Partitioning Forest‐Floor Respiration into Source  Based Emissions in a Boreal Forested Bog: Responses  to Experimental Drought

Munir, Tariq Muhammad; Khadka, Bhupesh; Xu, Bin; Strack, Maria

doi:10.3390/f8030075

Cited by 19 publications

(21 citation statements)

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“…Similar effects of drainage leading to increased pore water DOC concentrations have been reported for peatlands across a range of climatic conditions (Haapalehto, Kotiaho, Matilainen, & Tahvanainen, 2014;Hribljan et al, 2014;Lou, Zhai, Kang, Hu, & Hu, 2014). An expanded oxic zone can enhance organic matter decomposition, contributing to higher DOC concentrations, and this is supported by the increase in heterotrophic soil respiration previously reported for experimental and drained site plots (Munir, Khadka, Xu, & Strack, 2017). The overriding effect of water table lowering on DOC is also indicated by the separation of the control site from the experimental and drained sites in regressions of DOC concentration and SUVA versus GEP (Figure 4a,b).…”

Section: Links Between Vegetation Productivity and Doc Concentratiosupporting

confidence: 79%

“…The observed increase in DOC concentration and shift towards smaller, less aromatic molecules in the DOC pool suggest that these vegetation changes may result in more rapid carbon cycling in which greater CO 2 uptake by vascular plants is coupled to a larger labile carbon pool in the soil and more rapid microbial turnover. Previous studies have linked changes in the structure of the belowground carbon pool to shifts in microbial community structure (Bragazza et al, 2013;Jassey et al, 2013), whereas increased soil respiration at our study site (Munir et al, 2017) also suggest a shift in the location of carbon stocks from soil organic matter to standing biomass (e.g., Munir et al, 2015). Finally, a larger, more labile DOC pool may also lead to enhanced DOC export, although the rate will depend on the quantity and timing of discharge.…”

Section: Links Between Vegetation Productivity and Doc Concentratiomentioning

confidence: 50%

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Shrub abundance contributes to shifts in dissolved organic carbon concentration and chemistry in a continental bog exposed to drainage and warming

2019

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Northern peatlands are globally significant soil carbon sinks but contribute a significant amount of dissolved organic carbon (DOC) to streams. Climate change driven warming and drying will likely alter peatland DOC dynamics; however, few field studies have quantified the individual and interactive effects of temperature and moisture changes. Using a full factorial water table (control, drained 2 years [experimental], drained 12 years [drained]) × warming (ambient, open‐top chamber warming) × microform (hummock, hollow) study design, we monitored DOC concentration and spectrophotometric properties (specific ultraviolet absorbance [SUVA], E2/E3, E4/E6) in a wooded boreal bog in Alberta, Canada. Ecohydrological conditions including water table (WT), soil temperature, plant cover, biomass, and productivity were also measured at each plot. We observed a significant interaction between WT treatment, warming and microform for explaining variation in DOC concentrations, with the highest values at drained, warmed hummocks. Overall, drainage resulted in higher DOC concentration. DOC concentration and E2/E3 increased, whereas SUVA decreased, in response to greater plant productivity (i.e., more negative values of gross ecosystem photosynthesis). For DOC concentration and SUVA, this correlation was largely driven by drained, warmed hummocks where shrub growth increased. Moreover, redundancy analysis indicated that shrub and lichen cover, along with WT and soil temperature, were important for explaining variation in DOC concentration and quality. The results indicate that, although DOC concentrations in peatlands are likely to increase under climate change, much of this increase may be from recent carbon fixation, suggesting more rapid carbon cycling as opposed to destabilization of existing carbon stocks.

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Section: Links Between Vegetation Productivity and Doc Concentratiosupporting

confidence: 79%

Section: Links Between Vegetation Productivity and Doc Concentratiomentioning

confidence: 50%

Shrub abundance contributes to shifts in dissolved organic carbon concentration and chemistry in a continental bog exposed to drainage and warming

2019

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“…Within the peatland complex, three bog sites, namely, CONTROL (55°21′ N, 112°31′ W), EXPERIMENTAL (55°21′ N, 112°31′ W), and DRAINED (55°16′ N, 112°28′ W), were chosen or created in 2011 (geographical map is presented by Munir, Khadka, Xu, & Strack, ). Based on hydrological, vegetational, and chemical characteristics, the sites were classified as wooded bogs (Alberta, ).…”

Section: Methodsmentioning

confidence: 99%

Mineral nitrogen and phosphorus pools affected by water table lowering and warming in a boreal forested peatland

Munir

Khadka

et al. 2017

Ecohydrology

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Changes in atmospheric temperature and lowering in water‐table (WT) are expected to affect peatland nutrient dynamics. To understand the response of peatland nitrogen (N) and phosphorus (P) dynamics to warming and drainage in a continental wooded‐bog of hummock–hollow microtopography, we compared three sites: (a) control, (b) recently drained (2–3 years; experimental), and (c) older drained (12–13 years; drained), during 2013. The WT was lowered at experimental and drained sites to 74 and 120 cm, respectively, whereas a warming of ~1 °C was created at one half of the microforms using open‐top chambers. Responses of peat total inorganic nitrogen (TIN = nitrate nitrogen [NO3−‐N] + ammonium nitrogen [NH4+‐N]) and phosphate‐P (PO43−‐P) pools and vegetation C:N ratio, δ13C and δ15N to the experimental treatments were investigated across sites/microforms and over time. Peat TIN available and extractable pools increased with deepening of WT and over time and were greater at hummocks relative to hollows. In contrast, the PO4 pools increased with short‐term drainage but reverted to very close to their original (control) nutrient values in the longer term. The WT and warming driven change in the peat TIN pool was strongly reflected in the vascular vegetation C:N ratio and shrub δ13C and δ15N, whereas moss nutrient dynamics did not vary between sites. Therefore, we suggest that atmospheric warming combined with WT deepening can increase availability of mineral N and P, which then can be reflected in vascular vegetation and hence modify the productivity and ecosystem functioning of the northern midlatitude continental wooded bogs in the long term.

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“…Overall, eddy covariance measurements of NEE showed an average of −288. 33 Figure 7. The curve shows a good correlation between these two measurement methods, with R 2 = 0.93.…”

Section: Comparison Between Biometric and Eddy Covariance Measurementsmentioning

confidence: 99%

“…The trenching method was used to estimate the root respiration [33]. The trenched plot (20 m × 20 m) was established adjacent to the permanent plot at this site.…”

Section: Root Respirationmentioning

confidence: 99%

Biometric and Eddy Covariance Methods for Examining the Carbon Balance of a Larix principis-rupprechtii Forest in the Qinling Mountains, China

Yuan

Jose

et al. 2018

Forests

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Abstract:The carbon balance of forests is controlled by many component processes of carbon acquisition and carbon loss and depends on the age of vegetation, soils, species composition, and the local climate. Thus, examining the carbon balance of different forests around the world is necessary to understand the global carbon balance. Nevertheless, the available information on the carbon balance of Larix principis-rupprechtii forests in the Qinling Mountains remains considerably limited. We provide the first set of results (2010-2013) from a long-term project measuring forest-atmosphere exchanges of CO 2 at the Qinling National Forest Ecosystem Research Station (QNFERS), and compare the net ecosystem exchange (NEE) based on biometric measurements with those observed via the eddy covariance method. We also compare the total ecosystem respiration via scaled-up chamber and eddy covariance measurements. The net primary productivity (NPP) was 817.16 ± 81.48 g·C·m −2 ·y −1 , of which ∆B living and D total accounted for 77.7%, and 22.3%, respectively. Total ecosystem respiration was 814.47 ± 64.22 g·C·m −2 ·y −1 , and cumulative annual soil respiration, coarse woody debris respiration, stem respiration, and leaf respiration were 715.47 ± 28.48, 15.41 ± 1.72, 35.28 ± 4.78, and 48.31 ± 5.24 g·C·m −2 ·y −1 , respectively, accounting for 87.85%, 1.89%, 4.33%, and 5.93% of the total ecosystem respiration. A comparison between ecosystem respiration from chamber measurements and that from eddy covariance measurements showed a strong linear correlation between the two methods (R 2 = 0.93). The NEE of CO 2 between forests and the atmosphere measured by eddy covariance was −288.33 ± 25.26 g·C·m −2 ·y −1 , which revealed a carbon sink in the L. principis-rupprechtii forest. This number was 14% higher than the result from the biometric measurements (−336.71 ± 25.15 g·C·m −2 ·y −1 ). The study findings provided a cross-validation of the CO 2 exchange measured via biometric and eddy covariance, which are beneficial for obtaining the true ecosystem fluxes, and more accurately evaluating carbon budgets.

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Partitioning Forest‐Floor Respiration into Source Based Emissions in a Boreal Forested Bog: Responses to Experimental Drought

Cited by 19 publications

References 70 publications

Shrub abundance contributes to shifts in dissolved organic carbon concentration and chemistry in a continental bog exposed to drainage and warming

Shrub abundance contributes to shifts in dissolved organic carbon concentration and chemistry in a continental bog exposed to drainage and warming

Mineral nitrogen and phosphorus pools affected by water table lowering and warming in a boreal forested peatland

Biometric and Eddy Covariance Methods for Examining the Carbon Balance of a Larix principis-rupprechtii Forest in the Qinling Mountains, China

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