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Soil microbes' activity is very important for forming of the nutrient stock and, soil structure, as well as the carbon cycle simulation. This is particularly crucial for deep soil layers. Effect of soil microbes on the rate of acc...
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Soil microbes' activity is very important for forming of the nutrient stock and, soil structure, as well as the carbon cycle simulation. This is particularly crucial for deep soil layers. Effect of soil microbes on the rate of accumulation and decomposition of the soil organic carbon (SOC) has been found for different regions. However, it is known still a little on the SOC performance for different decomposition rates and its relation to the microbial activity in the saline-alkali desert ecosystem. Therefore, the main task of our research was investigation of interrelation between the soil organic carbon and microbial carbon (SMC) at different depths in the original saline-alkali Gurbantunggiit Desert. Our results showed in the soil vertical profile, (i) SMC and SOC presented a very significant positive linear correlation (R-2 = 0.63, P = 0.0003); (ii) SMC exhibited two obvious changed-interfaces - 20 cm and 80 cm, the SMC at depth of 0-20 cm, 20-80 cm and 80-500 cm was 2.24-3.06, 0.19-0.72, and 0.0017-0.0097 mg kg(-1), respectively; (iii) in the depth of 0-20 cm and 20-80 cm, the SMC had highly significant difference (P < 0.0001) and at 20-80 cm and 80-500 cm, significant difference (P = 0.013); (iv) according to the soil division based on the SMC, SOC also had some certain stratification; (v) organic carbon layers can be respectively defined according to different microbial activities as active, inert, and stable organic carbon pool. Therefore, these three kinds of organic carbon pools can be quantitatively measured by analyzing their location at different depths of the soil profile.
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We have assessed the content of different forms of organic carbon (total, bioaccessible, and assimilated) in the water of the Dnieper river in the area of the water intake of the Dnieper water station and in the water after all tr...
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We have assessed the content of different forms of organic carbon (total, bioaccessible, and assimilated) in the water of the Dnieper river in the area of the water intake of the Dnieper water station and in the water after all treatment stages used. The article has investigated seasonal changes in the content of different forms of organic carbon and the impact of water treatment on these indicators.
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Concentrations of dissolved and particulate organic carbon (DOC and POC) were documented in 1996-1997 at 4 different trophic state stations in Donghu Lake, a typical shallow eutro- phic lake along the Changjiang River's middle rea...
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Concentrations of dissolved and particulate organic carbon (DOC and POC) were documented in 1996-1997 at 4 different trophic state stations in Donghu Lake, a typical shallow eutro- phic lake along the Changjiang River's middle reaches. The mean concentrations of DOC were 15.11 ± 3.26, 15.19±4.24, 14.27±3.43, and 13.±3.30 mg/L in Station I, II, III, and IV, respective- ly. The DOC concentrations of the studied area were very similar to that in other lakes along the Changjiang River's middle reaches.
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Constructed wetland is a common measure for water purification and biodiversity conservation, but the mechanism of carbon storage is still unclear. Here, we researched the content and composition of soil organic carbon (SOC) and t...
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Constructed wetland is a common measure for water purification and biodiversity conservation, but the mechanism of carbon storage is still unclear. Here, we researched the content and composition of soil organic carbon (SOC) and the influencing factors in surface sediment in surface flow constructed wetlands (SFCW) and subsurface flow constructed wetlands (SSFCW). Results showed that the content and storage of SOC in SSFCW were significantly higher than those in SFCW. However, the higher proportion of light fraction organic carbon (LFOC) and lower proportion of heavy fraction organic carbon (HFOC) in SSFCW indicated that SSFCW had less stable organic carbon storage than SFCW. The composition of SOC in the two types of constructed wetlands was mainly affected by total nitrogen, which suggesting carbon-nitrogen coupling in constructed wetlands. The abundant microbial species in SSFCW and their positive correlation with SOC could explain the higher carbon storage in SSFCW than in SFCW. In addition, plant biomass was the principle factor limiting LFOC proportion in SFCW, while it was moisture content in SSFCW. The study has important implications for understanding and management of ecological function of carbon sequestration in contrasted wetlands, and also provides a special perspective to understand the carbon storage mechanism in wetlands.
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Several experimental methods have been developed to fractionate soil organic carbon (SOC) into functional sub-pools. However, which fractions had the potential to better reflect the SOC dynamics responding to fertilisation are sti...
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Several experimental methods have been developed to fractionate soil organic carbon (SOC) into functional sub-pools. However, which fractions had the potential to better reflect the SOC dynamics responding to fertilisation are still under discussion. Thus, we compared different SOC fractions (microbial biomass carbon, MBC; dissolved organic carbon, DOC; permanganate-oxidisable carbon, POXC; particle organic carbon, POC, and aggregation organic carbon fractions) and the soil respiration rate in a wheat-corn rotation field after 40 years of manure and N fertilisation in North China to search for the most sensitive SOC fractions to fertilisation. Manure increased the organic carbon (OC) contents of all the soil fractions (26.5 to 362.8%) and the POC (18.0 to 43.7%) and macro-aggregation percentages (3.0 to 4.4%), which indicated an increasing physical-protected aggregated OC fraction. N fertilisation alone slightly increased the OC contents of all the soil fractions and DOC percentage, but decreased the macro-aggregation OC percentage, which suggests the increasing possibility that the SOC is exposed to microbial communities causing a decreasing aggregation formation. However, when a high level of both the manure and N fertiliser were applied, the excessive N in the soil stimulates the soil microbial activity and decreases the SOC content comparing it to the same level of the manure fertiliser addition. ? 2022 Czech Academy of Agricultural Sciences. All rights reserved.
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Zooplankton are an important link between trophic levels in aquatic ecosystems, and their response to organic carbon is likely to have broad implications for lake food webs. The main objective of the research was to determine vari...
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Zooplankton are an important link between trophic levels in aquatic ecosystems, and their response to organic carbon is likely to have broad implications for lake food webs. The main objective of the research was to determine variations in zooplankton communities against the background of the structural heterogeneity of the lake and to link the observed patterns to the organic carbon content of the lake water. Spatial differences were noted in the organic carbon content of the lake water. Higher total organic carbon (TOC) and dissolved organic carbon (DOC) concentrations were recorded in the vegetated littoral area than in the lake pelagic zone. Zooplankton distribution and response to organic carbon content varied among habitats. At sites covered by plants, DOC and the bacterial sized fraction of particulate organic carbon were positively correlated with zooplankton biomass. In reeds, the grazing pressure by zooplankton on bacterial sized organic carbon was particularly strong. This implied that the microbial carbon link could be an important food web component providing carbon to higher trophic levels in areas covered by plants. This assumption corresponded well with the results of redundancy analysis (RDA).
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Particulate matter (PM), including PM10 and PM2.5, is one of the major impacts on air quality, visibility, climate change, earth radiation balance, and public health. Organic carbon (OC) and elemental carbon (EC) are the major com...
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Particulate matter (PM), including PM10 and PM2.5, is one of the major impacts on air quality, visibility, climate change, earth radiation balance, and public health. Organic carbon (OC) and elemental carbon (EC) are the major components of PM. 804 samples (PM10 and PM2.5) were simultaneously collected from six urban sites covering 3 districts in Baotou, in January, April, September, and November 2014. As to a long-term study on the effects of carbonaceous aerosol, data were collected annually at Environmental Protection Agency of Baotou (EPB). The concentrations of PM10 and PM2.5, the spatial distribution and content of OC and EC, the relationship between OC and EC, and the formation of secondary organic carbon (SOC) have been investigated. The findings indicated that the concentrations of these particle matter are higher than that in US or European standards. The average concentrations of OC in PM10 and PM2.5 follow the order: January> November> April > September; and for EC in PM10 and PM2.5 follow the order: January> November> September > April. Affected by metrological factors, it was indicated that high wind speed and low relative humidity were beneficial for removal of OC and EC in January and November. Pearson correlations and cluster analysis on OC and EC concentrations in PM10 and PM2.5 with gaseous pollutants (SO2, NO2, and CO) suggested that OC shared the same emission sources with SO2 and CO from combustion, while EC's sources mainly came from vehicles exhaust and combustion which contributed to NO2 as well. The OC concentration is mainly primary in warm months, while it appears secondary in cold months in Baotou. There is a common characteristic among the cities with higher SOC in winter, wherever the coal combustion can lead to the severe pollution. This work is important for the construction of the database of OC and EC concentrations in PM10 and PM2.5 at spatial and time intervals, and it can provide scientific suggestion for similar PM atmospheric pollutant control and air quality improvement in Baotou. (C) 2016 Elsevier B.V. All rights reserved.
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More than 400 PM_(2.5)samples were collected at four urban sites in Beijing (BJ), Tianjin (TJ), Shijiazhuang (SJZ), and Chengde (CD), and also one site in Shangdianzi (SDZ), which was used as a regional background station, over fo...
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More than 400 PM_(2.5)samples were collected at four urban sites in Beijing (BJ), Tianjin (TJ), Shijiazhuang (SJZ), and Chengde (CD), and also one site in Shangdianzi (SDZ), which was used as a regional background station, over four seasons from 2009 to 2010. The organic carbon (OC) and elemental carbon (EC) in each sample were analyzed. The average annual concentrations were 71.8-191.2 μg m~(-3) for PM_(2.5), 10.8-26.4 μg m~(-3) for OC, and 3.9-9.7 μg m~(-3) for EC at the five sites. OC and EC concentrations were lower in the spring and summer and much higher in the autumn and winter, mainly due to aerosol emissions from additional fuel combustion for heating. OC/EC ratios were lowest in the summer and highest in the winter at SDZ, BJ, TJ, and SJZ. These seasonal trends indicate that the characteristics of carbonaceous aerosol pollution were spatially similar and season-dependent in the plain area of Beijing, Tianjin, and Hebei (BTH). An EC tracer method was used to calculate the concentrations for secondary organic carbon (SOC); SOC concentrations were also higher in the autumn and winter and lowest during the summer at all five sites. A stable atmosphere and low temperatures, which were more frequent during the winter and autumn, facilitated the accumulation of air pollutants and accelerated the condensation or adsorption of volatile organic compounds in the BTH area. Over the past ten years (1999-2009), Beijing had observed a decrease in the EC concentrations during every season and a remarkable reduction in aerosol emissions from coal combustion for heating.
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Carbonaceous aerosols are linked to severe haze and health effects, while its origins remain still unclear over China. PM2.5 samples covering four seasons from Jan. 2016 to Jan. 2017 were collected at six sites in Chifeng, a repre...
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Carbonaceous aerosols are linked to severe haze and health effects, while its origins remain still unclear over China. PM2.5 samples covering four seasons from Jan. 2016 to Jan. 2017 were collected at six sites in Chifeng, a representative agro-pastoral transitional zone of North China focusing on the characteristics and sources of organic carbon (OC) and elemental carbon (EC). The annual averages of OC, EC were 9.00 +/- 7.24 mu g m(-3), 1.06 +/- 0.79 mu g m(-3) with site Songshan in coal mining region exhibited significantly enhanced levels. The residential heating emissions, air stagnation, and secondary organic formation all contributed the higher OC, EC levels in winter. Meanwhile, the impacts from open biomass burning were most intensive in spring. The retroplumes via Lagrangian model highlighted a strong seasonality of regional sources which had more impacts on EC increases. The Positive Matrix Factorization (PMF) model resolved six primary sources, namely, coal combustion, biomass burning, industrial processes, oil combustion, fugitive dust, and fireworks. Coal combustion and biomass burning comprised large fractions of OC (30.57%, 30.40%) and EC (23.26%, 38.47%) across the sites, while contributions of industrial processes and oil combustion clearly increased in the sites near industrial sources as smelters. PMF and EC tracer method gave well correlated (r=0.65) estimates of Secondary OC (SOC). The proportion of coal combustion and SOC were more enhanced along with PM2.5 elevation compared to other sources, suggesting their importances during the pollution events. (C) 2019 Elsevier Ltd. All rights reserved.
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