Physical Sciences and Mathematics Commons^™

The Role Of Microbial Exopolymers In Determining The Fate Of Oil And Chemical Dispersants In The Ocean, Antonietta Quigg, Uta Passow, Wei-Chun Chin, Chen Xu, Shawn Doyle, Laura Bretherton, Manoj Kamalanathan, Alicia K. Williams, Jason B. Sylvan, Zoe V. Finkel, Anthony H. Knap, Kathleen A. Schwehr, Saijin Zhang, Luni Sun, Terry L. Wade, Wassim Obeid, Patrick G. Hatcher, Peter H. Santschi

Chemistry & Biochemistry Faculty Publications

The production of extracellular polymeric substances (EPS) by planktonic microbes can influence the fate of oil and chemical dispersants in the ocean through emulsification, degradation, dispersion, aggregation, and/or sedimentation. In turn, microbial community structure and function, including the production and character of EPS, is influenced by the concentration and chemical composition of oil and chemical dispersants. For example, the production of marine oil snow and its sedimentation and flocculent accumulation to the seafloor were observed on an expansive scale after the Deepwater Horizon oil spill in the Northern Gulf of Mexico in 2010, but little is known about the underlying …

Discrimination Of Subparallel Beach Ridges Using Detrital Ilmenite Composition And Fourier Shape Analysis, Allen E. Evans Jr.

OES Theses and Dissertations

Elemental composition (Fe, Ti, Mn, Mg, V, Cu, Ni, Zn, and Cr) and Fourier shape analysis of magnetically separated detrital ilmenite from seven Pleistocene and modern beach sand deposits of the Southeastern Virginia Coastal Plain were used to distinguish each deposit. Geomorphic expression, crosscutting relationships and proximity to the present shoreline differentiates the relative age of the seven sampled beach deposits. Analysis of ilmenite elemental composition, independent of geomorphic expression, distinguished beach sands of

different age and was successful in determining that each beach contained ilmenite similar in composition. Of the seven beach ridges tested, subtle yet significant differences in …

Depositional Model For The Auriferous Gravels In The Payan Mining District Department Of Narino, Columbia, South America, Jim R. Garrett

OES Theses and Dissertations

Unlike placer deposits in arid and semi-arid environments where gold concentration is closely tied to the position of the bedrock, Payan placer deposits have no association with bedrock. Gold concentration values show highest gold concentrations occur at the contact of a coarse sand unit and its underlying gravel unit. Comparisons of the size and shape distributions of gold grain populations with their associated black sand populations indicate the gold and black sand were not deposited in hydraulic equilibrium. The mean size of each gold population is consistently coarser than the mean size of its associated black sand population despite the …

Stability And Local Effects Of An Offshore Sand Storage Mound, Dam Neck Disposal Site, Virginia Inner Continental Shelf, William Joslyn Saumsiegle

OES Theses and Dissertations

From 1967 to 1974 medium to coarse sand dredged from the Chesapeake Bay was stockpiled approximately three miles offshore of Dam Neck, Virginia in hopes that the sand could be recovered for local beach renourishment projects. The resulting mound was surveyed over a two year period to determine if the sand is being removed by wave and current action and if the creation of a new feature on the ocean bottom changes the wave refraction patterns and perhaps creates local erosion.

Bathymetric profiles across the storage mound show some apparent morphological changes, but a detailed analysis of this data is …