Decadal Variability of Total Alkalinity in the North Pacific Ocean

Jessica N Cross1,2, Brendan R Carter1,3, Samantha A Siedlecki3, Simone R Alin1, Andrew G Dickson4, Richard A Feely1, Jeremy T Mathis5, Richard H Wanninkhof6, Alison M Macdonald7, Sabine Mecking8 and Lynne D Talley9, (1)NOAA Pacific Marine Environmental Laboratory, Seattle, WA, United States, (2)Cooperative Institute for Alaska Research, University of Alaska, Fairbanks, Fairbanks, AK, United States, (3)University of Washington, JISAO, Seattle, WA, United States, (4)Scripps Institution of Oceanography, UCSD, La Jolla, CA, United States, (5)NOAA Arctic Research Program, Ocean and Atmospheric Research, Silver Spring, MD, United States, (6)Atlantic Oceanographic and Meteorological Laboratory, Miami, FL, United States, (7)Woods Hole Oceanographic Institution, Woods Hole, MA, United States, (8)Applied Physics Laboratory University of Washington, Kenmore, WA, United States, (9)University of California San Diego, La Jolla, CA, United States
Abstract:
Recent observations of acidification-driven shoaling of the calcium carbonate saturation horizon in the North Pacific have prompted new interest in carbonate cycling in this region, particularly related to impacts on biogenic calcification at the surface layer. Some estimates project that the impacts of OA on alkalinity cycling are beginning to emerge. Here, we present total alkalinity concentrations along a meridional transect of the North Pacific (WOCE, CLIVAR, and US GO-SHIP line P16N; 152 °W) over a period of three decades. The largest source of variability in alkalinity concentrations is related to North Pacific circulation, particularly in the surface mixed layer. Precise normalization of these data reveal some small spatial and temporal variability in the background. We explore these decadal trends in the context of decadal oscillations, ocean biogeochemical cycles, and global change processes such as ocean acidification.
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