Humin

Hayes, M.H.B.; Mylotte, Rosaleen; Swift, R. S.

doi:10.1016/bs.agron.2017.01.001

Cited by 93 publications

(29 citation statements)

References 226 publications

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“…Se ha reportado que las características del humus se relacionan con ambientes y moléculas precursoras (Wu et al, 2017), en las chinampas la formación de humus debe estar asociada al ambiente lacustre y a moléculas precursoras como azúcares, ligninas o celulosa que provienen principalmente de lodos, estiércoles y compost (Xiao-Xia et al, 2019). En todos los suelos estudiados, hubo mayores contenidos de carbono en huminas que en AH y AF (Figuras 2A, 2B), este comportamiento, también lo señalaron Wiesmeier et al (2019), en suelos agrícolas o forestales, donde la fracción dominante, de las sustancias húmicas, fueron huminas (más de 40%), lo que implicó en ambos casos, presencia de materiales insolubles con dominio de cadenas alifáticas de carbohidratos lípidos, ceras, así como de carbohidratos tipo celulosa (Hayes et al, 2017). Los índices E 4 /E 6 con menores valores se encontraron en suelos de pastizal y Tláhuac (Figura 2C, 2D) e indicaron, que hubo mayor aromaticidad molecular en el humus de estos sitios.…”

Section: Resultados Y Discusión Características Del Humusunclassified

Características de la actividad enzimática y el humus en suelos de chinampa.

Reyes-Ortigoza

2019

Terra

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The chinampas are protected natural areas that have suffered degradation due to saline contamination and type of management. The objective was to study enzymatic activity and type of humus in chinampas with different salinity, land use and geographical location. Forty-five soil samples were studied, 15 at each site (Xochimilco, San Gregorio Atlapulco (SGA) and Tláhuac). Each site had a different use: five had pastures, five had agricultural crops and five were abandoned. pH, EC, saline ions, enzymatic activity (glucosidase, phosphatase, urease, sulfatase, catalase and dehydrogenase) and carbon in humic substances were evaluated. EC, PSI and pH classified the cultivated soils of SGA and Xochimilco as saline, but in Tláhuac the soils of abandoned and pasture chinampas were sodic saline. Geographic location and land use changed enzyme activity (except for urease and glucosidase) and characteristics of the humus [percentages of carbon of humic acids (HA) (humic acids), fulvic acids (FA), and humins]. There were statistical differences (Tukey P < 0.05). The cultivated soils had more urease, phosphatase and sulfatase activity, while in the pasturelands dehydrogenase and catalase were more active. Higher carbon content in AH was found in pastureland and chinampas of Tlahuac, while in SGA and abandoned chinampas carbon content was higher in FA.

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Section: Resultados Y Discusión Características Del Humusunclassified

Características de la actividad enzimática y el humus en suelos de chinampa.

Reyes-Ortigoza

2019

Terra

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“…Consequently, these results highlight the importance but unrecognized role of POM in naturally occurring AgNPs in soils. Given POM is associated with iron oxides, clays and DOM in natural soils and sediments 3–5 , the formation of AgNPs could be more complex in nature. This reductive pathway will ultimately raise the concerns of POM in the biogeochemistry of contaminants that are reactive towards phenol-like groups.…”

Section: Discussionmentioning

confidence: 99%

“…Most organic matter in soils is in particulate, known as humin, rather than in a dissolved form 3 . Particulate organic matter (POM) has been identified as a metastable phase 4,5 , i.e., insoluble but could be chemically active in extracellular electron transfer in microbial reduction of, for example, iron oxide and pentachlorophenol dechlorination 6–8 . However, the effects of POM on the geochemical transformation of trace metals are unclear.…”

Section: Introductionmentioning

confidence: 99%

“…However, the effects of POM on the geochemical transformation of trace metals are unclear. Considering that POM is distributed worldwide in high abundance 3,5 , typically comprising >50% of soil organic matter in mineral soils and >70% of that in lithified sediments 4 , identifying the mechanisms underlying its reactivity will provide new insight into its role in the cycling of numerous trace metals within surface environments.…”

Section: Introductionmentioning

confidence: 99%

“…Although silver ions (Ag + ) can be readily reduced to AgNPs by microorganisms and their associated extracellular polymeric substances 14–16 , the mechanism allowing the abiotic reduction of Ag + is largely unknown. Studies on the role of organic matter in natural formation of AgNPs have focused on dissolved organic matter (DOM) in lakes and rivers 17–20 , but an extrapolation of the results to POM is difficult due to the distinct differences in the physical and the chemical properties of these two media 4,5,21 . Therefore, DOM fails to explain the natural formation of AgNPs in soils 17,19 .…”

Section: Introductionmentioning

confidence: 99%

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Significant contribution of metastable particulate organic matter to natural formation of silver nanoparticles in soils

et al. 2019

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Particulate organic matter (POM) is distributed worldwide in high abundance. Although insoluble, it could serve as a redox mediator for microbial reductive dehalogenation and mineral transformation. Quantitative information on the role of POM in the natural occurrence of silver nanoparticles (AgNPs) is lacking, but is needed to re-evaluate the sources of AgNPs in soils, which are commonly considered to derive from anthropogenic inputs. Here we demonstrate that POM reduces silver ions to AgNPs under solar irradiation, by producing superoxide radicals from phenol-like groups. The contribution of POM to the naturally occurring AgNPs is estimated to be 11–31%. By providing fresh insight into the sources of AgNPs in soils, our study facilitates unbiased assessments of the fate and impacts of anthropogenic AgNPs. Moreover, the reducing role of POM is likely widespread within surface environments and is expected to significantly influence the biogeochemical cycling of Ag and other contaminants that are reactive towards phenol-like groups.

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Bioremediation

Prince¹

2019

Kirk-Othmer Encyclopedia of Chemical Technology

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Bioremediation is the process of thoughtfully exploiting biological processes to minimize an unwanted environmental impact; usually the aim is the removal of a contaminant from the biosphere. Like most definitions in biology, that of bioremediation is the subject of some debate. A narrow definition might focus on the conversion of contaminating organic molecules to CO 2 , water, and inorganic ions, and the oxidation or reduction of contaminating inorganic ions such as nitrate or ammonia to harmless forms, in this case nitrogen gas. A broader definition would include biological processes for ameliorating extremes of pH, concentrating contaminants so that they can be more easily removed by physical techniques, converting toxic species to less toxic or less bioavailable forms that pose less of a threat to the environment, and restoring functional ecosystems to contaminated or disturbed sites when the contaminants or disturbance cannot be removed.

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Humin

Cited by 93 publications

References 226 publications

Características de la actividad enzimática y el humus en suelos de chinampa.

Características de la actividad enzimática y el humus en suelos de chinampa.

Significant contribution of metastable particulate organic matter to natural formation of silver nanoparticles in soils

Bioremediation

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