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Articles 1 - 8 of 8
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The Effects Of Sediment Acidification And Temperature On The Immune Capacity Of The Atlantic Jackknife (Razor) Clam (Ensis Leei M. Huber, 2015), Brian Preziosi
The Effects Of Sediment Acidification And Temperature On The Immune Capacity Of The Atlantic Jackknife (Razor) Clam (Ensis Leei M. Huber, 2015), Brian Preziosi
Electronic Theses and Dissertations
Sediment acidification has been shown to negatively impact clams of economic importance such as the soft-shell clam, Mya arenaria Linnaeus, 1758, and hard clam, Mercenaria mercenaria (Linnaeus, 1758). Effects of sediment acidification on razor clams, including the Atlantic jackknife clam Ensis leei M. Huber, 2015, are unknown. E. leei has been identified as a species with potential for aquaculture operations on the New England coast. E. leei may be resilient to acidification and thus persist in acidified sediments where other clams cannot. To this end, the impact of acidified surface sediment on the internal immune capacity of adult (mean shell …
Mechanisms Of Ice Core Stable Isotope Variability In The Upper Kaskawulsh-Donjek Region, St. Elias Mountains, Yukon, Canada, Erin A. Mcconnell
Mechanisms Of Ice Core Stable Isotope Variability In The Upper Kaskawulsh-Donjek Region, St. Elias Mountains, Yukon, Canada, Erin A. Mcconnell
Electronic Theses and Dissertations
I use instrumental and ice core records to examine drivers of observed isotope variability in the Upper Kaskawulsh-Donjek (UKD) region of the St. Elias Mountains, Yukon, Canada over the time frame of instrument-proxy overlap (mid-1900s to present). One of the drivers of post-depositional isotope signal alteration is the vertical percolation of meltwater from the glacier surface through shallow layers of snow, which causes a reduction in the amplitude of the isotope signal recorded in ice cores. I examine isotope signal preservation in two sites in the St. Elias Mountains: Eclipse Icefield and Icefield Divide. These sites are relatively close (~30 …
Fractures, Fluids, And Metamorphism: Shear Zone Initiation In The Marcy Anorthosite Massif, Adirondacks, New York, Usa, James Hodge
Electronic Theses and Dissertations
Localized shear zones are important rheological features that influence deformation behavior throughout the Earth’s middle-to-lower crust. Therefore, the processes through which shear zones initiate and localize remains an important geologic question. The study of strain localization and shear zone initiation is made difficult due to continued deformation overprinting the microstructures which lead to initiation and obfuscating the context in which localization occurred. The Marcy anorthosite in the Adirondack Highlands, New York, is a nominally granulite-facies, plagioclase-rich massif cut by centimeter-to-meter scale shear zones which provides a natural example of shear zone localization within the middle-to-lower crust. My work focuses on …
Improved Estimates Of Tributary Nitrogen Load To Casco Bay, Maine, Whitley J. Gray
Improved Estimates Of Tributary Nitrogen Load To Casco Bay, Maine, Whitley J. Gray
Electronic Theses and Dissertations
Over the past two decades, total nitrogen (TN) concentrations have increased in Casco Bay (CBEP 2015). The sources of the increased nitrogen are poorly understood but occur with simultaneous population growth and land use changes. The total riverine nitrogen load to Casco Bay was previously estimated by Liebman and Milstead (2012) using the United States Geologic Survey’s (USGS) SPAtially Referenced Regression On Watershed attributes (SPARROW) model. The SPARROW model uses watershed characteristics, regional monitoring data and nitrogen source data to estimate nitrogen loading but was not validated using measurements of nitrogen in the Casco Bay watershed. This study attempts to …
A Multi-Proxy Paleoecological Reconstruction Of Holocene Climate, Vegetation, Fire And Human Activity In Jamaica, West Indies, Mario A. Williams
A Multi-Proxy Paleoecological Reconstruction Of Holocene Climate, Vegetation, Fire And Human Activity In Jamaica, West Indies, Mario A. Williams
Electronic Theses and Dissertations
Jamaica is located in the Caribbean biodiversity hotspot and has a rich flora and fauna, most notably characterized by exceptional levels of plant endemism. These natural resources are imperiled by climate change and increasing anthropogenic pressures, therefore highlighting the importance of implementing effective conservation programs to mitigate ecosystem degradation. Paleoecological studies that investigate the diversity and distributions of organisms and their habitats over millennial timescales provide critical long-term spatial and temporal context for the assessment of contemporary environmental problems. Lake sediments are a highly useful archive for the study of prehistoric climate and ecological changes, as biological, chemical and geophysical …
Past, Present, And Future Arctic Climate And National/Community Risk Assessment, Jeff Auger
Past, Present, And Future Arctic Climate And National/Community Risk Assessment, Jeff Auger
Electronic Theses and Dissertations
The Arctic is warming at a rate nearly double that of the global average. The enhanced rate of warming impacts weather and climate across the Northern Hemisphere. As the meridional (south to north) thermal gradient weakens, the middle-latitude westerlies are expected to slow and become “wavier” increasing heat and moisture advection to higher latitudes. A quasi-stationary ridge-trough system of the jet stream increases chances for droughts, floods, heatwaves, and cold spells. These impacts have already been observed as North American forest fires and early or extended Great Lake ice out. It is more important than ever to understand how the …
Determining The Influence Of Lateral Margin Mechanical Properties On Glacial Flow, Kate Hruby
Determining The Influence Of Lateral Margin Mechanical Properties On Glacial Flow, Kate Hruby
Electronic Theses and Dissertations
The lateral margins of glaciers and ice streams play a significant role in glacial flow. Depending on their properties, like temperature and ice crystal orientation, they can cause a resistance to flow or enhance it. In combination with our current changing climate, flow patterns can dictate the mass balance of an ice body. It is therefore more important than ever to understand the impact that variations at the margins can have on flow. However, the lateral margins of glaciers and ice streams are an often-neglected part of ice dynamics; they are harder to sample than the center of a glacier’s …
Root Biomass And Other Soil Properties Affecting The Co2 Flush From Laboratory Dried And Rewetted Soils, Audrey E. Laffely
Root Biomass And Other Soil Properties Affecting The Co2 Flush From Laboratory Dried And Rewetted Soils, Audrey E. Laffely
Electronic Theses and Dissertations
Soil that has been dried and rewetted has been observed to release a ‘burst’ or ‘flush’ of carbon dioxide (CO 2 ) upon rewetting. This CO 2 flush has been proposed as an indicator of soil health. This may be a valuable indicator of soil health, however the CO 2 flush has yet to be fully evaluated. Roots and root exudates influence the soil in a variety of ways that may impact the CO 2 flush, such as increasing aggregation, organic carbon (C), and microbial biomass. We conducted both field and greenhouse experiments to elucidate the relationship of root biomass …