Ice Age‐Holocene Similarity of Foraminifera‐Bound Nitrogen Isotope Ratios in the Eastern Equatorial Pacific
نویسندگان
چکیده
Bulk sediment δ15N records from the eastern tropical Pacific (ETP) extending back to last ice age most often show low glacial δ15N, then a deglacial maximum, followed by gradual decline late Holocene that is typically higher than of Last Glacial Maximum (LGM). The lower LGM has been interpreted reflect an reduction in water column denitrification. We report foraminifera shell-bound nitrogen isotope (FB-δ15N) measurements for two species Neogloboquadrina dutertrei and incompta over 35 ka cores equatorial (EEP), both which have typical LGM-to-Holocene increase bulk δ15N. FB-δ15N contrasts with not indicating during LGM. Instead, are dominated comparable values. may be artifact, possibly related greater exogenous N inputs and/or weaker sedimentary diagenesis new data raise possibility previously inferred ETP denitrification was incorrect. A review reconstructed conditions geochemical box model output provides mechanistic support this possibility. However, ocean circulation nitrate-rich surface overlying core sites allow other possible interpretations, calling replication at non-equatorial sites.
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ژورنال
عنوان ژورنال: Paleoceanography and paleoclimatology
سال: 2021
ISSN: ['2572-4517', '2572-4525']
DOI: https://doi.org/10.1029/2020pa004063