Date of Award

Winter 3-20-2026

Document Type

Thesis (Master's)

Department or Program

Earth Sciences

First Advisor

Mukul Sharma

Second Advisor

Erich Osterberg

Third Advisor

Wil Leavitt & George O'Toole

Abstract

@font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-536870145 1107305727 0 0 415 0;}@font-face {font-family:"Times New Roman \(Body CS\)"; panose-1:2 11 6 4 2 2 2 2 2 4; mso-font-alt:"Times New Roman"; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:auto; mso-font-signature:0 0 0 0 0 0;}p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0cm; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman",serif; mso-fareast-font-family:"Times New Roman";}.MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; mso-fareast-font-family:Calibri; mso-fareast-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman \(Body CS\)";}div.WordSection1 {page:WordSection1;}

It has been proposed that export of organic carbon from the epipelagic zone to the seafloor can be increased by the addition of 20 mg L-1 of clay minerals to phytoplankton blooms. In natural environments, bacterial digestion of organic carbon sourced from phytoplankton blooms leads to the creation of oxygen minimum zones, where denitrifying marine bacteria produce nitrous oxide, a potent greenhouse gas. It is unknown if additional nitrous oxide results from the additional organic carbon transported to the seafloor via this method; therefore, a simulated oxygen minimum zone was developed that allowed us to measure the contribution of clay minerals to the production of nitrous oxide in oxygen minimum zone conditions. We developed an approach to test the influence of a proposed marine carbon capture and storage method on the production of nitrous oxide by denitrifying bacteria in the oxygen minimum zone. After purging the microcosms with helium to remove any gases save those produced by bacteria within the microcosm, then incubating microcosms containing representative marine bacteria and nutrients, we found that the addition of clay minerals did not change the amount of nitrous oxide produced via denitrification. This suggests that this method provides an effective means of increasing the transfer of organic carbon to the seafloor without risking additional greenhouse gas generation. Because the organic carbon found in phytoplankton blooms is primarily derived from atmospheric carbon dioxide, this method also provides a possible pathway to capture and sequester atmospheric carbon on a geologic timescale.

Download

Share

COinS