Details:

Journal Title:
Science Advances
Personal Author:
Burls, Natalie J. ; Fedorov, Alexey V. ; Sigman, Daniel M. ; Jaccard, Samuel L. ; Tiedemann, Ralf ; ... More +
Burls, Natalie J. ; Fedorov, Alexey V. ; Sigman, Daniel M. ; Jaccard, Samuel L. ; Tiedemann, Ralf ; Haug, Gerald H. Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research)
Description:
An essential element of modern ocean circulation and climate is the Atlantic meridional overturning circulation (AMOC), which includes deep-water formation in the subarctic North Atlantic. However, a comparable overturning circulation is absent in the Pacific, theworld's largest ocean, where relatively fresh surface waters inhibitNorth Pacific deep convection. We present complementary measurement and modeling evidence that the warm, similar to 400-ppmv (parts per million by volume) CO2 world of the Pliocene supported subarctic North Pacific deep-water formation and a Pacific meridional overturning circulation (PMOC) cell. In Pliocene subarctic North Pacific sediments, we report orbitally paced maxima in calcium carbonate accumulation rate, with accompanying pigment and total organic carbon measurements supporting deep-ocean ventilation-driven preservation as their cause. Together with high accumulation rates of biogenic opal, these findings require vigorous bidirectional communication between surface waters and interior waters down to similar to 3 km in the western subarctic North Pacific, implying deep convection. Redoxsensitive trace metal data provide further evidence of higher Pliocene deep-ocean ventilation before the 2.73-Ma (million years) transition. This observational analysis is supported by climate modeling results, demonstrating that atmospheric moisture transport changes, in response to the reduced meridional sea surface temperature gradients of the Pliocene, were capable of eroding the halocline, leading to deep-water formation in the western subarctic Pacific and a strong PMOC. This second Northern Hemisphere overturning cell has important implications for heat transport, the ocean/atmosphere cycle of carbon, and potentially the equilibrium response of the Pacific to global warming.
Keywords:
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Climate Change Ocean Circulation Paleoclimatology
Source:
Science Advances 3(9), 2017
DOI:
https://doi.org/10.1126/sciadv.1700156
Pubmed Central ID:
PMC5597313
Document Type:
Journal Article
Funding:
Grant no. NA14OAR4310160
Place as Subject:
Pacific Ocean
Rights Information:
CC BY
Compliance:
PMC
Main Document Checksum:
[+]
urn:sha256:1bd2d209617a8b4eab07e8dba6a8eb196819e3bdd4c0bbb610c92179b10998eb
Download URL:
https://repository.library.noaa.gov/view/noaa/24731/noaa_24731_DS1.pdf
File Type:

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