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Quaternary glacial and deglacial Ostracoda in the thermocline of the Little Bahama Bank (NW Atlantic): Palaeoceanographic implications

Palaeogeography, Palaeoclimatology, Palaeoecology

By:
and
DOI: 10.1016/S0031-0182(99)00048-6

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Abstract

We determined faunal and oceanographic changes during the last glacial and deglacial in the Providence Channel, Little Bahama Bank (LBB), using modern ocean (from LBB, Florida-Hatteras Slope and Blake Plateau, western North Atlantic) and late Quaternary (LBB) distributions of the benthic ostracode genus Krithe from the mid-depth (300-1600 m) subtropical North Atlantic Ocean. Nine species of Krithe are limited in their bathymetric distribution by warm bottom water temperatures (or a temperature-related parameter) in the thermocline of the modern Atlantic. During the last glacial interval in the northwest Providence Channel of the Little Bahama Bank five species of Krithe (K. aequabilis, K. dolichodeira, K. gr. minima, K. reversa and K. trinidadensis) migrated upslope; conversely, during the deglaciation, most Krithe species migrated downslope, re-occupying their deeper niches. These vertical species migrations are attributed to decreased glacial bottom water temperatures and perhaps increased dissolved oxygen during the last glacial and warmer water temperatures during the deglacial. Based upon thermal values of recent depth ranges of selected species of Krithe, we estimate that glacial waters cooled about 4??C (shallower than 900 m) and about 2??C (deeper than 900 m) and deglacial waters warmed about the same values in shallow and mid-depth water masses, comparing to modern temperatures. The discovery of common Halocypris, a mesopelagic ostracode, in Little Bahama Bank glacial and deglacial sediments also suggests greater oxygenation relative to the late Holocene.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Quaternary glacial and deglacial Ostracoda in the thermocline of the Little Bahama Bank (NW Atlantic): Palaeoceanographic implications
Series title:
Palaeogeography, Palaeoclimatology, Palaeoecology
DOI:
10.1016/S0031-0182(99)00048-6
Volume
152
Issue:
3-4
Year Published:
1999
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Palaeogeography, Palaeoclimatology, Palaeoecology
First page:
339
Last page:
364