Large-scale response of the Eastern Mediterranean thermohaline circulation to African monsoon intensification during sapropel S1 formation

T. Tesi, A. Asioli, D. Minisini, V. Maselli, G. Dalla Valle, F. Gamberi, L. Langone, A. Cattaneo, P. Montagna, F. Trincardi

Research output: Contribution to journalArticle

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Abstract

The formation of Eastern Mediterranean sapropels has periodically occurred during intensification of northern hemisphere monsoon precipitation over North Africa. However, the large-scale response of the Eastern Mediterranean
thermohaline circulation during these monsoon-fuelled freshening episodes is poorly constrained. Here, we investigate the formation of the youngest sapropel (S1) along an across-slope transect in the Adriatic Sea. Foraminifera-based
oxygen index, redox-sensitive elements and biogeochemical parameters reveal – for the first time – that the Adriatic S1 was synchronous with the deposition of south-eastern Mediterranean S1 beds. Proxies of paleo thermohaline
currents indicate that the bottom-hugging North Adriatic Dense Water (NAdDW) suddenly decreased at the sapropel onset simultaneously with the maximum freshening of the Levantine Sea during the African Humid Period. We
conclude that the lack of the “salty” Levantine Intermediate Water hampered the preconditioning of the northern Adriatic waters necessary for the NAdDW formation prior to the winter cooling. Consequently, a weak NAdDW limited
in turn the Eastern Mediterranean Deep Water (EMDWAdriatic) formation with important consequences for the ventilation of the Ionian basin as well. Our results highlight the importance of the Adriatic for the deep water ventilation
and the interdependence among the major eastern Mediterranean water masses whose destabilization exerted firstorder control on S1 deposition.
Original languageEnglish
Pages (from-to)139-154
Number of pages16
JournalQuaternary Science Reviews
Volume159
Early online date7 Feb 2017
DOIs
Publication statusPublished - 1 Mar 2017

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sapropel
dense water
thermohaline circulation
monsoon
water
deep water formation
Mediterranean Water
intermediate water
foraminifera
water mass
ventilation
Northern Hemisphere
transect
deep water
cooling
winter
basin
Northern Africa
Africa
Water

Keywords

  • Sapropel S1
  • Mediterannean Sea
  • African monsoons
  • Anoxia
  • Thermohaline circulation

Cite this

Large-scale response of the Eastern Mediterranean thermohaline circulation to African monsoon intensification during sapropel S1 formation. / Tesi, T. ; Asioli, A.; Minisini, D.; Maselli, V.; Dalla Valle, G. ; Gamberi, F.; Langone, L.; Cattaneo, A.; Montagna, P.; Trincardi, F.

In: Quaternary Science Reviews, Vol. 159, 01.03.2017, p. 139-154.

Research output: Contribution to journalArticle

Tesi, T, Asioli, A, Minisini, D, Maselli, V, Dalla Valle, G, Gamberi, F, Langone, L, Cattaneo, A, Montagna, P & Trincardi, F 2017, 'Large-scale response of the Eastern Mediterranean thermohaline circulation to African monsoon intensification during sapropel S1 formation', Quaternary Science Reviews, vol. 159, pp. 139-154. https://doi.org/10.1016/j.quascirev.2017.01.020
Tesi, T. ; Asioli, A. ; Minisini, D. ; Maselli, V. ; Dalla Valle, G. ; Gamberi, F. ; Langone, L. ; Cattaneo, A. ; Montagna, P. ; Trincardi, F. / Large-scale response of the Eastern Mediterranean thermohaline circulation to African monsoon intensification during sapropel S1 formation. In: Quaternary Science Reviews. 2017 ; Vol. 159. pp. 139-154.
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abstract = "The formation of Eastern Mediterranean sapropels has periodically occurred during intensification of northern hemisphere monsoon precipitation over North Africa. However, the large-scale response of the Eastern Mediterraneanthermohaline circulation during these monsoon-fuelled freshening episodes is poorly constrained. Here, we investigate the formation of the youngest sapropel (S1) along an across-slope transect in the Adriatic Sea. Foraminifera-basedoxygen index, redox-sensitive elements and biogeochemical parameters reveal – for the first time – that the Adriatic S1 was synchronous with the deposition of south-eastern Mediterranean S1 beds. Proxies of paleo thermohalinecurrents indicate that the bottom-hugging North Adriatic Dense Water (NAdDW) suddenly decreased at the sapropel onset simultaneously with the maximum freshening of the Levantine Sea during the African Humid Period. Weconclude that the lack of the “salty” Levantine Intermediate Water hampered the preconditioning of the northern Adriatic waters necessary for the NAdDW formation prior to the winter cooling. Consequently, a weak NAdDW limitedin turn the Eastern Mediterranean Deep Water (EMDWAdriatic) formation with important consequences for the ventilation of the Ionian basin as well. Our results highlight the importance of the Adriatic for the deep water ventilationand the interdependence among the major eastern Mediterranean water masses whose destabilization exerted firstorder control on S1 deposition.",
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note = "This study was supported by Shell International Exploration and Production Inc. We thank the R/V URANIA crew for at sea assistance. This is the ISMAR contribution n. 1914. We thank Dr. L. Capotondi and Dr. L. Vigliotti for their constructive comments on the first draft of the manuscript. We also thank Dr. Daria Pasqual (University of Padova, Dept. of Geosciences) for her assistance in XRF analyses. We thank two anonymous reviewers and the Editor H. Bauch for their constructive comments. We also acknowledge Prof. Gerhard Schmiedl (Universit{\"a}t Hamburg) and Associate Prof. Syee Weldeab (Earth Science, UC Santa Barbara) for providing published data used in this study.",
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T1 - Large-scale response of the Eastern Mediterranean thermohaline circulation to African monsoon intensification during sapropel S1 formation

AU - Tesi, T.

AU - Asioli, A.

AU - Minisini, D.

AU - Maselli, V.

AU - Dalla Valle, G.

AU - Gamberi, F.

AU - Langone, L.

AU - Cattaneo, A.

AU - Montagna, P.

AU - Trincardi, F.

N1 - This study was supported by Shell International Exploration and Production Inc. We thank the R/V URANIA crew for at sea assistance. This is the ISMAR contribution n. 1914. We thank Dr. L. Capotondi and Dr. L. Vigliotti for their constructive comments on the first draft of the manuscript. We also thank Dr. Daria Pasqual (University of Padova, Dept. of Geosciences) for her assistance in XRF analyses. We thank two anonymous reviewers and the Editor H. Bauch for their constructive comments. We also acknowledge Prof. Gerhard Schmiedl (Universität Hamburg) and Associate Prof. Syee Weldeab (Earth Science, UC Santa Barbara) for providing published data used in this study.

PY - 2017/3/1

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N2 - The formation of Eastern Mediterranean sapropels has periodically occurred during intensification of northern hemisphere monsoon precipitation over North Africa. However, the large-scale response of the Eastern Mediterraneanthermohaline circulation during these monsoon-fuelled freshening episodes is poorly constrained. Here, we investigate the formation of the youngest sapropel (S1) along an across-slope transect in the Adriatic Sea. Foraminifera-basedoxygen index, redox-sensitive elements and biogeochemical parameters reveal – for the first time – that the Adriatic S1 was synchronous with the deposition of south-eastern Mediterranean S1 beds. Proxies of paleo thermohalinecurrents indicate that the bottom-hugging North Adriatic Dense Water (NAdDW) suddenly decreased at the sapropel onset simultaneously with the maximum freshening of the Levantine Sea during the African Humid Period. Weconclude that the lack of the “salty” Levantine Intermediate Water hampered the preconditioning of the northern Adriatic waters necessary for the NAdDW formation prior to the winter cooling. Consequently, a weak NAdDW limitedin turn the Eastern Mediterranean Deep Water (EMDWAdriatic) formation with important consequences for the ventilation of the Ionian basin as well. Our results highlight the importance of the Adriatic for the deep water ventilationand the interdependence among the major eastern Mediterranean water masses whose destabilization exerted firstorder control on S1 deposition.

AB - The formation of Eastern Mediterranean sapropels has periodically occurred during intensification of northern hemisphere monsoon precipitation over North Africa. However, the large-scale response of the Eastern Mediterraneanthermohaline circulation during these monsoon-fuelled freshening episodes is poorly constrained. Here, we investigate the formation of the youngest sapropel (S1) along an across-slope transect in the Adriatic Sea. Foraminifera-basedoxygen index, redox-sensitive elements and biogeochemical parameters reveal – for the first time – that the Adriatic S1 was synchronous with the deposition of south-eastern Mediterranean S1 beds. Proxies of paleo thermohalinecurrents indicate that the bottom-hugging North Adriatic Dense Water (NAdDW) suddenly decreased at the sapropel onset simultaneously with the maximum freshening of the Levantine Sea during the African Humid Period. Weconclude that the lack of the “salty” Levantine Intermediate Water hampered the preconditioning of the northern Adriatic waters necessary for the NAdDW formation prior to the winter cooling. Consequently, a weak NAdDW limitedin turn the Eastern Mediterranean Deep Water (EMDWAdriatic) formation with important consequences for the ventilation of the Ionian basin as well. Our results highlight the importance of the Adriatic for the deep water ventilationand the interdependence among the major eastern Mediterranean water masses whose destabilization exerted firstorder control on S1 deposition.

KW - Sapropel S1

KW - Mediterannean Sea

KW - African monsoons

KW - Anoxia

KW - Thermohaline circulation

U2 - 10.1016/j.quascirev.2017.01.020

DO - 10.1016/j.quascirev.2017.01.020

M3 - Article

VL - 159

SP - 139

EP - 154

JO - Quaternary Science Reviews

JF - Quaternary Science Reviews

SN - 0277-3791

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