Now showing items 452-471 of 845

  • Low-frequency bottom backscattering data analysis using multiple constraints beamforming 

    Li, Dan (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1995-05)
    The data analysis of a deep-sea bottom backscattering experiment, carried out over a sediment pond on the western flank of the Mid-Atlantic Ridge in July 1993 with a 250- 650 Hz chirp source and a vertical receiving array ...
  • Low-latitude western north atlantic climate variability during the past millennium : insights from proxies and models 

    Saenger, Casey P. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2009-09)
    Estimates of natural climate variability during the past millennium provide a frame of reference in which to assess the significance of recent changes. This thesis investigates new methods of reconstructing low-latitude ...
  • A magmatic trigger for the Paleocene-Eocene Thermal Maximum? 

    Dubin, Andrea R. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2015-06)
    Fifty-six million years ago Earth experienced rapid global warming (~6°C) that was caused by the release of large amounts of carbon into the ocean-atmosphere system. This Paleocene-Eocene Thermal Maximum (PETM) is often ...
  • Magmatism and dynamics of continental breakup in the presence of a mantle plume 

    Korenaga, Jun (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2000-02)
    This thesis studies the dynamics of mantle melting during continental breakups by geophysical, geochemical, and numerical analyses. The first part focuses on the mantle melting and crustal accretion processes during the ...
  • Maintaining contact : design and use of acoustic signals in killer whales, Orcinus orca 

    Miller, Patrick J. O. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2000-09)
    This thesis presents data on the structure and use of acoustic signals produced by free-ranging resident killer whales. The analysis focuses on signal features that might be useful for animals to maintain contact and ...
  • Mantle plume-midocean ridge interaction : geophysical observations and mantle dynamics 

    Ito, Garrett T. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1996-09)
    We analyze bathymetric and gravity anomalies at five plume-ridge systems to constrain crustal and mantle density structure at these prominent oceanic features. Numerical models are then used to explore the physical ...
  • Mantle upwelling, melt generation, and magma transport beneath mid-ocean ridges 

    Magde, Laura S. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1997-03)
    The formation of new oceanic crust is the result of a complex geodynamic system in which mantle rises beneath spreading centers and undergoes decompression melting. The melt segregates from the matrix and is focused to ...
  • 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 Isabelle (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 ...