Biogeochemistry Commons^™

Soil Biogeochemistry In Riparian And Restored Tidal Wetlands: Monitoring And Method Evaluation, Joseph Loffredo

Open Access Master's Theses

Although soils are essential for sustaining ecosystems, they are often overlooked in routine monitoring efforts during restoration projects. This thesis tries to address the interest in and challenges of measuring and monitoring soil biogeochemical properties and processes to evaluate restoration trajectories. In the first part of this thesis (Chapter 1), I monitored tidal marsh vegetation and soil biogeochemical responses to restoration by thin-layer placement (TLP) of dredged sediments in a greenhouse mesocosm study and a parallel field study at an active restoration site in southern RI. In the greenhouse, aboveground plant biomass in mesocosms treated with +5 cm and +10 …

Monitoring 2019 Bonnet Carré Spillway Impacts - Final Report, Jill Hendon, Jerry Wiggert

Faculty Publications

Due to the multiple and extended openings of the Bonnet Carré Spillway in 2019, the University of Southern Mississippi (USM) was tasked by the Mississippi Department of Marine Resources to conduct ecological sampling in the Mississippi Sound and adjacent waters. in an effort to better understand the impacts of the extensive freshwater diversion of Bonnet Carré Spillway operations on Mississippi's coastal and marine resources. The period of performance for this project was June 1, 2019, to August 31, 2019. This technical report summarizes the three months of weekly surveys and analyses, over June - August 2019, conducted by the University …

Denitrification In Soils: From Genes To Environmental Outcomes

Dissertations, Master's Theses and Master's Reports - Open

Denitrification is an important process of global nitrogen cycle as it removes reactive nitrogen from the biosphere, and acts as the primary source of nitrous oxide (N₂O). This thesis seeks to gain better understanding of the biogeochemistry of denitrification by investigating the process from four different aspects: genetic basis, enzymatic kinetics, environmental interactions, and environmental consequences. Laboratory and field experiments were combined with modeling efforts to unravel the complexity of denitrification process under microbiological and environmental controls.

Dynamics of denitrification products observed in laboratory experiments revealed an important role of constitutive denitrification enzymes, whose presence were further confirmed …

Gone With The Wind: Soil Moisture Effects On Gaseous Nitrogen Removal From Wastewater, Faith Anderson

Senior Honors Projects

Onsite wastewater treatment systems (OWTS), or septic systems, release nitrogen (N), which can be detrimental to aquatic ecosystems. The final step in the treatment of wastewater is dispersal onto a drainfield, where it percolates through the soil. Part of the N is removed from wastewater and released into the atmosphere as N₂ and N₂O by denitrification, which requires anoxic conditions. Previous studies looking at the effect of soil water-filled pore space (WFPS) on denitrification using clean water with a high level of dissolved O₂ (DO) have identified a minimum of 60% WFPS for denitrification to take …

Carbon In The Deep Biosphere: Forms, Fates, And Biogeochemical Cycling, Susan Lang, Andrew Steen, Magdalena Osburn

Faculty Publications

Building on the synthesis of carbon reservoirs in Earth's subsurface, this chapter focuses on the forms, cycling, and fate of the carbon supporting microbial life in the terrestrial and marine subsurface. As the subsurface is estimated to host a vast reservoir of life on Earth, identifying the carbon compounds that life uses for energy and growth is key to understanding ecosystem functioning in the past and at present, and also for extrapolating these findings to the search for life in the universe. This chapter highlights advances in quantifying small carbon compounds, measuring rates of carbon turnover, and the fate of …

Snow-Patch Influence On Soil Biogeochemical Processes And Invertebrate Distribution In The Mcmurdo Dry Valleys, Antarctica, W. Lyons, John Barrett, Peter Doran, Ross Virginia, Diana Wall, Diana Wall, Ross Virginia, Michael Gooseff, Dorota Porazinska, Andrew Fountain, Andrew Fountain, Peter Doran

Geography Faculty Publications and Presentations

The McMurdo Dry Valleys is the largest of the ice-free areas in Antarctica. Precipitation events in excess of 1 cm of snow accumulation are rare. During the winter, snow is transported by strong katabatic winds blowing from the polar plateau, and deposited into the lee of topographic features (e.g., stream channels and other topographic depressions). At the start of the austral summer (early October), as much as 10% of the valley soils may be covered by distributed snow patches. Because liquid water is the primary driver of biological, physical, and chemical processes in this polar desert, quantifying fluxes of water …

Modeling Stromatolite Formation With Diffusion-Limited Aggregation, Laura Stevens

Graduate Student Theses, Dissertations, & Professional Papers

Stromatolites, microbialites, and other microbially induced sedimentary structures exist in the rock record as far back as 3.6 billion years ago and continue to form in the present day. Better characterizing these structures and better understanding how they form is crucial in distinguishing these biosignatures from similar, abiotic structures, which can help us to understand the conditions of early Earth and early Mars. To that end, I have modified DLA 3D EXT, an open-source stromatolite modeling program, to more closely reflect the process of microbial trapping-and-binding by filamentous microbes in a calcite-precipitating hot spring system. This modified program includes a …

A Geochemical Analysis Of Fulgurites: From The Inner Glass To The Outer Crust, Michael Joseph

Graduate School Theses and Dissertations

Cloud-to-ground lightning strikes produce natural glasses on the surface of the Earth, called fulgurites. These natural glasses are tubular in shape with a central void surrounded by an inner glass, and the inner glass is surrounded by an outer crust or toasted region. Previous studies report different kinds of melts existing in several different types of fulgurites; however, little to no chemical data has been collected that tracks chemical variations from the inner glass to the outer crust of a fulgurite. This study uses microprobe and laser ablation inductively coupled plasma mass spectrometer analytical techniques to collect transects of chemical …

Investigating The Thermal Stratification Patterns Of A Shallow Polymictic Boreal Shield Lake And The Effectiveness Of Models In Predicting Shallow Lake Thermal Profiles, Matthew Roberts

Theses and Dissertations (Comprehensive)

Thermal stratification is a core process of lakes which plays a critical role in shaping the ecological dynamics of lakes, influencing major processes like nutrient cycling and oxygen availability. For shallow polymictic lakes, thermal stratification patterns present some unique differences due to the complex and variable nature of these lakes. In this thesis, I examined thermal stratification in a shallow polymictic lake in northwestern Ontario during the ice-free season of 2019 to investigate the frequency, duration, and driving factors of thermal stratification. The lake underwent 146 separate stratification events, with a median duration of 2 hours per event, with a …

Kudzu Invasion And Control In Southern Upland Forests Of Mississippi, Gina Profetto

University of New Orleans Theses and Dissertations

Kudzu, Pueraria montana var. lobata (Willd.), is a common invasive species throughout the American South. In southern upland mixed oak-pine forests of Mississippi, kudzu invasion generally and indiscriminately suppressed the pre-invasion plant community. Three different control methods reduced kudzu density but differed in the level of reduction achieved and in their effects on the pre-existing plant community. A combination of burning and herbicides produced the most desirable outcome in terms of restoring the pre-invasion community. Kudzu invasion significantly increased nitrate pools compared to control sites, but had no effect on ammonium or nitrite, or on the microbial processes of mineralization …