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Full-Text Articles in Physical Sciences and Mathematics
Spatial Variation In Tooth Shape Of Miocene Populations Of Carcharocles Megalodon Across Ocean Basins, Maxwell John Bertsos
Spatial Variation In Tooth Shape Of Miocene Populations Of Carcharocles Megalodon Across Ocean Basins, Maxwell John Bertsos
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The extinct Lamniform species, Carcharocles megalodon, were some of the most geographically widespread apex predators in the fossil record. However, whether this cosmopolitan distribution was related to population level differences is unknown. The objective of this study is to assess whether variation in tooth morphology coincided with geographic dispersal. The underlying hypothesis is that variation in an aspect of functional morphology, such as tooth shape, suggests some level of population structuring. Detecting this relationship could potentially provide a mechanism that links population to functional relationships inherent in tooth morphology that may reflect period differences in ocean basins. This would offer …
Mercury Distributions And Cycling In The North Atlantic And Eastern Tropical Pacific Oceans, Katlin L. Bowman
Mercury Distributions And Cycling In The North Atlantic And Eastern Tropical Pacific Oceans, Katlin L. Bowman
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The distribution of mercury (Hg) in the ocean is complex as a result of in situ chemical transformations and inputs from natural and anthropogenic sources. Within the ocean, inorganic Hg is methylated to monomethylmercury (MMHg), which bioaccumulates and biomagnifies in marine food webs and poses a health risk to humans who eat fish. The biogeochemistry of Hg in the ocean has been studied for decades, however, recently improved sampling and analytical techniques have allowed for an enhanced understanding of global distributions of different Hg species. This dissertation uses a newly developed method for the analysis of MMHg that improves detection …
Trace Metals In Sediments On The Continental Margin Of The Northwest Atlantic Ocean, Daniel L. Marsh
Trace Metals In Sediments On The Continental Margin Of The Northwest Atlantic Ocean, Daniel L. Marsh
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Trace metals in the ocean are derived from natural and anthropogenic sources. Despite increased human impact on the marine environment and biological productivity of continental margins, trace metal studies in marine sediments have focused primarily on near-shore regions. I investigated 22 metals in sediments on the continental margin of the northwest Atlantic Ocean to calculate enrichment factors (EF) relative to upper continental crust and identify spatial variations with distance from shore and depth below the sediment-seawater interface. Metals were well correlated with Al, Fe, organic matter, or CaCO3. No clear trends in metal EFs with distance from shore were evident …