The Experts below are selected from a list of 65544 Experts worldwide ranked by ideXlab platform
Nie Yong-feng - One of the best experts on this subject based on the ideXlab platform.
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Effects of ultrasonic disintegration on sludge Microbial Activity and dewaterability.
Journal of Hazardous Materials, 2008Co-Authors: Li Huan, Jin Yiying, Rasool Bux Mahar, Wang Zhiyu, Nie Yong-fengAbstract:Ultrasonic treatment can disintegrate sludge, enhance Microbial Activity and improve sludge dewaterability at different energy inputs. To find their relationship, the three phenomena during ultrasonic treatment were investigated synchronously, and an experimental model was established to describe the process of ultrasonic sludge disintegration. Analysis results showed that the changes of sludge Microbial Activity and dewaterability were dependent on sludge disintegration degree during ultrasonic treatment. When sludge disintegration degree was lower than 20%, sludge flocs were disintegrated into micro-floc aggregates and the Microbial Activity increased over 20%. When sludge disintegration degree was over 40%, most cells were destroyed at different degree, and sludge Activity decreased drastically. Only when sludge disintegration degree was 2–5%, sludge dewaterability was improved with the conditioning of FeCl3. It was also found that the sonication with low density and long duration was more efficient than sonication with high density and short duration at the same energy input for sludge disintegration, and a transmutative power function model can be used to describe the process of ultrasonic disintegration.
William R. Whalley - One of the best experts on this subject based on the ideXlab platform.
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The effect of Microbial Activity on soil water diffusivity.
European journal of soil science, 2018Co-Authors: B. U. Choudhury, Stefano Ferraris, Rhys W. Ashton, David S. Powlson, William R. WhalleyAbstract:In this study, we explored the effects of Microbial Activity on the evaporation of water from cores of a sandy soil under laboratory conditions. We applied treatments to stimulate Microbial Activity by adding different amounts of synthetic analogue root exudates. For comparison, we used soil samples without synthetic root exudates as control and samples treated with mercuric chloride to suppress Microbial Activity. Our results suggest that increasing Microbial Activity reduces the rate of evaporation from soil. Estimated diffusivities in soil with the largest amounts of added root exudates were one third of those estimated in samples where Microbial Activity was suppressed by adding mercuric chloride. We discuss the effect of our results with respect to water uptake by roots. HIGHLIGHTS: We explored effects of Microbial Activity on the evaporation of water from cores of a sandy soil. We found the effect of Microbial Activity on water release characteristic was small. Increasing Microbial Activity reduced evaporation from soil, while Microbial suppression increased it. Effect of Microbial Activity on root water uptake was estimated to be equivalent to a change in soil structure.
Jürgen Rullkötter - One of the best experts on this subject based on the ideXlab platform.
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Deep pore water profiles reflect enhanced Microbial Activity towards tidal flat margins
Ocean Dynamics, 2009Co-Authors: Melanie Beck, Jürgen Köster, Bert Engelen, Jan M. Holstein, Antje Gittel, Martin Könneke, Thomas Riedel, Kai Wirtz, Heribert Cypionka, Jürgen RullkötterAbstract:Microbial Activity in permeable tidal flat margin sediments is enhanced by two main processes. First, organic matter is supplied by rapid sedimentation at prograding tidal flat margins. Second, surface and deep pore water advection lead to a replenishment of the dissolved organic matter and sulfate pools. Increasing Microbial Activity towards the low water line is reflected in sulfate and methane profiles as well as in total cell numbers, sulfate reduction rates, and remineralization products. The impact of high sedimentation rates on pore water biogeochemistry is confirmed by inverse modeling reproducing the depth profiles obtained by measurements. In central parts of the tidal flats, low sedimentation rates and pore water flow velocities limit Microbial Activity despite the high availability of electron acceptors for Microbial respiration such as sulfate. Therefore, tidal flat margins with high Microbial Activity are of special importance for budgeting biogeochemical cycling in tidal flat areas.
Laura Lapham - One of the best experts on this subject based on the ideXlab platform.
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Microbial Activity in the marine deep biosphere: progress and prospects
Frontiers in microbiology, 2013Co-Authors: Beth N. Orcutt, Douglas E. Larowe, Jennifer F. Biddle, F. S. Colwell, Brian T. Glazer, Brandi Kiel Reese, John B. Kirkpatrick, Laura Lapham, Heath J. Mills, Jason B. SylvanAbstract:The vast marine deep biosphere consists of Microbial habitats within sediment, pore waters, upper basaltic crust and the fluids that circulate throughout it. A wide range of temperature, pressure, pH, and electron donor and acceptor conditions exists – all of which can combine to affect carbon and nutrient cycling and result in gradients on spatial scales ranging from millimeters to kilometers. Diverse and mostly uncharacterized microorganisms live in these habitats, and potentially play a role in mediating global scale biogeochemical processes. Quantifying the rates at which Microbial Activity in the subsurface occurs is a challenging endeavor, yet developing an understanding of these rates is essential to determine the impact of subsurface life on Earth's global biogeochemical cycles, and for understanding how microorganisms in these "extreme" environments survive (or even thrive). Here, we synthesize recent advances and discoveries pertaining to Microbial Activity in the marine deep subsurface, and we highlight topics about which there is still little understanding and suggest potential paths forward to address them. This publication is the result of a workshop held in August 2012 by the NSF-funded Center for Dark Energy Biosphere Investigations (C-DEBI) "theme team" on Microbial Activity (www.darkenergybiosphere.org).
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Microbial Activity in surficial sediments overlying acoustic wipeout zones at a gulf of mexico cold seep
Geochemistry Geophysics Geosystems, 2008Co-Authors: Laura Lapham, Jeffrey P Chanton, Christopher S Martens, Ken Sleeper, Robert J WoolseyAbstract:[1] Down core concentration gradients of dissolved methane and sulfate; isotope gradients of methane, dissolved inorganic carbon, and authigenic carbonate; and organic matter elemental ratios are incorporated into a vent evolution model to describe spatial and temporal variability of sedimentary Microbial Activity overlying acoustic wipeout zones at Mississippi Canyon (MC) 118, Gulf of Mexico. We tested the hypothesis that these zones indicate areas where sediments are exposed to elevated fluid flux and therefore should contain saturated methane concentrations and enhanced Microbial Activity from sulfate reduction (SR), anaerobic oxidation of methane (AOM), and methanogenesis (MP). Thirty surficial cores (between 22 and 460 cm deep) were collected from sediments overlying and outside the wipeout zones and analyzed for pore water and solid phase constituents. Outside the wipeout zones, sulfate and methane concentrations were similar to overlying-water values and did not vary with depth; indicating low Microbial Activity. Above the wipeouts, nine cores showed moderate Activity with gently sloping sulfate and methane concentration gradients, methane concentrations <20 μM, and isotope depth gradients indicative of organic matter oxidation. In stark contrast to this moderate Activity, four cores showed high Microbial Activity where sulfate concentrations were depleted by ∼50 cm below seafloor, maximum methane concentrations in the decompressed cores were above 4 mM, and down core profiles of δ13C-CH4 and δ13C-dissolved inorganic carbon (DIC) indicated distinct depth zones of SR, AOM, and MP. Bulk organic matter analysis suggested that the high Activity was supported by an organic source that was enriched in carbon (C:N ∼15) and depleted in δ15N and δ13C compared to other Activity groups, possibly due to the influx of petroleum or chemosynthetically fixed carbon. Within high Activity cores, the δ13C-DIC values were similar to the δ13C-CaCO3 values, a result expected for authigenic carbonate recently precipitated. However, these values were dissimilar in moderate Activity cores, suggesting that Microbial Activity was higher in the past. This study provides evidence that the fluid flux at MC 118 varies over time and that the Microbial Activity responds to such variability. It also suggests that sediments overlying wipeout zones are not always saturated with respect to methane, which has implications for the formation and detection of gas hydrate.
Li Huan - One of the best experts on this subject based on the ideXlab platform.
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Effects of ultrasonic disintegration on sludge Microbial Activity and dewaterability.
Journal of Hazardous Materials, 2008Co-Authors: Li Huan, Jin Yiying, Rasool Bux Mahar, Wang Zhiyu, Nie Yong-fengAbstract:Ultrasonic treatment can disintegrate sludge, enhance Microbial Activity and improve sludge dewaterability at different energy inputs. To find their relationship, the three phenomena during ultrasonic treatment were investigated synchronously, and an experimental model was established to describe the process of ultrasonic sludge disintegration. Analysis results showed that the changes of sludge Microbial Activity and dewaterability were dependent on sludge disintegration degree during ultrasonic treatment. When sludge disintegration degree was lower than 20%, sludge flocs were disintegrated into micro-floc aggregates and the Microbial Activity increased over 20%. When sludge disintegration degree was over 40%, most cells were destroyed at different degree, and sludge Activity decreased drastically. Only when sludge disintegration degree was 2–5%, sludge dewaterability was improved with the conditioning of FeCl3. It was also found that the sonication with low density and long duration was more efficient than sonication with high density and short duration at the same energy input for sludge disintegration, and a transmutative power function model can be used to describe the process of ultrasonic disintegration.