Dissolved organic carbon export with North Pacific Intermediate Water formation

[1] An evaluation of DOC export with the formation of North Pacific Intermediate Water is presented. Data from sites representing the relevant North Pacific water masses (subtropical, subpolar, and subtropical transitional) are used to demonstrate the process. We suggest that dissolved organic carbon (DOC)-replete Oyashio (subpolar) water mixes with DOC-depleted Kuroshio (subtropical) water in the mixed water region east of Japan. The new intermediate water, formed at a rate of 2–5 Sv, exports DOC at 13 ± 6 Tg DOC yr � 1 . On the basis of these findings we present an alternative model to explain the 14 C-DOC age gradient recently reported for intermediate depths of the North Pacific. INDEX TERMS: 4806 Oceanography: Biological and Chemical: Carbon cycling; 4805 Oceanography: Biological and Chemical: Biogeochemical cycles (1615); 4283 Oceanography: General: Water masses; KEYWORDS: dissolved organic carbon; DOC; North Pacific Intermediate Water; carbon export; carbon