scholarly journals Study of CO2 flux and soil carbon in northern Pantanal, Brazil

2018 ◽  
Vol 9 (5) ◽  
pp. 29-38
Author(s):  
Osvaldo Borges Pinto Junior ◽  
Paula Valéria Carvalho ◽  
Eduardo Guimarães Couto
Keyword(s):  
Carbon Source ◽  
Soil Carbon ◽  
High Tide ◽  
Co2 Flux ◽  
Co2 Concentration ◽  
Wetland Soil ◽  
Co2 Fluxes ◽  
Soil Co2 ◽  
Mato Grosso ◽  
Tree Island

The determination of greenhouse gas emissions from wetlands are of great interest given the biogeochemistry these areas exhibit. We measure soil CO2 concentration and monthly fluxes on a tree island of the Northern Pantanal of Mato Grosso, Brazil, and estimate the role of soil as a carbon source or sink during high tide, low tide, flooding, and drought seasons. The average value of the CO2 fluxes in the wetland soil was 0.54 ± 0.30 g (CO2)·m- 2·h- 1 with the soil acting as a carbon source at -9.11 ton.·ha-1 over the one year cycle. Soil CO2 fluxes were significantly correlated with soil moisture and temperature at 5 cm depth. Soil CO2 concentrations reached more than 100 ppm. Soil carbon stocks did not correlate significantly with variables in this study, suggesting that non-measured variables can influence soil carbon dynamics.

scholarly journals Field Study on Correlation between CO2 Concentration and Surface Soil CO2 Flux in Closed Coal Mine Goaf

ACS Omega ◽  
2019 ◽  
Vol 4 (7) ◽  
pp. 12136-12145 ◽  
Author(s):  
Yongjun Wang ◽  
Xiaoming Zhang ◽  
Hemeng Zhang ◽  
Kyuro Sasaki
Keyword(s):  
Field Study ◽  
Coal Mine ◽  
Surface Soil ◽  
Co2 Flux ◽  
Co2 Concentration ◽  
Soil Co2 ◽  
Soil Co2 Flux

scholarly journals Explaining CO<sub>2</sub> fluctuations observed in snowpacks

2018 ◽  
Vol 15 (3) ◽  
pp. 847-859
Author(s):  
Laura Graham ◽  
David Risk
Keyword(s):  
Diffusion Model ◽  
Meteorological Data ◽  
Negative Relationship ◽  
Flux Measurement ◽  
Co2 Flux ◽  
Co2 Concentration ◽  
Physical Factors ◽  
Advective Transport ◽  
Soil Co2 ◽  
C Cycle

Abstract. Winter soil carbon dioxide (CO2) respiration is a significant and understudied component of the global carbon (C) cycle. Winter soil CO2 fluxes can be surprisingly variable, owing to physical factors such as snowpack properties and wind. This study aimed to quantify the effects of advective transport of CO2 in soil–snow systems on the subdiurnal to diurnal (hours to days) timescale, use an enhanced diffusion model to replicate the effects of CO2 concentration depletions from persistent winds, and use a model–measure pairing to effectively explore what is happening in the field. We took continuous measurements of CO2 concentration gradients and meteorological data at a site in the Cape Breton Highlands of Nova Scotia, Canada, to determine the relationship between wind speeds and CO2 levels in snowpacks. We adapted a soil CO2 diffusion model for the soil–snow system and simulated stepwise changes in transport rate over a broad range of plausible synthetic cases. The goal was to mimic the changes we observed in CO2 snowpack concentration to help elucidate the mechanisms (diffusion, advection) responsible for observed variations. On subdiurnal to diurnal timescales with varying winds and constant snow levels, a strong negative relationship between wind speed and CO2 concentration within the snowpack was often identified. Modelling clearly demonstrated that diffusion alone was unable to replicate the high-frequency CO2 fluctuations, but simulations using above-atmospheric snowpack diffusivities (simulating advective transport within the snowpack) reproduced snow CO2 changes of the observed magnitude and speed. This confirmed that wind-induced ventilation contributed to episodic pulsed emissions from the snow surface and to suppressed snowpack concentrations. This study improves our understanding of winter CO2 dynamics to aid in continued quantification of the annual global C cycle and demonstrates a preference for continuous wintertime CO2 flux measurement systems.

scholarly journals Fractal Dimension Analysis Applied to Soil CO2 Fluxes in Campotosto’s Seismic Area, Central Italy

Geosciences ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 233
Author(s):  
Simone D’Incecco ◽  
Piero Di Carlo ◽  
Eleonora Aruffo ◽  
Nikolaos Chatzisavvas ◽  
Ermioni Petraki ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Central Italy ◽  
Fractal Dimensions ◽  
Co2 Flux ◽  
Co2 Fluxes ◽  
Soil Co2 ◽  
Flux Chamber ◽  
Dimension Analysis ◽  
Fractal Dimension Analysis ◽  
Seismic Area

This article reports fractal dimension analysis applied to soil CO2 fluxes measured in an Italian seismic area. The work was carried out with the use of a calibrated flux chamber unit. The fractal dimension (FD) from isotropic variograms was used as a method to understand related scale-dependent phenomena. The aim was to investigate the spatial variability of CO2 flux measurements in four directions (horizontal, vertical, 45° and 135° directions) related to different distances between the measuring points and from a fault. High fractal dimension values were found (2.5 ≤ FD ≤ 3.0). These imply strong anti-persistent behavior near to and far from the fault. Lower fractal dimensions were addressed at longer distances from the fault.

scholarly journals Ecosystem responses to elevated CO<sub>2</sub> using airborne remote sensing at Mammoth Mountain, California

2018 ◽  
Author(s):  
Kerry Cawse-Nicholson ◽  
Joshua B. Fisher ◽  
Caroline A. Famiglietti ◽  
Amy Braverman ◽  
Florian M. Schwandner ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Co2 Emissions ◽  
Elevated Co2 ◽  
Co2 Flux ◽  
Ecosystem Structure ◽  
Co2 Fluxes ◽  
Soil Co2 ◽  
Ecosystem Responses ◽  
Mammoth Mountain ◽  
And Function

Abstract. We present an exploratory study examining the use of airborne remote sensing observations to detect ecological responses to elevated CO2 emissions from active volcanic systems. To evaluate these ecosystem responses, existing spectroscopic, thermal, and lidar data acquired over forest ecosystems on Mammoth Mountain volcano, California, were exploited, along with in situ measurements of volcanic soil CO2 fluxes. The elevated CO2 response was used to statistically model ecosystem structure, composition and function, evaluated via data products including biomass, plant foliar traits and vegetation indices, and evapotranspiration (ET). Using regression ensemble models, we found that soil CO2 flux was a significant predictor for ecological variables, including Normalized Vegetation Difference Index (NDVI), canopy nitrogen, ET, and biomass. Additionally, the relationships between ecological variables changed with increasingly elevated (volcanically influenced) over non-volcanic background soil CO2 fluxes, suggesting a shift in coupling/decoupling among ecosystem structure, composition, and function synergies. For example, ET and biomass were significantly correlated for areas without elevated CO2 flux, but decoupled with elevated CO2 flux. This study demonstrates that a) volcanic systems show great potential as a means to study the properties of ecosystems and their responses to elevated CO2 emissions and b) these ecosystem responses are measureable using a suite of airborne remotely sensed data.

Seasonal Dynamics of Soil CO2 Concentration and CO2 Fluxes from the Soil of the Former Lake Texcoco, Mexico

2018 ◽  
Vol 51 (6) ◽  
pp. 674-681 ◽  
Author(s):  
E. N. Ikkonen ◽  
N. E. García-Calderón ◽  
A. Ibáñez-Huerta ◽  
J. D. Etchevers-Barra ◽  
P. V. Krasilnikov
Keyword(s):  
Seasonal Dynamics ◽  
Co2 Concentration ◽  
Co2 Fluxes ◽  
Soil Co2 ◽  
Soil Co2 Concentration

scholarly journals Carbon Cycles of Forest Ecosystems in a Typical Climate Transition Zone under Future Climate Change: A Case Study of Shaanxi Province, China

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1150
Author(s):  
Siqi Liang ◽  
Shouzhang Peng ◽  
Yunming Chen
Keyword(s):  
Climate Change ◽  
Carbon Source ◽  
Soil Carbon ◽  
Arid Region ◽  
Forest Ecosystems ◽  
Co2 Concentration ◽  
Future Climate ◽  
Future Climate Change ◽  
Humid Region ◽  
Climate Transition

As global climate change has a large effect on the carbon cycle of forests, it is very important to understand how forests in climate transition regions respond to climate change. Specifically, the LPJ-GUESS (Lund-Potsdam-Jena General Ecosystem Simulator) model was used to simulate net ecosystem productivity (NEP) and soil heterotrophic respiration (Rh) dynamics of two forest ecosystems of different origins between 1951 and 2100, to quantitatively analyze the carbon source and sink functions and potential changes in soil carbon dynamics in arid and humid regions under future climate change, simulate the dynamics of forest net primary productivity (NPP) under different climatic factors, and analyze the sensitivity of forests in arid and humid regions to temperature, precipitation, and carbon dioxide (CO2) concentration. We found that: (1) in both the historical and future periods, the average NEP of both studied forests in the humid region was larger than that in the arid region, the carbon sink function of the humid region being predicted to become stronger and the arid zone possibly becoming a carbon source; (2) between 1951 and 2100, the forest soil Rh in the arid region was lower than that in the humid region and under future climate change, forest in the humid region may have higher soil carbon loss; (3) increasing temperature had a negative effect and CO2 concentration had a positive effect on the forests in the study area, and forests in arid areas are more sensitive to precipitation change. We believe our research could be applied to help policy makers in planning sustainable forest management under future climate change.

scholarly journals A regional carbon data assimilation system and its preliminary evaluation in East Asia

2015 ◽  
Vol 15 (2) ◽  
pp. 1087-1104 ◽  
Author(s):  
Z. Peng ◽  
M. Zhang ◽  
X. Kou ◽  
X. Tian ◽  
X. Ma
Keyword(s):  
Transport Model ◽  
Atmospheric Transport ◽  
Co2 Flux ◽  
Co2 Concentration ◽  
Preliminary Evaluation ◽  
Co2 Fluxes ◽  
Scaling Factors ◽  
Multi Scale ◽  
Co2 Concentrations ◽  
Inflation Factor

Abstract. In order to optimize surface CO2 fluxes at grid scales, a regional surface CO2 flux inversion system (Carbon Flux Inversion system and Community Multi-scale Air Quality, CFI-CMAQ) has been developed by applying the ensemble Kalman filter (EnKF) to constrain the CO2 concentrations and applying the ensemble Kalman smoother (EnKS) to optimize the surface CO2 fluxes. The smoothing operator is associated with the atmospheric transport model to constitute a persistence dynamical model to forecast the surface CO2 flux scaling factors. In this implementation, the "signal-to-noise" problem can be avoided; plus, any useful observed information achieved by the current assimilation cycle can be transferred into the next assimilation cycle. Thus, the surface CO2 fluxes can be optimized as a whole at the grid scale in CFI-CMAQ. The performance of CFI-CMAQ was quantitatively evaluated through a set of Observing System Simulation Experiments (OSSEs) by assimilating CO2 retrievals from GOSAT (Greenhouse Gases Observing Satellite). The results showed that the CO2 concentration assimilation using EnKF could constrain the CO2 concentration effectively, illustrating that the simultaneous assimilation of CO2 concentrations can provide convincing CO2 initial analysis fields for CO2 flux inversion. In addition, the CO2 flux optimization using EnKS demonstrated that CFI-CMAQ could, in general, reproduce true fluxes at grid scales with acceptable bias. Two further sets of numerical experiments were conducted to investigate the sensitivities of the inflation factor of scaling factors and the smoother window. The results showed that the ability of CFI-CMAQ to optimize CO2 fluxes greatly relied on the choice of the inflation factor. However, the smoother window had a slight influence on the optimized results. CFI-CMAQ performed very well even with a short lag-window (e.g. 3 days).

scholarly journals The relationships between termite mound CH<sub>4</sub>/CO<sub>2</sub> emissions and internal concentration ratios are species specific

2013 ◽  
Vol 10 (4) ◽  
pp. 2229-2240 ◽  
Author(s):  
H. Jamali ◽  
S. J. Livesley ◽  
L. B. Hutley ◽  
B. Fest ◽  
S. K. Arndt
Keyword(s):  
Co2 Emissions ◽  
Co2 Flux ◽  
Co2 Fluxes ◽  
Soil Co2 ◽  
Termite Mounds ◽  
Termite Species ◽  
Ch4 Flux ◽  
Gas Concentration ◽  
Significant Relationships ◽  
Species Specific

Abstract. We investigated the relative importance of CH4 and CO2 fluxes from soil and termite mounds at four different sites in the tropical savannas of northern Australia near Darwin and assessed different methods to indirectly predict CH4 fluxes based on CO2 fluxes and internal gas concentrations. The annual flux from termite mounds and surrounding soil was dominated by CO2 with large variations among sites. On a carbon dioxide equivalent (CO2-e) basis, annual CH4 flux estimates from termite mounds were 5- to 46-fold smaller than the concurrent annual CO2 flux estimates. Differences between annual soil CO2 and soil CH4 (CO2-e) fluxes were even greater, soil CO2 fluxes being almost three orders of magnitude greater than soil CH4 (CO2-e) fluxes at site. The contribution of CH4 and CO2 emissions from termite mounds to the total CH4 and CO2 emissions from termite mounds and soil in CO2-e was less than 1%. There were significant relationships between mound CH4 flux and mound CO2 flux, enabling the prediction of CH4 flux from measured CO2 flux; however, these relationships were clearly termite species specific. We also observed significant relationships between mound flux and gas concentration inside mound, for both CH4 and CO2, and for all termite species, thereby enabling the prediction of flux from measured mound internal gas concentration. However, these relationships were also termite species specific. Using the relationship between mound internal gas concentration and flux from one species to predict mound fluxes from other termite species (as has been done in the past) would result in errors of more than 5-fold for mound CH4 flux and 3-fold for mound CO2 flux. This study highlights that CO2 fluxes from termite mounds are generally more than one order of magnitude greater than CH4 fluxes. There are species-specific relationships between CH4 and CO2 fluxes from a mound, and between the inside mound concentration of a gas and the mound flux emission of the same gas, but these relationships vary greatly among termite species. Thus, there is no generic relationship that will allow for the accurate prediction of CH4 fluxes from termite mounds of all species, but given the data limitations, the above methods may still be used with caution.

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