Effect of terrestrial organic matter on ocean acidification and CO2 flux in an Arctic shelf sea
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Date
2020-04-10
Authors
Capelle, David W.
Kuzyk, Zou Zou A.
Papakyriakou, Tim
Gueguen, Celine
Miller, Lisa A.
Macdonald, Robie W.
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier Ltd.
Abstract
Recent research has focused on the changing ability of oceans to absorb atmospheric CO2 and the consequences
for ocean acidification, with Arctic shelf seas being among the most sensitive regions. Hudson Bay is a large shelf
sea in northern Canada whose location at the margin of the cryosphere places it in the vanguard of global climate
change. Here, we develop a four-compartment box-model and carbon budget using published and recently
collected measurements to estimate carbon inputs, transformations, and losses within Hudson Bay. We estimate
the annual effects of terrestrial carbon remineralization on aragonite saturation (ΩAr, a proxy for ocean acidification)
and on the partial pressure of CO2 (pCO2, a proxy for air-sea CO2 flux) within each compartment, as
well as the effects of marine primary production, marine organic carbon remineralization, and terrestrial calcium
carbonate dissolution. We find that the remineralization of terrestrial dissolved organic carbon is the main driver
of CO2 accumulation and aragonite under-saturation in coastal surface waters, but this is largely offset by marine
primary production. Below the surface mixed layer, marine organic carbon remineralization is the largest
contributor to CO2 accumulation and aragonite under-saturation, and is partially offset by terrestrial CaCO3
dissolution. Overall, the annual delivery and processing of carbon reduces ΩAr of water flowing through HB by
up to 0.17 units and raises pCO2 by up to 165 μatm. The similarities between Hudson Bay and other Arctic shelf
seas suggest these areas are also significantly influenced by terrestrial carbon inputs and transformation.
Description
Keywords
Aragonite, Carbon-cycle, Carbon-dioxide, Arctic, Ocean acidification
Citation
David W. Capelle, Zou Zou A. Kuzyk, Tim Papakyriakou, Céline Guéguen, Lisa A. Miller, Robie W. Macdonald, Effect of terrestrial organic matter on ocean acidification and CO2 flux in an Arctic shelf sea, Progress in Oceanography, Volume 185, 2020, 102319, ISSN 0079-6611, https://doi.org/10.1016/j.pocean.2020.102319.