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Changes in Deep‐Sea Oxygenation in the Northeast Pacific Ocean During 32–10 ka
Author(s) -
Saravanan Ponnusamy,
Gupta Anil K.,
Zheng Hongbo,
Rai Santosh K.,
Panigrahi Mruganka K.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl086613
Subject(s) - oceanography , benthic zone , stadial , geology , productivity , paleoclimatology , quaternary , deep sea , climate change , climatology , paleontology , holocene , economics , macroeconomics
Climatic variations in the northeastern (NE) Pacific Ocean have been related to the strength of intermediate water‐driven productivity and global ocean circulation. Productivity variations and ocean circulation during the late Quaternary may have caused changes in the intensity of the oxygen minimum zone (OMZ). To understand these changes in productivity and resultant OMZ fluctuations, we analyzed benthic foraminiferal assemblages from the Cascadia margin which reveal major faunal and ecological shifts associated with the millennial‐scale climate changes during ~32–10 ka. The intermediate waters were highly variable during ~20–14 ka with increased productivity and nutrient supply to the subsurface during circa 15.5–14.5 ka. Our results suggest that suboxic environmental conditions occurred during the warm interstadials, and the Bølling‐Ållerød event was favorable for the dysoxic species. Our results further indicate that paleoclimate variations in the northeast Pacific region were mainly driven by the Pacific Intermediate Water Current.