| 1. |
- de la Rosa, Jose M., et al.
(författare)
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Contribution of black carbon in recent sediments of the Gulf of Cadiz : Applicability of different quantification methodologies
- 2011
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Ingår i: Quaternary International. - : Elsevier BV. - 1040-6182 .- 1873-4553. ; 243:2, s. 264-272
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Tidskriftsartikel (refereegranskat)abstract
- In the Southwestern Iberian Peninsula, vegetation fires are rather common, and produce a considerable amount of charred material that, due to erosion, is fluvially transported to the continental margins. The present study constitutes the first comparative assessment of the contribution of this charred material (generally black carbon, BC) to marine sediments of the inner continental shelf of the Gulf of Cadiz (GoC). Given the ambiguity of BC definition and the heterogeneity of quantification techniques, four of the most common and well established methodologies were applied to obtain a representative range of the BC content on four surface sediments: chemical-thermal oxidation (GBC), molecular markers (benzenopolycarboxylic acids, BPCA), thermogravimetry coupled to mass spectrometry (TG-DSC-QMS), and chemical oxidation with sodium chlorite. The BC results obtained for the GoC sediments are compared, and the applicability of each technique on marine sediments is discussed. The mean BC values of the four methods (4.4-14.4% total organic carbon) were within ranges previously reported for marine sediments from diverse origins. However, a large variability was observed within individual samples when comparing the BC results obtained with the four methods (relative standard deviation from 31% to 75%). The BPCA approach produced the highest BC values, whereas the GBC method the lowest. This reflects the analytical variability derived from the different windows composing the BC continuum. The results derived from the TG-DSC-QMS application generated certain uncertainties, despite the correction factor introduced to reduce the BC overestimation previously reported for this method. Considerable differences in the BC content of spatially close samples evidenced the complexity of coastal currents and sediment fluxes in the area, suggesting the existence of other factors affecting the BC distribution. The lack of correlation between the BC and TOC, as well as between the BC and lignin contents in all samples, ruled out the occurrence of charring artifacts. Preferential degradation and/or erosion of BC could explain the BC distribution in the area. The use of ancillary terrigenous biomarkers (lignin and inorganic silica) pointed to a preferential fluvial transport of the terrestrial organic matter and indicated that the longer distance from the source, the greater degradation of the OM. In addition, the northern dominant winds in the region may have favored the additional introduction of airborne transported BC in the marine system.
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| 2. |
- Fernandez-Anez, Nieves, et al.
(författare)
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Current Wildland Fire Patterns and Challenges in Europe : A Synthesis of National Perspectives
- 2021
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Ingår i: Air, Soil and Water Research. - : SAGE Publications. - 1178-6221. ; 14, s. 1-19
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Forskningsöversikt (refereegranskat)abstract
- Changes in climate, land use, and land management impact the occurrence and severity of wildland fires in many parts of the world. This is particularly evident in Europe, where ongoing changes in land use have strongly modified fire patterns over the last decades. Although satellite data by the European Forest Fire Information System provide large-scale wildland fire statistics across European countries, there is still a crucial need to collect and summarize in-depth local analysis and understanding of the wildland fire condition and associated challenges across Europe. This article aims to provide a general overview of the current wildland fire patterns and challenges as perceived by national representatives, supplemented by national fire statistics (2009–2018) across Europe. For each of the 31 countries included, we present a perspective authored by scientists or practitioners from each respective country, representing a wide range of disciplines and cultural backgrounds. The authors were selected from members of the COST Action “Fire and the Earth System: Science & Society” funded by the European Commission with the aim to share knowledge and improve communication about wildland fire. Where relevant, a brief overview of key studies, particular wildland fire challenges a country is facing, and an overview of notable recent fire events are also presented. Key perceived challenges included (1) the lack of consistent and detailed records for wildland fire events, within and across countries, (2) an increase in wildland fires that pose a risk to properties and human life due to high population densities and sprawl into forested regions, and (3) the view that, irrespective of changes in management, climate change is likely to increase the frequency and impact of wildland fires in the coming decades. Addressing challenge (1) will not only be valuable in advancing national and pan-European wildland fire management strategies, but also in evaluating perceptions (2) and (3) against more robust quantitative evidence.
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| 3. |
- Kupryianchyk, Darya, et al.
(författare)
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Sorption of hydrophobic organic compounds to a diverse suite of carbonaceous materials with emphasis on biochar
- 2016
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 144, s. 879-887
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Tidskriftsartikel (refereegranskat)abstract
- Carbonaceous materials like biochars are increasingly recognized as effective sorbent materials for sequestering organic pollutants. Here, we study sorption behavior of two common hydrophobic organic contaminants 2,2',5,5'-tetrachlorobiphenyl (CB52) and phenanthrene (PHE), on biochars and other carbonaceous materials (CM) produced at a wide range of conditions and temperatures from various feedstocks. The primary aim was to establish structure–reactivity relationships responsible for the observed variation in CM and biochar sorption characteristics. CM were characterized for their elemental composition, surface area, pore size distribution, aromaticity and thermal stability. Freundlich sorption coefficients for CB52 and PHE (i.e. LogKF,CB52 and KF,PHE, respectively) to CM showed a variation of two to three orders of magnitude, with LogKF,CB52 ranging from 5.12 ± 0.38 to 8.01 ± 0.18 and LogKF,PHE from 5.18 ± 0.09 to 7.42 ± 1.09. The highest LogKF values were observed for the activated CM, however, non-activated biochars produced at high temperatures (>700 °C) sorbed almost as strongly (within 0.2–0.5 Log units) as the activated ones. Sorption coefficients significantly increased with pyrolysis temperature, CM surface area and pore volume, aromaticity, and thermal stability, and decreased with H/C, O/C, (O + N)/C content. The results of our study contribute to the understanding of processes underlying HOC sorption to CM and explore the potential of CM as engineered sorbents for environmental applications.
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| 4. |
- Leiva-Suarez, Blanca, et al.
(författare)
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Soil amendment with sewage sludge-derived chars increases C-sequestration potential and provides N and P for plant growth during a second cropping period with Lolium perenne
- 2021
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Ingår i: European Journal of Soil Science. - : John Wiley & Sons. - 1351-0754 .- 1365-2389. ; 72:3, s. 1256-1269
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Tidskriftsartikel (refereegranskat)abstract
- Hydrothermal carbonization and dry pyrolysis transform sewage sludge (SS) into nitrogen- (N) and phosphorus- (P) rich hydrochars (Hyd) and pyrochars (Py), respectively, which may act as slow-release fertilizers with carbon (C) sequestration potential. Whereas this has been mostly studied with short-term experiments, this study focused on the cycling of char-derived N, P and C after ageing during a second grass cropping cycle. Lolium perenne was grown for 3 months in pots on soil mixed with 13C and 15N-enriched SS, Hyd or Py and allowed to age during a first cropping period of 10-month incubation. The δ15 of the plants confirmed that even during the second cropping, N derived from the amendments was plant accessible. Higher uptake of N from Hyd than from Py is explained by the lower biodegradability of the latter. Plant growth during the second cropping period was associated with a decrease of total P in all treatments, but only the soils with Hyd and Py evidenced an increase of Olsen P. Thus, during the second cropping, more insoluble P was mobilized from the carbonized residues than P needed for plant growth. Compared to control soils prepared with and without KNO3, higher biomass production was yielded with the amended soils. Hyd proved to have the highest longer-term N mobilization potential. Following the change in δ 13C of the soil, we observed that during the second incubation, independently of their aromaticity, all amendments and the native soil organic matter had comparable turnover rates, although the amount of organic matter with slower turnover added with the amendment increased with aromaticity. A rough estimation of the impact of thermal treatment of SS on its C-sequestration potential revealed no major differences between char types. The higher fertilization capacity of Hyd, however, indicates that it is a good candidate for soil amendment as long-term fertilization is combined with a long-term increase of the SOC pool.HighlightsMedium-term fertilization and C-sequestration potential of chars from sewage sludge were tested.Hydrochar (Hyd) and pyrochar (Py) provide N and P for plant growth during a second cropping period.Compared to soils with and without KNO3, Hyd and Py increase plant productivity of the second crop.On a long-term scale, native SOM, amended SS, its aged Hyd and Py show comparable turnover rates.
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| 5. |
- Medina, Jorge, et al.
(författare)
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Utilization of inorganic nanoparticles and biochar as additives of agricultural waste composting : Effects of end-products on plant growth, c and nutrient stock in soils from a mediterranean region
- 2021
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Ingår i: Agronomy. - : MDPI. - 2073-4395. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- This study was conducted to evaluate the effect of compost produced with agricultural residues and oat-based biochar, iron oxide and halloysite nanoparticles as additives of the process of composting on soil chemical properties, nutrient status and growth of ryegrass Lolium perenne L. For this, a 90-day mesocosm experiment was carried out under greenhouse conditions. Bare soil and a basal fertilization treatment were compared to soils amended with nonadditive compost (NA compost), compost supplied with oat-based biochar (Bioch compost), iron oxide nanoparticles (Fe compost), and halloysite nanoparticles (Ha compost). Compost supplied with nanoparticles and biochar combined were also considered. The incorporation of compost with or without additives increased the content of total C and N in soil, with N diminishing (total and mineral forms) and C/N modifications after 90 days. The addition of compost and co-composted treatments also increased the total contents of main nutrients such as Ca, K, P and S. Furthermore, the supply of additives into composting did not increase the concentration of trace toxic elements. At the end of the experiment, plant biomass increased by the addition of the different organic amendments, with the highest shoot biomass in soils amended with compost supplied with nanoparticles. These results suggest that the addition of compost based on agricultural residues with additives such as halloysite or biochar improves chemical properties and nutritional status of soil that favor and increase plant growth of Lollium perenne stablished in soils from the Mediterranean Region.
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| 6. |
- Paneque, Marina, et al.
(författare)
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Changes in the bio-availability of phosphorus in pyrochars and hydrochars derived from sewage sludge after their amendment to soils
- 2021
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Ingår i: Agronomy. - : MDPI. - 2073-4395. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- The expected shortage of global phosphate has enforced the search for alternative resources for P fertilizers. Therefore, the present study focuses on the turnover of phosphorus (P) of hydrochars and pyrochars derived from sewage sludge (SS) in soils during plant growth. We designed a pot experiment in which Lolium perenne L. was allowed to grow on a Calcic Cambisol amended with SS-derived chars. Hydrothermal carbonization (HTC) yielded the SS-hydrochars (200◦C, 260◦C; 30 min, 3 h), whereas the SS-pyrochars were obtained after dry pyrolysis (600◦C, 1 h). Increasing severity of HTC lowered the recovery of total P (PT) from the feedstock to 76%. The Olsen-P diminished from 4% PT in the untreated sludge to 1% PT in the hydrochars, whereas the pyrochars exhibited an Olsen-P between 3 and 6%. At the end of the pot experiment, the soils amended with pyrochars and with hydrochars produced at 200◦C contained more Olsen-P than the unamended soils, proving that P-rich chars can indeed serve as a P fertilizer. Part of the P sequestered in the chars turned into a mobile form during the experiment. After addition of our chars, the soil pH remained alkaline, allowing the conclusion that P could not have been solubilized through just abiotic processes. We suggest that biological and biochemical processes are involved in this mobilization. This work demonstrates that, in order to evaluate the efficiency of an organic amendment as a P fertilizer, the knowledge of their P availability alone is not sufficient and a better understanding of the biochemical processes involved in the cycling of its immobilized P is certainly required.
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