Biogeochemistry Commons^™

Exploring Greenhouse Gas Emissions From Beaver Ponds In Southern Rhode Island, Molly K. Welsh, Arthur J. Gold, Kelly Addy, Julia Lazar

Senior Honors Projects

Climate change is one of the largest environmental issues facing humanity today, having the potential to alter fresh water availability, agricultural yields, forest productivity, and global sea levels. As climate change is likely to increase the intensity of extreme weather events, the potential for massive human and financial consequences is of further concern. The Intergovernmental Panel on Climate Change asserts that climate change is due to anthropogenic alterations of the atmosphere’s composition, with additional contributions from natural biochemical processes. In particular, the rapid increase in the concentrations of greenhouse gases (GHGs) in the atmosphere can trigger atmospheric warming as ...

Shellfish Harvest On The Coast Of British Columbia: The Archaeology Of Settlement And Subsistence Through High-Resolution Stable Isotope Analysis And Sclerochronology, Meghan Burchell

Open Access Dissertations and Theses

In many interpretations of hunter-gatherer settlement systems, archaeologists have assumed implicitly or explicitly that a pattern of mobilitybased on seasonally-scheduled movements between different site locations waspracticed. This pattern of mobility is often characterized as a seasonal round, where different locations are used during specific times of the year for different purposes. An implication of this pattern of mobility is that short-term occupation sites are visited annually, approximately at the same time each year and longer-term residential sites can span multiple seasons. To interpret seasonality, indirect indicators are often used but the high-resolution methods presented in this study provide direct evidence ...

Interpreting Stable Carbon And Nitrogen Isotope Ratios In Archaeological Remains: An Overview Of The Processes Influencing The Δ13c And Δ15n Values Of Type I Collagen, Alexander J. Leatherdale

Totem: The University of Western Ontario Journal of Anthropology

The application of isotopic ratio mass spectrometry to archaeological science has produced many important contributions to the study and understanding of ancient human and animal populations. Paleodietary reconstruction through the analysis of stable isotope ratios in skeletal, dental, and soft tissue remains presents another avenue for interpreting the past. The methodology employed to obtain isotopic data from archaeological remains directly influences the types of questions that can be addressed and the interpretation of the data. Furthermore, there are fundamental idiosyncrasies of archaeological specimens and their ante- and post-mortem environments that may influence the results of an isotopic study. This paper ...

Chemostratigraphy Of The Early Pliocene Diatomite Interval From Mis And-1b Core (Antarctica): Paleoenvironment Implications, Giovanna Scopelliti, Adriana Bellanca, Donata Monien, Gerhard Kuhn

ANDRILL Research and Publications

The AND-1B drill core (1285 m-long) was recovered, inside the ANDRILL (ANtarctic geological DRILLing) Program, during the austral summer of 2006/07 from beneath the floating McMurdo Ice Shelf. Drilling recovered a stratigraphic succession of alternating diamictites, diatomites and volcaniclastic sediments spanning about the last 14 Ma. A core portion between 350 and 480 mbsf, including a 80 m-thick diatomite interval recording the early Pliocene warming event, was investigated in term of opal biogenic content and element geochemistry. Across the diatomite interval, in spite of the lithological uniformity, a fluctuating biogenic opal profile mirrors the δ18O record, testifying a decrease ...

Topographic Influences On Trends And Cycles In Nutrient Export From Forested Catchments On The Precambrian Shield, Samson G. Mengistu

Electronic Thesis and Dissertation Repository

This dissertation explored topographic controls on spatial and temporal patterns in water yield and nutrient (carbon, nitrogen and phosphorus) export from forested headwater catchments in the Turkey Lakes Watershed in central Ontario, where other factors contributing to differences in water yield and nutrient export, including climate, geology, forest, and soils, are relatively constant. Topographic characteristics, including (a) hydrological flushing potential (expansion of water table into nitrate-N producing areas); (b) hydrological storage potential (area of wetlands, which can alternatively allow water and nutrients to bypass wetlands when storage capacity is filled with water or to trap them when not filled); and ...

Characterization Of Novel Ichnofossils In Meteorite Impact Glass From The Ries Impact Structure, Germany, Haley M. Sapers

Electronic Thesis and Dissertation Repository

The initial catastrophic biological effects of hypervelocity impacts are well established. However, a growing body of evidence suggests that meteorite impact events have beneficial effects for microbial life. This, in turn, has led many to suggest that impact craters may have been important habitats for life on early Earth. Any large meteorite impact into a water-rich target on a solid planetary body has the potential to generate hydrothermal systems. Impact-generated hydrothermal systems expand the potential environments for microbial colonization to environments without endogenous volcanic heat sources to drive hydrothermal activity. Examination of impact glass from the Ries impact structure, Germany ...

Understanding Magnetosome Formation And Organization Using Scanning Transmission X-Ray Microscopy – X-Ray Magnetic Circular Dichroism, Samanbir Kalirai

Open Access Dissertations and Theses

Magnetotactic bacteria (MTB) are ubiquitous, multi-phylogenetic bacteria that actively synthesize chains of magnetic, membrane bound; single domain magnetite (Fe₃O₄) or greigite (Fe₃S₄) crystals, termed magnetosomes in order to better navigate to their preferred chemical environment using the Earth’s magnetic field. Discovered in 1963, the field is now focused on understanding magnetosome chain formation and associated processes through genetic studies as well as analytical techniques such as Transmission Electron Microscopy (TEM) and Scanning Transmission X-ray Microscopy – X-ray Magnetic Circular Dichroism (STXM-XMCD).

This thesis performed studies on Candidatus Magnetovibrio blakemorei strain MV-1 using STXM at ...

Interactions Of Zooplankton And Phytoplankton With Cyanobacteria, Rebecca Alexander

Dissertations & Theses in Natural Resources

Cyanobacteria are a major concern in Nebraska reservoirs and are capable of producing toxins that can cause skin irritations and gastrointestinal problems, as well as affect the nervous system. It is important to determine the mechanisms that can cause cyanobacteria blooms due to the effect they can have on human health. The interaction of zooplankton and other phytoplankton groups with cyanobacteria is important because there is a biological component in surface waters that should be taken into consideration along with the physical and chemical parameters that have been noted to promote cyanobacteria. For example, zooplankton have the ability to alter ...

Investigating Diet And Regional Origins In The Smith's Knoll Skeletal Sample, Stoney Creek, Using Stable Isotopes, Matthew V. Emery

Open Access Dissertations and Theses

This thesis uses stable isotopic analysis to identify diet, geographic origins and long-term residency in a sub-sample of the Smith’s Knoll skeletal collection, soldiers who died during the June 6^th 1813 Battle of Stoney Creek. The major objectives of this study have been to differentiate between two major modes of dietary consumption, one wheat-based, the other maize-based, in an attempt to decipher British colonial from American soldiers. These objectives were paired with stable oxygen and strontium isotopes, two isotopic elements presently used to identify migration and regional origins. Oxygen isotopic results from teeth suggest that, as children, 5 ...

Soil Nutrient Composition In Afromontane Forests Of Northern Ethiopia, Maria Baimas-George

Colgate Academic Review

Deforestation in the northern highlands of Ethiopia has left 35,000 forest fragments ranging in size from 3 to 300 ha (Bongers et al 2006). Deforestation produces edges which increase disturbance within the forest such as decreased water availability and increased light. To determine the degree of these edge effects and the nutrient status of these forests, I analyzed the nutrient composition of soils along a gradient from pasture, exterior forest, interior forest and canopy. I examined two forests at different elevations: Bahir Dar (1800 m) and Debre Tabor (2800 m). Deforestation had a strong, negative effect on soil nutrients ...