Masters of Science / Located on the western offshore on the Atlantic Ocean margin of Southern Africa, the Orange Basin is the youngest and largest of the South Africa’s seven sedimentary basins. This passive margin basin in known for its hydrocarbon potential and therefore is the focus of attraction of several oil exploration companies. The study area lies near the continental margin in which four exploratory wells were drilled. An attempt has been made in this work to understand the depositional settings of these reservoirs and their biostratigraphy. Distribution of important planktonic index foraminifera helps in dating the reservoir sections. Paleoecological studies of benthic foraminifera were used for understanding the prevailing environment during the Cretaceous period. The study indicates that most of the reservoirs are distributed in the Albian (Early Cretaceous) and a few in the Cenomanian age sediments. Relatively shallow shelf sedimentation prevailed in the Late Aptian to middle part of Albian with deposition of arenaceous units. There were periodic localised deepening as well as very shallow depositional condition leading to exposure (diastem) as indicated by lithology and faunal composition. Gradual rise in sea level started in Late Albian and the entire area was under bathyal environment till the end of Cenomanian stage. This is indicated by deposition of claystone rich units and the associated fossil benthics indicates deposition in slope area. The few relatively minor argillaceous sandstone and siltstone units are with poor reservoir quality.

Beca JAE-Predoctoral CISC; Proyecto LARECO CTM2011-25929

In this paper spectral solar zenith radiances are analyzed which were obtained from ship–based measurements over the Atlantic ocean. In combination with high–resolution lidar and microwave remote sensing optical and microphysical cloud properties were retrieved using spectral radiation data. To overcome problems of existing transmissivity–based cloud retrievals, a new retrieval algorithm is introduced which circumvents retrieval ambiguities and reduces the influence of measurement uncertainties. The method matches radiation measurements of ratios of spectral transmissivity at six wavelengths with modeled transmissivities. The new retrieval method is fast and accurate, and thus suitable for operational purposes. It is applied to homogeneous and inhomogeneous liquid water and cirrus clouds. The results from the new algorithm are compared to observations of liquid water path obtained from a microwave radiometer, yielding an overestimation for thick liquid water clouds but a slight underestimation for thin clouds. / In dem vorliegenden Artikel werden abwärtsgerichtete spektrale Strahldichten analysiert, die mithilfe schiffsgebundener Beobachtungen über dem Atlantischen Ozean gemessen wurden. In Verbindung mit hochauflösenden Lidar und Mikrowellenradiometer Fernerkundungsverfahren werden optische und mikrophysikalische Wolkeneigenschaften aus spektralen Daten abgeleitet. Um Probleme bereits existierender Verfahren, die auf Transmissionen basieren, zu beseitigen, wird ein neuer Fernerkundungsalgorithmus vorgestellt, der nicht nur Zweideutigkeiten in der Bestimmung der Parameter umgeht, sondern auch den Einfluss von Messunsicherheiten verringert. Die Methode vergleicht gemessene spektrale Transmissionsverhältnisse bei sechs Wellenlängen mit modellierten Verhältnissen. Die neue Fernerkundungsmethode ist schnell und exakt, sodass sie für operative Zwecke geeignet ist. Sie wird für homogene und inhomogene Wasserwolken als auch für Cirren angewendet. Die Ergebnisse des neuen Ableitungsverfahrens werden mit Beobachtungen des Flüssigwasserpfades eines Mikrowellenradiometers verglichen. Daraus ergibt sich eine Überschätzung des Flüssigwasserpfades unter dicken Wolken, jedoch eine leichte Unterschätzung für dünne Wolken.

This is the first survey of subtidal marine tardigrades from the Bahamas, and we compare our results with earlier studies of Bahamian intertidal habitats. In 2011 and 2014 we collected 60 subtidal sand samples from Bimini, the Berry Islands, New Providence, Eleuthera, and the Exumas. We found 11 species only one of which, Dipodarctus subterraneus (Renaud- Debyser, 1959), had been found in the previous intertidal Bahamian collections. Thus, 10 species are new records for the Bahamas, and four of these are new to science. We describe two of the new species (Archechiniscus bahamensis sp. nov. and Anisonyches eleutherensis sp. nov.). Additional material is needed for a conclusive identification of the undescribed species of Batillipes and Florarctus. Based on examination of the holotype of Anisonyches diakidius Pollock, 1975, we redescribe this species and give an emended diagnosis of the genus and the species. We also provide new keys to the spe-cies in the genera Archechiniscus and Anisonyches. A Chao2 species richness estimate indicated that our sampling effort was extensive and probably recovered most common species. Correlations of abundance and diversity indices with regard to depth, distance to nearest shore, and sediment grain size were not significant.

Thesis. 1975. M.S.--Massachusetts Institute of Technology. Dept. of Meteorology. / Bibliography: leaves 70-72. / M.S.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Meteorology, 1979. / Vita. / Bibliography: leaves 121-122. / by Hsien Wang Ou. / Ph.D.

Flame retardants (FRs) are widely used in a variety of consumer products, including electronics, textiles, vehicles, furniture foams, and children’s toys. Many of these chemicals are halogenated compounds that are persistent in the environment over long periods of time and are known or suspected endocrine disruptors. As a result, FRs may have a variety of negative health effects on humans and wildlife. Following the discontinuation of commercial polybrominated diphenyl ether (PBDE) mixtures, a variety of alternative FRs have been developed and employed. In comparison with legacy FRs, relatively little is known about the ability of these emerging FRs to bioaccumulate and biomagnify in various systems. The primary objective of my dissertation was to better understand the contamination status of both legacy and emerging FR in the biota of the northwestern Atlantic Specifically my objectives were to (1) identify and quantify legacy and emerging FRs in high trophic level predator species (sharks) of the northwestern Atlantic, (2) determine Tropic Magnification Factors (TMFs) for legacy and emerging FRs within the same food web, and (3) evaluate the maternal transfer of a variety of brominated and chlorinated FRs in viviparous Atlantic sharks.

Recently, a highly resolved, finite element mesh was developed for the purpose of performing hydrodynamic calculations in the Western North Atlantic Tidal (WNAT) model domain. The WNAT model domain consists of the Gulf of Mexico, the Caribbean Sea, and the entire portion of the North Atlantic Ocean found west of the 60° W meridian. This high resolution mesh (333K) employs 332,582 computational nodes and 647,018 triangular elements to provide approximately 1.0 to 25 km node spacing. In the previous work, the 333K mesh was applied in a Localized Truncation Error Analysis (LTEA) to produce nodal density requirements for the WNAT model domain. The goal of the work herein is to use these LTEA-based element sizing guidelines in order to obtain a more optimal finite element mesh for the WNAT model domain, where optimal refers to minimizing nodes (to enhance computational efficiency) while maintaining model accuracy, through an automated procedure. Initially, three finite element meshes are constructed: 95K, 60K, and 53K. The 95K mesh consists of 95,062 computational nodes and 182,941 triangular elements providing about 0.5 to 120 km node spacing. The 60K mesh contains 60,487 computational nodes and 108,987 triangular elements. It has roughly 0.5 to 185 km node spacing. The 53K mesh includes 52,774 computational nodes and 98,365 triangular elements. This is a particularly coarse mesh, consisting of approximately 0.5 to 160 km node spacing. It is important to note that these three finite element meshes were produced automatically, with each employing the bathymetry and coastline (of various levels of resolution) of the 333K mesh, thereby enabling progress towards an optimal finite element mesh. Tidal simulations are then performed for the WNAT model domain by solving the shallow water equations in a time marching manner for the deviation from mean sea level and depth-integrated velocities at each computational node of the different finite element meshes. In order to verify the model output and compare the performance of the various finite element mesh applications, historical tidal constituent data from 150 tidal stations located within the WNAT model domain are collected and examined. These historical harmonic data are applied in two types of comparative analyses to evaluate the accuracy of the simulation results. First, qualitative comparisons are based on visual sense by utilizing plots of resynthesized model output and historical tidal constituents. Second, quantitative comparisons are performed via a statistical analysis of the errors between model response and historical data. The latter method elicits average phase errors and goodness of average amplitude fits in terms of numerical values, thus providing a quantifiable way to present model error. The error analysis establishes the 53K finite element mesh as optimal when compared to the 333K, 95K, and 60K meshes. However, its required time step of less than ten seconds constrains its application. Therefore, the 53K mesh is manually edited to uphold accurate simulation results and to produce a more computationally efficient mesh, by increasing its time step, so that it can be applied to forecast tide and storm surge in the Western North Atlantic Ocean on a real-time basis.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1980. / Microfiche copy available in Archives and Science. / Vita. / Bibliography: leaves 111-115. / by Frances Luellen Stephenson Hotchkiss. / M.S.

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