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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 13 of 13 for “"Heterotrophic Activity"”.
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Comparison of Heterotrophic Activity in Forested Streams Originating from Wetland and Agricultural Tile Drainage Sources
… inputs on stream ecosystem function, I compared heterotrophic activity (i.e., organic matter breakdown and benthic respiration) in forested streams originating from wetland and agricultural tile drainage sources over four seasons. I found a reduction in heterotrophic activity in the tile-sourced …
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An evaluation of the radiorespirometric technique as a method for detecting changes in heterotrophic activity
… technique, a modification of the heterotrophic activity assay, was evaluated as a monitor of toxic perturbation. The basis for the technique consists of trapping ¹⁴CO₂ evolved from the catabolism of a ¹⁴C-labeled substrate, and analyzing the resultant activity in a scintillation …
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Development of a test system for screening toxic substances: a comparison using organic substances
… chemicals' effects on primary productivity and heterotrophic activity though other effects are also noted. The toxicity of the chemicals in this study was compared to those from other toxicological evaluations based on threshhold toxicity values (EC20 and LC50). The screening test sytem …
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A study of nitrification kinetics
One autotrophic and two heterotrophic chemostats were operated during the study period. The autotrophic unit was operated using an inorganic synthetic ammonium medium to provide a culture of nitrifying organism and to study cell yield. The two heterotrophic units were operated with a feed …
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Elucidating Factors that Impact the Removal of Organic Microconstituents by Ammonia Oxidizing and Heterotrophic Bacteria
… oxidizing bacteria (AOB), laboratory enriched heterotrophic cultures free of active nitrifiers with low (Ox⁻) or high (Ox⁺) oxygenase activity, and a nitrifying activated sludge (NAS) from a full-scale wastewater treatment plant) to determine whether partitioning dictates removal of individual …
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The use of radiorespirometry for evaluation of subsurface biodegradation
… groundwater contaminants. A modification of the heterotrophic activity assay, the radiorespirometric method, was employed as the ¹⁴C-tracer technique. The microorganisms used were those present in soil sampled aseptically at locations in Pennsylvania and Virginia. Both saturated and unsaturated …
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Assessing Respiration Rates and Nutrient Dynamics of Aritifical Reef Biofilms and Bacterioplankton in the Mississippi Sound
… in the presence of biofilm. This suggests that heterotrophic activity was high but bacterial abundance was limited by some factor, such as grazing pressure. P04 and NH4 production were often observed in incubation experiments, and production rates were higher in the presence of biofilm, …
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Freshwater Invertebrate Assimilation Nutrients from Detrital Biofilms Under Light and Phosphorus Manipulation
… influences are increasing algal biomass and activity within aquatic ecosystems, stimulating debate regarding interactions between “green” and “brown” food webs. Specifically, in forested streams, the removal of forest canopy or riparian zones increases light exposure and nutrient fluxes to …
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Ecosystem metabolism in coastal plain streams of southeast Louisiana : environmental and watershed effects
… growth or organic pollution that stimulates heterotrophic activity. In the following studies, the effect of the presence or absence of a riparian canopy, watershed land use, and stochastic events such as flooding on ecosystem metabolism in coastal plain streams of southeast Louisiana are …
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SEASONAL BIOCHEMISTRY IN THE SEDIMENTS OF THE GREAT BAY ESTUARINE COMPLEX, NEW HAMPSHIRE
… to examine the interactions among bacterial activity, geochemistry and bioturbation. The upper 8-10 cm of sediments near the Jackson Estuarine Laboratory (JEL) were bioturbated actively from June to December. Sediments at the mouth of the Lamprey and Squamscott rivers (SQUAM) were not …
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Structural dynamics of community gene expression In a freshwater cyanobacterial bloom over a day-night cycle
… both the taxonomic composition (structure) and activity (function) of complex microbial systems in response to dynamic environmental conditions. We have used next-generation Illumina sequencing to characterize the metatranscriptome of a tropical eutrophic drinking water reservoir dominated by …
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An ephemeral perspective of fluvial ecosystems: Viewing ephemeral rivers in the context of current lotic ecology
… for various organisms, forming "hotspots" of heterotrophic activity analogous to patterns reported from perennial streams. Large amounts of fine particulate and dissolved organic matter (FPOM and DOM) deposited in the lower reaches of the rivers serve to fuel this heterotrophic biota. As a …
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Evaluation Of Nitrification Kinetics For A 2.0 MGD IFAS Process Demonstration
… and relates to the localization of nitrification activity in the IFAS basin. Similar to trends observed for carrier biomass content (Regmi, 2008), ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) activity also shifted from the fixed film to the suspended phase as water …