Drought and waterlogging stress regimes in northern peatlands detected through satellite retrieved solar-induced chlorophyll fluorescence

• Published in: Geophysical Research Letters
• Main Authors: Valkenborg, Bram, De Lannoy, Gabrielle J. M., Gruber, Alexander, Miralles, Diego, Koehler, Philipp, Frankenberg, Christian, Desai, Ankur R., Humphreys, Elyn, Klatt, Janina, Lohila, Annalea, Nilsson, Mats B., Tuittila, Eeva-Stiina, Bechtold, Michel
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: Earth and Environmental Sciences; peatlands; solar induced chlorophyll fluorescence; carbon cycle; hydrology; drought; gross primary production; SUN-INDUCED FLUORESCENCE; CARBON-DIOXIDE; WATER-TABLE; SPECTRAL REFLECTANCE; BOREAL FEN; PHOTOSYNTHESIS; FLUXES; ASSIMILATION; TEMPERATURE; ACCUMULATION; Hudson Bay
• Online Access: https://biblio.ugent.be/publication/01HF6G8XFT380BWWM7WYMV2HDK; http://hdl.handle.net/1854/LU-01HF6G8XFT380BWWM7WYMV2HDK; https://doi.org/10.1029/2023GL105205; https://biblio.ugent.be/publication/01HF6G8XFT380BWWM7WYMV2HDK/file/01HF6GAX23C793T9P79VNBV5N6

The water table depth (WTD) in peatlands determines the soil carbon decomposition rate and influences vegetation growth, hence the above-ground carbon assimilation. Here, we used satellite-observed Solar-Induced chlorophyll Fluorescence (SIF) as a proxy of Gross Primary Production (GPP) to investigate water-related vegetation stress over northern peatlands. A linear model with interaction effects was used to relate short- and long-term anomalies in SIF with WTD anomalies and the absolute WTD. Most locations showed the occurrence of drought and waterlogging stress though regions with exclusively waterlogging or drought stress were also detected. As a spatial median, minimal water-related vegetation stress was found for a WTD of -0.22 m (short-term) and -0.20 m (long-term) (+/- 0.01 m, 95% confidence interval of statistical uncertainty). The stress response observed with SIF is supported by an analysis of in situ GPP data. Our findings provide insight into how changes in WTD of northern peatlands could affect GPP under climate change. Water table depth is an important variable influencing the carbon cycle and vegetation growth in northern peatlands. In this paper, the impact of changing wetness conditions on vegetation growth over peatlands was studied through satellite measurements of solar-induced fluorescence (SIF), which is a radiation signal emitted by vegetation during photosynthesis. Previous studies over ecosystems on mineral soil, that is, not over peatland, suggested a response of SIF to drought conditions. In our study, it was shown that peatland vegetation experiences moisture-related growth stress under both very wet and very dry conditions, which might reduce the photosynthesis efficiency and the ability to capture and store CO2. Stress due to drought conditions was detected for peatlands in the south of the Western Siberian Lowlands and the Boreal Plains. Stress due to prolonged wet conditions occurred for example, in the north of the Western Siberian Lowlands and the north of the Hudson Bay ...