Comparing data set of carbonate species and other hydrographic chemical properties in 1999, 2000 and 2006 in the Okhotsk Sea, we found that salinity-normalized alkalinity in the subsurface water has shown a rate of increase by 2.6 ± 0.1 μmol kg−1 y−1 while the increase in salinity-normalized dissolved inorganic carbon corrected by AOU was almost half of that in alkalinity. Therefore, pH has increased by 0.013 ± 0.001 pH unit y−1 in the subsurface water (26.5 – 27.3 σ 
) which is the origin of the North Pacific intermediate water. This increase in pH could be explained by the increase in alkalinity in the Amur River in the last decade, suggesting a possibility that could mitigate one-fifth of recent ocean acidification in the North Pacific.
Watanabe, Y. W., J. Nishioka, M. Shigemitsu, A. Mimura, and T. Nakatsuka (2009), Influence of riverine alkalinity on carbonate species in the Okhotsk Sea, Geophys. Res. Lett., 36, L15606, doi:10.1029/2009GL038520. Article (subscription required).
