North Atlantic ventilation of southern-sourced deep water in the glacial ocean

Eun Young Kwon, Mathis P. Hain, Daniel Mikhail Sigman, Eric D. Galbraith, Jorge Louis Sarmiento, J. R. Toggweiler

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

One potential mechanism for lowering atmospheric CO2 during glacial times is an increase in the fraction of the global ocean ventilated by the North Atlantic, which produces deep water with a low concentration of unused nutrients and thus drives the ocean's biological pump to a high efficiency. However, the data indicate that during glacial times, a water mass low in 13C/12C and 14C/C occupied the deep Atlantic, apparently at the expense of North Atlantic Deep Water (NADW). This water is commonly referred to as "southern-sourced" because of its apparent entry into the Atlantic basin from the South, prompting the inference that it was ventilated at the Southern Ocean surface. Here, we propose that this deep Atlantic water mass actually included a large fraction of North Atlantic-ventilated water, the chemical characteristics of which were altered by recirculation in the deep Southern and Indo-Pacific oceans. In an ocean model sensitivity experiment that reduces Antarctic Bottom Water formation and weakens its overturning circulation, we find that a much greater fraction of NADW is transported into the Southern Ocean without contacting the surface and is entrained and mixed into the southern-sourced deep water that spreads into the global abyssal ocean. Thus, North Atlantic ventilation takes over more of the ocean interior, lowering atmospheric CO2, and yet the abyssal Atlantic is filled from the South with old water low in 13C/ 12C and 14C/C, consistent with glacial data.

Original languageEnglish (US)
Article numberPA2208
JournalPaleoceanography
Volume27
Issue number2
DOIs
StatePublished - Jun 1 2012

Fingerprint

ventilation
deep water
ocean
North Atlantic Deep Water
water mass
biological pump
Antarctic Bottom Water
global ocean
water
sea surface
nutrient
basin
experiment

All Science Journal Classification (ASJC) codes

  • Oceanography
  • Palaeontology

Cite this

Kwon, E. Y., Hain, M. P., Sigman, D. M., Galbraith, E. D., Sarmiento, J. L., & Toggweiler, J. R. (2012). North Atlantic ventilation of southern-sourced deep water in the glacial ocean. Paleoceanography, 27(2), [PA2208]. https://doi.org/10.1029/2011PA002211
Kwon, Eun Young ; Hain, Mathis P. ; Sigman, Daniel Mikhail ; Galbraith, Eric D. ; Sarmiento, Jorge Louis ; Toggweiler, J. R. / North Atlantic ventilation of southern-sourced deep water in the glacial ocean. In: Paleoceanography. 2012 ; Vol. 27, No. 2.
@article{44ae19ccce7b4e5894c3b9b36775b01b,
title = "North Atlantic ventilation of southern-sourced deep water in the glacial ocean",
abstract = "One potential mechanism for lowering atmospheric CO2 during glacial times is an increase in the fraction of the global ocean ventilated by the North Atlantic, which produces deep water with a low concentration of unused nutrients and thus drives the ocean's biological pump to a high efficiency. However, the data indicate that during glacial times, a water mass low in 13C/12C and 14C/C occupied the deep Atlantic, apparently at the expense of North Atlantic Deep Water (NADW). This water is commonly referred to as {"}southern-sourced{"} because of its apparent entry into the Atlantic basin from the South, prompting the inference that it was ventilated at the Southern Ocean surface. Here, we propose that this deep Atlantic water mass actually included a large fraction of North Atlantic-ventilated water, the chemical characteristics of which were altered by recirculation in the deep Southern and Indo-Pacific oceans. In an ocean model sensitivity experiment that reduces Antarctic Bottom Water formation and weakens its overturning circulation, we find that a much greater fraction of NADW is transported into the Southern Ocean without contacting the surface and is entrained and mixed into the southern-sourced deep water that spreads into the global abyssal ocean. Thus, North Atlantic ventilation takes over more of the ocean interior, lowering atmospheric CO2, and yet the abyssal Atlantic is filled from the South with old water low in 13C/ 12C and 14C/C, consistent with glacial data.",
author = "Kwon, {Eun Young} and Hain, {Mathis P.} and Sigman, {Daniel Mikhail} and Galbraith, {Eric D.} and Sarmiento, {Jorge Louis} and Toggweiler, {J. R.}",
year = "2012",
month = "6",
day = "1",
doi = "https://doi.org/10.1029/2011PA002211",
language = "English (US)",
volume = "27",
journal = "Paleoceanography and Paleoclimatology",
issn = "2572-4517",
publisher = "John Wiley and Sons Inc.",
number = "2",

}

Kwon, EY, Hain, MP, Sigman, DM, Galbraith, ED, Sarmiento, JL & Toggweiler, JR 2012, 'North Atlantic ventilation of southern-sourced deep water in the glacial ocean', Paleoceanography, vol. 27, no. 2, PA2208. https://doi.org/10.1029/2011PA002211

North Atlantic ventilation of southern-sourced deep water in the glacial ocean. / Kwon, Eun Young; Hain, Mathis P.; Sigman, Daniel Mikhail; Galbraith, Eric D.; Sarmiento, Jorge Louis; Toggweiler, J. R.

In: Paleoceanography, Vol. 27, No. 2, PA2208, 01.06.2012.

Research output: Contribution to journalArticle

TY - JOUR

T1 - North Atlantic ventilation of southern-sourced deep water in the glacial ocean

AU - Kwon, Eun Young

AU - Hain, Mathis P.

AU - Sigman, Daniel Mikhail

AU - Galbraith, Eric D.

AU - Sarmiento, Jorge Louis

AU - Toggweiler, J. R.

PY - 2012/6/1

Y1 - 2012/6/1

N2 - One potential mechanism for lowering atmospheric CO2 during glacial times is an increase in the fraction of the global ocean ventilated by the North Atlantic, which produces deep water with a low concentration of unused nutrients and thus drives the ocean's biological pump to a high efficiency. However, the data indicate that during glacial times, a water mass low in 13C/12C and 14C/C occupied the deep Atlantic, apparently at the expense of North Atlantic Deep Water (NADW). This water is commonly referred to as "southern-sourced" because of its apparent entry into the Atlantic basin from the South, prompting the inference that it was ventilated at the Southern Ocean surface. Here, we propose that this deep Atlantic water mass actually included a large fraction of North Atlantic-ventilated water, the chemical characteristics of which were altered by recirculation in the deep Southern and Indo-Pacific oceans. In an ocean model sensitivity experiment that reduces Antarctic Bottom Water formation and weakens its overturning circulation, we find that a much greater fraction of NADW is transported into the Southern Ocean without contacting the surface and is entrained and mixed into the southern-sourced deep water that spreads into the global abyssal ocean. Thus, North Atlantic ventilation takes over more of the ocean interior, lowering atmospheric CO2, and yet the abyssal Atlantic is filled from the South with old water low in 13C/ 12C and 14C/C, consistent with glacial data.

AB - One potential mechanism for lowering atmospheric CO2 during glacial times is an increase in the fraction of the global ocean ventilated by the North Atlantic, which produces deep water with a low concentration of unused nutrients and thus drives the ocean's biological pump to a high efficiency. However, the data indicate that during glacial times, a water mass low in 13C/12C and 14C/C occupied the deep Atlantic, apparently at the expense of North Atlantic Deep Water (NADW). This water is commonly referred to as "southern-sourced" because of its apparent entry into the Atlantic basin from the South, prompting the inference that it was ventilated at the Southern Ocean surface. Here, we propose that this deep Atlantic water mass actually included a large fraction of North Atlantic-ventilated water, the chemical characteristics of which were altered by recirculation in the deep Southern and Indo-Pacific oceans. In an ocean model sensitivity experiment that reduces Antarctic Bottom Water formation and weakens its overturning circulation, we find that a much greater fraction of NADW is transported into the Southern Ocean without contacting the surface and is entrained and mixed into the southern-sourced deep water that spreads into the global abyssal ocean. Thus, North Atlantic ventilation takes over more of the ocean interior, lowering atmospheric CO2, and yet the abyssal Atlantic is filled from the South with old water low in 13C/ 12C and 14C/C, consistent with glacial data.

UR - http://www.scopus.com/inward/record.url?scp=84861695737&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84861695737&partnerID=8YFLogxK

U2 - https://doi.org/10.1029/2011PA002211

DO - https://doi.org/10.1029/2011PA002211

M3 - Article

VL - 27

JO - Paleoceanography and Paleoclimatology

JF - Paleoceanography and Paleoclimatology

SN - 2572-4517

IS - 2

M1 - PA2208

ER -