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Summer Surface CO 2 Dynamics on the Bering Sea and Eastern Chukchi Sea Shelves From 1989 to 2019
Author(s) -
Wang Hongjie,
Lin Peigen,
Pickart Robert S.,
Cross Jessica N.
Publication year - 2022
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2021jc017424
Subject(s) - upwelling , oceanography , sink (geography) , outgassing , environmental science , sea ice , shoal , marine ecosystem , sea surface temperature , climatology , geology , ecosystem , geography , ecology , cartography , chemistry , organic chemistry , biology
By compiling boreal summer (June to October) CO 2 measurements from 1989 to 2019 on the Bering and eastern Chukchi Sea shelves, we find that the study areas act as a CO 2 sink except when impacted by river runoff and wind‐driven upwelling. The CO 2 system in this area is seasonally dominated by the biological pump especially in the northern Bering Sea and near Hanna Shoal, while wind‐driven upwelling of CO 2 ‐rich bottom water can cause episodic outgassing. Seasonal surface Δ f CO 2 (oceanic f CO 2 – air f CO 2 ) is dominantly driven by temperature only during periods of weak CO 2 outgassing in shallow nearshore areas. However, after comparing the mean summer Δ f CO 2 during the periods of 1989–2013 and 2014–2019, we suggest that temperature does drive long‐term, multi‐decadal patterns in Δ f CO 2 . In the northern Chukchi Sea, rapid warming concurrent with reduced seasonal sea‐ice persistence caused the regional summer CO 2 sink to decrease. By contrast, increasing primary productivity caused the regional summer CO 2 sink on the Bering Sea shelf to increase over time. While additional time series are needed to confirm the seasonal and annual trajectory of CO 2 changes and ocean acidification in these dynamic and spatially complex ecosystems, this study provides a meaningful mechanistic analysis of recent changes in inorganic carbonate chemistry. As high‐resolution time series of inorganic carbonate parameters lengthen and short‐term variations are better constrained in the coming decades, we will have stronger confidence in assessing the mechanisms contributing to long‐term changes in the source/sink status of regional sub‐Arctic seas.