Biogenic volatile organic compound ambient mixing ratios and emission rates in the Alaskan Arctic tundra
<p>Rapid Arctic warming, a lengthening growing season, and the increasing abundance of biogenic volatile-organic-compound-emitting shrubs are all anticipated to increase atmospheric biogenic volatile organic compounds (BVOCs) in the Arctic atmosphere, with implications for atmospheric oxidatio...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-12-01
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| Series: | Biogeosciences |
| Online Access: | https://bg.copernicus.org/articles/17/6219/2020/bg-17-6219-2020.pdf |
| Summary: | <p>Rapid Arctic warming, a lengthening growing season, and the increasing abundance
of biogenic volatile-organic-compound-emitting shrubs are all
anticipated to increase atmospheric biogenic volatile organic compounds (BVOCs) in the Arctic atmosphere, with implications for atmospheric oxidation processes and climate feedbacks. Quantifying these changes requires an accurate understanding of the underlying processes driving BVOC emissions in the Arctic. While boreal ecosystems have been widely studied, little attention has been paid to Arctic tundra environments. Here, we report terpenoid (isoprene, monoterpenes, and sesquiterpenes) ambient mixing ratios and emission rates from key dominant vegetation species at Toolik Field Station (TFS; 68<span class="inline-formula"><sup>∘</sup></span>38<span class="inline-formula"><sup>′</sup></span> N, 149<span class="inline-formula"><sup>∘</sup></span>36<span class="inline-formula"><sup>′</sup></span> W) in northern Alaska during two back-to-back field campaigns (summers of 2018 and 2019) covering the entire growing season. Isoprene ambient mixing ratios observed at TFS fell within the range of values reported in the Eurasian taiga (0–500 parts per trillion by volume – pptv), while
monoterpene and sesquiterpene ambient mixing ratios were respectively close
to and below the instrumental quantification limit (<span class="inline-formula">∼2</span> pptv).
Isoprene surface emission rates ranged from 0.2 to 2250 <span class="inline-formula">µ</span>gC m<span class="inline-formula"><sup>−2</sup></span> h<span class="inline-formula"><sup>−1</sup></span> (mean of 85 <span class="inline-formula">µ</span>gC m<span class="inline-formula"><sup>−2</sup></span> h<span class="inline-formula"><sup>−1</sup></span>) and monoterpene emission rates remained, on average, below 1 <span class="inline-formula">µ</span>gC m<span class="inline-formula"><sup>−2</sup></span> h<span class="inline-formula"><sup>−1</sup></span> over the course of the study. We
further quantified the temperature dependence of isoprene emissions from
local vegetation, including <i>Salix</i> spp. (a known isoprene emitter), and compared the results to predictions from the Model of Emissions of Gases and Aerosols from Nature version 2.1 (MEGAN2.1). Our observations suggest a 180 %–215 % emission increase in response to a 3–4 <span class="inline-formula"><sup>∘</sup></span>C warming, and the MEGAN2.1 temperature algorithm exhibits a close fit with observations for enclosure temperatures in the 0–30 <span class="inline-formula"><sup>∘</sup></span>C range. The data presented here provide a baseline for investigating future changes in the BVOC emission potential of
the under-studied Arctic tundra environment.</p> |
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| ISSN: | 1726-4170 1726-4189 |