Biogeochemistry Commons^™

The Ecological Effects Of Nitrogen Enrichment In Aridlands, Jennifer Holguin

Open Access Theses & Dissertations

Anthropogenic nitrogen (N) deposition is one of the most prominent factors driving global change. Across the globe, N deposition has driven major changes in terrestrial ecosystems, such as declines in plant biodiversity, enhanced exotic plant growth, and changes to biogeochemical processes involved in carbon and nutrient cycling. While noteworthy effort has been put forth to investigate the effects of N deposition on terrestrial ecosystems, a disproportionate number of N addition studies have been conducted in temperate mesic systems. Thus, we lack a holistic and mechanistic understanding of how N deposition impact aridland ecosystems. Additionally, our predictions of the effects of …

The Emergence Of Convergence, Shana M. Sundstrom, David G. Angeler, Jessica G. Ernakovich, Jorge H. Garcia, Joseph A. Hamm, Orville Huntington, Craig R. Allen

Faculty Publications

Science is increasingly a collaborative pursuit. Although the modern scientific enterprise owes much to individuals working at the core of their field, humanity is increasingly confronted by highly complex problems that require the integration of a variety of disciplinary and methodological expertise. In 2016, the U.S. National Science Foundation launched an initiative prioritizing support for convergence research as a means of “solving vexing research problems, in particular, complex problems focusing on societal needs.” We discuss our understanding of the objectives of convergence research and describe in detail the conditions and processes likely to generate successful convergence research. We use our …

Short-Term Responses Of Soil Carbon, Nitrogen, And Microbial Biomass To Cover Crop Mixtures And Monocultures, Igor Alexandre De Souza, Amanda B. Daly, Jorg Schnecker, Nicholas D. Warren, Adalfredo Rocha Lobo Jr., Richard G. Smith, Andre Fonseca Brito, A. Stuart Grandy

Faculty Publications

Increasingly, cover crops are being adopted for the purpose of improving soil health, yet the timescale and magnitude by which living annual cover crops might modify soil chemical and biological aspects of soil health is not well understood. At the same time, there is growing interest among farmers in cover crop mixtures due to perceptions that species-rich cover crop communities will enhance soil health relative to monocultures. In a field experiment in southeast New Hampshire, we investigated how groups of cover crops grown as monocultures and mixtures for specific seasonal niches (winter/spring, summer, and fall) influenced levels of soil nitrogen …

Environmental Chemical Analysis Method Optimization And Application To Northwest Cuban Marine Sediment, Thea R. Bartlett

USF Tampa Graduate Theses and Dissertations

A method for gas chromatography tandem mass spectrometry (GC-MS/MS) in selected reaction monitoring (SRM) mode has been optimized to quantify 250 compounds of a variety of compound classes such as polycyclic aromatic hydrocarbons (PAHs), oxidized PAHs, organochlorinated pesticides, polychlorinated biphenyls, biomarkers (hopanes, steranes, tri-aromatic steroids, and fecal sterols), aliphatic hydrocarbons, and plastic additives. This method was validated based on available QA/QC standards using several environmental samples, both sediment and biota, and standard reference materials. This contaminant-focused method can be used as a forensic geochemistry tool to evaluate oil contamination and other contaminant histories in future research studies. When applied to …

Microbial Carbon Use Efficiency Promotes Global Soil Carbon Storage, Feng Tao, Yuanyuan Huang, Bruce A. Hungate, Stefano Manzoni, Serita D. Frey, Michael W. I. Schmidt, Markus Reichstein, Nuno Carvalhais, Philippe Ciais, Lifen Jiang, Johannes Lehmann, Ying-Ping Wang, Benjamin Z. Houlton, Bernhard Ahrens, Umakant Mishra, Gustaf Hugelius, Toby D. Hocking, Xingjie Lu, Zheng Shi, Kostiantyn Viatkin, Ronald Vargas, Yusuf Yigini, Christian Omuto, Ashish A. Malik, Guillermo Peralta, Rosa Cuevas-Corona, Luciano E. Di Paolo, Isabel Luotto, Cuijuan Liao, Yi-Shuang Liang, Vinisa S. Saynes, Xiaomeng Huang, Yiqi Luo

Faculty Publications

Soils store more carbon than other terrestrial ecosystems1,2. How soil organic carbon (SOC) forms and persists remains uncertain1,3, which makes it challenging to understand how it will respond to climatic change3,4. It has been suggested that soil microorganisms play an important role in SOC formation, preservation and loss5,6,7. Although microorganisms affect the accumulation and loss of soil organic matter through many pathways4,6,8,9,10,11, microbial carbon use efficiency (CUE) is an integrative metric that can capture the balance of these processes12,13. Although CUE has the potential to act as a predictor of variation in SOC storage, the role of CUE in SOC …

Small Community Water Systems Have The Highest Prevalence Of Mn In Drinking Water In California, Usa, Miranda Aiken, Samantha C. Ying

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Manganese (Mn) is currently regulated as a secondary contaminant in California, USA; however, recent revisions of the World Health Organization drinking water guidelines have increased regulatory attention of Mn in drinking water due to increasing reports of neurotoxic effects in infants and children. In this study, Mn concentrations reported to California’s Safe Drinking Water Information System were used to estimate the potentially exposed population within California based on system size. We estimate that between 2011 and 2021, over 525,000 users in areas with reported Mn data are potentially exposed to Mn concentrations exceeding the WHO health-based guideline (80 μg L …

The Dynamics Of Sedimentary Chlorophyll Α At A High-Energy Beach, Sarah (Gray) Abel

Honors Theses

Productive sandy beaches are one of the most crucial areas serving our ecosystem today. While often overlooked in scientific research, productive beaches have many essential functions that lead to the preservation and protection of many different species as well as ecological wellness and stability. A key factor that is linked to this productivity is the presence of chlorophyll in the sediments. Piston cores of the sediments at the low-tide mark at Waties Island, South Carolina, were collected across multiple years and subsequently analyzed for chlorophyll concentrations through fluorometry after acetone extraction and acidification. Each core profile was processed to calculate …

Investigation Of A Possible Switch Of Benthic Photosynthetic Organisms And Phytoplanktonic Organisms In White Point Swash, South Carolina, Nathan Easterling

Honors Theses

This research study examined the possible switch from benthic photosynthetic organisms to phytoplankton in the water column at White Point Swash, Long Bay, South Carolina, and what is causing this switch to occur. During Dr. Hannides’ and his group’s studies at this and other swashes in the past, they noticed this phenomenon of the benthic photosynthetic organisms taking over during a certain time and then the phytoplankton in the water column taking over during a different time. In this study, I measured the relative benthic macroalgal area coverage and sedimentary chlorophyll a concentration as measures of the abundance of benthic …

Suboxic And Anaerobic Respiration Across A Sandy-Shore-To-Estuarine Gradient, Jacey Ballard

Honors Theses

Sulfate is an inorganic ion that is one of the major ions of seawater. Sulfate is also an essential reactant in microbially mediated anaerobic respiration that produces sulfide, an energy source during chemosynthesis. Sulfide is widely found in sediment, and water rich in decaying organic material, as well as hydrothermal vents. While sulfate reduction occurs extensively in muds, such as those of marshes, it is not expected to occur in sand which is much better aerated. Recent research in our group documented extensive sub aerobic respiration in coastal sands which suggests that sulfate reduction may have also been happening. This …

Spot1328 Meira Spit, Robert C. Mahon, Elizabeth J. Trower, Benjamin P. Smith, Tyler A. Lincoln, Juliana Olsen-Valdez, John S. Magyar, Cedric J. Hagen

2D Wave Spectral Data, South Arm, Great Salt Lake, Utah

Data in this folder are produced by a SoFarOcean Spotter wave buoy deployed along the south arm of the Great Salt Lake, near Antelope Island State Park from the period of July 13, 2021 through June 28, 2022, in relatively shallow water, approximately 1.6m.

IMPORTANT NOTE: Water depths for #1328 (Miera Spit) started at ~1.7 m, but dropped rapidly to 0.9 m on July 15, 2021 and dropped further to ~0.4 m on August 17, 2021. The timing of these rapid water depth changes matches the timing of buoy location changes when the anchor was dragged inshore by waves. When …

Spot1328 Meira Spit Derived Data, Robert C. Mahon, Elizabeth J. Trower, Benjamin P. Smith, Tyler A. Lincoln, Juliana Olsen-Valdez, John S. Magyar, Cedric J. Hagen

2D Wave Spectral Data, South Arm, Great Salt Lake, Utah

Data in this folder are produced by a SoFarOcean Spotter wave buoy deployed along the south arm of the Great Salt Lake, near Antelope Island State Park from the period of July 13, 2021 through June 28, 2022, in relatively shallow water, approximately 1.6m.

IMPORTANT NOTE: Water depths for #1328 (Miera Spit) started at ~1.7 m, but dropped rapidly to 0.9 m on July 15, 2021 and dropped further to ~0.4 m on August 17, 2021. The timing of these rapid water depth changes matches the timing of buoy location changes when the anchor was dragged inshore by waves. When …

Spot1356 Black Rock, Robert C. Mahon, Elizabeth J. Trower, Benjamin P. Smith, Tyler A. Lincoln, Juliana Olsen-Valdez, John S. Magyar, Cedric J. Hagen

2D Wave Spectral Data, South Arm, Great Salt Lake, Utah

Data in this folder are produced by a SoFarOcean Spotter wave buoy deployed along the south arm of the Great Salt Lake, near Antelope Island State Park from the period of July 13, 2021 through June 28, 2022, in relatively shallow water, approximately 1.6m.

Spot1356 Black Rock Derived Data, Robert C. Mahon, Elizabeth J. Trower, Benjamin P. Smith, Tyler A. Lincoln, Juliana Olsen-Valdez, John S. Magyar, Cedric J. Hagen

2D Wave Spectral Data, South Arm, Great Salt Lake, Utah

Data in this folder are produced by a SoFarOcean Spotter wave buoy deployed along the south arm of the Great Salt Lake, near Antelope Island State Park from the period of July 13, 2021 through June 28, 2022, in relatively shallow water, approximately 1.6m.

The Terroir Of Swiss Cheese: A Temporal And Geomorphological Investigation Of The Martian Co2 Sublimation Pits, Racine D. Cleveland

Graduate Theses and Dissertations

Observations by NASA Mars Global Surveyor showed evidence of rough topography on the South Pole of Mars. The topography is the result of CO2 sublimation processes that occur through the changing seasons on the red planet. These sublimation areas are known to scientists as Swiss Cheese Features (SCF). SCF are erosional degradation pits that have been studied for over two decades. Studies show that these SCF increase in area over time, but these values are collected by hand on a per feature basis. Models for the pit evolution have also played a part in understanding these SCF. This work is …

The Impact Of Glacial Proximity On The Elemental Composition Of Leachate Derived From Sediment Weathering, Karoline Ford

Theses/Capstones/Creative Projects

This study assesses chemical weathering trends as they relate to glacial retreat. The chemical environment of surfaces exposed to the atmosphere differs significantly from beneath a glacier. As a glacier melts, changes to the biogeochemical processes generate environmental gradients. This study analyzed chemical weathering signals at different distances from a glacial front by comparing the elemental composition of leachate derived from sediments in southeastern Greenland. Samples from proglacial, nonglacial, and moraine locations were weathered in a laboratory setting, and ion chromatography was used to determine the elemental composition of the products. Divergent trends in leachate composition were observed as distance …

Molecular Evidence For The Export Of Terrigenous Organic Matter To The North Gulf Of Mexico By Solid-State 13C Nmr And Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Of Humic Acids, Sarah Ann Ware

Chemistry & Biochemistry Theses & Dissertations

Marine organic matter is mainly believed to originate from autochthonous organic matter, while terrigenous organic matter is assumed to be largely degraded prior to reaching the open ocean or more recently replaced by marine organic matter via a stripping process. Sediment samples along a transect extending from the Mississippi River Birdsfoot Delta to the Mississippi Canyon on the Louisiana continental shelf were examined by advanced analytical techniques, electrospray ionization coupled to a 12T Fourier transform ion cyclotron resonance mass spectrometer (ESI-FTICR-MS) and quantitative solid-state multiple cross polarization magic angle spinning (multi-CPMAS) ¹³C NMR in an effort to understand the …

Linking Decomposition Reactions In Arctic Soils To Microbial Enzyme Production, Jane Karen Martinez

Open Access Theses & Dissertations

Microbial processes such as soil enzyme production are a major driver of decomposition and a current topic of interest in arctic soils due to the effects of climate warming. Despite the advances in understanding soil enzymes, there are still knowledge gaps regarding the role of enzymes in decomposition. In this dissertation, I addressed three of those gaps in the following chapters: (Ch.2) to explore the location of enzymes within the soil matrix, (Ch.3) to identify peptides matched to soil enzymes produced by microorganisms for organic matter decomposition, and (Ch.4) understand the longevity of enzymes in the soil after microbial production. …

Dissolved Copper Distributions In The Western Mississippi Sound: Characterizing An Unrecognized Endmember, Megan Hansen

Honors Theses

This study examined the distribution of dissolved copper (Cu) in the western Mississippi Sound, as the element can be beneficial or harmful to organisms depending on its concentration and its chemical form. A mixing experiment eliminated flocculation as a control on Cu distributions during estuarine mixing in both dissolved and colloidal fractions. Field sampling of the western Mississippi Sound occurred during a low river discharge period, and distributions of Cu indicated conservative mixing between fresh ([Cu] ≈ 17 nM) and saline ([Cu] ≈ 2 nM) sources in mid-to-high salinities. Storm outfalls were sampled after rain events to evaluate the impact …

The Phosphorus Puzzle: Why Metal Phosphites Could Be The Missing Piece, Eleanor Boyle, Thomas J. Leyden Iii

Symposium of Student Scholars

It is well understood that phosphorylation of organic molecules is a keystone mechanism toward developing early cell function. However, the source of phosphorous in prebiotic chemistry is under debate. Phosphate minerals were abundant on the early Earth, but they are highly insoluble. In comparison, metal phosphites are significantly more soluble. While they may not have been preserved in the geological record, there are several plausible pathways for their formation under prebiotic conditions. We hypothesize that metal phosphites were a major source of phosphorus. To test our hypothesis, we synthesized and characterized metal phosphites, containing the most abundant cations on the …

The Effects Of Imposed Drought And Nutrient Availability On Soil Microbial Biomass And Enzyme Activity In A Long-Term Restored Grassland, Ashley A. Wojciechowski

2023 Midwest Ecology & Evolution Conference

Restoring agricultural lands back to grassland aims to reverse many negative impacts of agriculture on the ecosystem including nutrient export from soil and depletion of soil carbon. Planting prairie on agricultural soil promotes recovery of soil microbial biomass and their enzymes, which create demand for nitrogen by microbes to reduce the rate of nutrient cycling and loss. A complicating factor in the development of a restored grassland the influence of several anthropogenic global changes including increasing frequency of drought and nutrient enrichment. Drought has been found to negatively affect microbial biomass, soil enzyme activity and nutrient cycling. Nutrient (often N) …