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Continuous High-Frequent Measurements of CO2, CH4 and N2O Fluxes in a Riparian Deciduous Forest: The Role of Hot Moments in 2.5 Year Period
- 1.0544675 - ÚVGZ 2022 US eng A - Abstract
Mander, Ülo - Krasnova, A. - Schindler, Thomas - Escuer-Gatius, J. - Espenberg, M. - Macháčová, Kateřina - Pärn, J. - Kasak, K. - Niinemets, Ü. - Soosaar, Kaido
Continuous High-Frequent Measurements of CO2, CH4 and N2O Fluxes in a Riparian Deciduous Forest: The Role of Hot Moments in 2.5 Year Period.
AGU Fall Meeting. American Geophysical Union, 2020.
[AGU Fall Meeting 2020. 01.12.2020-17.12.2020, online everywhere]
Institutional support: RVO:86652079
Keywords : methane * nitrous oxide * carbon dioxide * alder * alnus incana * hemi-boreal forest * soil * tree stem * eddy covariance
OECD category: Plant sciences, botany
https://agu.confex.com/agu/fm20/meetingapp.cgi/Paper/746168
The carbon and nitrogen budgets of temperate riparian forests are sensitive to interannual climatic variability. In turn, riparian
forests are hot spots of greenhouse gas (GHG) fluxes in landscapes. Here we analyse data from the first long-term (Sept.
2017-Dec. 2019) continuous high-frequent study of soil emissions (automated chambers) and ecosystem (eddy-covariance,
EC) fluxes of CO , CH and N O in a 40-year old riparian grey alder forest in Estonia. It is supported by a 1.5-year study of
CH and N O fluxes from tree stems (manual chambers).
Based on EC data, the forest is a sequesterer of CO (-5.6 kg C ha y ) and CH (-0.35 kg C ha y ) and emitter of N O
(0.3 kg N O-N ha y ). Hot moments (Wet: Sept.-Nov. 2017, Dry with Drought Onset: May–July 2018, Freeze–Thaw: Feb.
2019, and Dry Minor: June 2019) play an important role in GHG fluxes. For ecosystem level fluxes of all three gases no hot
moments were observed however, unlike several forests in the area, during the severe heat wave in summer 2018, the riparian
forest continued sequester CO . The Wet period was remarkable due to high CH emissions from stems – almost 100% of
ecosystem (EC) level CH came from stems. Small N O emission from stems was found in the Wet period. In contrast, soil
N O flux was mainly depending on hot moments: about 60% of all emissions came from these periods. Especially, during
Drought Onset when soil water content (SWC) rapidly decreased, average flux reached >150 μg N O-N m h . In this
period, we observed a very clear optimum related to SWC – N O emission peaked at 50% SWC. During the Freeze–Thaw
period, another hot moment of N O, clear correlation was found with near-surface air temperature. Likewise, CH emission
from stems in the Wet period showed an optimum at 75% SWC. Surprisingly, total N O emission from the soil was about 5
times higher than that measured at the ecosystem level. For CH the EC level flux was coherent with the sum of soil and stem
fluxes.
Permanent Link: http://hdl.handle.net/11104/0321511
Number of the records: 1