Non-growing season carbon emissions in a northern peatland are projected to increase under global warming

Rafat, Arash; Rezanezhad, Fereidoun; Quinton, William L.; Humphreys, Elyn; Webster, Kara; Cappellen, Philippe Van

doi:10.1038/s43247-021-00184-w

Cited by 21 publications

(14 citation statements)

References 106 publications

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“…We found that soil freezing, and thawing combined with changes in air and soil temperature caused a high degree of variability in CO 2 fluxes in all treatments. This indicated that soil warming regulated and enhanced microbial respiration during the spring freeze-thaw (Byun et al, 2021;King et al, 2021;Rafat et al, 2021). We found that CO 2 fluxes were different among freeze-thaw phases where the dry phase had highest flux compared to the wet and waterlogged phases.…”

Section: Freeze Thaw Phases and Temperature Influence On Greenhouse G...mentioning

confidence: 71%

Spring Freeze–Thaw Stimulates Greenhouse Gas Emissions From Agricultural Soil

Badewa

Yeung²,

Rezanezhad³

et al. 2022

Front. Environ. Sci.

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In temperate cold regions, the gradual resurgence of soil microbial activity during spring freeze-thaw events is frequently associated with greenhouse gas emissions. Enhanced greenhouse gas fluxes during spring freeze-thaw are related to the mineralization of bioavailable substrates, which may be elevated when soil is amended with organic residues (e.g., biobased residues such as compost, digestate, biosolids). The objective of this study was to determine the impact of biobased residues, compared to urea fertilizer, on greenhouse gas emissions during spring freeze-thaw events. The field treatments included urea (170 kg N ha−1 y−1), composted food waste (240 kg N ha−1 y−1), hydrolyzed biosolids (215 kg N ha−1 y−1), and anaerobic digestate (231 kg N ha−1 y−1). Headspace gases were sampled from a closed static chamber in each replicate plot (n = 4) and categorized with three transient spring freeze-thaw phases (waterlogged, wet, and dry). Among the treatments, nitrous oxide (N2O) flux was significantly different (p < 0.05) where compost had the highest emission and digestate lowest while carbon dioxide (CO2) and methane (CH4) fluxes were not significantly different (p > 0.05). The greenhouse gas fluxes were significantly different among the freeze-thaw events (p < 0.05) likely due to intense microbial activity and anaerobic conditions. The CO2 and CH4 emissions were related to N2O emission (p < 0.05), and soil temperature strongly correlated with CO2 fluxes. This suggested that soil warming driven by ambient conditions as well as the type and quantity of carbon input influenced soil microbial activity, leading to greenhouse gases production. Therefore, soil amended with biobased residues may either increase or reduce greenhouse gas fluxes during spring freeze-thaw events depending on the source and production method of the organic material.

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Section: Freeze Thaw Phases and Temperature Influence On Greenhouse G...mentioning

confidence: 71%

Spring Freeze–Thaw Stimulates Greenhouse Gas Emissions From Agricultural Soil

Badewa

Yeung²,

Rezanezhad³

et al. 2022

Front. Environ. Sci.

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“…The snow depth and coverage influence both surface and subsurface processes. Snow cover insulates the soil and, hence, protects it against extreme temperature fluctuations during the winter, while patchy snow melt can expose Sphagnum mosses to light, hence, contributing to early spring photosynthesis [16,29]. If sufficient snow cover phenology information is not available, using an air or soil temperature threshold of 1°C may be the next best choice to flexibly delineate the NGS.…”

Section: Resultsmentioning

confidence: 99%

“…This has repercussions for net ecosystem-scale carbon fluxes considering the uncertainties in carbon offsets from growing season primary productivity [1][2][3][4]. A growing body of literature has emerged alluding to substantial increases in soil carbon dioxide (CO 2 ) and methane (CH 4 ) emissions during the NGS [5][6][7][8][9][10][11][12][13][14][15][16][17]. Despite these findings, there is a lack of consistency in how the NGS is defined, with the start and end dates of the NGS in a calendar year assigned differently among studies [18].…”

Section: Introductionmentioning

confidence: 99%

The definition of the non-growing season matters: a case study of net ecosystem carbon exchange from a Canadian peatland

Rafat¹,

Byun²,

Rezanezhad³

et al. 2022

Environ. Res. Commun.

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Climate change is a threat to the 500 Gt carbon stored in northern peatlands. As the region warms, the rise in mean temperature is more pronounced during the non-growing season (NGS, i.e., winter and parts of the shoulder seasons) when net ecosystem loss of carbon dioxide (CO2) occurs. Many studies have investigated the impacts of climate warming on NGS CO2 emissions, yet there is a lack of consistency amongst researchers in how the NGS period is defined. This complicates the interpretation of NGS CO2 emissions and hinders our understanding of seasonal drivers of key carbon exchange processes. Here, we analyze the impact of alternative definitions of the NGS for a peatland site with multiple years of CO2 flux records. Three climatic parameters were considered to define the NGS: air temperature, soil temperature, and snow cover. Our findings reveal positive correlations between estimates of the cumulative non-growing season net ecosystem CO2 exchange (NGS-NEE) and the length of the NGS for each alternative definition, with the greatest proportion of variability explained using snow cover (R 2 = 0.89, p < 0.001), followed by air temperature (R 2 = 0.79, p < 0.001) and soil temperature (R 2 = 0.54, p = 0.006). Using these correlations, we estimate average daily NGS CO2 emitted between 1.42 and 1.90 gCO2 m-2, depending on which NGS definition is used. Our results highlight the need to explicitly define the NGS based on available climatic parameters to account for regional climate and ecosystem variability.

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“…Rafat et al . (2021) 20 show that peatland carbon loss has a positive climate feedback loop based on 13 years of continuous eddy covariance flux measurements from Mer Blue Bog, Canada. Using a radiative forcing model and areal data from the Global Peatlands Database shows that forcing CH 4 emission due to rewetting activities does not damage climate change.…”

Section: Discussionmentioning

confidence: 99%

Peatland groundwater level in the Indonesian maritime continent as an alert for El Niño and moderate positive Indian Ocean dipole events

Sulaiman

Osaki

Takahashi

et al. 2023

Sci Rep

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In general, it is known that extreme climatic conditions such as El Niño and positive Indian Ocean Dipole (IOD+) cause prolonged drought in Indonesia's tropical peatlands so that groundwater levels (GWL) drop and peat is prone to fire. However, 27 years of GWL measurements in Central Kalimantan peat forests show the opposite condition, where the lowest GWL occurs several weeks before El Niño and after IOD+ reaches its peaks. We show that the dropped sea surface temperature anomaly induced by anomalously easterly winds along the southern Java-Sumatra occurs several weeks before the GWL drop to the lowest value. Local rainfall decreased, and GWL dropped sharply by 1.0 to 1.5 m, during the super El Niño events in 1997/98 and 2015, as well as remarkable events of IOD+ in 2019. It is suggested that the tropical peatland ecohydrological system (represented by the GWL), El Niño Southern Oscillation (ENSO), and IOD+ are teleconnected. Hence, monitoring GWL variability of peatland over the IMC is a possibility an alert for extreme climate events associated with El Niño and/or moderate IOD+.

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Non-growing season carbon emissions in a northern peatland are projected to increase under global warming

Cited by 21 publications

References 106 publications

Spring Freeze–Thaw Stimulates Greenhouse Gas Emissions From Agricultural Soil

Spring Freeze–Thaw Stimulates Greenhouse Gas Emissions From Agricultural Soil

The definition of the non-growing season matters: a case study of net ecosystem carbon exchange from a Canadian peatland

Peatland groundwater level in the Indonesian maritime continent as an alert for El Niño and moderate positive Indian Ocean dipole events

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