Near‐neutral carbon dioxide balance at a seminatural, temperate bog ecosystem

Hurkuck, Miriam; Brümmer, Christian; Kutsch, Werner L.

doi:10.1002/2015jg003195

Cited by 16 publications

(24 citation statements)

References 90 publications

(128 reference statements)

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“…At the SPRUCE study site, using a unique collar enclosure method (1.13 m 2 ) that excluded trees (but likely not tree roots) Hanson et al [] reported annual NEE ranging from a slight sink of −3.1 g C m −2 yr −1 in 2013 to a C source ranging from 21 to 65 g C m −2 yr −1 across 2011, 2012, and 2014 (our main year of measurement). Annual net CO 2 exchange for temperate bogs typically ranges from slight sources (10 g C m −2 yr −1 ) to slight sinks (−76 g C m −2 yr −1 ) depending on bog site and the variable environmental conditions including water table, snow cover, and day and nighttime temperatures [ Lafleur et al ., ; Sottocornola and Kiely , ; Hommeltenberg et al ., ; Hurkuck et al ., ].…”

Section: Discussionmentioning

confidence: 99%

Biophysical drivers of seasonal variability in Sphagnum gross primary production in a northern temperate bog

Walker

Carter

et al. 2017

JGR Biogeosciences

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Sphagnum mosses are the keystone species of peatland ecosystems. With rapid rates of climate change occurring in high latitudes, vast reservoirs of carbon accumulated over millennia in peatland ecosystems are potentially vulnerable to rising temperature and changing precipitation. We investigate the seasonal drivers of Sphagnum gross primary production (GPP)—the entry point of carbon into wetland ecosystems. Continuous flux measurements and flux partitioning show a seasonal cycle of Sphagnum GPP that peaked in the late summer, well after the peak in photosynthetically active radiation. Wavelet analysis showed that water table height was the key driver of weekly variation in Sphagnum GPP in the early summer and that temperature was the primary driver of GPP in the late summer and autumn. Flux partitioning and a process‐based model of Sphagnum photosynthesis demonstrated the likelihood of seasonally dynamic maximum rates of photosynthesis and a logistic relationship between the water table and photosynthesizing tissue area when the water table was at the Sphagnum surface. The model also suggested that variability in internal resistance to CO2 transport, a function of Sphagnum water content, had minimal effect on GPP. To accurately model Sphagnum GPP, we recommend the following: (1) understanding seasonal photosynthetic trait variation and its triggers in Sphagnum; (2) characterizing the interaction of Sphagnum photosynthesizing tissue area with water table height; (3) modeling Sphagnum as a “soil” layer for consistent simulation of water dynamics; and (4) measurement of Sphagnum “canopy” properties: extinction coefficient (k), clumping (Ω), and maximum stem area index (SAI).

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Section: Discussionmentioning

confidence: 99%

Biophysical drivers of seasonal variability in Sphagnum gross primary production in a northern temperate bog

Walker

Carter

et al. 2017

JGR Biogeosciences

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“…Concerning sites analyzed in our study, Aurela et al (2007) reported that at the nutrient-poor fen FI-Sii site, drought increased respiration and thus diminished carbon uptake; Adkinson et al (2011) reported that reduced water availability constrained photosynthesis capacity at the rich fen CAWp3 and consequently suppressed NEE, while the poor fen CA-Wp2 did not show a significant response to the lower water table. At the moderately rich treed fen CA-Wp1 site, Flanagan and Syed (2011) reported that both photosynthesis and respiration increased in response to the warmer and drier conditions; Hurkuck et al (2016) stated that temperature and light played a more important role than water table depth in controlling respiration and photosynthesis at the DE-Bou bog. Based on the field observations, the timing, duration, and intensity of drought have a major impact on the responses of peatland ecosystems.…”

Section: Orchidee-peat Groups Various Peatland Vegetation Into One Plmentioning

confidence: 99%

ORCHIDEE-PEAT (revision 4596), a model for northern peatland CO<sub>2</sub>, water, and energy fluxes on daily to annual scales

et al. 2018

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Abstract. Peatlands store substantial amounts of carbon and are vulnerable to climate change. We present a modified version of the Organising Carbon and Hydrology In Dynamic Ecosystems (ORCHIDEE) land surface model for simulating the hydrology, surface energy, and CO 2 fluxes of peatlands on daily to annual timescales. The model includes a separate soil tile in each 0.5 • grid cell, defined from a global peatland map and identified with peat-specific soil hydraulic properties. Runoff from non-peat vegetation within a grid cell containing a fraction of peat is routed to this peat soil tile, which maintains shallow water tables. The water table position separates oxic from anoxic decomposition. The model was evaluated against eddy-covariance (EC) observations from 30 northern peatland sites, with the maximum rate of carboxylation (V cmax ) being optimized at each site. Regarding short-term day-to-day variations, the model performance was good for gross primary production (GPP) (r 2 = 0.76; NashSutcliffe modeling efficiency, MEF = 0.76) and ecosystem respiration (ER, r 2 = 0.78, MEF = 0.75), with lesser accuracy for latent heat fluxes (LE, r 2 = 0.42, MEF = 0.14) and and net ecosystem CO 2 exchange (NEE, r 2 = 0.38, MEF = 0.26). Seasonal variations in GPP, ER, NEE, and energy fluxes on monthly scales showed moderate to high r 2 values (0.57-0.86). For spatial across-site gradients of annual mean GPP, ER, NEE, and LE, r 2 values of 0.93, 0.89, 0.27, and 0.71 were achieved, respectively. Water table (WT) variation was not well predicted (r 2 < 0.1), likely due to the uncertain water input to the peat from surrounding areas. However, the poor performance of WT simulation did not greatly affect predictions of ER and NEE. We found a significant relationship between optimized V cmax and latitude (temperature), which better reflects the spatial gradients of annual NEE than using an average V cmax value.

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“…micrometeorological (Mauder and Foken, 2004) (Hurkuck et al, 2016) which was placed next to the ΣN r setup allows us to calculate correction factors after IPS for ΣN r .…”

Section: In-situ Power-spectral Methods [Ips]mentioning

confidence: 99%

“…It is an ombrotrophic, moderately drained bog with high ambient NH 3 concentrations (Zöll et al, 2016) dominating the local deposition of ΣN r (Hurkuck et al, 2014). A detailed description of the site is given in Hurkuck et al (2014Hurkuck et al ( , 2016).…”

Section: Sites and Experimental Setupmentioning

confidence: 99%

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Correcting high-frequency losses of reactive nitrogen flux measurements

Wintjen¹,

Ammann²,

Schrader³

et al. 2019

Preprint

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Abstract. The eddy-covariance (EC) technique is nowadays widely used in experimental field studies to measure land surface-atmosphere exchange of a variety of trace gases. In recent years applying the EC technique to reactive nitrogen compounds has become more important since atmospheric nitrogen deposition influences the productivity and biodiversity of (semi-)natural ecosystems and its carbon dioxide (CO2) exchange. Fluxes which are calculated by EC have to be corrected for setup-specific effects like attenuation in the high-frequency range. However, common methods for correcting such flux losses are mainly optimized for inert greenhouse gases like CO2 and methane or water vapor. In this study, we applied a selection of correction methods to measurements of total reactive nitrogen (ΣNr) conducted in different ecosystems using the Total Reactive Atmospheric Nitrogen Converter (TRANC) coupled to a chemiluminescence dectector (CLD). Average flux losses calculated by methods using measured cospectra and ogives were about 26–38 % for a semi-natural peatland and about 16–22 % for a mixed forest. The investigation of the different methods showed that damping factors calculated with measured heat and gas flux cospectra using an empirical spectral transfer function were most reliable. Flux losses of ΣNr with this method were on the upper end of the median damping range, i.e. 38 % for the peatland site and 22 % for the forest site. Using modified Kaimal cospectra for damping estimation worked well for the forest site, but underestimates damping for the peatland site by about 12 %. Correction factors of methods based on power spectra or on site-specific and instrumental parameters were mostly less than 10 %. Power spectra of ΣNr were heavily affected likely by white noise and deviated substantially at lower frequencies from the temperature (power) spectrum. Our study suggests using an empirical method for estimating flux losses of ΣNr or any reactive nitrogen compound and locally measured cospectra.

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Near‐neutral carbon dioxide balance at a seminatural, temperate bog ecosystem

Cited by 16 publications

References 90 publications

Biophysical drivers of seasonal variability in Sphagnum gross primary production in a northern temperate bog

Biophysical drivers of seasonal variability in Sphagnum gross primary production in a northern temperate bog

ORCHIDEE-PEAT (revision 4596), a model for northern peatland CO<sub>2</sub>, water, and energy fluxes on daily to annual scales

Correcting high-frequency losses of reactive nitrogen flux measurements

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Near‐neutral carbon dioxide balance at a seminatural, temperate bog ecosystem

Cited by 16 publications

References 90 publications

Biophysical drivers of seasonal variability in Sphagnum gross primary production in a northern temperate bog

Biophysical drivers of seasonal variability in Sphagnum gross primary production in a northern temperate bog

ORCHIDEE-PEAT (revision 4596), a model for northern peatland CO&lt;sub&gt;2&lt;/sub&gt;, water, and energy fluxes on daily to annual scales

Correcting high-frequency losses of reactive nitrogen flux measurements

Contact Info

Product

Resources

About

ORCHIDEE-PEAT (revision 4596), a model for northern peatland CO<sub>2</sub>, water, and energy fluxes on daily to annual scales