The marine biogeochemistry of molybdenum
Thesis (Ph. D.)--Joint Program in Marine Geology and Geophysics (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, and the Woods Hole Oceanographic Institution), 2003.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2010
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| Online Access: | http://hdl.handle.net/1721.1/58369 |
| _version_ | 1826215195356168192 |
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| author | Tuit, Caroline Beth, 1973- |
| author2 | Gregory E. Ravizza. |
| author_facet | Gregory E. Ravizza. Tuit, Caroline Beth, 1973- |
| author_sort | Tuit, Caroline Beth, 1973- |
| collection | MIT |
| description | Thesis (Ph. D.)--Joint Program in Marine Geology and Geophysics (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, and the Woods Hole Oceanographic Institution), 2003. |
| first_indexed | 2024-09-23T16:18:39Z |
| format | Thesis |
| id | mit-1721.1/58369 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T16:18:39Z |
| publishDate | 2010 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/583692022-01-14T19:11:08Z The marine biogeochemistry of molybdenum Tuit, Caroline Beth, 1973- Gregory E. Ravizza. Woods Hole Oceanographic Institution. Joint Program in Marine Geology and Geophysics Woods Hole Oceanographic Institution Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Joint Program in Marine Geology and Geophysics. Earth, Atmospheric, and Planetary Sciences. Woods Hole Oceanographic Institution. Marine sediments Analysis Seawater Analysis Molybdenum Nitrogen Fixation Measurement Thesis (Ph. D.)--Joint Program in Marine Geology and Geophysics (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, and the Woods Hole Oceanographic Institution), 2003. Includes bibliographical references. 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 nitrogenase, the enzyme responsible for N2 fixation, and nitrate reductase, which catalyzes assimilatory and dissimilatory nitrate reduction. Laboratory culture work on two N2 fixing marine cyanobacteria, Trichodesmium and Crocosphaera, and a marine facultative denitrifier, Marinobacter hydrocarbanoclasticus, showed that Mo cell quotas in these organisms were positively correlated with Mo-containing enzyme activity. Mo concentrations in Crocosphaera dropped almost to blank levels when not fixing N2 suggesting daily synthesis and destruction of the entire nitrogenase enzyme and release of Mo. Trichodesmium cultures, however, retained a pool of cellular Mo even when not fixing N2. Colonies of Trichodesmium collected in the field have Mo:C tenfold higher than seen in culture, these Mo:C ratios were reflected in SPM samples from the same region. Fe:C ratios for Trichodesmium were between 12-160 pmol:mol in field and culured samples. The Fe:C ratio of Crocosphaera was established to be 15.8 =/+ 11.3 under N2 fixing conditions. Mo cellular concentrations in cultured organisms were too small to significantly influence dissolved Mo distributions, but may slightly affect Suspended Particulate Matter (SPM) distributions. Mean SPM Mo:C ratios were slightly elevated in regions of N2 fixation and denitrification.. A high precision (=/+ 0.5%) isotope dilution ICP-MS method for measuring Mo was developed to re-evaluate the marine distribution of Mo in the dissolved and particulate phase. (cont.) Mn oxides were not found to significantly influence either the dissolved or SPM Mo distribution. Dissolved Mo profiles from the Sargasso and Arabian Sea were conservative. However, dissolved Mo profiles from the Eastern Tropical Pacific showed both depletion and enrichment of dissolved Mo possibly associated with interaction of Mo with coastal sediments. Dissolved Mo profiles in several California Borderland Basins showed 1-2 nM Mo depletions below sill depth. A more focused study of water column response to sediment fluxes using the high precision Mo analyses is necessary to determine whether these phenomena are related. by Caroline Beth Tuit. Ph.D. 2010-09-03T18:28:48Z 2010-09-03T18:28:48Z 2003 2003 Thesis http://hdl.handle.net/1721.1/58369 52710845 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 254 leaves application/pdf Massachusetts Institute of Technology |
| spellingShingle | Joint Program in Marine Geology and Geophysics. Earth, Atmospheric, and Planetary Sciences. Woods Hole Oceanographic Institution. Marine sediments Analysis Seawater Analysis Molybdenum Nitrogen Fixation Measurement Tuit, Caroline Beth, 1973- The marine biogeochemistry of molybdenum |
| title | The marine biogeochemistry of molybdenum |
| title_full | The marine biogeochemistry of molybdenum |
| title_fullStr | The marine biogeochemistry of molybdenum |
| title_full_unstemmed | The marine biogeochemistry of molybdenum |
| title_short | The marine biogeochemistry of molybdenum |
| title_sort | marine biogeochemistry of molybdenum |
| topic | Joint Program in Marine Geology and Geophysics. Earth, Atmospheric, and Planetary Sciences. Woods Hole Oceanographic Institution. Marine sediments Analysis Seawater Analysis Molybdenum Nitrogen Fixation Measurement |
| url | http://hdl.handle.net/1721.1/58369 |
| work_keys_str_mv | AT tuitcarolinebeth1973 themarinebiogeochemistryofmolybdenum AT tuitcarolinebeth1973 marinebiogeochemistryofmolybdenum |