Controls on autotrophic and heterotrophic respiration in an ombrotrophic bog

Rankin, Tracy; Roulet, Nigel T.; Moore, Tim R.

doi:10.5194/bg-2021-270

Cited by 3 publications

(2 citation statements)

References 58 publications

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“…The heterotrophic peat respiration thus accounted for 59 % of the soil respiration or 49 % of total ER. This agrees well with the available measurements from Mer Bleue, showing that heterotrophic respiration accounted for 30 %-63 % of the total ER (Stewart, 2006;Rankin et al, 2022).…”

Section: Carbon Fluxessupporting

confidence: 90%

Water level variation at a beaver pond significantly impacts net CO₂ uptake of a continental bog

Moore²,

Humphreys³

et al. 2023

Hydrol. Earth Syst. Sci.

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Abstract. The carbon (C) dynamics of northern peatlands are sensitive to hydrological changes owing to ecohydrological feedbacks. We quantified and evaluated the impact of water level variations in a beaver pond (BP) on the CO2 flux dynamics of an adjacent, raised Sphagnum–shrub-dominated bog in southern Canada. We applied the CoupModel to the Mer Bleue bog, where the hydrological, energy and CO2 fluxes have been measured continuously for over 20 years. The lateral flow of water from the bog to the BP was estimated by the hydraulic gradient between the peatland and the BP's water level and the vertical profile of peat hydraulic conductivity. The model outputs were compared with the measured hydrological components, CO2 flux and energy flux data (1998–2019). CoupModel was able to reproduce the measured data well. The simulation shows that variation in the BP water level (naturally occurring or due to management) influenced the bog net ecosystem exchange (NEE) of CO2. Over 1998–2004, the BP water level was 0.75 to 1.0 m lower than during 2017–2019. Simulated net CO2 uptake was 55 gCm-2yr-1 lower during 1998–2004 compared to 2017–2019 when there was no BP disturbance, which was similar to the differences in measured NEE between those periods. Peatland annual NEE was well correlated with water table depth (WTD) within the bog, and NEE also shows a linear relation with the water level at the BP, with a slope of −120 gCO2-Cm-2yr-1m-1. The current modelling predicts that the bog may switch from CO2 sink to source when the BP water levels drop lower than ∼ 1.7 m below the peat surface at the eddy covariance (EC) tower, located on the bog surface 250 m from the BP. This study highlights the importance of natural and human disturbances to adjacent water bodies in regulating the net CO2 uptake function of northern peatlands.

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Section: Carbon Fluxessupporting

confidence: 90%

Water level variation at a beaver pond significantly impacts net CO₂ uptake of a continental bog

Moore²,

Humphreys³

et al. 2023

Hydrol. Earth Syst. Sci.

View full text Add to dashboard Cite

show abstract

“…The heterotrophic peat respiration thus accounted for 59% of the soil respiration or 49% of total ER. This agrees well with the available 245 measurements from Mer Bleue showing heterotrophic respiration accounted for 30-63% of the total ER (Stewart, 2006;Rankin et al, 2021).…”

Section: Carbon Fluxessupporting

confidence: 90%

Water level variation at a beaver pond significantly impacts net CO₂ uptake of a continental bog

Moore

Humphreys

et al. 2021

Preprint

Self Cite

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Abstract. The carbon (C) dynamics of northern peatlands are sensitive to hydrological changes owing to ecohydrological feedback. We quantified and evaluated the impact of water level variations in a beaver pond (BP) on the CO2 flux dynamics of an adjacent, raised Sphagnum – shrub-dominated bog in southern Canada. We applied the CoupModel to the Mer Bleue bog, where the hydrological, energy and CO2 fluxes have been measured continuously for over 20 years. The lateral flow from the bog to the BP was estimated by the hydraulic gradient between the peatland and the BP's water level and the vertical profile of peat hydraulic conductivity. The model outputs were compared with the measured hydrological components, CO2 flux and energy flux data (1998–2019). CoupModel was able to reproduce the measured data well. The simulation shows that variation in the BP water level (naturally occurring or due to management) influenced the bog net ecosystem exchange of CO2 (NEE). Over 1998–2004, the BP water level was 0.75 to 1.0 m lower than during 2017–2019. Simulated net CO2 uptake was 55 g C m−2 yr−1 lower during 1998–2004 compared to 2017–2019 when there was no BP disturbance, which was similar to the differences in measured NEE between those periods. Peatland annual NEE was well correlated with water table depth within the bog, and NEE also shows a linear relation with the water level at the BP, with a slope of −120 g CO2-C m−2 yr−1 m−1. The current modelling predicts the bog may switch from CO2 sink to source when the BP water levels drop lower than ~ 1.7 m below the peat surface at the eddy covariance tower, 250 m from the BP. This study highlights the importance of natural and human disturbances to adjacent water bodies in regulating net CO2 uptake function of northern peatlands.

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Carbon flux estimates are sensitive to data source: a comparison of field and lab temperature sensitivity data

Patel

Bond‐Lamberty

Morris

et al. 2022

Environ. Res. Lett.

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A large literature exists on mechanisms driving soil production of the greenhouse gases CO2 and CH4. Although it is common knowledge that measurements obtained through field studies vs. laboratory incubations can diverge because of the vastly different conditions of these environments, few studies have systematically examined these patterns. These data are used to parametrize and benchmark ecosystem- to global-scale models, which are then susceptible to the biases of the source data. Here, we examine how greenhouse gas measurements may be influenced by whether the measurement/incubation was conducted in the field vs. laboratory, focusing on CO2 and CH4 measurements. We use Q10 of greenhouse gas flux (temperature sensitivity) for our analyses because this metric is commonly used in biological and Earth system sciences and is an important parameter in many modeling frameworks. We predicted that laboratory measurements would be less variable, but also less representative of true field conditions. However, there was greater variability in the Q10 values calculated from lab-based measurements of CO2 fluxes, because lab experiments explore extremes rarely seen in situ, and reflect the physical and chemical disturbances occurring during sampling, transport, and incubation. Overall, respiration Q10 values were significantly greater in laboratory incubations (mean = 4.19) than field measurements (mean = 3.05), with strong influences of incubation temperature and climate region/biome. However, this was in part because field measurements typically represent total respiration (Rs), whereas lab incubations typically represent heterotrophic respiration (Rh), making direct comparisons difficult to interpret. Focusing only on Rh-derived Q10, these values showed almost identical distributions across laboratory (n = 1110) and field (n = 581) experiments, providing strong support for using the former as an experimental proxy for the latter, although we caution that geographic biases in the extant data make this conclusion tentative. Due to a smaller sample size of CH4 Q10 data, we were unable to perform a comparable robust analysis, but we expect similar interactions with soil temperature, moisture, and environmental/climatic variables. Our results here suggest the need for more concerted efforts to document and standardize these data, including sample and site metadata.

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Controls on autotrophic and heterotrophic respiration in an ombrotrophic bog

Cited by 3 publications

References 58 publications

Water level variation at a beaver pond significantly impacts net CO₂ uptake of a continental bog

Water level variation at a beaver pond significantly impacts net CO₂ uptake of a continental bog

Water level variation at a beaver pond significantly impacts net CO₂ uptake of a continental bog

Carbon flux estimates are sensitive to data source: a comparison of field and lab temperature sensitivity data

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Controls on autotrophic and heterotrophic respiration in an ombrotrophic bog

Cited by 3 publications

References 58 publications

Water level variation at a beaver pond significantly impacts net CO2 uptake of a continental bog

Water level variation at a beaver pond significantly impacts net CO2 uptake of a continental bog

Water level variation at a beaver pond significantly impacts net CO2 uptake of a continental bog

Carbon flux estimates are sensitive to data source: a comparison of field and lab temperature sensitivity data

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Water level variation at a beaver pond significantly impacts net CO₂ uptake of a continental bog

Water level variation at a beaver pond significantly impacts net CO₂ uptake of a continental bog

Water level variation at a beaver pond significantly impacts net CO₂ uptake of a continental bog