Semester of Graduation

Summer 2026

Degree

Master of Science (MS)

Department

Oceanography and Coastal Sciences

Document Type

Thesis

Abstract

The ocean’s biological carbon pump (BCP) mediates global carbon cycling through the uptake of CO2 and its subsequent export in the form of organic carbon. Faced with climate change driven ecosystem shifts, the efficacy of the BCP is projected to change in the future. However, modelled BCP projections are plagued with high uncertainty in part due to the spatiotemporal variability in the BCP and the lack of in-situ data for some high impact regions, such as the Southern Ocean. The Ross Sea is a bay of the SO that experiences vast phytoplankton blooms following sea ice retreat and represents the most productive sectors of the Southern Ocean. In order to better characterize export in the Ross Sea and improve export models in the SO, this study used 234Th –238U disequilibria to determine particulate organic carbon (POC) and particulate biogenic silica (bSi) export fluxes within the Ross Sea seasonal ice zone at the end of austral summer (late February–late March). POC fluxes over 100 m ranged from 5.4 ± 1.8 mmol C m-2 day-1 to 54.5 ± 3.5 mmol C m-2 day-1 for particles >51 μm. BSi fluxes over 200 m ranged from 1.2 ± 1.6 mmol Si m-2 day-1 to 17.5 ± 1.3 mmol Si m-2 day-1 for particles >51 μm. While there was high variability between stations, the trends across stations in bSi fluxes and POC fluxes were similar, providing insight into the relationship between POC and mineral fluxes. These observations will be valuable for refining global export models to better predict SO export fluxes.

Date

5-28-2026

Committee Chair

Maiti, Kanchan

LSU Acknowledgement

1

LSU Accessibility Acknowledgment

1

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Available for download on Thursday, May 26, 2033

Included in

Oceanography Commons

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