Organic Carbon Linkage with Soil Colloidal Phosphorus at Regional and Field Scales: Insights from Size Fractionation of Fine Particles

2021 ◽  
Author(s):  
Fayong Li ◽  
Qian Zhang ◽  
Erwin Klumpp ◽  
Roland Bol ◽  
Volker Nischwitz ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Fine Particles ◽  
Size Fractionation ◽  
Colloidal Phosphorus

scholarly journals Dynamics of organic carbon losses by water erosion after biocrust removal

2014 ◽  
Vol 62 (4) ◽  
pp. 258-268 ◽  
Author(s):  
Yolanda Cantón ◽  
Jose Raúl Román ◽  
Sonia Chamizo ◽  
Emilio Rodríguez-Caballero ◽  
María José Moro
Keyword(s):  
Organic Carbon ◽  
Fine Particles ◽  
Water Erosion ◽  
Strong Increase ◽  
Runoff Water ◽  
Erosion Rates ◽  
Soil Crusts ◽  
C Balance ◽  
Carbon Losses ◽  
Arid And Semiarid

Abstract In arid and semiarid ecosystems, plant interspaces are frequently covered by communities of cyanobacteria, algae, lichens and mosses, known as biocrusts. These crusts often act as runoff sources and are involved in soil stabilization and fertility, as they prevent erosion by water and wind, fix atmospheric C and N and contribute large amounts of C to soil. Their contribution to the C balance as photosynthetically active surfaces in arid and semiarid regions is receiving growing attention. However, very few studies have explicitly evaluated their contribution to organic carbon (OC) lost from runoff and erosion, which is necessary to ascertain the role of biocrusts in the ecosystem C balance. Furthermore, biocrusts are not resilient to physical disturbances, which generally cause the loss of the biocrust and thus, an increase in runoff and erosion, dust emissions, and sediment and nutrient losses. The aim of this study was to find out the influence of biocrusts and their removal on dissolved and sediment organic carbon losses. One-hour extreme rainfall simulations (50 mm h-1) were performed on small plots set up on physical soil crusts and three types of biocrusts, representing a development gradient, and also on plots where these crusts were removed from. Runoff and erosion rates, dissolved organic carbon (DOC) and organic carbon bonded to sediments (SdOC) were measured during the simulated rain. Our results showed different SdOC and DOC for the different biocrusts and also that the presence of biocrusts substantially decreased total organic carbon (TOC) (average 1.80±1.86 g m-2) compared to physical soil crusts (7.83±3.27 g m-2). Within biocrusts, TOC losses decreased as biocrusts developed, and erosion rates were lower. Thus, erosion drove TOC losses while no significant direct relationships were found between TOC losses and runoff. In both physical crusts and biocrusts, DOC and SdOC concentrations were higher during the first minutes after runoff began and decreased over time as nutrient-enriched fine particles were washed away by runoff water. Crust removal caused a strong increase in water erosion and TOC losses. The strongest impacts on TOC losses after crust removal occurred on the lichen plots, due to the increased erosion when they were removed. DOC concentration was higher in biocrust-removed soils than in intact biocrusts, probably because OC is more strongly retained by BSC structures, but easily blown away in soils devoid of them. However, SdOC concentration was higher in intact than removed biocrusts associated with greater OC content in the top crust than in the soil once the crust is scraped off. Consequently, the loss of biocrusts leads to OC impoverishment of nutrient-limited interplant spaces in arid and semiarid areas and the reduction of soil OC heterogeneity, essential for vegetation productivity and functioning of this type of ecosystems.

Positive sampling artifacts of organic carbon fractions for fine particles and nanoparticles in a tunnel environment

2012 ◽  
Vol 54 ◽  
pp. 225-230 ◽  
Author(s):  
Chong-Shu Zhu ◽  
Chuen-Jinn Tsai ◽  
Sheng-Chieh Chen ◽  
Jun-Ji Cao ◽  
Gwo-Dong Roam
Keyword(s):  
Organic Carbon ◽  
Fine Particles ◽  
Carbon Fractions ◽  
Sampling Artifacts ◽  
Organic Carbon Fractions

scholarly journals CARACTERÍSTICAS GEOQUÍMICAS DE LOS SEDIMENTOS SUPERFICIALES DE LA LAGUNA LA RESTINGA, ISLA DE MARGARITA, VENEZUELA.

2016 ◽  
Author(s):  
Juan Velásquez ◽  
Arístide Márquez ◽  
Ivis Fermín ◽  
Fabiola López ◽  
Deudedit Hernández ◽  
...  
Keyword(s):  
Organic Matter ◽  
Calcium Carbonate ◽  
Organic Carbon ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Fine Particles ◽  
Sandy Loam ◽  
Aliphatic Hydrocarbons ◽  
Main Body ◽  
Total Organic Matter

This research aims to evaluate some chemical parameters of surface sediments of La Restinga coastal lagoon, located in Margarita Island, Nueva Esparta State, Venezuela. Using classical methodology for geochemical studies, grain size and texture of sediment percentage of organic carbon and total organic matter, as well as calcium carbonate were analyzed. Additionally, the concentrations of total nitrogen, total phosphorus and aliphatic hydrocarbons were determined. The results showed that in La Restinga lagoon sedimentary sandy texture dominate above sandy-loam and sandy-clay. The percentages of total organic carbon, total organic matter and calcium carbonate respectively varied as follows: 1.70-25.53%, 11.10-82.10% and 2.93-44.01%. Concentrations of 282.10-1571.80 mg kg-1 in total nitrogen, 419.50-2033.70 mg kg-1 in total phosphorus and 5.65-63.18 mg kg-1 for aliphatic hydrocarbons were determined. The total organic matter in the lagoon La Restinga is distributed based on the fine particles of sediment and the presence of mangroves, in turn calcium carbonate, was associated mainly to contributions from organisms with calcareous shell. The low values of the ratio NT/PT (under 5) suggest limitation of nitrogen in the ecosystem, and natural or anthropogenic enrichment of phosphorus in the sediment. The levels found of certain aliphatic hydrocarbons, are not considered as contamination levels as established by CARIPOL (1980), except in the eastern end of the main body of the lagoon. According to the points made in this study, we can infer that La Restinga Lagoon showed symptoms of degradation product of human intervention in the ecosystem.

scholarly journals Size-resolved measurements of brown carbon and estimates of their contribution to ambient fine particle light absorption based on water and methanol extracts

2013 ◽  
Vol 13 (7) ◽  
pp. 18233-18276 ◽  
Author(s):  
J. Liu ◽  
M. Bergin ◽  
H. Guo ◽  
L. King ◽  
N. Kotra ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Light Absorption ◽  
Fine Particle ◽  
Elemental Carbon ◽  
Fine Particles ◽  
Water Soluble ◽  
Rural Site ◽  
Brown Carbon ◽  
Methanol Extracts ◽  
Carbon Absorption

Abstract. Light absorbing organic carbon, often termed brown carbon, has the potential to significantly contribute to the visible light absorption budget, particularly at shorter wavelengths. Currently, the relative contributions of particulate brown carbon to light absorption, as well as the sources of brown carbon are poorly understood. With this in mind field measurements were made at both urban (Atlanta), and rural (Yorkville) sites in Georgia. Measurements in Atlanta were made at both a central site and a road side site adjacent to a main highway near the city center. Fine particle brown carbon optical absorption is estimated based on Mie calculations using direct size resolved measurements of chromophores in filter extracts. Size-resolved atmospheric aerosol samples were collected using a cascade impactor and analyzed for water-soluble organic carbon (WSOC), organic and elemental carbon (OC and EC), and solution light absorption spectra of water and methanol extracts. Methanol extracts were more light-absorbing than water extracts for all size ranges and wavelengths. Absorption refractive indices of the organic extracts were calculated from solution measurements for a range of wavelengths and used with Mie theory to predict the light absorption by fine particles comprised of these components, under the assumption that brown carbon and other aerosol components were externally mixed. For all three sites, chromophores were predominately in the accumulation mode with an aerodynamic mean diameter of 0.5 μm, an optically effective size range resulting in predicted particle light absorption being a factor of 2 higher than bulk solution absorption. Fine particle absorption was also measured with a Multi-Angle Absorption Photometer (MAAP) and seven-wavelength Aethalometer. Scattering-corrected aethalometer and MAAP absorption were in good agreement at 670 nm and Mie-estimated absorption based on size-resolved EC data were within 30% of these optical instruments. When applied to solution measurements, at all sites, Mie-predicted brown carbon absorption at 350 nm contributed a significant fraction (20 to 40%) relative to total light absorption, with highest contributions at the rural site where organic to elemental carbon ratios were highest. Brown carbon absorption, however, was highest by the roadside site due to vehicle emissions. The multi-wavelength aethalometer did not detect brown carbon, having an absorption Ångstrom exponent near one. Although the results are within the estimated Aethalometer uncertainties, the direct measurement of brown carbon in solution definitively shows that it is present and this Mie analysis suggests it is optically important in the near UV range in both a rural and urban environment during summer when biomass burning emissions are low.

scholarly journals Source apportionment of fine organic carbon at an urban site of Beijing using a chemical mass balance model

2021 ◽  
Vol 21 (9) ◽  
pp. 7321-7341
Author(s):  
Jingsha Xu ◽  
Di Liu ◽  
Xuefang Wu ◽  
Tuan V. Vu ◽  
Yanli Zhang ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Mass Balance ◽  
Source Apportionment ◽  
Biomass Burning ◽  
Coal Combustion ◽  
Fine Particles ◽  
Inorganic Ions ◽  
Balance Model ◽  
Urban Site ◽  
Chemical Mass Balance

Abstract. Fine particles were sampled from 9 November to 11 December 2016 and 22 May to 24 June 2017 as part of the Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-China) field campaigns in urban Beijing, China. Inorganic ions, trace elements, organic carbon (OC), elemental carbon (EC), and organic compounds, including biomarkers, hopanes, polycyclic aromatic hydrocarbons (PAHs), n-alkanes, and fatty acids, were determined for source apportionment in this study. Carbonaceous components contributed on average 47.2 % and 35.2 % of total reconstructed PM2.5 during the winter and summer campaigns, respectively. Secondary inorganic ions (sulfate, nitrate, ammonium; SNA) accounted for 35.0 % and 45.2 % of total PM2.5 in winter and summer. Other components including inorganic ions (K+, Na+, Cl−), geological minerals, and trace metals only contributed 13.2 % and 12.4 % of PM2.5 during the winter and summer campaigns. Fine OC was explained by seven primary sources (industrial and residential coal burning, biomass burning, gasoline and diesel vehicles, cooking, and vegetative detritus) based on a chemical mass balance (CMB) receptor model. It explained an average of 75.7 % and 56.1 % of fine OC in winter and summer, respectively. Other (unexplained) OC was compared with the secondary OC (SOC) estimated by the EC-tracer method, with correlation coefficients (R2) of 0.58 and 0.73 and slopes of 1.16 and 0.80 in winter and summer, respectively. This suggests that the unexplained OC by the CMB model was mostly associated with SOC. PM2.5 apportioned by the CMB model showed that the SNA and secondary organic matter were the two highest contributors to PM2.5. After these, coal combustion and biomass burning were also significant sources of PM2.5 in winter. The CMB results were also compared with results from the positive matrix factorization (PMF) analysis of co-located aerosol mass spectrometer (AMS) data. The CMB model was found to resolve more primary organic aerosol (OA) sources than AMS-PMF, but the latter could apportion secondary OA sources. The AMS-PMF results for major components, such as coal combustion OC and oxidized OC, correlated well with the results from the CMB model. However, discrepancies and poor agreements were found for other OC sources, such as biomass burning and cooking, some of which were not identified in AMS-PMF factors.

scholarly journals Effects of Biochar on Soil Aggregation and Distribution of Organic Carbon Fractions in Aggregates

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1431
Author(s):  
Ming-Hsi Lee ◽  
Ed-Haun Chang ◽  
Chia-Hsing Lee ◽  
Jyun-Yuan Chen ◽  
Shih-Hao Jien
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Fine Particles ◽  
Dynamic Change ◽  
Soil Aggregation ◽  
Organic C ◽  
Carbon Fractions ◽  
Sequestration Potential ◽  
Aggregation Processes ◽  
Organic Carbon Fractions

Soil aggregates are among crucial factors for determining both the quality and erosion resistance of soils. Biochar is a soil amendment that has seen increasing use to improve specific soil properties, mainly the physical structure and the preserving capacity of water and nutrients, as well as sequestration of soil organic carbon. In this study, we applied the rice husk biochar (RHB) and cattle manure compost (COM) in a sandy loam rural soil, which is widely distributed in southern Taiwan, to investigate the combined effects of the biochar and compost on soil aggregation and dynamic change of organic carbon fractions. Through our incubation experiment, both biochar and compost could promote the soil aggregation after eight weeks incubation. The total amounts of macroaggregates (MaAs, >2.0 mm) and mesoaggregates (MeAs, 0.25–2.0 mm) increased by 1.3–9%. During aggregation processes, a considerably greater amount of the soil organic carbon was found to enrich mainly in MaAs and MeAs in all treatments. The COM addition in the soil further promotes organic carbon enrichment in microaggregates (MiAs, <0.25 mm) + fine particles and MeAs after incubation. Increasing labile organic C (LOC) fractions were significantly found in MaAs and MeAs during aggregation processes, whereas decreasing LOC fractions were found in MiAs. The input of fresh organic matter (RHB and COM) initial acts as binding agents in MiAs, and then further enhances the formation of MeAs and MaAs gradually. In conclusion, RHB promotes the physical protection of organic C by increasing soil aggregation and is hence a management option to enhance the C sequestration potential.

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