Substrate Quality And Concentration Control Decomposition And Microbial Strategies In A Model Soil System,
2019
University of New Hampshire, Durham
Substrate Quality And Concentration Control Decomposition And Microbial Strategies In A Model Soil System, Jorg Schnecker, Timothy Bowles, Erik A. Hobbie, Richard G. Smith, A. Stuart Grandy
Faculty Publications
Soil carbon models typically scale decomposition linearly with soil carbon (C) concentration, but this linear relationship has not been experimentally verified. Here we investigated the underlying biogeochemical mechanisms controlling the relationships between soil C concentration and decomposition rates. We incubated a soil/sand mixture with increasing amounts of finely ground plant residue in the laboratory at constant temperature and moisture for 63 days. The plant residues were rye (Secale cereale, C/N ratio of 23) and wheat straw (Triticum spp., C/N ratio of 109) at seven soil C concentrations ranging from 0.38 to 2.99%. We measured soil respiration, dissolved organic carbon (DOC) …
The Potential Acidification Of The Mulberry River, Arkansas,
2019
University of Arkansas, Fayetteville
The Potential Acidification Of The Mulberry River, Arkansas, Jason Richard Burgess-Conforti
Graduate Theses and Dissertations
The Mulberry River is a 110 km long tributary of the Arkansas River in northwest Arkansas and has been designated as a National Wild and Scenic River since 1992. In 2008, the Mulberry River was added to the 303(d) list of impaired water bodies due to the low pH of a 14.6 km segment of the river which has since increased to 68.7 km. To date, there has been little research performed on the Mulberry River and long-term routinely sampled water quality data is unavailable. The objectives of this dissertation were 1) to evaluate changes in water quality of the …
Losses Of Mineral Soil Carbon Largely Offset Biomass Accumulation Fifteen Years After Whole-Tree Harvest In A Northern Hardwood Forest,
2019
University of New Hampshire, Durham
Losses Of Mineral Soil Carbon Largely Offset Biomass Accumulation Fifteen Years After Whole-Tree Harvest In A Northern Hardwood Forest, Matthew A. Vadeboncoeur, Steven P. Hamburg, Chris E. Johnson, Jonathan Sanderman
All Materials
Changes in soil carbon stocks following forest harvest can be an important component of ecosystem and landscape-scale C budgets in systems managed for bioenergy or carbon-trading markets. However, these changes are characterized less often and with less certainty than easier-to-measure aboveground stocks. We sampled soils prior to the whole-tree harvest of Watershed 5 at the Hubbard Brook Experimental Forest in 1983, and again in years 3, 8, and 15 following harvest. The repeated measures of total soil C in this stand show no net change in the O horizon over 15 years, though mixing with the mineral soil reduced observed …
Dissolved Inorganic Nitrogen Dynamics In Swash Zone Sands Of Long Bay, Sc,
2019
Coastal Carolina University
Dissolved Inorganic Nitrogen Dynamics In Swash Zone Sands Of Long Bay, Sc, Alexis F. Echols
Honors Theses
A key component affecting the biogeochemistry of the sedimentary environment is pore water between grains of sediments. Sedimentary microorganisms are constantly modifying chemical compounds as part of their life functions which are then exchanged between the sediment column and the overlying water column. Dissolved inorganic nitrogen, a major element for life, takes on several forms including nitrate, nitrite, and ammonium which vary in concentration throughout the sediment and with respect to each other. The relative concentrations of these nitrogen species have been previously briefly explored in sandy columns, where redox gradients that control their relative concentrations can be fairly deep …
Character And Water Quality Of Sandpiper Pond: A Coastal Pond Assessment, Fifteen Years After Restoration,
2019
Coastal Carolina University
Character And Water Quality Of Sandpiper Pond: A Coastal Pond Assessment, Fifteen Years After Restoration, Nicholas E. Workman
Honors Theses
Sandpiper Pond is a coastal pond at Huntington Beach State Park, South Carolina. Originally a tidal inlet surrounded by marshland, it was isolated in 1989 and rechanneled in 2004-2005 under a community-based wetland restoration project. The project was designed to restore the pond to a tidal inlet to improve water quality and biodiversity. Since then, the tidal connection with the ocean has been severed once more and the main influx of seawater occurs from the marsh during spring high tides. In this three-month study, the current state of Sandpiper Pond is evaluated using fundamental biogeochemical indicators that are indicative of …
Coupling Metaproteomics With Taxonomy To Determine Responses Of Bacterioplankton To Organic Perturbations In The Western Arctic Ocean,
2019
Old Dominion University
Coupling Metaproteomics With Taxonomy To Determine Responses Of Bacterioplankton To Organic Perturbations In The Western Arctic Ocean, Molly P. Mikan
OES Theses and Dissertations
Understanding how the functionality of marine microbial communities change over time and space, and which taxonomic groups dominate distinct metabolic pathways, are essential to understanding the ecology of these microbiomes and the factors contributing to their regulation of elemental cycles in the oceans. The primary goal of this dissertation was to investigate the community metabolic and taxonomic responses and the degradation potential of two compositionally distinct marine microbiomes within the shallow shelf ecosystem of the Chukchi Sea after rapid fluctuations in algal organic matter availability. Novel bioinformatics tools were collaboratively developed and used together with community proteomics (metaproteomics) to characterize …
Spatiotemporal Variation Of Benthic Silica Fluxes In The Ngom Shelf,
2019
Louisiana State University
Spatiotemporal Variation Of Benthic Silica Fluxes In The Ngom Shelf, Byron Ebner
LSU Master's Theses
Dissolved silica (DSi), plays an important role in regulating primary productivity of silicifying organisms, such as diatoms which precipitate hard parts composed of biogenic silica (bSi) in coastal and shelf ecosystems fed by major rivers. In the Northern Gulf of Mexico (NGOM), loading of nitrogen and phosphorous have increased compared to a decline in DSi in the Mississippi River. Continued decreasing in DSi loading could lead to limited diatom growth and production or shifts in community composition, therefore, it is important understand the role of benthic fluxes in providing silica to the overlying water column as there are few regional …
Data For Paper "Microbial Generation Of Elemental Mercury From Dissolved Methylmercury In Seawater",
2019
SUNY Stony Brook
Data For Paper "Microbial Generation Of Elemental Mercury From Dissolved Methylmercury In Seawater", Cheng-Shiuan Lee, Nicholas S. Fisher
SoMAS Research Data
Elemental mercury (Hg0) formation from other mercury species in seawater results from photoreduction and microbial activity, leading to possible evasion from seawater to overlying air. Microbial conversion of monomethylmercury (MeHg) to Hg0 in seawater remains unquantified. A rapid radioassay method was developed using gamma-emitting 203Hg as a tracer to evaluate Hg0 production from Hg(II) and MeHg in the low pM range. Bacterioplankton assemblages in Atlantic surface seawater and Long Island Sound water were found to rapidly produce Hg0, with production rate constants being directly related to bacterial biomass and independent of dissolved Hg(II) and MeHg …
Iron Mediated Organic Preservation In A River Influenced Continental Margin,
2019
Louisiana State University
Iron Mediated Organic Preservation In A River Influenced Continental Margin, Neha Ajit Ghaisas
LSU Doctoral Dissertations
Continental margins such as the Mississippi river influenced Louisiana shelf (MIS), are important land-ocean interfaces where excessive water column productivity and rapid burial results in large amounts of organic carbon (OC) being sequestered in the sediments. The preservation of OC in sediments is controlled by a number of processes among which mineral-OC interactions are considered to be more important. Specifically, the interactions between sediment iron (Fe) species and OC have been shown to promote carbon preservation. However, the exact nature of preservation mechanism is not well understood and is based on limited global data, which specifically lacks estimates from large …
Evaluating Seasonal Nutrient Fluxes In Emerging And Eroding Wetlands Of The Louisiana Delta Plain,
2019
Louisiana State University and Agricultural and Mechanical College
Evaluating Seasonal Nutrient Fluxes In Emerging And Eroding Wetlands Of The Louisiana Delta Plain, Kiran Upreti
LSU Doctoral Dissertations
Deltaic wetlands can ameliorate high NO3- loads via denitrification, a dominant NO3- reduction pathway in inland and coastal habitats. Dissimilatory Nitrate Reduction to Ammonia (DNRA), in contrast to denitrification, conserves N within the system and has been found to be favored over denitrification with increase in salinity and temperature. There are no studies in the Louisiana Deltaic plain with simultaneous estimation of denitrification and DNRA. Increased P availability has been shown to increase denitrification so it is essential to understand P biogeochemistry when studying N cycle. Here, we evaluated net denitrification using N2:Ar and …
Soil Macroinvertebrate Presence Alters Microbial Community Composition And Activity In The Rhizosphere,
2019
Cornell University
Soil Macroinvertebrate Presence Alters Microbial Community Composition And Activity In The Rhizosphere, Natalie Bray, Jenny Kao-Kniffin, Serita D. Frey, Timothy Fahey, Kyle Wickings
Faculty Publications
Soil Macroinvertebrate Presence Alters Microbial Community Composition and Activity in the Rhizosphere
Restoration Of Soil Microbial Function Following Degradation On Department Of Defense Lands: Mediating Biological Invasions In A Global Change Context,
2019
University of Massachusetts, Amherst
Restoration Of Soil Microbial Function Following Degradation On Department Of Defense Lands: Mediating Biological Invasions In A Global Change Context, Kristina Stinson, Serita D. Frey
Faculty Publications
This project was designed to better understand the roles of soil biota in 1 mediating native species-NIS interactions and 2 facilitating the recovery of degraded ecosystems. The associated Research Needs were listed as follows 1. To quantify the functional diversity of soil biota and the role of key taxa in maintaining desired functional ecosystem attributes 2. To identify processes by which desired soil properties and associated soil biotic communities are degraded by NIS invasion and test potential mechanisms to restore them 3. To examine the role of disturbance in determining the functional attributes of the soil community 4. To test …
The Microbiome Stress Project: Toward A Global Meta-Analysis Of Environmental Stressors And Their Effects On Microbial Communities,
2019
Duke University
The Microbiome Stress Project: Toward A Global Meta-Analysis Of Environmental Stressors And Their Effects On Microbial Communities, Jennifer D. Rocca, Marie Simonin, Joanna R. Blaszczak, Jessica G. Ernakovich, Sean M. Gibbons, Firas S. Midani, Alex D. Washburne
Faculty Publications
Microbial community structure is highly sensitive to natural (e.g., drought, temperature, fire) and anthropogenic (e.g., heavy metal exposure, land-use change) stressors. However, despite an immense amount of data generated, systematic, cross-environment analyses of microbiome responses to multiple disturbances are lacking. Here, we present the Microbiome Stress Project, an open-access database of environmental and host-associated 16S rRNA amplicon sequencing studies collected to facilitate cross-study analyses of microbiome responses to stressors. This database will comprise published and unpublished datasets re-processed from the raw sequences into exact sequence variants using our standardized computational pipeline. Our database will provide insight into general response patterns …
Influence Of Ligand Complexation On Nickel Toxicity, Speciation And Bioavailability In Marine Waters,
2019
Wilfrid Laurier University
Influence Of Ligand Complexation On Nickel Toxicity, Speciation And Bioavailability In Marine Waters, Samantha Sherman
Theses and Dissertations (Comprehensive)
Currently there are no site-specific bioavailability-based prediction models for assessing the impacts of nickel (Ni) in marine environments although there are indications that these may be warranted. The aim of this research was to characterize the complexation of Ni in relation to toxicity and speciation. Various complexing ligands were used, and it was predicted that the binding affinity (logKf) of ligands would be inversely correlated to toxicity based on dissolved Ni concentrations ([NiD]) but that on a free ion concentration ([Ni2+]) basis, toxicity would not vary. A two-phased approach was used; the first was a proof of principle where synthetic …
Resuscitation Of Microalgae From Mississippi River Plume Sediments,
2019
Auburn University
Resuscitation Of Microalgae From Mississippi River Plume Sediments, Chase C. Chaplin, Marnie Tabor, Israel A. Marquez, Kanchan Maiti, Jeffrey W. Krause
Gulf and Caribbean Research
No abstract provided.
Seasonal Soil Carbon Fluxes In Transitioning Agricultural Soils In Central Washington State: Relations To Land-Use, Environmental Factors And Soil Carbon-Nitrogen Characteristics,
2019
Central Washington University
Seasonal Soil Carbon Fluxes In Transitioning Agricultural Soils In Central Washington State: Relations To Land-Use, Environmental Factors And Soil Carbon-Nitrogen Characteristics, Brandon Kautzman
All Master's Theses
Changing agricultural land-use practices to increase soil carbon sequestration contributes to climate change mitigation and improved food security by moving CO2 from the atmosphere into soil as soil organic carbon (SOC). In 2016, a farm in Thorp, Washington, Spoon Full Farm, began converting land historically farmed using conventional methods of tillage and synthetic fertilizers to conservation farming methods with direct seeding and organic soil amendments with a goal of sequestering carbon in the soil. This project evaluates relationships of soil CO2 respiration and net ecological exchange (NEE) with land-use types, seasonal environmental factors (air temperature, relative humidity, soil …
Carbon In The Deep Biosphere: Forms, Fates, And Biogeochemical Cycling,
2019
University of South Carolina - Columbia
Carbon In The Deep Biosphere: Forms, Fates, And Biogeochemical Cycling, Susan Q. Lang, Magdalena R. Osburn, Andrew D. Steen
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 …
The Role Of Small Reservoirs In Reducing Reactive N Export Via Denitrification,
2019
University of New Hampshire, Durham
The Role Of Small Reservoirs In Reducing Reactive N Export Via Denitrification, Margaret Phillips, Wil Wollheim
Honors Theses and Capstones
Reactive nitrogen (N), which harms ecosystem health, has been increasing in the biosphere, leading to higher N export to coastal ecosystems. Although man-made reservoirs can be significant sources of greenhouse gases, they can also retain N, thus reducing N export. Because many dams are relics from industrial hydropower, their removal is becoming increasingly common. It is therefore crucial to understand the ecological tradeoffs of man-made reservoirs. While previous studies have examined nutrient budgets and denitrification at inputs and outputs of large reservoirs, small reservoir dynamics remain understudied. In this study, we measured inputs and outputs of NO3 and N …
Compositions And Structures Of Particulate And Colloidal Organic Matter In Aquatic Environment By Advanced Analytical Techniques,
2019
Guangzhou Institute of Geochemistry
Compositions And Structures Of Particulate And Colloidal Organic Matter In Aquatic Environment By Advanced Analytical Techniques, Yong Ran, Dainan Zhang, Shujie Hu, Yu Yang, Jingdong Mao
Chemistry & Biochemistry Faculty Publications
Dissolved, colloidal and particulate organic matter (DOM, COM and POM) is important in the global carbon cycle and knowledge of their sources and structures can be critical to understanding their roles in biogeochemical cycles. This study explored the sources and chemical structures of COM and POM samples from the Pearl River Basin, China by elemental, chlorophyll a (Chl a), radiocarbon and stable carbon isotopic analyses, NMR techniques, and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis. The chemical and nano-sclae structures of two ultrafiltered dissolved organic matter (UDOM) samples from surface seawater of the Pacific and Atlantic Ocean …
Utilizing Lipid Biomarkers To Understand The Microbial Community Structure Of Deep Subsurface Black Shale Formations,
2019
West Virginia University
Utilizing Lipid Biomarkers To Understand The Microbial Community Structure Of Deep Subsurface Black Shale Formations, Rawlings Akondi
Graduate Theses, Dissertations, and Problem Reports (ETD)
The deep subsurface environment has been known to host microbes as early as 1926 and has also been suggested to potentially account for as much as 50% of the Earth`s biomass. Researchers have shown that microbes alter their membrane lipid components in response to physiological stress, producing stress indicative lipid biomarkers. However, little effort has been made to understand the subsurface microbial community of the shale ecosystem which is increasingly being exploited and altered by addition of drilling and hydraulic fluids to meet our growing energy needs. Phospholipid fatty acids (PLFAs) are microbial lipid biomarkers and are found in all …
