Diel Variation of Biogenic Volatile Organic Compound Emissions--A field Study in the Sub, Low and High Arctic on the Effect of Temperature and Light.

Frida Lindwall,Patrick Faubert,Riikka Rinnan,Sean M Schaeffer

doi:10.1371/journal.pone.0123610

Frida Lindwall, Patrick Faubert + Show 2 more

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https://doi.org/10.1371/journal.pone.0123610

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Abstract

Many hours of sunlight in the midnight sun period suggest that significant amounts of biogenic volatile organic compounds (BVOCs) may be released from arctic ecosystems during night-time. However, the emissions from these ecosystems are rarely studied and limited to point measurements during daytime. We measured BVOC emissions during 24-hour periods in the field using a push-pull chamber technique and collection of volatiles in adsorbent cartridges followed by analysis with gas chromatography- mass spectrometry. Five different arctic vegetation communities were examined: high arctic heaths dominated by Salix arctica and Cassiope tetragona, low arctic heaths dominated by Salix glauca and Betula nana and a subarctic peatland dominated by the moss Warnstorfia exannulata and the sedge Eriophorum russeolum. We also addressed how climate warming affects the 24-hour emission and how the daytime emissions respond to sudden darkness. The emissions from the high arctic sites were lowest and had a strong diel variation with almost no emissions during night-time. The low arctic sites as well as the subarctic site had a more stable release of BVOCs during the 24-hour period with night-time emissions in the same range as those during the day. These results warn against overlooking the night period when considering arctic emissions. During the day, the quantity of BVOCs and the number of different compounds emitted was higher under ambient light than in darkness. The monoterpenes α-fenchene, α -phellandrene, 3-carene and α-terpinene as well as isoprene were absent in dark measurements during the day. Warming by open top chambers increased the emission rates both in the high and low arctic sites, forewarning higher emissions in a future warmer climate in the Arctic.

Highlights

Biogenic volatile organic compounds (BVOCs) have been frequently studied in temperate and boreal ecosystems (e.g. [1,2,3,4,5])
Emissions of other VOCs accounted for approximatively 1% of the total BVOC emissions and were significantly lower only at 21:00 compared to the noon emission rate (P
BVOC emissions from arctic and subarctic ecosystems are of importance, even during nighttime, and should be considered in global models

Summary

Introduction

Biogenic volatile organic compounds (BVOCs) have been frequently studied in temperate and boreal ecosystems (e.g. [1,2,3,4,5]). The global emission of BVOCs from terrestrial ecosystems, estimated to be 700–1000 Tg C yr-1 [7], contributes to physical and chemical properties in the atmosphere. Globally the most abundant individual BVOC [7], is not stored in plants, but is emitted directly from de novo synthesis, which is dependent on products from photosynthesis [11]. Emissions of MTs and SQTs can derive from both de novo synthesis and storage pools, such as glandular trichomes and resin ducts [11,12]. Emission of BVOCs often peaks during midday and decreases with decreasing light and temperature (see e.g. McKinney et al [13]). The emission from arctic ecosystems, with low temperature, low foliar density and low solar angle, has been previously estimated to be minimal [14]. Schollert et al [6] reported significant BVOC emission rates for high arctic vegetation (20–60 μg m-2 h-1), up to the same order of magnitude as the emissions from subarctic vegetation (45 μg m-2 h-1) [15]

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