TY - JOUR

T1 - High emission rates and strong temperature response make boreal wetlands a large source of isoprene and terpenes

AU - Vettikkat, Lejish

AU - Miettinen, Pasi

AU - Buchholz, Angela

AU - Rantala, Pekka

AU - Yu, Hao

AU - Schallhart, Simon

AU - Petäjä, Tuukka

AU - Seco, Roger

AU - Männistö, Elisa

AU - Kulmala, Markku

AU - Tuittila, Eeva Stiina

AU - Guenther, Alex B.

AU - Schobesberger, Siegfried

N1 - Funding Information: Lejish Vettikkat was financially supported by the UEF EPHB doctoral degree program. This work was financially supported by the Academy of Finland Flagship program (grant nos. 337550 and 337549) and Academy of Finland project no. 310682. Simon Schallhart was supported by Academy of Finland project no. 323255. Tuukka Pet j was supported by Academy of Finland project nos. 1325681 and 1328616. Elisa M nnist and Eeva-Stiina Tuittila were supported by Academy of Finland project no. 330840. Roger Seco was supported by a Ram n y Cajal grant (RYC2020-029216-I) funded by MCIN/AEI/10.13039/501100011033 and by "ESF Investing in your future", as well as project PID2021-122892NAI00 funded by MCIN/AEI and by "ERDF A way of making Europe". IDAEA-CSIC is a Severo Ochoa Centre of Research Excellence (MCIN/AEI, Project CEX2018-000794-S). Alex B. Guenther was supported by the US National Science Foundation award ANS- 2041250. We thank Heidi Hell n, Pontus Roldin, Robin Wollesen de Jonge, Lukas Fischer, Michael Boy, and Petri Clusius for valuable discussions.We highly appreciate the help and support provided by the SMEAR II station team, especially Matti Salminen and Lauri Ahonen, in setting up and maintaining our measurements in Siikaneva. Funding Information: Lejish Vettikkat was financially supported by the UEF EPHB doctoral degree program. This work was financially supported by the Academy of Finland Flagship program (grant nos. 337550 and 337549) and Academy of Finland project no. 310682. Simon Schallhart was supported by Academy of Finland project no. 323255. Tuukka Petäjä was supported by Academy of Finland project nos. 1325681 and 1328616. Elisa Männistö and Eeva-Stiina Tuittila were supported by Academy of Finland project no. 330840. Roger Seco was supported by a Ramón y Cajal grant (RYC2020-029216-I) funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future”, as well as project PID2021-122892NA-I00 funded by MCIN/AEI and by “ERDF A way of making Europe”. IDAEA-CSIC is a Severo Ochoa Centre of Research Excellence (MCIN/AEI, Project CEX2018-000794-S). Alex B. Guenther was supported by the US National Science Foundation award ANS-2041250. Publisher Copyright: © 2023 Lejish Vettikkat et al.

PY - 2023

Y1 - 2023

N2 - Wetlands cover only 3g% of the global land surface area, but boreal wetlands are experiencing an unprecedented warming of four times the global average. These wetlands emit isoprene and terpenes (including monoterpenes (MT), sesquiterpenes (SQT), and diterpenes (DT)), which are climate-relevant highly reactive biogenic volatile organic compounds (BVOCs) with an exponential dependence on temperature. In this study, we present ecosystem-scale eddy covariance (EC) fluxes of isoprene, MT, SQT, and DT (hereafter referred to together as terpenes) at Siikaneva, a boreal fen in southern Finland, from the start to the peak of the growing season of 2021 (19 May 2021 to 28 June 2021). These are the first EC fluxes reported using the novel state-of-the-art Vocus proton transfer reaction mass spectrometer (Vocus-PTR) and the first-ever fluxes reported for DTs from a wetland. Isoprene was the dominant compound emitted by the wetland, followed by MTs, SQTs, and DTs, and they all exhibited a strong exponential temperature dependence. The Q10 values, the factor by which terpene emissions increases for every 10gg C rise in temperature, were up to five times higher than those used in most BVOC models. During the campaign, the air temperature peaked above 31gg C on 21-22 June 2021, which is abnormally high for boreal environments, and the maximum flux for all terpenes coincided with this period. We observed that terpene emissions were elevated after this abnormally "high-temperature stress period", indicating that past temperatures alter emissions significantly. The standardized emission factor (EF) of the fen for isoprene (EFiso) was 11.1g±g 0.3gnmolgm-2gs-1, which is at least two times higher than in previous studies and as high as the emission factors typical for broadleaf and other forests in the lower latitudes. We observed EFMT of 2.4g±g 0.1gnmolgm-2gs-1, EFSQT of 1.3g±g0.03gnmolgm-2gs-1, higher than typical for needle leaf and broadleaf tree functional types, and EFDT of 0.011g±g0.001gnmolgm-2gs-1. We also compared the landscape average emissions to the model of emissions of gases and aerosols from nature (MEGAN) v2.1 and found that the emissions were underestimated by over 9 times for isoprene, over 300 times for MTs, and 800 times for SQTs. Our results show that due to very high EFs and high sensitivity to increasing temperatures, these high-latitude ecosystems can be a large source of terpenes to the atmosphere, and anthropogenic global warming could induce much higher BVOC emissions from wetlands in the future.

AB - Wetlands cover only 3g% of the global land surface area, but boreal wetlands are experiencing an unprecedented warming of four times the global average. These wetlands emit isoprene and terpenes (including monoterpenes (MT), sesquiterpenes (SQT), and diterpenes (DT)), which are climate-relevant highly reactive biogenic volatile organic compounds (BVOCs) with an exponential dependence on temperature. In this study, we present ecosystem-scale eddy covariance (EC) fluxes of isoprene, MT, SQT, and DT (hereafter referred to together as terpenes) at Siikaneva, a boreal fen in southern Finland, from the start to the peak of the growing season of 2021 (19 May 2021 to 28 June 2021). These are the first EC fluxes reported using the novel state-of-the-art Vocus proton transfer reaction mass spectrometer (Vocus-PTR) and the first-ever fluxes reported for DTs from a wetland. Isoprene was the dominant compound emitted by the wetland, followed by MTs, SQTs, and DTs, and they all exhibited a strong exponential temperature dependence. The Q10 values, the factor by which terpene emissions increases for every 10gg C rise in temperature, were up to five times higher than those used in most BVOC models. During the campaign, the air temperature peaked above 31gg C on 21-22 June 2021, which is abnormally high for boreal environments, and the maximum flux for all terpenes coincided with this period. We observed that terpene emissions were elevated after this abnormally "high-temperature stress period", indicating that past temperatures alter emissions significantly. The standardized emission factor (EF) of the fen for isoprene (EFiso) was 11.1g±g 0.3gnmolgm-2gs-1, which is at least two times higher than in previous studies and as high as the emission factors typical for broadleaf and other forests in the lower latitudes. We observed EFMT of 2.4g±g 0.1gnmolgm-2gs-1, EFSQT of 1.3g±g0.03gnmolgm-2gs-1, higher than typical for needle leaf and broadleaf tree functional types, and EFDT of 0.011g±g0.001gnmolgm-2gs-1. We also compared the landscape average emissions to the model of emissions of gases and aerosols from nature (MEGAN) v2.1 and found that the emissions were underestimated by over 9 times for isoprene, over 300 times for MTs, and 800 times for SQTs. Our results show that due to very high EFs and high sensitivity to increasing temperatures, these high-latitude ecosystems can be a large source of terpenes to the atmosphere, and anthropogenic global warming could induce much higher BVOC emissions from wetlands in the future.

U2 - 10.5194/acp-23-2683-2023

DO - 10.5194/acp-23-2683-2023

M3 - Journal article

AN - SCOPUS:85149463265

VL - 23

SP - 2683

EP - 2698

JO - Atmospheric Chemistry and Physics

JF - Atmospheric Chemistry and Physics

SN - 1680-7316

IS - 4

ER -