_wet_sedge_opt_500.jpeg.
USGS Alaska Science Center. Arctic ground subsidence. Retrieved from http://eros.usgs.gov/lir/changing-arctic-ecosystems-mapping-long-term-changes-vegetationimportant-migratory-birds-and.