Arctic Field Projects

Project Title: Collaborative Research: Environmental changes alter the carbon cycle of High Arctic ecosystems: shifts in the ages and sources of CO2 and DOC (Award# 0909514)

PI: Czimczik, Claudia (
Phone: (949) 824.5693 
Institute/Department: U of California, Irvine, Earth System Science 
IPY Project? NO
Funding Agency: US\Federal\NSF\GEO\OPP\ARC\ARCSS
Program Manager: Dr. Neil Swanberg (
Discipline(s): | Biology |

Project Web Site(s):

Science Summary:
This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The Arctic is undergoing structural and functional changes that appear to be the result of climate change, including shifts in vegetation distribution, increases in CO2 and CH4 efflux from ecosystems to the atmosphere, and the acceleration of dissolved organic carbon (DOC) export from land to oceans. Research in NW Greenland has produced four lines of evidence that climate change is affecting the High Arctic C cycle in ways we do not fully understand. First, soil organic C pools in polar semi-deserts, which occupy 1 x 106 km2 of the Arctic land surface, may be at least 6× greater than previous estimates, and ancient (>30 ky BP) and young soil C pools are present in the active layer. Second, CO2 ecosystem exchange measurements have consistently shown net C losses during the growing season; these C losses are, however, reversed under warmer and wetter conditions and with modest snow depth increases during the previous winter. In situ ecosystem respiration has been found to increase by 25 and 35% with experimental summer warming of 1.3 and 2.4°C, respectively, but by 50% when the higher level of warming was combined with irrigation. Third, soil CO2 efflux measurements indicate that ancient soil C is being degraded by microbes before vegetation leaf-out. Losses are expected to continue throughout the growing season, but masked by high rates of plant respiration (recently-fixed C) during the mid-summer. Forth, interannual and temporal patterns of riverine DOC are not explained by simple differences in summer weather conditions. Articulating the magnitudes of CO2 and CH4 exchange and DOC export along with the ages of soil respired CO2 and DOC in soil solution and rivers, and determining the sensitivity of microbial degradation of different soil C pools to temperature and moisture will transform our understanding of environmental change, ecosystem function and C cycling in the Arctic. This study will address these questions: 1. How does the age (recently-fixed vs. older) of soil respired CO2 and DOC change over the course of a year, to what extent is this influenced by inter-annual variability in temperature and precipitation, and how does it correspond with the patterns of CO2 and CH4 fluxes? 2. To what extent do long-term experimental increases in temperature (+2 and + 4oC), and in water inputs (summer rain and winter snow) alter the ages, magnitudes, and patterns of C fluxes (CO2, CH4, and DOC)? 3. Are there differences in the extent of microbial degradation of young as opposed to older soil C pools and how sensitive are the degradation rates to changes in climate?

Logistics Summary:
For this collaborative effort—Czimczik Green (0909514, U of California, LEAD), Welker (0909538, UAA) and Schimel (0909510, UCSB)—researchers will conduct an analysis of carbon dynamics in the high Arctic. Science teams will work at Thule Air Base seasonally from spring 2010 through Sept 2012. For the duration of the field experiment, teams of 4 will conduct field measurements during one-week trips in April of each year, in addition to a long summer field season from May-September. A team of 2-6 people will join the core team of 4 for two weeks in May of each year to help set up the summer experiments. In addition to the experiment, a team of two will travel to Qaanaaq in 2011 for outreach. Travel for that work will be carried under the Oberbauer/Welker grant (0856710).

CPS will provide AMC travel, Thule user days, vehicle rentals and helicopter support when the road to the polar desert site is not accessible. In addition, CPS will provide power to the experiment site. The PI will arrange and pay for all other logistics through the grant.
SeasonField SiteDate InDate Out#People
2010Greenland - Thule05 / 27 / 2010 08 / 20 / 201010
2011Greenland - Qaanaaq0
2011Greenland - Thule05 / 12 / 2011 08 / 26 / 20119
2012Greenland - Thule05 / 24 / 2012 08 / 24 / 201210

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