CHASING SOOT ACROSS THE SEA: THE FATE AND TRANSPORT OF PARTICULATE BLACK CARBON IN THE EQUATORIAL ATLANTIC

Author

Samuel D. Katz, University of Rhode IslandFollow

Date of Award

2024

Degree Type

Dissertation

Degree Name

Doctor of Philosophy in Oceanography

Department

Oceanography

First Advisor

Rainer Lohmann

Abstract

This study investigated BC in the equatorial Atlantic Ocean and Congo River outflow, aiming to elucidate its origins, distribution, fluxes and understand methodological differences in BC quantification. Sediment and atmospheric samples were collected from the Equatorial Atlantic and Congo River outflow. For the sedimentary analysis, the chemothermal oxidation at 375°C method was primally used, while different BC quantification methods were employed with the Congo core, together with stable and radiogenic carbon isotope measurements, to trace BC sources and age. BC air samples were quantified using the thermal optical transmission method, air mass back trajectories, and polycyclic aromatic hydrocarbon (PAH) diagnostic ratios were used to identify combustion sources and persistent organic pollutants. Results indicate that BC in the equatorial Atlantic is predominantly derived from African biomass burning. Sedimentary BC showed a decrease in δ¹³C values and increased age with distance from Africa, highlighting the mixing of biomass-derived BC with fossil fuel combustion products. Particulate BC aerosols followed similar transport patterns, with seasonal variations observed in the concentrations. Gaseous polychlorinated biphenyls (PCBs) exhibit significant longitudinal transport but decrease in concentration compared to prior results. Multimethodological analysis of the Congo River sediment core revealed temporal variations in BC sources and deposition rates, and methodological differences. These findings enhance our understanding of BC dynamics, emphasizing the need for regional approaches and methodological consistency when studying BC’s environmental and climatic impacts. This research provides a framework for future studies that aim to disentangle the carbon cycle.

Recommended Citation

Katz, Samuel D., "CHASING SOOT ACROSS THE SEA: THE FATE AND TRANSPORT OF PARTICULATE BLACK CARBON IN THE EQUATORIAL ATLANTIC" (2024). Open Access Dissertations. Paper 1692.
https://digitalcommons.uri.edu/oa_diss/1692