Carbon fluxes of surfaces vs. ecosystems: advantages of measuring eddy covariance and soil respiration simultaneously in dry grassland ecosystems

Nagy, Zoltán; Pintér, Krisztina; Pavelka, Marián; Dařenová, Eva; Balogh, János

doi:10.5194/bg-8-2523-2011

Cited by 24 publications

(16 citation statements)

References 47 publications

(47 reference statements)

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“…[] and Nagy et al . [], we used a “paired observations” approach. We examined the difference between soil respiration ( R s ) measurements made at the same FD chamber exactly 24 h apart

normalR normalE = ((), {R_{s}}_{_{t = 0}} - {R_{s}}_{_{t = 24 h}}) true/ \sqrt 2

…”

Section: Methodsmentioning

confidence: 99%

A practical approach for uncertainty quantification of high‐frequency soil respiration using Forced Diffusion chambers

2015

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This paper examines the sources of uncertainty for the Forced Diffusion (FD) chamber soil respiration (R s ) measurement technique and demonstrates a protocol for uncertainty quantification that could be appropriate with any soil flux technique. Here we sought to quantify and compare the three primary sources of uncertainty in R s : (1) instrumentation error; (2) scaling error, which stems from the spatial variability of R s ; and (3) random error, which arises from stochastic or unpredictable variation in environmental drivers and was quantified from repeated observations under a narrow temperature, moisture, and time range. In laboratory studies, we found that FD instrumentation error remained constant as R s increased. In field studies from five North American ecosystems, we found that as R s increased from winter to peak growing season, random error increased linearly with average flux by about 40% of average R s . Random error not only scales with soil flux but scales in a consistent way (same slope) across ecosystems. Scaling error, measured at one site, similarly increased linearly with average R s , by about 50% of average R s . Our findings are consistent with previous findings for both soil fluxes and eddy covariance fluxes across other northern temperate ecosystems that showed random error scales linearly with flux magnitude with a slope of~0.2. Although the mechanistic basis for this scaling of random error is unknown, it is suggestive of a broadly applicable rule for predicting flux random error. Also consistent with previous studies, we found the random error of FD follows a Laplace (double-exponential) rather than a normal (Gaussian) distribution.

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“…[] and Nagy et al . [], we used a “paired observations” approach. We examined the difference between soil respiration ( R s ) measurements made at the same FD chamber exactly 24 h apart

normalR normalE = ((), {R_{s}}_{_{t = 0}} - {R_{s}}_{_{t = 24 h}}) true/ \sqrt 2

…”

Section: Methodsmentioning

confidence: 99%

A practical approach for uncertainty quantification of high‐frequency soil respiration using Forced Diffusion chambers

2015

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“…Isotopic signals of soil-respired CO 2 were studied extensively but several uncertainties related to the different methods were also revealed. Steady-state methods were found to provide more robust estimates than static chambers but still charged with biases (e.g., diffusive fractionation; Nickerson and Risk, 2009). Open systems have the advantage of unattended automatic measurement collecting large amount of data but are less sensitive to small isotopic differences (Midwood and Millard, 2011).…”

Section: Uncertainty Assessmentmentioning

confidence: 99%

Autotrophic component of soil respiration is repressed by drought more than the heterotrophic one in dry grasslands

Balogh¹,

Papp

Pintér

et al. 2016

Biogeosciences

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Abstract. Summer droughts projected to increase in central Europe due to climate changes strongly influence the carbon cycle of ecosystems. Persistent respiration activities during drought periods are responsible for a significant carbon loss, which may turn the ecosystem from a sink into a source of carbon. There are still gaps in our knowledge regarding the characteristic changes taking place in the respiration of the different components of the ecosystem in response to drought events.In the present study, we combined a physical separation of soil respiration components with continuous measurements of soil CO2 efflux and its isotopic (13C) signals at a dry grassland site in Hungary. The physical separation of soil respiration components was performed by means of inox meshes and tubes inserted into the soil. The root-excluded and root- and mycorrhiza-excluded treatments served to measure the isotopic signals of the rhizospheric, mycorrhizal fungi and heterotrophic components, respectively.In the dry grassland investigated in the study the three components of the soil CO2 efflux decreased at different rates under drought conditions. During drought the contribution made by the heterotrophic components was the highest (54 ± 8 %; mean ±SE). Rhizospheric component was the most sensitive to soil drying with its relative contribution to the total soil respiration dropping from 66 ± 7 (non-stressed) to 35 ± 17 % (mean ±SE) under drought conditions. According to our results the heterotrophic component of soil respiration is the major contributor to the respiration activities during drought events in the dry grassland ecosystem studied.

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“…The grassland (500 ha) has been grazed by cattle for a minimum of 20 years (Nagy et al, 2011). The average annual precipitation at the area is 562 mm and the annual mean temperature is 10.4°C (Nagy et al, 2011). The grazing period of cattle (1.02 cattle/ha) on the grazed site in the previous year of the present survey lasted from June to July and from October to December in 2011.…”

Section: Microcoenological Investigationmentioning

confidence: 99%

“…Grasslands cover approximately 11% of Hungary and are an important sink for carbon dioxide (Haszpra et al, 2011, Nagy et al, 2011. However, changes in the management usually result in changes in carbon sequestration potential (NIR, 2010) and changes in species composition of grasslands (Moog, 2002, Jantunen, 2003.…”

Section: Introductionmentioning

confidence: 99%

Effect of Grazing and Mowing on the Micro Coenological Composition of a Semi - Arid Grassland in Hungary

et al. 2014

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Abstract. Grasslands play an important role in carbon sequestration. Different management regimes may change the species composition of plants in grasslands, thus may affect the carbon sequestration potential. Therefore, we investigated if short-term changes in species composition occurred in response to shift in grazing to mowing in a semi-arid grassland in Hungary (Bugac). Species abundances were recorded as frequencies of species in contiguous 5 cm × 5 cm quadrates along six (5 meters long) permanent transects at adjacent grazed and mowed sites in the spring and fall of 2012. High variation of vegetation characteristics was found within the management units at patch scale (at few m scale). The species richness, relative abundance of species, species density, Shannon diversity index, and forage quality differed among transects; however, no differences were observed between the two managements regimes at site scale (at hectar scale) (ANOVA, p>0.05). The average species abundance of the grazed and mowed sites were very similar (Poa spp.: 13.48±5.34%, 14.67±6,9%; Carex spp.:12.46±8.75%, 14.24±10.16%; Cynodon dactylon: 10±8.52%, 16.01±3.49%., respectively). Our results suggest that species composition differences can not be the main factors explaining short-term differences in carbon sequestration in natural semiarid grasslands.

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Carbon fluxes of surfaces vs. ecosystems: advantages of measuring eddy covariance and soil respiration simultaneously in dry grassland ecosystems

Cited by 24 publications

References 47 publications

A practical approach for uncertainty quantification of high‐frequency soil respiration using Forced Diffusion chambers

A practical approach for uncertainty quantification of high‐frequency soil respiration using Forced Diffusion chambers

Autotrophic component of soil respiration is repressed by drought more than the heterotrophic one in dry grasslands

Effect of Grazing and Mowing on the Micro Coenological Composition of a Semi - Arid Grassland in Hungary

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