Now showing items 433-452 of 838

  • Late Pleistocene-Holocene chemical stratigraphy and paleolimnology of the Rift Valley lakes of central Africa 

    Hecky, Robert E.; Degens, Egon T. (Woods Hole Oceanographic Institution, 1973-05)
    The interaction of climate and geology in Central Africa during Late Pleistocene and Holocene is examined. The study is based on sedimentological and limnological work on the main lakes of the Western Branch of the East ...
  • Late Quaternary climate variability and terrestrial carbon cycling in tropical South America 

    Fornace, Kyrstin L. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2016-02)
    Characterizing global and regional climate variability and climate-carbon cycle interactions in the past provides critical context for evaluating present and future climate trends. In this thesis, I use stable isotope ...
  • Lateral organic carbon supply to the deep Canada Basin 

    Hwang, Jeomshik; Eglinton, Timothy I.; Krishfield, Richard A.; Manganini, Steven J.; Honjo, Susumu (American Geophysical Union, 2008-06-12)
    Understanding the processes driving the carbon cycle in the Arctic Ocean is important for assessing the impacts of the predicted rapid and amplified climate change in this region. We analyzed settling particle samples ...
  • Leaf wax biomarkers in transit record river catchment composition 

    Ponton, Camilo; West, A. Joshua; Feakins, Sarah J.; Galy, Valier (John Wiley & Sons, 2014-09-24)
    Rivers carry organic molecules derived from terrestrial vegetation to sedimentary deposits in lakes and oceans, storing information about past climate and erosion, as well as representing a component of the carbon cycle. ...
  • Life-cycle modification in open oceans accounts for genome variability in a cosmopolitan phytoplankton 

    von Dassow, Peter; John, Uwe; Ogata, Hiroyuki; Probert, Ian; Bendif, El Mahdi; Kege, Jessica U.; Audic, Stephane; Wincker, Patrick; Da Silva, Corinne; Claverie, Jean-Michel; Doney, Scott C.; Glover, David M.; Flores, Daniella Mella; Herrera, Yeritza; Lescot, Magali; Garet-Delmas, Marie-Jose; de Vargas, Colomban (Nature Publishing Group, 2014-12-02)
    Emiliania huxleyi is the most abundant calcifying plankton in modern oceans with substantial intraspecific genome variability and a biphasic life cycle involving sexual alternation between calcified 2N and flagellated 1N ...
  • Light-driven cycling of dimethylsulfide (DMS) in the Sargasso Sea : closing the loop 

    Toole, Dierdre A.; Siegel, David A. (American Geophysical Union, 2004-05-06)
    The factors driving dimethylsulfide (DMS) cycling in oligotrophic environments are isolated using a time-series of DMS sampled in the Sargasso Sea. The observed distribution of DMS is inconsistent with bottom-up processes ...
  • A light-driven, one-dimensional dimethylsulfide biogeochemical cycling model for the Sargasso Sea 

    Toole, Dierdre A.; Siegel, David A.; Doney, Scott C. (American Geophysical Union, 2008-04-12)
    We evaluate the extent to which dimethylsulfide (DMS) cycling in an open-ocean environment can be constrained and parameterized utilizing emerging evidence for the significant impacts of solar ultraviolet radiation (UVR) ...
  • Links from mantle to microbe at the Lau Integrated Study Site : insights from a back-arc spreading center 

    Tivey, Margaret K.; Becker, Erin; Beinart, Roxanne; Fisher, Charles R.; Girguis, Peter R.; Langmuir, Charles H.; Michael, Peter J.; Reysenbach, Anna-Louise (The Oceanography Society, 2012-03)
    The Lau Integrated Study Site (ISS) has provided unique opportunities for study of ridge processes because of its back-arc setting in the southwestern Pacific. Its location allows study of a biogeographical province distinct ...
  • Lipid biomarkers in Symbiodinium dinoflagellates : new indicators of thermal stress 

    Kneeland, Jessie M.; Hughen, Konrad A.; Cervino, J. M.; Hauff, B.; Eglinton, Timothy I. (2013-06-13)
    Lipid content and fatty acid profiles of corals and their dinoflagellate endosymbionts are known to vary in response to high temperature stress. To better understand the heat stress response in these symbionts, we investigated ...
  • Lipid biomarkers of coral stress : calibration and exploration 

    Kneeland, Jessie M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2011-06)
    Corals are increasingly threatened by warming sea surface temperatures and other anthropogenic changes. The delicate symbiosis between corals and their algal endosymbionts (zooxanthellae) is easil ...
  • Loading and fate of particulate organic carbon from the Himalaya to the Ganga–Brahmaputra delta 

    Galy, Valier; France-Lanord, Christian; Lartiges, Bruno (2008-01-26)
    We use the evolution of river sediment characteristics and sedimentary Corg from the Himalayan range to the delta to study the transport of Corg in the Ganga-Brahmaputra system and especially its fate during floodplain ...
  • Long-term biological effects of petroleum residues on fiddler crabs in salt marshes 

    Culbertson, Jennifer B.; Valiela, Ivan; Peacock, Emily E.; Reddy, Christopher M.; Carter, Anna; VanderKruik, Rachel (2007)
    In September 1969,the Florida barge spilled 700,000 L of No. 2 fuel oil into the salt marsh sediments of Wild Harbor (Buzzards Bay, MA). Today the aboveground environment appears unaffected, but a substantial amount of ...
  • Low reservoir ages for the surface ocean from mid-Holocene Florida corals 

    Druffel, Ellen R. M.; Robinson, Laura F.; Griffin, Sheila; Halley, Robert B.; Southon, John R.; Adkins, Jess F. (American Geophysical Union, 2008-05-13)
    The 14C reservoir age of the surface ocean was determined for two Holocene periods (4908–4955 and 3008–3066 calendar (cal) B.P.) using U/Th-dated corals from Biscayne National Park, Florida, United States. We found that ...
  • Lower export production during glacial periods in the equatorial Pacific derived from (231Pa/230Th)xs,0 measurements in deep-sea sediments 

    Pichat, Sylvain; Sims, Kenneth W. W.; Francois, Roger; McManus, Jerry F.; Leger, Susan Brown; Albarede, Francis (American Geophysical Union, 2004-12-16)
    The (231Pa/230Th)xs,0 records obtained from two cores from the western (MD97-2138; 1°25′S, 146°24′E, 1900 m) and eastern (Ocean Drilling Program Leg 138 Site 849, 0°11.59′N, 110°31.18′W, 3851 m) equatorial Pacific display ...
  • 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 ...
  • A manganese-rich environment supports superoxide dismutase activity in a lyme disease pathogen, Borrelia burgdorferi 

    Aguirre, J. Dafhne; Clark, Hillary M.; McIlvin, Matthew R.; Vazquez, Christine; Palmere, Shaina L.; Grab, Dennis J.; Seshu, J.; Hart, P. John; Saito, Mak A.; Culotta, Valeria C. (2013-01-28)
    The Lyme disease pathogen Borrelia burgdorferi represents a novel organism in which to study metalloprotein biology in that this spirochete has uniquely evolved with no requirement for iron. Not only is iron low, but we ...
  • Mantle 3He distribution and deep circulation in the Indian Ocean 

    Srinivasan, Ashwanth; Top, Zafer; Schlosser, Peter; Hohmann, Roland; Iskandarani, Mohamed; Olson, Donald B.; Lupton, John E.; Jenkins, William J. (American Geophysical Union, 2004-06-10)
    The World Ocean Circulation Experiment Indian Ocean helium isotope data are mapped and features of intermediate and deep circulation are inferred and discussed. The 3He added to the deep Indian Ocean originates from (1) a ...
  • 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 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, ...