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Glacial‐interglacial modulation of eastern tropical North Pacific denitrification over the last 1.8‐Myr
Author(s) -
Liu Zhonghui,
Altabet Mark A.,
Herbert Timothy D.
Publication year - 2005
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 - 10.1029/2005gl024439
Subject(s) - interglacial , glacial period , pleistocene , oceanography , denitrification , geology , climatology , ice core , quaternary , early pleistocene , context (archaeology) , environmental science , paleontology , physics , quantum mechanics , nitrogen
A 1.8 Myr‐long δ 15 N record from the California margin provides the first continuous record of denitrification in the Eastern Tropical North Pacific (ETNP) over the entire Pleistocene epoch. Comparison of the nitrogen isotopic time series with proxies for ice volume, sea surface temperature (SST), and biological productivity place variations in the intensity of the denitrification zone in the context of global and regional climatic changes. Throughout the Pleistocene, ETNP denitrification remained linked to glacial‐interglacial climate cycles. The pacing of denitrification cycles switched from 41‐kyr in the mid‐ to early Pleistocene to 100‐kyr in the late Pleistocene, in tandem with the well‐known frequency shift identified from ice volume records. It therefore appears that denitrification remained an integral component of the marine feedbacks to orbital forcing, and through its effect on the nitrate inventory of the ocean might have played a role in driving atmospheric CO 2 cycles throughout the Pleistocene.