Now showing items 477-496 of 879

    • The marine biogeochemistry of dissolved and colloidal Iron 

      Fitzsimmons, Jessica N. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2013-09)
      Iron is a redox active trace metal micronutrient essential for primary production and nitrogen acquisition in the open ocean. Dissolved iron (dFe) has extremely low concentrations in marine waters that can drive phytoplankton ...
    • The marine biogeochemistry of molybdenum 

      Tuit, Caroline Beth (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2003-02)
      Prevailing wisdom holds that the vertical distribution of molybdenum (Mo) in the open ocean is conservative, despite Mo's important biological role and association with Mn oxides and anoxic sediments. Mo is used in both ...
    • The marine biogeochemistry of zinc isotopes 

      John, Seth G. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007-06)
      Zinc (Zn) stable isotopes can record information about important oceanographic processes. This thesis presents data on Zn isotopes in anthropogenic materials, hydrothermal fluids and minerals, cultured marine phytoplankton, ...
    • The marine geochemistry of iron and iron isotopes 

      Bergquist, Bridget A. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2004-09)
      This thesis addressed questions about the Fe cycle by measuring detailed profiles and transects of Fe species in the ocean and also by exploring the use of a new tracer of Fe, Fe isotopic fractionation. In the subtropical ...
    • The marine geochemistry of methane 

      Scranton, Mary I. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1977-08)
      In the highly productive coastal surface waters near Walvis Bay, methane is present in concentrations considerably above those which would be predicted from solubility equilibrium with the atmosphere. A one dimensional ...
    • The marine geochemistry of the rare earth elements 

      Baar, Hein J. W. de (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1983-09)
      Novel methods were developed for the determination of 12 of the 14 Rare Earth Elements (REE) in seawater. Initial extractions of the REE by chelating ion exchange chromatography is followed by cation exchange for removal ...
    • The marine geochemistry of thorium and protactinium 

      Anderson, Robert F. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1980-11)
      Suspended particulate matter was collected by sediment traps deployed in the Sargasso Sea (Site S2), the north equatorial Atlantic (Site E), the north equatorial Pacific (Site P), and the Panama Basin (STIE Site). Additional ...
    • The marine geochemistry of trace metals 

      Boyle, Edward A. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1976-04)
      The marine geochemical cycles of iron, copper, nickel, and cadmium were studied in order to provide a basis for oceanographic models for trace metals. Copper, nickel, and cadmium can be determined in a 100 ml seawater ...
    • Marine microbial intact polar diacylglycerolipids and their application in the study of nutrient stress and bacterial production 

      Popendorf, Kimberly J. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2013-02)
      Intact polar diacylglycerolipids (IP-DAGs) were used to study microbial dynamics in the surface ocean. IP-DAGs from surface ocean seawater were quantified using high performance liquid chromatography-mass spectrometry ...
    • Marine microbial production of dimethylsulfide from dissolved dimethylsulfoniopropionate 

      Ledyard, Kathleen Mei (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1993-02)
      Dimethylsulfide (DMS) plays a central role in the transfer of sulfur from the ocean to the atmosphere, and ultimately to land. The most abundant volatile organosulfur compound in seawater, DMS is believed to account for ...
    • Marine particle dynamics : sinking velocities, size distributions, fluxes, and microbial degradation rates 

      McDonnell, Andrew M. P. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2011-02)
      The sinking flux of particulate matter into the ocean interior is an oceanographic phenomenon that fuels much of the metabolic demand of the subsurface ocean and affects the distribution of carbon and other elements ...
    • Marine sedimentary organic matter : delineation of marine and terrestrial sources through radiocarbon dating; and the role of organic sulfur in early petroleum generation 

      Benitez-Nelson, Bryan C. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1996-05)
      This thesis details two years of research conducted with the guidance and support of three advisors: Dr. J. K. Whelan, Dr. J. S. Seewald and Dr. T. I. Eglinton. Each of the three chapters represents a different, ...
    • Mark-recapture statistics and demographic analysis 

      Fujiwara, Masami (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2002-06)
      Mark-recapture analysis of populations is becoming an important tool in population biology. Mark-recapture methods can be used to estimate transition probabilities among life-stages from capture histories of marked ...
    • Mass, heat and nutrient fluxes in the Atlantic Ocean determined by inverse methods 

      Rintoul, Stephen R. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1988-03)
      Inverse methods are applied to historical hydrographic data to address two aspects of the general circulation of the Atlantic Ocean. The method allows conservation statements for mass and other properties, along with a ...
    • Mass, heat, oxygen and nutrient fluxes at 30°S and their implications for the Pacific-Indian through flow and the global heat budget 

      Macdonald, Alison M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1991-07)
      Six hydrographic basinwide sections, two in each of the three major ocean basins, are employed in a set of inverse calculations to determine the extent of exchange between the Pacific and Indian Oceans through the ...
    • A matched field processing approach to long range acoustic navigation 

      Deffenbaugh, Max (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1994-02)
      This thesis presents the design and simulation of an acoustic listen-only navigation system for use in a time-varying high-multipath environment. The system uses a ray tracing model of sound propagation in a horizontally ...
    • Maximizing AUV slow speed performance 

      LeBas, Phillip J. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1997-09)
      A review of the Odyssey IIB autonomous underwater vehicle shows that energy costs associated with vehicle controls can be reduced and operational flexibility improved with relatively simple, low cost improvements. Because ...
    • Maximum likelihood time-domain beamforming using simulated annealing 

      Xu, Kevin (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1999-09)
      An algorithm is developed for underwater acoustic signal processing with an array of hydrophones. With various acoustic signals coming from different directions, the maximum likelihood approach is used to estimate the ...
    • Measurements and models of fine-structure, internal gravity waves and wave breaking in the deep ocean 

      Eriksen, Charles C. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1976-09)
      Measurements of horizontal and vertical current by propeller cluster current meters and temperature by thermistors mounted on a rigid array 8 m high and 20 m long moored in the oceanic main thermocline near Bermuda are ...
    • Measurements of a barotropic planetary vorticity mode in an eddy-resolving quasi-geostrophic model using acoustic tomography 

      Lawrence, Wendy B. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1988-08)
      A tomographic array is placed in a 2-layer, flat bottom, steady-wind driven quasi-geostrophic circulation model to investigate whether the analysis of acoustic travel time changes can detect large-scale barotropic ...