Abstract:

The GP16 Eastern Pacific Zonal Transect cruise from Peru to Tahiti in 2013 along 12-15°S crossed the large eastern tropical South Pacific oxygen deficient zone (ODZ) in the eastern half of the transect, which was expected to be an important source of dissolved iron into the ocean interior.  Contrary to expectations, there was no significant iron plume in the heart of the ODZ around 250 m that extended beyond the coastal margin, despite the ODZ penetrating several thousand of kilometers into the interior.  Surprisingly, a deep coastal iron plume in oxygenated waters centered around 2000 m was observed to penetrate >1000 km into the interior. In this talk, I examine the possible reasons behind the unexpected high Fe from the oxygenated deep slope relative to the more reducing ODZ above. 

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