Release of dissolved organic carbon from coastal erosion into the southern Canadian Beaufort Sea
Arctic regions are highly vulnerable to climatic change processes and are currently undergoing the most rapid environmental transition experienced on Earth, at a pace that is expected to increase over the coming decades. Changing environmental conditions affect the sensitive ice-rich permafrost coas...
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| Format: | Thesis |
| Language: | unknown |
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2013
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| Online Access: | https://epic.awi.de/id/eprint/38851/ https://epic.awi.de/id/eprint/38851/1/Master_thesis_George_Tanski_final.pdf https://hdl.handle.net/10013/epic.46109 https://hdl.handle.net/10013/epic.46109.d001 |
| Summary: | Arctic regions are highly vulnerable to climatic change processes and are currently undergoing the most rapid environmental transition experienced on Earth, at a pace that is expected to increase over the coming decades. Changing environmental conditions affect the sensitive ice-rich permafrost coasts in northern Canada that erode due to warmer climate, longer open water seasons and stronger storms. Coastal erosion in the Canadian Arctic that is among the highest in the world releases terrestrial organic carbon stored in ice-rich permafrost into the Arctic Ocean, which fosters the feedback mechanisms between carbon cycle and climate. The Yukon Coastal Plain is located in the western Canadian Arctic between the Mackenzie Delta and the Alaskan border and is characterized by the occurrence of ice-rich permafrost and large massive ground ice bodies. This ice contributes to facilitate coastal erosion, which is known to occur at a pace greater than in temperate regions during the short summer season. Erosion contributes to the release of large amounts of particulate organic carbon to the Arctic Ocean through the export of sediments. Additionally, large amounts of particulate and dissolved organic carbon (DOC) are released by rivers into the Arctic Ocean. Ground ice in permafrost also contains organic carbon in the dissolved state that will also be released to the ocean by coastal erosion, but the amounts of DOC present in the ground and eventually lost to the sea are unknown. It was therefore the objective of this thesis to quantify the amount of DOC present in massive ground ice and the amounts released by coastal erosion into the nearshore zone of the southern Beaufort Sea (Arctic Ocean). Several massive ground ice bodies and ice wedges, exposed by coastal erosion or thermal denudation, were sampled on Herschel Island and along the mainland coast of the Yukon Territory. In total, 41 samples of ice blocks were obtained from these bodies and analyzed in the laboratories of the Alfred Wegener Institute. DOC ... |
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