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Sea surface p CO 2 and O 2 dynamics in the partially ice‐covered A rctic O cean
Author(s) -
Islam Fakhrul,
DeGrandpre Michael D.,
Beatty Cory M.,
Timmermans MaryLouise,
Krishfield Richard A.,
Toole John M.,
Laney Samuel R.
Publication year - 2017
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2016jc012162
Subject(s) - sea ice , oceanography , environmental science , sea ice thickness , biogeochemical cycle , arctic ice pack , sea ice concentration , arctic , atmospheric sciences , climatology , geology , chemistry , environmental chemistry
Understanding the physical and biogeochemical processes that control CO 2 and dissolved oxygen (DO) dynamics in the Arctic Ocean (AO) is crucial for predicting future air‐sea CO 2 fluxes and ocean acidification. Past studies have primarily been conducted on the AO continental shelves during low‐ice periods and we lack information on gas dynamics in the deep AO basins where ice typically inhibits contact with the atmosphere. To study these gas dynamics, in situ time‐series data have been collected in the Canada Basin during late summer to autumn of 2012. Partial pressure of CO 2 ( p CO 2 ), DO concentration, temperature, salinity, and chlorophyll‐a fluorescence (Chl‐ a ) were measured in the upper ocean in a range of sea ice states by two drifting instrument systems. Although the two systems were on average only 222 km apart, they experienced considerably different ice cover and external forcings during the 40–50 day periods when data were collected. The p CO 2 levels at both locations were well below atmospheric saturation whereas DO was almost always slightly supersaturated. Modeling results suggest that air‐sea gas exchange, net community production (NCP), and horizontal gradients were the main sources of p CO 2 and DO variability in the sparsely ice‐covered AO. In areas more densely covered by sea ice, horizontal gradients were the dominant source of variability, with no significant NCP in the surface mixed layer. If the AO reaches equilibrium with atmospheric CO 2 as ice cover continues to decrease, aragonite saturation will drop from a present mean of 1.00 ± 0.02 to 0.86 ± 0.01.