Spatial soil respiration measurements under varying environmental conditions in a dry grassland

2020 ◽  
Author(s):  
János Balogh ◽  
Szilvia Fóti ◽  
Bernadett Gecse ◽  
Marianna Papp ◽  
Gabriella Süle ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Spatial Variability ◽  
Environmental Conditions ◽  
Summer Drought ◽  
Dry Grassland ◽  
Greenhouse Gas Flux ◽  
Major Disadvantage ◽  
Flux Measurements ◽  
Eddy Covariance Measurements ◽  
Footprint Area

<p>Spatial variability of ecosystem processes constitutes significant uncertainty source in greenhouse gas flux measurements and estimations. The major disadvantage of the chamber-based flux measurements is the poor spatial representativeness, but eddy-covariance measurements also have an uncertainty due to the unequal and not constant footprint area. One way to overcome these difficulties is the spatial sampling improving the field-scale data coverage.</p><p>The aim of this study was to describe the spatial variability of grassland soil CO<sub>2</sub> efflux under varying environmental conditions. For this reason, we conducted spatial measurements on a range of variables including soil respiration, above-ground biomass, greenness index of the vegetation, soil water content and soil temperature during a seven-year study in a dry grassland site in Hungary. Altitude and soil organic carbon (SOC) content of the measuring positions were also used as background factors. Measurements were repeated 19 times at 78 positions during the study, in the main phenological stages of the grassland vegetation: spring growth, summer drought, autumn regrowth. The sampling scheme was based on 80×60 m grid of 10 m resolution. SOC content was highly variable among the positions due to the exposure differences and their environmental constrains. We analyzed the effect of the drivers on soil respiration grouping the measuring positions by the SOC content of the soil.</p>

Variability of total soil respiration in a Mediterranean vineyard

Soil Research ◽  
2015 ◽  
Vol 53 (5) ◽  
pp. 531 ◽  
Author(s):  
Egidio Lardo ◽  
Assunta Maria Palese ◽  
Vitale Nuzzo ◽  
Cristos Xiloyannis ◽  
Giuseppe Celano
Keyword(s):  
Soil Respiration ◽  
Spatial Variability ◽  
Co2 Emissions ◽  
Temporal Dynamics ◽  
Non Invasive ◽  
Total Soil ◽  
Greenhouse Gas Flux ◽  
Flux Measurements ◽  
Total Soil Respiration

Total soil respiration (TSR) is the major component of the CO2 global flux. The knowledge of the temporal-spatial variability of TSR allows for a better interpretation of a critical component of global greenhouse gas flux measurements. The objective of the research was to evaluate the TSR dynamic over a long measurement period in a vineyard in the South of Italy. A static home-made automatic system was used to measure TSR for a three year period. A portable gas analyser (Li-Cor 6400-09) was used to study TSR spatial variability. A non-invasive geophysical technique (Electromagnetic Induction – EMI) was applied to search for a significant relationship between apparent soil electrical conductivity (ECa), the EMI signal and TSR. Long-term measurements of TSR enabled to study its temporal dynamics. CO2 rates ranged from 0.78 to 43.7 g CO2 m–2 day–1. TSR increased during spring and decreased by 45–50% during the mid-summer. The daily trend of TSR showed differences between the seasons studied reporting a clearly variation among TSR measured on row and inter-row positions. The supplemental irrigation significantly affected (P < 0.001) CO2 soil effluxes which showed a weekly mean increase of 300%. Significant inverse relationships were found by interpolating TSR values and ECa (coefficient of correlation ranging from –0.43 to –0.83 at P < 0.001). The spatialisation of TSR at field scale was performed using the linear regression between TSR values and EMI signals. TSR spatialisation gave a more detailed view of CO2 emissions distribution within the vineyard. EMI technique could be a useful tool to compute accurately the global CO2 emissions which are a complex and hard to measure component of the agrosystem carbon balance.

Low-cost methane (CH4) sensors for use in in flux chambers

2020 ◽  
Author(s):  
David Bastviken ◽  
Jonatan Nygren ◽  
Jonathan Schenk ◽  
Roser Parrelada Massana ◽  
Nguyen Thanh Duc
Keyword(s):  
Greenhouse Gas ◽  
Environmental Conditions ◽  
Large Scale ◽  
Variable Temperature ◽  
Low Cost ◽  
Local Level ◽  
Limiting Factor ◽  
Gas Flux ◽  
Greenhouse Gas Flux ◽  
Flux Measurements

&lt;p&gt;The lack of reliable low-cost greenhouse gas flux measurement approaches limit our ability quantify regulation and verify mitigation efforts at the local level. &amp;#160;&amp;#160;Methane (CH4), one of the most important greenhouse gases, is particularly dependent on local measurements because levels are regulated by a complex combination of sources, sinks and environmental conditions. There are still major gaps in the global methane budget and the reasons for the irregular development over time remains unclear. Facilitation of local flux measurements in all parts of the world therefore seem important to constrain large-scale assessments. As the high cost of gas analysers is a limiting factor for flux measurements, we here present how low-cost CH4 sensors can be used outside their specified range to yield reasonably accurate chamber-based flux measurements. By using a two-step calibration approach, testing multiple alternatives on how to model interference from temperature and humidity, an R2 &amp;#8805; 0.99 was achieved over a CH4 concentration range of 2 &amp;#8211; 700 ppm under variable temperature and relative humidity. We also demonstrate ways to reach such calibration results without complicated calibration experiments and instead using in the order of 20 in situ reference measurements at different environmental conditions. Finally we, constructed and described a make-it-yourself Arduino based logger with the tested sensors for CH&lt;sub&gt;4&lt;/sub&gt;, temperature, humidity and carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) intended for flux chamber use with a material cost of approximately 200 Euro. We hope that this can contribute to more widespread greenhouse gas flux measurements in many environments and countries.&lt;/p&gt;

Spatial variability in responses to environmental conditions in Southern Hemisphere long-finned pilot whales

2019 ◽  
Vol 629 ◽  
pp. 207-218 ◽  
Author(s):  
V Hamilton ◽  
K Evans ◽  
B Raymond ◽  
E Betty ◽  
MA Hindell
Keyword(s):  
Spatial Variability ◽  
Southern Hemisphere ◽  
Environmental Conditions ◽  
Pilot Whales

Spatial variability of soil respiration (R s ) and its controls are subjected to strong seasonality in an even‐aged European beech ( Fagus sylvatica L.) stand

2021 ◽  
Author(s):  
Ana‐Maria Hereș ◽  
Cosmin Bragă ◽  
Any Mary Petritan ◽  
Ion Catalin Petritan ◽  
Jorge Curiel Yuste
Keyword(s):  
Soil Respiration ◽  
Spatial Variability ◽  
Fagus Sylvatica ◽  
European Beech ◽  
Fagus Sylvatica L ◽  
Strong Seasonality

Characterization and Understanding of Bare Soil Respiration Spatial Variability at Plot Scale

2009 ◽  
Vol 8 (3) ◽  
pp. 762-771 ◽  
Author(s):  
M. Herbst ◽  
N. Prolingheuer ◽  
A. Graf ◽  
J. A. Huisman ◽  
L. Weihermüller ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Spatial Variability ◽  
Bare Soil

scholarly journals Localized basal area affects soil respiration temperature sensitivity in a coastal deciduous forest

2020 ◽  
Vol 17 (3) ◽  
pp. 771-780 ◽  
Author(s):  
Stephanie C. Pennington ◽  
Nate G. McDowell ◽  
J. Patrick Megonigal ◽  
James C. Stegen ◽  
Ben Bond-Lamberty
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Spatial Variability ◽  
Temperature Sensitivity ◽  
Large Scale ◽  
Deciduous Forest ◽  
Basal Area ◽  
Soil Surface ◽  
Study Sites ◽  
Positive Effect

Abstract. Soil respiration (Rs), the flow of CO2 from the soil surface to the atmosphere, is one of the largest carbon fluxes in the terrestrial biosphere. The spatial variability of Rs is both large and poorly understood, limiting our ability to robustly scale it in space. One factor in Rs spatial variability is the autotrophic contribution from plant roots, but it is uncertain how the presence of plants affects the magnitude and temperature sensitivity of Rs. This study used 1 year of Rs measurements to examine the effect of localized basal area on Rs in the growing and dormant seasons, as well as during moisture-limited times, in a temperate, coastal, deciduous forest in eastern Maryland, USA. In a linear mixed-effects model, tree basal area within a 5 m radius (BA5) exerted a significant positive effect on the temperature sensitivity of soil respiration. Soil moisture was the dominant control on Rs during the dry portions of the year, while soil moisture, temperature, and BA5 all exerted significant effects on Rs in wetter periods. Our results suggest that autotrophic respiration is more sensitive to temperature than heterotrophic respiration at these sites, although we did not measure these source fluxes directly, and that soil respiration is highly moisture sensitive, even in a record-rainfall year. The Rs flux magnitudes (0.46–15.0 µmol m−2 s−1) and variability (coefficient of variability 10 %–23 % across plots) observed in this study were comparable to values observed in similar forests. Six Rs observations would be required in order to estimate the mean across all study sites to within 50 %, and 518 would be required in order to estimate it to within 5 %, with 95 % confidence. A better understanding of the spatial interactions between plants and microbes, as well as the strength and speed of above- and belowground coupling, is necessary to link these processes with large-scale soil-to-atmosphere C fluxes.

scholarly journals PTR-TOF-MS eddy covariance measurements of isoprene and monoterpene fluxes from an eastern Amazonian rainforest

2020 ◽  
Vol 20 (12) ◽  
pp. 7179-7191 ◽  
Author(s):  
Chinmoy Sarkar ◽  
Alex B. Guenther ◽  
Jeong-Hoo Park ◽  
Roger Seco ◽  
Eliane Alves ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Atmospheric Chemistry ◽  
Sensible Heat Flux ◽  
Proton Transfer Reaction ◽  
Strongly Correlated ◽  
Mixing Ratios ◽  
Flux Measurements ◽  
Eddy Covariance Measurements ◽  
Emission Models ◽  
Tof Ms

Abstract. Biogenic volatile organic compounds (BVOCs) are important components of the atmosphere due to their contribution to atmospheric chemistry and biogeochemical cycles. Tropical forests are the largest source of the dominant BVOC emissions (e.g. isoprene and monoterpenes). In this study, we report isoprene and total monoterpene flux measurements with a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) using the eddy covariance (EC) method at the Tapajós National Forest (2.857∘ S, 54.959∘ W), a primary rainforest in eastern Amazonia. Measurements were carried out from 1 to 16 June 2014, during the wet-to-dry transition season. During the measurement period, the measured daytime (06:00–18:00 LT) average isoprene mixing ratios and fluxes were 1.15±0.60 ppb and 0.55±0.71 mg C m−2 h−1, respectively, whereas the measured daytime average total monoterpene mixing ratios and fluxes were 0.14±0.10 ppb and 0.20±0.25 mg C m−2 h−1, respectively. Midday (10:00–14:00 LT) average isoprene and total monoterpene mixing ratios were 1.70±0.49 and 0.24±0.05 ppb, respectively, whereas midday average isoprene and monoterpene fluxes were 1.24±0.68 and 0.46±0.22 mg C m−2 h−1, respectively. Isoprene and total monoterpene emissions in Tapajós were correlated with ambient temperature and solar radiation. Significant correlation with sensible heat flux, SHF (r2=0.77), was also observed. Measured isoprene and monoterpene fluxes were strongly correlated with each other (r2=0.93). The MEGAN2.1 (Model of Emissions of Gases and Aerosols from Nature version 2.1) model could simulate most of the observed diurnal variations (r2=0.7 to 0.8) but declined a little later in the evening for both isoprene and total monoterpene fluxes. The results also demonstrate the importance of site-specific vegetation emission factors (EFs) for accurately simulating BVOC fluxes in regional and global BVOC emission models.

scholarly journals Lessons learned from more than a decade of greenhouse gas flux measurements at boreal forests in eastern Siberia and interior Alaska

Polar Science ◽  
2020 ◽  
pp. 100607 ◽  
Author(s):  
Tetsuya Hiyama ◽  
Masahito Ueyama ◽  
Ayumi Kotani ◽  
Hiroki Iwata ◽  
Taro Nakai ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Boreal Forests ◽  
Lessons Learned ◽  
Eastern Siberia ◽  
Gas Flux ◽  
Interior Alaska ◽  
Greenhouse Gas Flux ◽  
Flux Measurements

Multiyear greenhouse gas flux measurements on a temperate fen soil used for cropland or grassland

2015 ◽  
Vol 178 (1) ◽  
pp. 99-111 ◽  
Author(s):  
Colja Beyer ◽  
Horst Liebersbach ◽  
Heinrich Höper
Keyword(s):  
Greenhouse Gas ◽  
Gas Flux ◽  
Greenhouse Gas Flux ◽  
Flux Measurements

scholarly journals Spatial variability in airborne surface flux measurements during HAPEX-Sahel

1997 ◽  
Vol 188-189 ◽  
pp. 878-911 ◽  
Author(s):  
F. Saïd ◽  
J.L. Attié ◽  
B. Bénech ◽  
A. Druilhet ◽  
P. Durand ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Surface Flux ◽  
Flux Measurements
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