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Full-Text Articles in Physical Sciences and Mathematics

Sediment Resuspension In A Microtidal Estuary: Causative Forces And Links With Algal Blooms, Samantha C. Mcgill Oct 2019

Sediment Resuspension In A Microtidal Estuary: Causative Forces And Links With Algal Blooms, Samantha C. Mcgill

OES Theses and Dissertations

After years of efforts to restore the Chesapeake Bay, bacterial levels are down and species diversity has increased, however, algal blooms (primarily dinoflagellates) persist, occurring nearly every summer. Dinoflagellates produce resting cysts that accumulate in the bottom sediments and are thought to provide seed populations for future algal blooms when they are resuspended. When estuarine sediments are advected from a bed, other materials, such as pollutants, nutrients, and organic matter are also released into the water column. Thus, resuspended sediments can contribute to the degradation of water quality, habitat, and aquatic life, and impart negative impacts on local ecosystems and …


Circum-Arctic Mineralogy & Pan-Arctic Chronostratigraphy Of Late Pleistocene Sediments: Developing A Comprehensive Age Model For The Western Arctic Ocean Using Unique Ice-Rafted Signals, Wesley Blake Myers Oct 2019

Circum-Arctic Mineralogy & Pan-Arctic Chronostratigraphy Of Late Pleistocene Sediments: Developing A Comprehensive Age Model For The Western Arctic Ocean Using Unique Ice-Rafted Signals, Wesley Blake Myers

OES Theses and Dissertations

To improve understanding of geographic mineral distribution from the circum-Arctic Ocean, samples from the Arctic periphery were collected and analyzed for (semi-) quantitative mineral composition. Most samples were collected from the North American region of the Arctic Ocean, a region which has had limited mineral investigation. In addition, more than 1000 published clay mineral data points were gathered to provide the most comprehensive clay mineral distribution map to date. The identification of a smectite source within the Canadian Arctic may reduce the usefulness of this mineral as a unique provenance signal for the Eurasian region. Smectite speciation may be useful …


The Evolution Of The El Niño-Southern Oscillation And Tropical Pacific Climate Across The Last Deglaciation, Ryan Hunter Glaubke Jul 2019

The Evolution Of The El Niño-Southern Oscillation And Tropical Pacific Climate Across The Last Deglaciation, Ryan Hunter Glaubke

OES Theses and Dissertations

The El Niño – Southern Oscillation (ENSO) is the largest interannual component of Earth’s climate system, capable of exerting significant influence over global climate patterns that affect communities around the globe. Nevertheless, a comprehensive understanding of the ENSO system and its relationship to tropical Pacific climate dynamics remains unclear. Although new paleoceanographic proxies have shown promise in in their ability to constrain past ENSO change, little is known about how ENSO varied in response to millennial-scale climate events over the last 25,000 years. Here, I present new records of tropical Pacific mean state and ENSO variability over the last 25,000 …


Nutrient Controls Over Cyanobacterial Synthesis Of The Neurotoxin Β-N-Methylamino-L-Alanine (Bmaa) And Its Potential Accumulation In The Blue Crab (Callinectes Sapidus), Madeline M. Hummel Jul 2019

Nutrient Controls Over Cyanobacterial Synthesis Of The Neurotoxin Β-N-Methylamino-L-Alanine (Bmaa) And Its Potential Accumulation In The Blue Crab (Callinectes Sapidus), Madeline M. Hummel

OES Theses and Dissertations

Cyanobacteria are known to produce a variety of toxins that negatively impact both aquatic and terrestrial organisms. One putative neurotoxic compound is the non-protein amino acid β-N-methylamino-L-alanine (BMAA), which has epidemiological linkages to the development of several human neurological diseases. Three cyanobacterial species thought to produce BMAA —Microcystis aeruginosa, Synechococcus bacillaris, and Nostoc sp. —were grown in nutrient replete cultures to examine its synthesis and cellular distribution over a growth cycle. Production of BMAA was also examined in nutrient (nitrogen and phosphorus) deplete cultures of Microcystis aeruginosa. In addition, natural assemblages of phytoplankton dominated by …


Lipid Biomarkers Of Bering And Chukchi Sea Euphausiids And Their Application To Diet History, Rachel L. Pleuthner Jul 2019

Lipid Biomarkers Of Bering And Chukchi Sea Euphausiids And Their Application To Diet History, Rachel L. Pleuthner

OES Theses and Dissertations

In the eastern Bering Sea, Thysanoessa raschii are the most abundant krill species and a keystone trophic member that serve as both an important grazer and link to upper level consumers. In this system krill experience large annual variation in food resources, especially during ice advance and retreat; multiple lipid classes are used to temper the effects of those fluctuations, as well as to fuel reproduction and growth. Two shipboard feeding experiments that occurred during late spring and early summer of 2010, respectively, monitored the lipid retention in adult T. raschii and examined the fluctuation of specific lipid biomarkers under …


Coupling Metaproteomics With Taxonomy To Determine Responses Of Bacterioplankton To Organic Perturbations In The Western Arctic Ocean, Molly P. Mikan Apr 2019

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 …