Winter Interactions in the Arctic-Where have we been; where are we

now and where are we going?

Jeff Welker, Gus Jespersen, Josh Leffler, Eric Klein, Claudia Czimczik &

Shawn Pedron

Team WinterJace Fahnestock, Michael Jones, Paddy,

Sullivan, Max Lupascu, Kathy Kelsey, Stine Pedersen, Glen Liston, Mathew Sturm, Don Spalinger, Kelly Elder, Joe Sexton, Pertti Alo-

Ala, Kai Loe, Jessica Richter, Steve Oberbauer, Matt Rogers, Heidi Steltzer, Molly Welker,

Adam Csank, Liz Cooper, Torsten Bentzen et al.

Brooks Range, AK, March 2019

Arctic Finland-Pallas: Dec 2016 Toolik Lake AK, Sept. 1995

Svalbard, Feb. 2013 Coldfoot, AK, April 2019

Late 1980’s and early 1990’s it was clear

winter climates were warming

warmer air-more moisture-more snow

Decadal warming from 1971-2001

Winter

Spring

Summer

Fall

“Mike, I think the Arctic community has discovered

Winter”

Terry Chapin,

LAII ARCSS meeting 2000?Bell Harbor, SEA

Winter Climate & Biophysics

SnowAmounts, sources,

timing, distribution, traits

Thermal Consequence

PhysicalConsequence

EcohydrologicConsequence

Biological Consequences

Trace Gases. Microbial

Processes & Mineral Nutrition

Consequences

Vegetationwater sources,

mineral nutrition & forage quality

Caribou & Reindeer

Sea IceStorm TracksClimate

Oscillations

Key Questions about Winter Ecology and Ecosystem Processes

What are magnitudes and patterns of trace gas fluxes in winter, how do they vary across the Arctic, & how are they effected by changes in snow depth?

(CO2 & CH4)

Do changes in winter snow depth carry –over to effect summer

ecosystem processes?(N, H2O, growth, forage quality)

In the beginning in a galaxy far far awayITEX-Coupled Winter and Summer

Changes in Climate (1994)

Fahnestock et al. JGR-Atmos 1998Jones et al. AAAR 1999

Early ITEX years, landscape winter CO2 fluxesWinter C losses can

account fro up to 30-40% of the total

annual ecosystem respiration

Tussock tundra

Polar semi-desert

Toolik Lake, Moist Tussock Tundra site

Thule NW Greenland, Polar Semi-desert site

ITEX Experiments: More winter snow

Tussock tundra

Consequences of deeper snow

warmer soils in winter

added melt water

shortened growing season

deeper active layer thaw

Greater CO2 emissions

Betula nana Salix pulchraOpen=+ snowFilled=ambient snow

Welker et al. 2005 Oikos

B S

Leffler et al. 2016 Oecologia

Winter snow drives Arctic plant

ecophysiologyThule, NW Greenland

Leffler & Welker 2013 ERL

Salix arctica

Sturm et al. BioScience 2005ATLAS Workshop-Vancouver Island,

2003

Winter Climate & Biophysics

SnowAmounts, sources,

timing, distribution, traits

Thermal Consequence

PhysicalConsequence

EcohydrologicConsequence

Biological Consequences

Trace Gases. Microbial

Processes & Mineral Nutrition

Consequences

Vegetationwater sources,

mineral nutrition & forage quality

Caribou & Reindeer

Sea IceStorm TracksClimate

Oscillations

Jespersen et al. Oecologica 2018

Jespersen, Leffler, Oberbauer & Welker; Oecologia 2018

Snow-shrub-Biogeochemical-Ecohydrologic Feedback Model

Old C-Permafrost

Younger C-Active layer

Atmospheric CO2 pool (~700 Pg)

+, -, or =

818 Pg-globally

Schure et al.

Amount and timing of permafrost carbon release in

response to climate warmingTellus 2011

Schaeffer et al.

Greenland Ice Sheet

Ice Ramp (Camp Century and Camp Tuto)

Biocomplexity in the High Arctic: Ancient C emissions from periglacial, polar semi-deserts

Czimczik and Welker, AAAR 2010

Polar stripes in NW Greenland-vegetation is primarily Dryas integrifolia

25,000 yr old arbon in polar semi deserts discovered; is it

being emitted into the modern atmosphere?

Pump

Flowmeter CO2 infrared gas analyzer

out in

Water trap

Isotope CO2 trap

out in

CO2 infrared gas analyzer

CO2

CO2 CO2

CO2

CO2CO2

CO2 CO2

CO2 CO2

CO2

CO2CO2

CO2

CO2 field sampling for

emissions and

production in the soil

Lupascuet al. 2014, 2015, 2016

Thule,NWGreenland

What are the sources and ages of winter respired CO2 from High

Arctic landscapes and how are these influenced by changes in winter

climate (deeper snow)?

Svalbard winter ancient CO2 emissions in response to deep snow

There is evidence that winter respired CO2 from the High Arctic

landscapes is partially composed of ancient C and that winter

emissions are greater where snow is deeper in winter

Lupascu et al. 2018

Blue Light Period-Svalbard

Nature Climate Change (September 2019)

Large loss of CO2 in winter observed across the pan-arctic permafrost region

Sullivan & Welker et al.

2008

Natali et al. 2019

Winter emissions of ancient CNSF EAGER-Czimczik and

Welker

Navigating the New Arctic: Monthly proporations of ancient C emissions as effected by snow depth-Toolik Lake

3 Depths20, 50, 80 cm

Continual Emissions Monthly integrated sampling for 14C

Winter the Final Frontier

Elena, Miquel & Jeff-Ecosystems 2019