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.
Results
Showing 1 to 20 of 58 for “"Knorr (Ship : 1970-) Cruise"”.
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The spatial and temporal abundance patterns of chaetognaths in the western North Atlantic Ocean
… Net and Environmental Sensing System) on six cruises in the western North Atlantic Ocean during the period from August 1975 to November 1977 as part of the study of the biology, physics, and chemistry of Gulf Stream cold core rings. The physical, chemical and biological properties of the Slope …
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Iron and Prochlorococcus
Iron availability and primary productivity in the oceans are intricately linked through photosynthesis. At the global scale we understand how iron addition induces phytoplankton blooms through meso-scale iron-addition experiments. At the atomic scale, we can describe the length and type of bonds …
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Investigations into the seasonal deep chlorophyll maximum in the western North Atlantic, and its possible significande to regional food chain relationships
… μm mesh) and water bottle casts taken on eight cruises in the western North Atlantic between November 1973 and August 1976. Parameters measured included: zooplankton biomass, zooplankton functional group abundance, phytoplankton species abundance, chlorophyll concentration, ATP concentration, …
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The biogeochemistry of marine nitrous oxide
Atmospheric nitrous oxide N2O concentrations have been rising steadily for the past century as a result of human activities. In particular, human perturbation of the nitrogen cycle has increased the N2O production rates of the two major sources of this greenhouse gas, soil and the ocean. …
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The tectonics and three-dimensional structure of spreading centers : microearthquake studies and tomographic inversions
Two-thirds of the Earth's surface has been formed along a global system of spreading centers that are presently manifested in several different structural forms, including the classic rift valley of the Mid-Atlantic Ridge, the more morphologically subdued East Pacific Rise, and the pronounced en …
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Biogeochemistry of dissolved free amino acids in marine sediments
Dissolved free amino acids (DFAA) were measured in interstitial water samples squeezed from sediments collected in a variety of depositional environments. These sediments were further characterized by measurements of total organic carbon, total nitrogen, dissolved organic carbon, total hydrolyzable …
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Gulf Stream temperature, salinity and transport during the last millennium
Benthic and planktonic foraminiferal δ18O (δ18Oc) from a suite of well-dated, high-resolution cores spanning the depth and width of the Straits of Florida reveal significant changes in Gulf Stream cross-current density gradient during the last millennium. These data imply that Gulf Stream transport …
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Siderophore production by heterotrophic bacterial isolates from the Costa Rica Upwelling Dome
… a select group of bacteria is available. On a cruise through the Costa Rica Dome (CRD) upwelling region in July 2005, a library of 867 isolates from five depth profiles inside and outside of the dome was obtained and screened for siderophore production using the Chrome Azurol-S (CAS) assay. …
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Iron limitation and the role of siderophores in marine Synechococcus
Marine cyanobacteria in the genus Synechococcus are widely distributed and contribute significantly to global primary productivity. In many parts of the ocean their growth is limited by a lack of iron, an essential nutrient that is virtually insoluble in seawater. To overcome this, Synechococcus …
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Zinc and cadmium in benthic foraminifera as tracers of ocean paleochemistry
Benthic foraminiferal δ13C, Cd/Ca, and Ba/Ca are important tools for reconstructing nutrient distributions, and thus ocean circulation, on glacial-interglacial timescales. However, each tracer has its own "artifacts" that can complicate paleoceanographic interpretations. It is therefore …
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A study of the seismic structure of upper oceanic crust using wide-angle reflections
The lateral homogeneity of oceanic crust on the scale of a seismic experiment is a condition that most methods of seismic interpretation depend on. Whether this condition is in fact true is largely unknown and only recently have efforts been made to test this hypothesis. This thesis is part of that …
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Interactions of cadmium, zinc, and phosphorus in marine Synechococcus : field uptake, physiological and proteomic studies
A combination of uptake field studies on natural phytoplankton assemblages and laboratory proteomic and physiological experiments on cyanobacterial isolates were conducted investigating the interactions of cadmium (Cd), zinc (Zn), and phosphorus (P) in marine Synechococcus. Enriched stable isotope …
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The biogeochemistry of lipid derived infochemical signals in the ocean
… A novel lipidomics approach was applied along a cruise track in the California Coastal System revealing that canonical diatom free fatty acids and oxylipins dominated the dissolved lipidome and oxylipin abundance was correlated with diatom bloom demise as assessed by phaeophytin and biogenic Si. …
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Effects of high hydrostatic pressure on neuromuscular transmission in shallow-living and deep-living crustaceans
The effects of high hydrostatic pressure on excitatory neuromuscular transmission in shallow- and deep-living crustaceans were compared. Pressure caused depression of the amplitude of excitatory junctional potentials (e.j.p.s) at the neuromuscular junction in the shallow-living crab, Libinia …
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The biogeochemistry of marine particulate trace metals
Marine particles include living and non-living solid components of seawater, representing a dynamic and chemically diverse mixture of phases. Through a combination of method development, basin-scale particulate collection and analyses, modeling, and field experiments, this thesis examines both the …
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Detailed studies of the structure, tectonics, near bottom magnetic anomalies and microearthquake seismicity of the Mid-Atlantic Ridge near 37°N
The Mid-Atlantic Ridge is one of the most well known and yet poorly understood spreading centers in the world. A detailed investigation of the Mid-Atlantic Ridge crest near 37°N (FAMOUS) was conducted using a deeply towed instrument package. The objective was to study the detailed structure and …
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Studies of deep-sea sedimentary microtopography in the North Atlantic Ocean
Many of the small-scale topographic features (dimensions of centimeters to kilometers) found on the Blake-Bahama Outer Ridge (western North Atiantic, water depth greater than 4000 m) and in the Rockall Trough (northeastern North Atlantic, water depth greater than 2000 m) have been formed as bed …
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Computational imaging and automated identification for aqueous environments
Sampling the vast volumes of the ocean requires tools capable of observing from a distance while retaining detail necessary for biology and ecology, ideal for optical methods. Algorithms that work with existing SeaBED AUV imagery are developed, including habitat classi fication with bag-of-words …
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Influences on the oceanic biogeochemical cycling of the hybrid-type metals : cobalt, iron, and manganese
… apparent by the observation of linear relationships between cobalt and phosphate in mid to low latitudes. The cobalt:phosphate ratios derived from these correlations changed over orders of magnitude, revealing dynamic variability in the utilization, demand, and sources of this micronutrient. …
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Advances in grasping and vehicle contact identification : analysis, design and testing of robust methods for underwater robot manipulation
This thesis focuses on improving the productivity of autonomous and telemanipulation systems consisting of a manipulator arm mounted to a free flying underwater vehicle. Part I minimizes system sensitivity to misalignment by developing a gripper and a suite of handles that passively self align when …
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