Biogeochemical processes in the eastern Pacific sector of the Southern Ocean

Abstract

This thesis explores the biogeochemical cycles of the Southern Ocean by utilising biogeochemical sensors on autonomous platforms and developing parameterisations for carbonate chemistry estimation. The study discusses and addresses various challenges in data quality and processing. Specifically, the difficulties encountered with Saildrone and Ocean Observatories Initiative sensors are described, and solutions are presented. The research highlights the effectiveness of novel parameterizations in estimating carbonate chemistry variables, surpassing alternative models in accuracy. Applying these parameterisations for pCO2 estimation is discussed, along with the remaining challenge of resolving the offset in its estimation. Moreover, this thesis investigates the estimation of air-sea oxygen fluxes and net community production using biogeochemical profiling floats in three frontal zones of the Eastern Pacific sector of the SO. The analysis emphasises the importance of integrating platforms with high temporal resolution and broad spatial coverage to accurately capture the dynamics of the carbonate system and provide valuable predictions. Distinct oceanic and atmospheric conditions are described across different frontal zones, underscoring the need for region-specific investigations. The comparison between mooring and float data underscores the significance of appropriate parameterisation selection and development, particularly in areas with high wind, to accurately estimate air-sea oxygen fluxes. In conclusion, this thesis significantly contributes to our understanding of the complex biogeochemical cycles in the SO. The research provides valuable insights into data quality, calibration efforts, and the development of parameterizations. Furthermore, it identifies future research directions, including improving data quality, resolving pCO2 estimation offsets, and enhancing parameterisations for comprehensive observations and accurate air-sea flux predictions in the SO.

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Identifiers

ORCID for Pablo Nicolas Trucco Pignata: orcid.org/0000-0003-3996-4600

ORCID for Alberto Naveira Garabato: orcid.org/0000-0001-6071-605X

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