New webinar recording:
OA CoP guest webinar with Krysten Rutherford, Ph.D. Candidate, Dalhousie University (April 14, 2021).
Source or Sink? A numerical modeling study of inorganic carbon fluxes on the Scotian Shelf
The webinar is ~45 minutes long, and is fully captioned.
Abstract: Continental shelves are thought to be disproportionately affected by climate change and are a large contributor to global air-sea CO2 fluxes. Additionally, it is often reported that low latitude shelves act as net sources of CO2 to the atmosphere whereas mid- and high-latitude shelves act as net sinks of CO2. Here, we focus on the Scotian Shelf, a mid-latitude shelf in the northwest North Atlantic. Whether the Scotian Shelf acts as a source or sink of CO2 is controversial in the literature. Here a high-resolution regional model is employed to explore shelf-wide pCO2 variability and better understand what processes are underlying the regional air-sea CO2 fluxes. Seasonally, surface pCO2 on the Scotian Shelf is strongly tied to the large drawdown in Dissolved Inorganic Carbon (DIC) during the spring bloom, and temperature effects associated with warming from 0oC in winter to nearly 20oC in summer. Spatially, pCO2 on the Scotian Shelf is relatively uniform, except for coastal upwelling events during the summer which lower nearshore pCO2 in the surface water. The model agrees with regional observations and reproduces seasonal patterns of pCO2. On the Scotian Shelf, the model simulates net annual outgassing of CO2 from the ocean, which is in contrast to the global pattern. Passive dye tracers are used to qualitatively diagnose the dominant transport pathways in the model and their effect on CO2 dynamics. This analysis suggests that the Scotian Shelf is highly influenced by cold, DIC-rich Arctic-originating water that is warmed as it travels, thus becoming oversaturated with CO2 and feeding outgassing from the ocean.
Speaker bio: Krysten Rutherford was born and raised in Southern Ontario. She did her undergraduate degree in Engineering Chemistry at Queen’s University in Kingston, ON. While there, she spent a couple summers with the Geography Department doing research on High Arctic watersheds. Shortly after graduating from Queen’s, she joined Dr. Katja Fennel’s lab group at Dalhousie University (Halifax, NS) to do her master’s degree in Oceanography. She enjoyed her work so much that after a couple years working on her master’s thesis, she decided to keep working with Dr. Fennel to complete her PhD. This work has focussed on using a biogeochemical model of the northwest North Atlantic to understand the carbon cycling and transport here. She will be defending her PhD within the next few months.
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