Processes of multibathyal aragonite undersaturation in the Arctic Ocean

Journal of Geophysical Research: Oceans
By: , and 

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Abstract

During 3 years of study (2010–2012), the western Arctic Ocean was found to have unique aragonite saturation profiles with up to three distinct aragonite undersaturation zones. This complexity is produced as inflow of Atlantic-derived and Pacific-derived water masses mix with Arctic-derived waters, which are further modified by physiochemical and biological processes. The shallowest aragonite undersaturation zone, from the surface to ∼30 m depth is characterized by relatively low alkalinity and other dissolved ions. Besides local influence of biological processes on aragonite undersaturation of shallow coastal waters, the nature of this zone is consistent with dilution by sea-ice melt and invasion of anthropogenic CO2 from the atmosphere. A second undersaturated zone at ∼90–220 m depth (salinity ∼31.8–35.4) occurs within the Arctic Halocline and is characterized by elevated pCO2 and nutrients. The nature of this horizon is consistent with remineralization of organic matter on shallow continental shelves bordering the Canada Basin and the input of the nutrients and CO2 entrained by currents from the Pacific Inlet. Finally, the deepest aragonite undersaturation zone is at greater than 2000 m depth and is controlled by similar processes as deep aragonite saturation horizons in the Atlantic and Pacific Oceans. The comparatively shallow depth of this deepest aragonite saturation horizon in the Arctic is maintained by relatively low temperatures, and stable chemical composition. Understanding the mechanisms controlling the distribution of these aragonite undersaturation zones, and the time scales over which they operate will be crucial to refine predictive models.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Processes of multibathyal aragonite undersaturation in the Arctic Ocean
Series title Journal of Geophysical Research: Oceans
DOI 10.1002/2016JC011696
Volume 121
Issue 11
Year Published 2016
Language English
Publisher AGU
Contributing office(s) St. Petersburg Coastal and Marine Science Center
Description 20 p.
First page 8248
Last page 8267
Other Geospatial Arctic Ocean