Publication Date:
2022-05-25
Description:
Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 30 (2015): 52–76, doi:10.1002/2014PA002662.
Description:
North Atlantic climate archives provide evidence for increased storm activity during the Little Ice Age (150 to 600 calibrated years (cal years) B.P.) and centered at 1700 and 3000 cal years B.P., typically in centennial-scale sedimentary records. Meteorological (tropical versus extratropical storms) and climate forcings of this signal remain poorly understood, although variability in the North Atlantic Oscillation (NAO) or Atlantic Meridional Overturning Circulation (AMOC) are frequently hypothesized to be involved. Here we present records of late Holocene storminess and coastal temperature change from a Bermudian submarine cave that is hydrographically circulated with the coastal ocean. Thermal variability in the cave is documented by stable oxygen isotope values of cave benthic foraminifera, which document a close linkage between regional temperature change and NAO phasing during the late Holocene. However, erosion of terrestrial sediment into the submarine cave provides a “storminess signal” that correlates with higher-latitude storminess archives and broader North Atlantic cooling events. Understanding the driver of this storminess signal will require higher-resolution storm records to disentangle the contribution of tropical versus extratropical cyclones and a better understanding of cyclone activity during hemispheric cooling periods. Most importantly, however, the signal in Bermuda appears more closely correlated with proxy-based evidence for subtle AMOC reductions than NAO phasing.
Description:
Field support for this project was provided by the Williams and Nolan Families and the Walsingham Land Trust, and data support from the Bermuda Weather Service and R. Johnson (BIOS). Awards from the National Sciences and Engineering Research Council of Canada (Alexander Graham Bell CGS and Post-Doctoral Fellowship) and the inaugural Johanna M. Resig Fellowship from the Cushman Foundation for Foraminiferal Research provided primary research support, along with research grants from the Geologic Society of America, Cave Research Foundation, the Bermuda Zoological Society, WHOI Ocean and Climate Change Institute, and in part funded by the NSF Division of Ocean Sciences (Award #1519557).
Description:
2015-08-18
Keywords:
Bermuda
;
Submarine caves
;
Benthic foraminifera
;
Oxygen isotopes
;
NAO
;
AMOC
Repository Name:
Woods Hole Open Access Server
Type:
Article
Format:
application/pdf
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