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.
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Showing 1 to 8 of 8 for “"Oxygen deficient zones"”.
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Investigating chromium cycling in global oxygen deficient zones with chromium isotopes
… with a focus on the redox processes in global oxygen deficient zones (ODZs). Firstly, we developed a method to analyze Cr isotopes of different Cr redox species. Tests on processing conditions demonstrated its robustness in obtaining accurate Cr isotope data. It is applicable to both frozen and …
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Investigating Chromium Cycling in Global Oxygen Deficient Zones with Chromium Isotopes
… with a focus on the redox processes in global oxygen deficient zones (ODZs). Firstly, we developed a method to analyze Cr isotopes of different Cr redox species. Tests on processing conditions demonstrated its robustness in obtaining accurate Cr isotope data. It is applicable to both frozen and …
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Nitrogen cycling in oxygen deficient zones : insights from δ15N and δ18O of nitrite and nitrate
… as natural seawater samples to determine the oxygen isotope systematics of nitrification. These experiments show that the accumulation of nitrite has a large effect on the resulting δ18ONO3. Also, the δ18ONO2 was developed as a unique tracer because it undergoes abiotic equilibration with …
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Nitrogen cycling in oxygen deficient zones : insights from [delta]¹⁵N and [delta]¹⁸O of nitrite and nitrate
… distinguish. Examples of such regions are "oxygen deficient zones" (ODZ). They are of particular interest because they are also important hot spots of fixed N loss and production of N₂O, a potent greenhouse gas. In order to interpret these isotope profiles, the isotope systematics of each …
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Ecology and adaptation of denitrifiers across genomes and environments
… as a major sink of fixed nitrogen within low oxygen environments, and contribute to emissions of the greenhouse gas nitrous oxide. While canonical studies typically use model complete denitrifiers capable of fully reducing nitrate to N2 gas, sequencing efforts have revealed a diversity of …
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The marine biogeochemistry of chromium isotopes
… The reduction of Cr(VI) to Cr(III) occurs in oxygen deficient zones (ODZs), and Cr reduction in general has been identified as a significant Cr isotope fractionation mechanism. This thesis presents the first Cr isotope variations (d53Cr) in ODZs of the ocean and adds to the sparse Cr isotope …
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In the Margins: Reconsidering the Range and Contribution of Diazotrophs in Nearshore Environments
… gradients (e.g., light, nutrients, oxygen) in nearshore environments of significance in global biogeochemical cycling: the major pelagic oxygen deficient zones (ODZs) in the Eastern Tropical South (ETSP) and North (ETNP) Pacific Ocean, and the broad continental shelf of the Western …
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The marine biogeochemistry of chromium isotopes
… The reduction of Cr(VI) to Cr(III) occurs in oxygen deficient zones (ODZs), and Cr reduction in general has been identified as a significant Cr isotope fractionation mechanism. This thesis presents the first Cr isotope variations (653 Cr) in ODZs of the ocean and adds to the sparse Cr isotope …