Title: Using atmospheric observations to quantify annual biogenic carbon dioxide fluxes on the Alaska North Slope

Abstract

The continued warming of the Arctic could release vast stores of carbon into the atmosphere from high-latitude ecosystems, especially from thawing permafrost. Increasing uptake of carbon dioxide (CO₂) by vegetation during longer growing seasons may partially offset such release of carbon. However, evidence of significant net annual release of carbon from site-level observations and model simulations across tundra ecosystems has been inconclusive. To address this knowledge gap, we combined top-down observations of atmospheric CO₂ concentration enhancements from aircraft and a tall tower, which integrate ecosystem exchange over large regions, with bottom-up observed CO₂ fluxes from tundra environments and found that the Alaska North Slope is not a consistent net source nor net sink of CO₂ to the atmosphere (ranging from ₋6 to +6 Tg C yr^-1 for 2012–2017). Our analysis suggests that significant biogenic CO₂ fluxes from unfrozen terrestrial soils, and likely inland waters, during the early cold season (September–December) are major factors in determining the net annual carbon balance of the North Slope, implying strong sensitivity to the rapidly warming freeze-up period. At the regional level, we find no evidence of the previously reported large late-cold-season (January–April) CO₂ emissions to the atmosphere during the study period. Despite the importancemore » of the cold-season CO₂ emissions to the annual total, the interannual variability in the net CO₂ flux is driven by the variability in growing season fluxes. During the growing season, the regional net CO₂ flux is also highly sensitive to the distribution of tundra vegetation types throughout the North Slope. This study shows that quantification and characterization of year-round CO₂ fluxes from the heterogeneous terrestrial and aquatic ecosystems in the Arctic using both site-level and atmospheric observations are important to accurately project the Earth system response to future warming.« less

Authors:

Schiferl, Luke D.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-5047-2490"

Watts, Jennifer D. ^[2]; Larson, Erik L. ^[3]; Arndt, Kyle A.  ^[4];

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Biraud, Sébastien C.  ^[5];

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Euskirchen, Eugénie S.  ^[6];

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Goodrich, Jordan P. ^[7]; Henderson, John M.  ^[8];

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Kalhori, Aram ^[9]; McKain, Kathryn  ^[10];

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Mountain, Marikate E. ^[8]; Munger, J. William  ^[11];

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Oechel, Walter C. ^[12]; Sweeney, Colm  ^[13];

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Yi, Yonghong ^[14]; Zona, Donatella  ^[15];

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Commane, Róisín  ^[16]

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• Search DOE PAGES for ORCID "0000-0003-1373-1550"

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1. Columbia Univ., Palisades, NY (United States). Lamont-Doherty Earth Observatory; Harvard John A. Paulson School of Engineering and Applied Sciences, Cambridge, MA (United States)
2. Woodwell Climate Research Center, Falmouth, MA (United States)
3. Harvard Univ., Cambridge, MA (United States)
4. Woodwell Climate Research Center, Falmouth, MA (United States); San Diego State Univ., CA (United States); Univ. of New Hampshire, Durham, NH (United States)
5. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
6. University of Alaska Fairbanks, AK (United States)
7. San Diego State Univ., CA (United States); Ministry for the Environment, Wellington (New Zealand)
8. Atmospheric and Environmental Research, Inc., Lexington, MA (United States)
9. San Diego State Univ., CA (United States); Helmholtz-Zentrum Potsdam (HZP), (Germany). German Research Centre for GeoSciences
10. National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.; Univ. of Colorado, Boulder, CO (United States)
11. Harvard John A. Paulson School of Engineering and Applied Sciences, Cambridge, MA (United States)
12. San Diego State Univ., CA (United States); Univ. of Exeter (United Kingdom)
13. National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.
14. Univ. of California, Los Angeles, CA (United States); Tongji University, Shanghai (China)
15. San Diego State Univ., CA (United States); Univ. of Sheffield (United Kingdom)
16. Columbia Univ., Palisades, NY (United States). Lamont-Doherty Earth Observatory; Columbia Univ., New York, NY (United States)

Publication Date:

Thu Dec 22 00:00:00 EST 2022

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC); National Aeronautics and Space Administration (NASA); National Science Foundation (NSF)

OSTI Identifier:

2242470

Grant/Contract Number:  

AC02-05CH11231; NNX17AC61A; 1848620; NNX17AE75G; 80NSSC19M0209; NNH17ZDA001N-NIP; 80NM0018D0004; 1503912; 0632264

Resource Type:

Accepted Manuscript

Journal Name:

Biogeosciences (Online)

Additional Journal Information:

Journal Name: Biogeosciences (Online); Journal Volume: 19; Journal Issue: 24; Journal ID: ISSN 1726-4189

Publisher:

Copernicus Publications, EGU

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES