Thawing permafrost - Sedimentary organic matter distribution across the Canadian Beaufort Sea
The Canadian Beaufort Sea experiences substantial input of sediment, organic carbon, and nutrients due to accelerated coastal erosion and transport from the Mackenzie River (Bröder et al. 2022). Ongoing climate change intensifies these fluxes along the land-ocean continuum and, thus, affect the mari...
| Main Author: | |
|---|---|
| Format: | Master Thesis |
| Language: | English |
| Published: |
2023
|
| Subjects: | |
| Online Access: | https://www.zora.uzh.ch/id/eprint/252801/ https://www.zora.uzh.ch/id/eprint/252801/1/Thesis_Bigler.pdf https://doi.org/10.5167/uzh-252801 |
| Summary: | The Canadian Beaufort Sea experiences substantial input of sediment, organic carbon, and nutrients due to accelerated coastal erosion and transport from the Mackenzie River (Bröder et al. 2022). Ongoing climate change intensifies these fluxes along the land-ocean continuum and, thus, affect the marine ecosystem on the shelf and deep sea. Terrestrial organic carbon (TerrOC) derived from permafrost thaw leads to uncertainties in the carbon cycle on the shelf and potentially further amplifies climate warming through the decomposition of the organic-rich material. This thesis examines the fate of TerrOC by analyzing compounds of surface sediments from across the Beaufort Shelf to address the ongoing debate on whether the Canadian Beaufort Shelf is carbon sink or source. Present data from molecular biomarkers and compound-specific radiocarbon dating on long-chain fatty acids show a decreasing influence TerrOC away from the coast with a relative increase in radiocarbon ages along some transects the river mouth towards offshore locations. Furthermore, a net carbon sourcing role of the shelf is suggested, based on the presented data. These findings add up on what was observed in previous studies but need to be further analyzed and compared with other assessed data to yield proper quantifications. The Beaufort-Mackenzie coastal margin seems to be a complex setting and further investigations on transport times and TerrOC pathways. |
|---|