Annual cycles of pCO2sw in the southeastern Beaufort Sea: New understandings of air-sea CO2 exchange in arctic polynya regions

From 23 October 2007 to 1 August 2008, we made continuous measurements of seasurface partial pressure of CO2 (pCO2sw) in three regions of the southeastern BeaufortSea (Canada): the Amundsen Gulf, the Banks Island Shelf, and the Mackenzie Shelf.All three regions are seasonally ice covered, with mobil...

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Bibliographic Details
Published in:Journal of Geophysical Research: Oceans
Main Authors: Else, BGT, Papakyriakou, TN, Galley, RJ, Mucci, A, Gosselin, M, Miller, LA, Shadwick, EH, Thomas, H
Format: Article in Journal/Newspaper
Language:English
Published: Amer Geophysical Union 2012
Subjects:
Earth Sciences
Oceanography
Chemical Oceanography
Arctic
Canada
Amundsen Gulf
Banks Island
Beaufort Sea
Mackenzie Shelf
Phytoplankton
Online Access:https://doi.org/10.1029/2011JC007346
http://ecite.utas.edu.au/77499
Description
Summary:From 23 October 2007 to 1 August 2008, we made continuous measurements of seasurface partial pressure of CO2 (pCO2sw) in three regions of the southeastern BeaufortSea (Canada): the Amundsen Gulf, the Banks Island Shelf, and the Mackenzie Shelf.All three regions are seasonally ice covered, with mobile winter ice and an early springopening that defines them as polynya regions. Amundsen Gulf was characterized byundersaturated pCO2sw (with respect to the atmosphere) in the late fall, followed by anunder-ice increase to near saturation in winter, a return to undersaturation during the spring,and an increase to near saturation in summer. The Banks Island Shelf acted similarly,while the Mackenzie Shelf experienced high supersaturation in the fall, followed by aspring undersaturation and a complex, spatially heterogeneous summer season. None ofthese patterns are similar to the annual cycle described or proposed for other Arctic polynyaregions. We hypothesize that the discrepancy reflects the influence of several previouslyunconsidered processes including fall phytoplankton blooms, upwelling, winter air-seagas exchange, the continental shelf pump, spring nutrient limitation, summer surfacewarming, horizontal advection, and riverine input. In order to properly predict current andfuture rates of air-sea CO2 exchange in such regions, these processes must be consideredon a location-by-location basis.

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