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Rapid variations in deep ocean temperature detected in the Holocene
Author(s) -
Bova Samantha C.,
Herbert Timothy D.,
FoxKemper Baylor
Publication year - 2016
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 - 10.1002/2016gl071450
Subject(s) - holocene , oceanography , geology , foraminifera , deep sea , climatology , sea surface temperature , benthic zone , forcing (mathematics) , deep ocean water , ocean current , paleoceanography , salinity
Abstract The observational record of deep ocean variability is short, which makes it difficult to attribute the recent rise in deep ocean temperatures to anthropogenic forcing. Here we test a new proxy—the oxygen isotopic signature of individual benthic foraminifera—to detect rapid (i.e., monthly to decadal) variations in deep ocean temperature and salinity in the sedimentary record. We apply this technique at 1000 m water depth in the Eastern Equatorial Pacific during seven 200 year Holocene intervals. Variability in foraminifer δ 18 O over the past 200 years is below the detection limit, but δ 18 O signatures from two mid‐Holocene intervals indicate temperature swings >2°C within 200 years. More vigorous transport between the surface and deep ocean or stronger eddy variability than that observed in the historical record are potential explanations. Distinguishing externally forced climate trends in deep ocean properties from unforced variability should be possible with systematic analysis of suitable deep sea cores.