Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 39 for “"Oceanus (Ship : 1975-) Cruise"”.
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Genetic variability and differentiation in niche components of marine phytoplankton species
… of variation). There is no obvious relationship between the amounts of genetic variability in the populations and the variability or predictability of the environments from which they were collected. No genetic differentiation was found within the Sargasso Sea in any of the oceanic species, …
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Variability in the North Atlantic Deep Western Boundary Current : upstream causes and downstream effects as observed at Line W
The variability in the DWBC, its connection to the forcing in the northern North Atlantic and interaction with the Gulf Stream were explored from a combination of remote sensing and in-situ measurements in the western North Atlantic. Using satellite altimetry and Sea Surface Temperature (SST) we …
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Shipboard and satellite observations of upper ocean velocity and transport variability in the Gulf Stream
… the eastern coast of the United States. Repeated shipboard measurements along an ascending GEOSAT subtrack between Bermuda and Cape Cod allow study of rapid Gulf Stream Variability along the track, and comparison of sea surface and velocity measurements with those computed from the GEOSAT …
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Investigating the role of trichodesmium spp. in the oceanic nitrogen cycle through observations and models
The nitrogen fixation and abundance of Trichodesmium colonies and their connections with physical processes were investigated through Video Plankton Recorder (VPR) and other observations collected in fall 2010 and spring 2011 in the western subtropical–tropical North Atlantic. A data processing …
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A study of North Atlantic ventilation using transient tracers
… North Atlantic measured on a 1988 hydrographic cruise between Iceland and the equator. CFC tagged seawater fills the entire sub-polar water column and subtropical thermocline. Measurable CFC levels are found at the ocean bottom as far south as 35°N; the CFC penetration depth shoals to about 750 …
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The sensory mediation of symbiosis between hyperiid amphipods and salps
Hyperiid amphipods are open ocean crustaceans which use gelatinous planktonic animals for food, shelter, and brooding space for their offspring. These associations involve varying degrees of host specificity; and there are few obvious correlations between gross morphology of the amphipods and the …
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The entrainment and homogenization of tracers within the cyclonic gulf stream recirculation gyre
… of the spiral during spin-up and its relationship to the occurrence of homogenization at steady state is examined. An asymmetry in the spiral exists due to the ellipticity of the gyre, which also effects homogenization. The anomalous properties that are fluxed into the NRG include salt, …
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Mixing and dynamics of the Mediterranean outflow
… two preferred isopycnals: 27.5 and 27.8 (Zenk 1975b). The spreading of the flow contains both a barotropic and baroclinic character. The average change in angle above and below the maximum velocity of the outflow is 8°while at the edges of the flow the average direction of the outflow diverges …
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Plutonium isotopes in the North Atlantic
… m.s. provide a unique insight into the relationship between the specific sources of fallout Pu and its geochemical behavior in the oceans. I find a systematic decrease in the 240Pu/239Pu ratio in sediments from 0.18 on the shelf to 0.10 in deep-sea (4500- 5000 m) sediments from the Northwest …
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N2 fixation by subsurface populations of Trichodesmium : an important source of new nitrogen to the North Atlantic Ocean
Trichodesmium, a genus of diazotrophic cyanobacteria, is an important contributor to the marine nitrogen (N) and carbon (C) cycles. The extent to which Trichodesmium dinitrogen (N2) fixation contributes to the marine N cycle has been modeled based on abundance data and rate estimates from surface …
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A characterization of internal solitons in the SWARM region of the New York bight
A field experiment was undertaken during July and August of 1995 aimed at understanding the interaction of acoustic signals with the internal wave field off the coast of New Jersey. As part of SWARM (Shallow Water Acoustics in a Random Medium), physical data were collected in 75 m of water near …
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Relating the biogeochemistries of zinc, cobalt, and phosphorus to phytoplankton activities in the sea
… in the North Pacific was demonstrated in a shipboard incubation and by comparing two phytoplankton pigment markers to total zinc and free zinc ion concentrations. In the North Atlantic, total dissolved zinc and cobalt concentrations were measured and compared to concentrations of dissolved …
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The role of heterotrophic microflagellates in plankton communities
The distribution and feeding behavior of bacterivorous micro flagellates (2-20 μm protozoa) and their ingestion by copepods were examined in an attempt to assess the importance of these protozoa as a trophic link between planktonic bacteria and zooplankton. The abundance of microflagellates …
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The influence of geothermal sources on deep ocean temperature, salinity, and flow fields
This thesis is a study of the effect of geothermal sources on the deep circulation, temperature and salinity fields. In Chapter 1 background material is given on the strength and distribution of geothermal heating. In Chapter 2 evidence for the influence of a hydrothermal system in the rift valley …
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The biogeochemistry of cobalt in the Sargasso Sea
Processes that enable marine phytoplankton to acquire trace metals are fundamental to our understanding of primary productivity and global carbon cycling. This thesis explored the biogeochemistry of cobalt using analytical chemistry and physiological experiments with the dominant phytoplankton …
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Moored observations of shelfbreak processes at the inflow to and outflow from the Arctic Ocean
Two high-resolution mooring arrays extending from the outer shelf to the mid continental slope are used to elucidate shelf-basin exchange at the inflow to and the outflow from the Arctic Ocean. Pacific Water entering the Arctic Ocean forms the Western Arctic shelfbreak current along the Beaufort …
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Distribution of thiols in the northwest Atlantic Ocean
Thiol substances can form stable complexes with metals (especially copper and mercury) in the surface ocean that can impact cycling and bioavailability of those elements. In this study, I present seven concentration profiles of cysteine and glutathione, two low-molecular weight thiols, from the …
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Assimilatory sulfur metabolism in marine microorganisms
… marine bacteria, with emphasis on the relationship between sulfur metabolism and protein synthesis. The goal of the study was to develop and apply a method for the quantitative assay of total bacterial protein synthesis in aerobic ocean waters. The study consisted of four parts: (1) The sulfate …
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Observed circulation and inferred sediment transport in Hudson Submarine Canyon
Velocity and temperature time series from Hudson Submarine Canyon and hydrographic surveys of seven canyons of the Middle Atlantic Bight indicate that the effects of storms, tides, and incoming internal waves are intensified in submarine canyons. Storms with strong eastward and westward wind stress …
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Acoustic classification of zooplankton
… gas-bearing (e.g. siphonophores). The relationship between backscattered energy and animal biomass has been shown to vary by a factor of —19,000 across these categories, so that to make accurate estimates of zooplankton biomass from acoustic backscatter measurements of the ocean, the acoustic …
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