Title of thesis: THE DISTRIBUTION AND FUNCTION OF DENITRIFICATION GENES: EXPLORING AGRICULTURAL MANAGEMENT AND SOIL CHEMICAL IMPLICATIONS Holly Bowen, Masters of Science, 2016 Thesis directed by: Professor Stephanie Yarwood Department of Environmental Science and Technology Denitrification is a microbially-mediated process that converts nitrate (NO3) to dinitrogen (N2) gas and has implications ...

The potential for denitrification in marl and peat sediments in the Shark River Slough in the Everglades National Park was determined by the acetylene blockage assay. The influence of nitrate concentration on denitrification rate and N(2)O yield from added nitrate was examined. The effects of added glucose and phosphate and of temperature on the denitrification potential were determined. The se...

Crab-shell chitin (SC-20) was evaluated for its ability to enhance biological denitrification in bench-scale tests. In the presence of SC-20, highly reducing conditions were generated, supporting both denitrification and sulfate reduction of aerated water. Rapid degradation of protein in SC-20 was observed to cause an initial high release of ammonium and carbon, while a slower, continuous relea...

Characterizing denitrification rates in aquatic ecosystems is essential to understanding how systems may respond to increased nutrient loading. Thus, it is important to ensure the precision and accuracy of the methods employed for measuring denitrification rates. The acetylene (C2H2) inhibition method is a simple technique for estimating denitrification. However, potential problems, such as inh...

Denitrifiers remove fixed nitrogen from aquatic environments and hydrologic conditions are one potential driver of denitrification rate and denitrifier community composition. In this study, two agriculturally impacted streams in the Sugar Creek watershed in Indiana, USA with different hydrologic regimes were examined; one stream is seasonally ephemeral because of its source (tile drainage), whe...

[1] We use a geochemical box model to investigate the changes in marine N-fixation and denitrification required to match the observed sedimentary ı15N changes between 30 kyr B.P. and the late Holocene. This is achieved by optimizing a set of seven parameters that describe the strengths of three ocean-internal N feedbacks and the response of the oceanic N cycle to four external forcings. Scenari...

[1] Satellite observations of denitrification and ice clouds in the Arctic lower stratosphere in February 1997 are used with Lagrangian microphysical box model calculations to evaluate nucleation mechanisms of solid polar stratospheric cloud (PSC) particles. The occurrences of ice clouds are not correlated in time and space with the locations of back trajectories of denitrified air masses, indi...

The paper summarizes the state-of-the-art of the most recent advances in biological nitrogen removal, including process design criteria and technological innovations. With reference to the Modified Ludzck Ettinger (MLE) process (pre-denitrification and nitrification in the activated sludge process), the most common nitrogen removal process used nowadays, a new design equation for the denitrific...

The large increase in impervious surface cover due to urbanization leads to “flashier” storm flows and increased runoff. This altered hydrology causes channel incision in urban stream channels and lower water tables in the riparian (next to the stream) zone. In turn, these physical changes alter many stream processes, including denitrification. Denitrification is the anaerobic microbial process...

Rates of denitrification and organic carbon (C) mineralization were measured simultaneously in soil suspensions maintained at 30°C under anoxic conditions. Nine mineral and seven organic soils were used in the study. Disappearance of NO3~ and production of CO2 were measured at various times during the 12-day incubation. Labeled NO, was used to differentiate denitrification from immobilization a...