The evolution of seafloor environmental conditions in the southern Red Sea continental shelf during the last 30 ka
The evolution of seafloor environmental conditions in the southern Red Sea continental shelf during the last 30 ka
The southern Red Sea is affected by intense interactions between monsoon and sea level changes in a semi-closed environment. Still, the impacts on the wide shelves remain poorly documented. We investigate the seafloor environmental conditions on the southern Red Sea shelf over the last 30 ka through sedimentological (visual inspection, granulometry, bulk density), geochemical (organic carbon, calcium carbonate and nitrogen content) and micropaleontological (benthic foraminifera) observations in a previously dated sediment core (FA09) from the Farasan Islands Archipelago. Glacial sediments exhibit high density and low carbonate contents, whereas post-glacial sediments reflect increased biogenic productivity. Seafloor oxygenation was limited in most of the glacial interval, along with hypersaline conditions. During the maximum sea level lowstand, an enhanced presence of eutrophic-indicator benthic assemblages likely reflects efficient organic matter preservation induced by weak water ventilation. Our proxies combined with a previous surface-water productivity reconstruction reveals a coupling between organic matter flux to the seafloor and surface productivity levels in the southern Red Sea shelf, particularly pronounced during periods of enhanced summer monsoon. This pattern is often accompanied by a decrease in seafloor oxygenation. In contrast, well oxygenated and more oligotrophic seafloor conditions are recorded around the time of Heinrich Stadial 2, when previous work indicates a reduction in summer monsoon intensity and surface productivity levels. A drastic decrease of benthic foraminifera along with increased organic carbon contents in late glacial and late Holocene reflect oxygen-depleted seafloor conditions that we attribute to expansion of an intensified southern Red Sea oxygen minimum zone (OMZ).
Benthic foraminifera, Monsoon, Paleoceanography, Red Sea, Sea level changes, Seafloor conditions
Sergiou, Spyros
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Geraga, Maria
89154b59-f214-4f46-bc5d-51843cc75d14
Rohling, Eelco
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Rodríguez-Sanz, Laura
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Prandekou, A.
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Noti, A.
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Paraschos, A.
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Sakellariou, D.
99ad6bc1-9e64-493b-b095-b583a471b348
Bailey, G.
7920e9a2-6699-4358-b4e0-ccdf5c0263a9
December 2022
Sergiou, Spyros
90d334e6-e443-411e-9dd6-4a775cb401c7
Geraga, Maria
89154b59-f214-4f46-bc5d-51843cc75d14
Rohling, Eelco
a2a27ef2-fcce-4c71-907b-e692b5ecc685
Rodríguez-Sanz, Laura
c8a7203f-705d-4c68-998d-9f2a3c5d8b5f
Prandekou, A.
4277a483-fd1c-4c15-8c89-104feb2b0c7e
Noti, A.
ee0d1f99-a789-4560-a9de-1cb82804bb26
Paraschos, A.
bc5b5e6f-5a6a-4d2b-b9ae-7213ccf55089
Sakellariou, D.
99ad6bc1-9e64-493b-b095-b583a471b348
Bailey, G.
7920e9a2-6699-4358-b4e0-ccdf5c0263a9
Sergiou, Spyros, Geraga, Maria, Rohling, Eelco, Rodríguez-Sanz, Laura, Prandekou, A., Noti, A., Paraschos, A., Sakellariou, D. and Bailey, G.
(2022)
The evolution of seafloor environmental conditions in the southern Red Sea continental shelf during the last 30 ka.
Marine Micropaleontology, 177, [102181].
(doi:10.1016/j.marmicro.2022.102181).
Abstract
The southern Red Sea is affected by intense interactions between monsoon and sea level changes in a semi-closed environment. Still, the impacts on the wide shelves remain poorly documented. We investigate the seafloor environmental conditions on the southern Red Sea shelf over the last 30 ka through sedimentological (visual inspection, granulometry, bulk density), geochemical (organic carbon, calcium carbonate and nitrogen content) and micropaleontological (benthic foraminifera) observations in a previously dated sediment core (FA09) from the Farasan Islands Archipelago. Glacial sediments exhibit high density and low carbonate contents, whereas post-glacial sediments reflect increased biogenic productivity. Seafloor oxygenation was limited in most of the glacial interval, along with hypersaline conditions. During the maximum sea level lowstand, an enhanced presence of eutrophic-indicator benthic assemblages likely reflects efficient organic matter preservation induced by weak water ventilation. Our proxies combined with a previous surface-water productivity reconstruction reveals a coupling between organic matter flux to the seafloor and surface productivity levels in the southern Red Sea shelf, particularly pronounced during periods of enhanced summer monsoon. This pattern is often accompanied by a decrease in seafloor oxygenation. In contrast, well oxygenated and more oligotrophic seafloor conditions are recorded around the time of Heinrich Stadial 2, when previous work indicates a reduction in summer monsoon intensity and surface productivity levels. A drastic decrease of benthic foraminifera along with increased organic carbon contents in late glacial and late Holocene reflect oxygen-depleted seafloor conditions that we attribute to expansion of an intensified southern Red Sea oxygen minimum zone (OMZ).
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Accepted/In Press date: 10 October 2022
e-pub ahead of print date: 18 October 2022
Published date: December 2022
Additional Information:
Funding Information:
The present study arises from the “DISPERSE: Dynamic Landscapes, Coastal Environments and Human Dispersals” research project, funded by the European Research Council under the Ideas Programme of the 7th Framework Programme as Advanced Grant 269586. We thank the Saudi Commission for Tourism and National Heritage (SCTH) and the Department of General Survey of the Ministry of Defense for fieldwork permissions. We are also grateful to the crew of the R/V AEGAEO for successfully undertaking the coring survey. Finally, S. Sergiou thanks the General Secretariat for Research and Technology (GSRT) and the Hellenic Foundation for Research and Innovation (HFRI) for scholarship funding during his research work. This is DISPERSE contribution no. 65.
Funding Information:
The present study arises from the “DISPERSE: Dynamic Landscapes, Coastal Environments and Human Dispersals” research project, funded by the European Research Council under the Ideas Programme of the 7th Framework Programme as Advanced Grant 269586 . We thank the Saudi Commission for Tourism and National Heritage (SCTH) and the Department of General Survey of the Ministry of Defense for fieldwork permissions. We are also grateful to the crew of the R/V AEGAEO for successfully undertaking the coring survey. Finally, S. Sergiou thanks the General Secretariat for Research and Technology (GSRT) and the Hellenic Foundation for Research and Innovation (HFRI) for scholarship funding during his research work. This is DISPERSE contribution no. 65.
Publisher Copyright:
© 2022 Elsevier B.V.
Keywords:
Benthic foraminifera, Monsoon, Paleoceanography, Red Sea, Sea level changes, Seafloor conditions
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Local EPrints ID: 472702
URI: http://eprints.soton.ac.uk/id/eprint/472702
ISSN: 0377-8398
PURE UUID: 97781241-55a4-4a1d-9c3a-6c71bf253576
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Date deposited: 15 Dec 2022 17:31
Last modified: 25 Oct 2024 04:01
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Contributors
Author:
Spyros Sergiou
Author:
Maria Geraga
Author:
Laura Rodríguez-Sanz
Author:
A. Prandekou
Author:
A. Noti
Author:
A. Paraschos
Author:
D. Sakellariou
Author:
G. Bailey
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