ICOS Science Conference 2020, Session 14

1. Effect of the 2018 drought on CH4 and
CO2 exchange of northern mire
ecosystems
J. RINNE, J.-P. TUOVINEN, L. KLEMENDTSSON, M. AURELA, A. LOHILA, P. WESLIEN, P. VESTIN, P.
ŁAKOMIEC, M. PEICHL, E.-S. TUITTILA, L. HEISKANEN, T. LAURILA, X. LI, P. ALEKSEYCHIK, I.
MAMMARELLA, L. STRÖM, P. CRILL, M.B. NILSSON

2. Climate anomaly
2
Temperature
Rainfall
Peters et al., 2020
Phil. Trans. R. Soc. B

3. Less rain, more evaporation: lower water table
3

4. Effect of lower water table on CO2 exchange
4
Drought
Drought
Aurela et al., 2007
Tellus
Aurela et al., 2007
Tellus
Lowered net CO2 uptake

5. Water table and methane emission
5
Rinne et al., 2018
Global Biogeochem. Cy.
There is also a temperature effect

6. 2018 drought: Mire measurement sites
6
Mires (black dots)
FI-Kaa: Kaamanen
FI-Lom: Lompolojänkkä
SE-Deg: Degerö
FI-Sii: Siikaneva
SE-Myc: Mycklemossen
Weather stations (diamonds)
Kevo FMI
Muonio FMI
Svartberget SLU
Hyytiälä FMI
Vänersborg SMHI
Uddevalla SMHI
Reference period
Climate data: 1981-2010
GHG fluxes:
Kaamanen: 2017
Lompolojänkkä: 2017
Degerö: 2015-2016
Siikaneva: 2010-2013
Mycklemossen: 2016
Rinne et al., 2020
Phil. Trans. R. Soc. B

7. Temperature
7
Rinne et al., 2020
Phil. Trans. R. Soc. B

8. Rainfall
8
Rinne et al., 2020
Phil. Trans. R. Soc. B

9. Summertime water table positions
9Rinne et al., 2020
Phil. Trans. R. Soc. B

10. CO2 fluxes at two of the sites
10
Rinne et al., 2020
Phil. Trans. R. Soc. B

11. CH4 fluxes
11
Rinne et al., 2020
Phil. Trans. R. Soc. B

12. Except for Lompolojänkkä…
12
Rinne et al., 2020
Phil. Trans. R. Soc. B

13. Annual fluxes
13
Rinne et al., 2020
Phil. Trans. R. Soc. B
46.6
2.9
-26.9
56.1
97.2
-1.9
-0.8
-4.1
7.0
-3.9
Difference Difference
Climatic effect calculated as pulse emission

14. Time evolving radiative forcing
14
Rinne et al., 2020
Phil. Trans. R. Soc. B

15. Conclusions
• The mire systems where the drought led to water table drawdown exhibited
lowered CO2 uptake and CH4 release.
• These have counteracting climatic effects, with cooling by methane dominating in
the first decade or two, followed by warming due to carbon dioxide.
• Data series still not very long for many sites: reference fluxes not well
established.
15