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We provide here an overview of the remarkable life and outstanding research of David (Dave) Charles Fork (March 4, 1929-December 13, 2021) in oxygenic photosynthesis. In the words of the late Jack Edgar Myers, he was a top 'photosynthetiker'. His research dealt with novel findings on light absorption, excitation energy distribution, and redistribution among the two photosystems, electron transfer, and their relation to dynamic membrane change as affected by environmental changes, especially temperature. David was an attentive listener and a creative designer of experiments and instruments, and he was also great fun to work with. He is remembered here by his family, coworkers, and friends from around the world including Australia, France, Germany, Japan, Sweden, Israel, and USA.
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Oxigênio , Fotossíntese , Humanos , Austrália , Transporte de Elétrons , AlemanhaRESUMO
A Chlamydomonas reinhardtii mutant lacking CGL71, a thylakoid membrane protein previously shown to be involved in photosystem I (PSI) accumulation, exhibited photosensitivity and highly reduced abundance of PSI under photoheterotrophic conditions. Remarkably, the PSI content of this mutant declined to nearly undetectable levels under dark, oxic conditions, demonstrating that reduced PSI accumulation in the mutant is not strictly the result of photodamage. Furthermore, PSI returns to nearly wild-type levels when the O2 concentration in the medium is lowered. Overall, our results suggest that the accumulation of PSI in the mutant correlates with the redox state of the stroma rather than photodamage and that CGL71 functions under atmospheric O2 conditions to allow stable assembly of PSI. These findings may reflect the history of the Earth's atmosphere as it transitioned from anoxic to highly oxic (1-2 billion years ago), a change that required organisms to evolve mechanisms to assist in the assembly and stability of proteins or complexes with O2-sensitive cofactors.
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Proteínas de Algas/metabolismo , Chlamydomonas reinhardtii/metabolismo , Proteínas de Cloroplastos/metabolismo , Complexo de Proteína do Fotossistema I/metabolismo , Proteínas das Membranas dos Tilacoides/metabolismo , Proteínas de Algas/genética , Chlamydomonas reinhardtii/genética , Proteínas de Cloroplastos/genética , Transporte de Elétrons/genética , Transporte de Elétrons/efeitos da radiação , Immunoblotting , Cinética , Luz , Mutação , Oxirredução , Oxigênio/metabolismo , Fotossíntese/genética , Fotossíntese/efeitos da radiação , Complexo de Proteína do Fotossistema I/genética , Proteínas das Membranas dos Tilacoides/genética , Tilacoides/metabolismoRESUMO
We present here the life and work of Shmuel Malkin (1934-2017), an accomplished scientist and a gifted musician who touched the lives of many around the world. His early scientific work addressed the dynamics of light harvesting and electron transport in photosynthesis. Later, he used photoacoustic and photothermal methodologies to explore all aspects of photosynthesis. As a musician, Shmuel played the piano often for family and friends but after his formal retirement, he produced a body of original musical compositions, many of which were performed publicly. Throughout his life, Shmuel was a caring and deeply thoughtful man, respected and loved by colleagues, family, and friends. This tribute presents a summary of Shmuel's work as well as remembrances written by his wife, Nava Malkin, their son, Eyal Malkinson, and many of his colleagues: Michael Havaux from France; Sandra and Marcel Jansen from Ireland; David Cahen, Marvin Edelmann, Joop and Onnie de Graaf, Jonathan Gressel, Uri Pick, Yona Siderer, and Elisha Tel-Or from Israel; Ulrich Schreiber from Germany; James Barber and Alison Telfer from the UK; Govindjee, Stephen Herbert and Thomas Sharkey from the USA. Minnie Ho and Iris Malkin of the USA wrote contributions about Shmuel's music.
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Técnicas Fotoacústicas , Fotossíntese , História do Século XX , História do Século XXI , Humanos , MúsicaRESUMO
In order to understand the physiological mechanism of potassium (K) application in enhancing sugar content of vegetable soybean seeds, pot experiments were conducted in 2014 and 2015 with two vegetable soybean (Glycine max L. Merr.) cultivars (c.v. Zhongkemaodou 1 and c.v. 121) under normal rate of nitrogen and phosphorus application. Three potassium (K) fertilization treatments were imposed: No K application (K0), 120 kg K2SO4 ha-1 at seeding (K1), and 120 kg K2SO4 ha-1 at seedling + 1% K2SO4 foliar application at flowering (K2). Contents of indole-3-acetic acid (IAA), gibberellins (GA), cytokinins (ZR) and abscisic acid (ABA) in seeds were determined from 4 to 8 weeks after flowering. K fertilization increased the contents of IAA, GA, ZR, soluble sugar, sucrose and fresh pod yield, but reduced ABA content consistently. When the contents of soluble sugar and sucrose reached the highest level at 7 weeks after flowering for the 2 cultivars, the contents of IAAãGAãZR all reached the lowest level in general. The content of ABA in seed was negatively correlated with the sucrose content (P < 0.01, r = -0.749**, -0.768** in 2014 and -0.535**, -0.791** in 2015 for c.v.121 and c.v. Zhongkemaodou 1 respectively). The changes in ratio of the ABA to (IAA + GA + ZR) from 4 to 8 weeks after flowering affected by K application were coincident to the changes of sucrose accumulation. The reduced ratio of ABA/(IAA + GA + ZR) affected by K nutrition particularly reduced abscisic acid content plays a critical role in enhancing sucrose content, which might be a partial mechanism involved in K nutrition to improve the quality of vegetable soybean.
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Ácido Abscísico/metabolismo , Glycine max/metabolismo , Potássio/metabolismo , Potássio/farmacologia , Sementes/química , Sementes/metabolismo , Sacarose/metabolismo , Citocininas/metabolismo , Fertilizantes , Flores/metabolismo , Giberelinas/metabolismo , Ácidos Indolacéticos/metabolismo , Nitrogênio/metabolismo , Reguladores de Crescimento de Plantas , Plântula , Sementes/efeitos dos fármacos , Glycine max/efeitos dos fármacos , Fatores de Tempo , Verduras/metabolismoRESUMO
BACKGROUND: Recent findings suggest that individuals living near the coast are healthier than those living inland. Here we investigated whether this may be related to higher levels of physical activity among coastal dwellers in England, arising in part as a result of more visits to outdoor coastal settings. METHOD: Participants (n=183,755) were drawn from Natural England's Monitor of Engagement with the Natural Environment Survey (2009-2012). Analyses were based on self-reported physical activity for leisure and transport. RESULTS: A small, but significant coastal proximity gradient was seen for the likelihood of achieving recommended guidelines of physical activity a week after adjusting for relevant area and individual level controls. This effect was statistically mediated by the likelihood of having visited the coast in the last seven days. Stratification by region, however, suggested that while the main effect was relatively strong for west coast regions, it was not significant for those in the east. CONCLUSIONS: In general, our findings replicate and extend work from Australia and New Zealand. Further work is needed to explain the marked regional differences in the relationship between coastal proximity and physical activity in England to better understand the coast's potential role as a public health resource.
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Exercício Físico , Atividade Motora , Oceanos e Mares , Adolescente , Adulto , Idoso , Inglaterra , Meio Ambiente , Feminino , Nível de Saúde , Inquéritos Epidemiológicos , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Saúde Pública , Adulto JovemRESUMO
PURPOSE: The National Health Service (NHS) in the United Kingdom (UK) is aiming to be carbon net zero by 2040 to help limit the dangerous effects of climate change. Radiotherapy contributes to this with potential sources quantified here. METHOD: Activity data for 42 patients from within the breast IMRT and prostate VMAT pathways were collected. Data for 20 prostate patients was also collected from 3 other centres to enable cross centre comparison. A process-based, bottom-up approach was used to calculate the carbon footprint. Additionally, patients were split into pre-COVID and COVID groups to assess the impact of protocol changes due to the pandemic. RESULTS: The calculated carbon footprint for prostate and breast pre-COVID were 148 kgCO2e and 101 kgCO2e respectively, and 226 kgCO2e and 75 kgCO2e respectively during COVID. The energy usage by the linac during treatment for a total course of radiotherapy for prostate treatments was 2-3 kWh and about 1 kWh for breast treatments. Patient travel made up the largest proportion (70-80%) of the calculated carbon footprint, with linac idle power second with â¼ 10% and PPE and SF6 leakage were both between 2 and 4%. CONCLUSION: These initial findings highlight that the biggest contributor to the external beam radiotherapy carbon footprint was patient travel, which may motivate increased used of hypofractionation. Many assumptions and boundaries have been set on the data gathered, which limit the wider application of these results. However, they provide a useful foundation for future more comprehensive life cycle assessments.
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COVID-19 , Pegada de Carbono , Masculino , Humanos , Medicina Estatal , COVID-19/radioterapia , Reino Unido , PróstataRESUMO
The beneficial effect of crop residue amendment on soil organic carbon (SOC) stock and stability depends on the functional response of soil microbial communities. Here we synchronized microbial metagenomic analysis, nuclear magnetic resonance and plant-15N labeling technologies to gain understanding of how microbial metabolic processes affect SOC accumulation in responses to differences in N supply from residues. Residue amendment brought increases in the assemblage of genes involved in C-degradation profiles from labile to recalcitrant C compounds as well as N mineralization. The N mineralization genes were correlated with the C and N accumulation in the particulate and mineral-associated C pools, and plant-derived aliphatic forms of SOC. Thus, the combined C and N metabolic potential of the microbial community transforms residue into persistent organic compounds, thereby increasing C and N sequestration in stable SOC pools. This study emphasizes potential microbially mediated mechanisms by which residue N affects C sequestration in soils.
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Microbiota , Solo , Carbono , Nitrogênio , Solo/química , Microbiologia do SoloRESUMO
Nitrogen dioxide (NO(2))-induced responses in wild type (wt) and salicylic acid (SA)-altering Arabidopsis mutants snc1 (suppressor of npr1-1, constitutive) with high SA level, transgenic line nahG with low SA level, npr1-1 (nonexpressor of PR gene) with SA signaling blockage and double mutant snc1nahG plants, were investigated. All mutant lines except sncl showed that NO(2) exposure at 0.25 microL L(-1) increased chlorophyll content and biomass accumulation, elevated photosynthetic rate, and decreased MDA content compared to their respective controls. The sncl plants were similar to the control plants for these measured indices. NO(2) exposure at 0.5 microL L(-1) and higher doses caused injury to wt, nahG, npr1-1 and snc1nahG plants, whereas the snc1 plants exhibited a stronger tolerance. To evaluate the resistance mechanism, we further investigated the changes in the mutants exposed to 1 microL L(-1) of NO(2) in relation to endogenous SA level, antioxidant capacity and redox status. The collected data demonstrated that the NO(2) tolerance in snc1, with a high SA level, was tightly linked to the increased antioxidant capacity and decreased oxidative stress. This suggests that SA may play an important protective function in plant response to NO(2) stress.
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Arabidopsis/efeitos dos fármacos , Dióxido de Nitrogênio/farmacologia , Ácido Salicílico/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Clorofila/metabolismo , Mutação , Estresse Oxidativo , Fotossíntese/efeitos dos fármacos , Plantas Geneticamente Modificadas/efeitos dos fármacos , Transdução de SinaisRESUMO
The goal of this research work was to determine widespread impact kiln-produced hardwood biochar has upon temperate agricultural soil characteristics in a long-term field experiment. This dataset is supplementary to the submitted research by [1] and presents select physical and chemical characteristics of the biochar and field plots amended with hardwood biochar. Data on soil gravimetric moisture content (GMC), soil acidity and soil nitrate-N concentration at lower depth of soil under different biochar application rates is presented. Fourier Transform Infrared (FTIR) spectroscopy is provided to demonstrate the difference between fresh and aged biochar in terms of surface functional group content.
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Exploring the transcriptome of crops in response to warming and elevated CO2 (eCO2) is important to gaining insights of botanical adaption and feedback to climate change. This study deployed Illumina sequencing technology to characterize transcriptomic profile of maize plants at the silking stage, which were grown under warming (2 °C higher than ambient temperature) and eCO2 (550 ppm) conditions. The treatment of ambient temperature and ambient CO2 concentration was considered as control (CK). Warming, eCO2 and warming plus eCO2 resulted in 2732, 1966 and 271 genes expressing differently (DEGs) compared to the CK, respectively. Among the DEGs, 48, 47 and 36 gene ontology (GO) terms were enriched in response to warming, eCO2 and warming plus eCO2 compared to the CK, respectively. The majority of genes were assigned to the biological process category and the cellular component category. Elevated CO2 significantly inhibited gene expressions in terms of photosynthesis and carbohydrate biosynthesis pathways. Warming not only negatively affected expressions of these genes, but also secondary pathways of nitrogen (N) metabolism, including key enzymes of GST30, GST7, GST26, GST15, GLUL and glnA. These results indicated the negative biochemical regulation and physiological functions in maize in response to warming and eCO2, highlighting the necessity to improve the genetic adaptability of plant to future climate change.
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Regulação da Expressão Gênica de Plantas , Aquecimento Global , Transcriptoma , Zea mays/genética , Aclimatação , Dióxido de Carbono/análise , Dióxido de Carbono/metabolismo , Mudança Climática , Fotossíntese , Zea mays/fisiologiaRESUMO
Excessive nitrogen (N) fertilizer input to agroecosystem fundamentally alters soil microbial properties and subsequent their ecofunctions such as carbon (C) sequestration and nutrient cycling in soil. However, between soils, the rhizobacterial community diversity and structure in response to N addition is not well understood, which is important to make proper N fertilization strategies to alleviate the negative impact of N addition on soil organic C and soil quality and maintain plant health in soils. Thus, a rhizo-box experiment was conducted with soybean grown in two soils, i.e. soil organic C (SOC)-poor and SOC-rich soil, supplied with three N rates in a range from 0 to 100 mg N kg-1. The rhizospheric soil was collected 50 days after sowing and MiSeq sequencing was deployed to analyze the rhizobacterial community structure. The results showed that increasing N addition significantly decreased the number of phylotype of rhizobacteria by 12.3%, and decreased Shannon index from 5.98 to 5.36 irrespective of soils. Compared to the SOC-rich soil, the increases in abundances of Aquincola affiliated to Proteobacteria, and Streptomyces affiliated to Actinobacteria were greater in the SOC-poor soil in response to N addition. An opposite trend was observed for Ramlibacter belong to Proteobacteria. These results suggest that N addition reduced the rhizobacterial diversity and its influence on rhizobacterial community structure was soil-specific.
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Understanding how elevated CO2 affects dynamics of nodal leaf growth and N assimilation is crucial for the construction of high-yielding canopy via breeding and N management to cope with the future climate change. Two soybean cultivars were grown in two Mollisols differing in soil organic carbon (SOC), and exposed to ambient CO2 (380 ppm) or elevated CO2 (580 ppm) throughout the growth stages. Elevated CO2 induced 4-5 more nodes, and nearly doubled the number of branches. Leaf area duration at the upper nodes from R5 to R6 was 4.3-fold greater and that on branches 2.4-fold higher under elevated CO2 than ambient CO2, irrespective of cultivar and soil type. As a result, elevated CO2 markedly increased the number of pods and seeds at these corresponding positions. The yield response to elevated CO2 varied between the cultivars but not soils. The cultivar-specific response was likely attributed to N content per unit leaf area, the capacity of C sink in seeds and N assimilation. Elevated CO2 did not change protein concentration in seeds of either cultivar. These results indicate that elevated CO2 increases leaf area towards the upper nodes and branches which in turn contributes yield increase.
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Dióxido de Carbono/metabolismo , Glycine max/metabolismo , Nitrogênio/metabolismo , Folhas de Planta/metabolismo , Solo , Biomassa , Carbono/metabolismo , China , Clorofila/metabolismo , Sementes/metabolismo , Solo/química , Especificidade da Espécie , TemperaturaRESUMO
Given the need for a light source, cyanobacteria and other photosynthetic microorganisms can be difficult and expensive to grow in large quantities. Lighted growth chambers and incubators typically cost 50-100% more than standard microbiological incubators. Self-shading of cells in liquid cultures prevents the growth of dense suspensions. Growing liquid cultures on a shaker table or lighted shaker incubator achieves greater cell densities, but adds considerably to the cost. For experiments in which gases other than air are required, the cost for conventional incubators increases even more. We describe an apparatus for growing photosynthetic organisms in exotic atmospheres that can be built relatively inexpensively (approximately 100 dollars U.S.) using parts available from typical hardware or department stores (e.g., Wal-mart or K-mart). The apparatus uses microfiltered air (or other gases) to aerate, agitate, and mix liquid cultures, thus achieving very high cell densities (A750 > 3). Because gases are delivered to individual culture tubes, a variety of gas mixes can be used without the need for enclosed chambers. The apparatus works with liquid cultures of unicellular and filamentous species, and also works with agar slants.
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Exobiologia/instrumentação , Técnicas Microbiológicas/instrumentação , Fotossíntese , Atmosfera , Custos e Análise de Custo , Cianobactérias/crescimento & desenvolvimento , Planeta Terra , Desenho de Equipamento , Eucariotos/crescimento & desenvolvimento , Exobiologia/economia , Gases , Técnicas Microbiológicas/economia , Origem da VidaRESUMO
Physical inactivity poses a significant challenge to physical and mental health. Environmental approaches to tackle physical inactivity have identified natural environments as potentially important public health resources. Despite this, little is known about characteristics of the activity involved when individuals visit different types of natural environment. Using Natural England's Monitor of Engagement with the Natural Environment Survey, we examined 71,603 English respondents' recreational visits to natural environments in the past week. Specifically, we examined the intensity of the activities they undertook on the visits (METs), the duration of their visit, and the associated total energy expenditure (MET minutes). Visits to countryside and urban greenspace environments were associated with more intense activities than visits to coastal environments. However, visits to coastal environments were associated with the most energy expenditure overall due to their relatively long duration. Results differed by the urbanity or rurality of the respondent's residence and also how far respondents travelled to their destination. Knowledge of what types of natural environment afford the highest volumes and intensities of physical activity could inform landscape architecture and exercise prescriptions. Isolating activity-supporting characteristics of natural environments that can be translated into urban design is important in providing physical activity opportunities for those less able to access expansive environments.
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Metabolismo Energético , Atividade Motora , Recreação , Estudos Transversais , Humanos , Saúde Mental , Saúde Pública , Reino UnidoRESUMO
Sorption and desorption are two important processes that influence the amount of pesticides retained by soils. However, the detailed sorption mechanisms as influenced by soil tillage management are unclear. This study examined the sorption and desorption characteristics of metolachlor [2-chloro-N-(2-ethyl-6-methyphenyl)-N-(2-methoxy-1-methylethyl)-acetamide] using the soil samples collected from the long-term conservation tillage (CnT) and conventional tillage (CT) research plots established in 1979 in Darlinton, SC. Humic acid (HA) and humin were extracted from the soils and used in the sorption experiments along with the whole soil samples. The sorption experiments were conducted using a batch-equilibration method. Three sequential desorption rinses were carried out following the sorption experiments. By comparing metolachlor sorption and desorption results we observed hysteresis for all soil samples and their organic matter fractions. Sorption nonlinearity (N) and hysteresis were dependent on the structure and composition of soil organic matter (SOM), e.g., Freundlich isotherm exponents (N) of HA and humin from CnT were higher than those of CT treatment, which may be related to high aromaticity of SOM fractions in CT treatment. Sorption capacity (K'f) was positively correlated with soil organic carbon (SOC) content. These results show that long-term tillage management can greatly affect metolachlor sorption and desorption behavior probably by qualitative differences in the structural characteristics of the humic substances.
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Acetamidas/análise , Agricultura , Herbicidas/análise , Poluentes do Solo/análise , Adsorção , CarbonoRESUMO
Sorption of sulfonamides on biochars is poorly understood, thus sulfamethoxazole (SMX) sorption on biochars produced at 300-600 °C was determined as a function of pH and SMX concentration, as well as the inorganic fractions in the biochars. Neutral SMX molecules (SMX(0)) were dominant for sorption at pH 1.0-6.0. Above pH 7.0, although biochars surfaces were negatively-charged, anionic SMX species sorption increased with pH and is regulated via charge-assisted H-bonds. SMX(0) sorption at pH 5.0 was nonlinear and adsorption-dominant for all the biochars via hydrophobic interaction, π-π electron donor-acceptor interaction and pore-filling. The removal of inorganic fraction reduced SMX sorption by low-temperature biochars (e.g., 300 °C), but enhanced the sorption by high-temperature biochars (e.g., 600 °C) due to the temperature-dependent inorganic fractions in the biochars. These observations are useful for producing designer biochars as engineered sorbents to reduce the bioavailability of antibiotics and/or predict the fate of sulfonamides in biochar-amended soils.
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Antibacterianos/química , Carvão Vegetal/química , Poluentes do Solo/química , Sulfametoxazol/química , Temperatura , Adsorção , Antibacterianos/análise , Recuperação e Remediação Ambiental , Modelos Químicos , Solo/química , Poluentes do Solo/análise , Sulfametoxazol/análiseRESUMO
Extensive use of biochar to mitigate N(2)O emission is limited by the lack of understanding on the exact mechanisms altering N(2)O emissions from biochar-amended soils. Biochars produced from giant reed were characterized and used to investigate their influence on N(2)O emission. Responses of N(2)O emission varied with pyrolysis temperature, and the reduction order of N(2)O emission by biochar (BC) was: BC200 ≈ BC600 > BC500 ≈ BC300 ≈ BC350 > BC400. The reduced emission was attributed to enhanced N immobilization and decreased denitrification in the biochar-amended soils. The remaining polycyclic aromatic hydrocarbons (PAHs) in low-temperature biochars (300-400 °C) played a major role in reducing N(2)O emission, but not for high-temperature biochars (500-600 °C). Removal of phenolic compounds from low-temperature (200-400 °C) biochars resulted in a surprising reduction of N(2)O emission, but the mechanism is still unknown. Overall, adding giant reed biochars could reduce N(2)O evolution from agricultural soil, thus possibly mitigating global warming.
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Agricultura , Poluentes Atmosféricos/análise , Carvão Vegetal/química , Recuperação e Remediação Ambiental/métodos , Óxido Nitroso/análise , Poluição do Ar/prevenção & controle , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Solo/química , Poluentes do Solo/análise , Poluentes do Solo/química , TemperaturaRESUMO
To investigate the effect of pyrolysis temperature on properties and nutrient values, biochars were produced from giant reed (Arundo donax L.) at 300-600°C and their properties such as elemental and mineral compositions, release of N, P and K, and adsorption of N and P were determined. With increasing temperatures, more N was lost and residual N was transformed into heterocyclic-N, whereas no P and K losses were observed. P was transformed to less soluble minerals, resulting in a reduction in available-P in high-temperature biochars. A pH of⩽5 favored release of NH(4)(+), PO(4)(3-) and K(+) into water. Low-temperature biochars (⩽ 400°C) showed appreciable NH(4)(+) adsorption (2102mgkg(-1)). These results indicate that low-temperatures may be optimal for producing biochar from giant reed to improve the nutrient availability.
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Carvão Vegetal/química , Poaceae/química , Adsorção , Temperatura Alta , Concentração de Íons de Hidrogênio , Nitratos/química , Nitrogênio/química , Fosfatos/química , Fósforo/química , Potássio/química , Compostos de Amônio Quaternário/química , Fatores de TempoRESUMO
Sorption of two herbicides, fluridone (FLUN) and norflurazon (NORO), by two types of biochars, whole sediment, and various soil/sediment organic matter (OM) fractions including nonhydrolyzable carbon (NHC), black carbon (BC) and humic acid (HA) was examined. The single-point organic carbon (OC)-normalized distribution coefficients (K(OC)) of FLUN and NORO at low solution concentration (C(e)=0.01S(W), solubility) for HA, NHC, and BC were about 3, 14, and 24 times and 3, 16, and 36 times larger than their bulk sediments, respectively, indicating the importance of different OM fractions in herbicide sorption. This study revealed that aliphatic moieties of the hydrothermal biochars and aromatic moieties of NHC samples, respectively, were possibly responsible for herbicide sorption. The hydrothermal biochar and condensed OM (i.e., NHC and BC) showed relatively high or similar herbicide sorption efficiency compared to the thermal biochar, suggesting that the hydrothermal biochar may serve as an amendment for minimizing off-site herbicide movement.