Carbon export and drivers in the southeastern Levantine Basin

Ronen Alkalay, Olga Zlatkin, Timor Katz, Barak Herut, Ludwik Halicz, Ilana Berman-Frank, Yishai Weinstein

Research output: Contribution to journalArticlepeer-review

Abstract

In this paper, we present C export data from the southeastern Levantine Basin, 50 km west of Haifa, at water depth of 1500 m. Particulate organic carbon (POC) fluxes were measured for 18 months by automated and single bottle sediment traps at the recently-deployed DeepLev observatory and compared with water column profiles of 234Th. Calculations, based on POC/234Th ratios, result in water column-integrated export of 18 mmolC m−2 d−1 at the end of summer (Dec 2017) and remineralization during spring (e.g. 14.4 mmolC m−2 d−1, Apr, 2018). Based on the sediment traps POC export in the basin was generally low (0.05–1 mmolC m−2 d−1 at the base of the photic zone during Dec 2017–May 2018). Fluxes were quite variable, and the export pattern was mainly controlled by coastal discharge or shelf-resuspension (winter peaks) rather than by marine primary production. This was demonstrated by: i) larger POC fluxes measured by deep water (1300 m) and twilight zone (280 m) traps compared to fluxes measured at the base of euphotic zone, ii) tight correlation of POC with total mass flux, iii) decrease of the POC percentage during winter peak events and iv) imbalance (large integrated deficit or excess) of water column 234Th. Both deficit and excess are evidence of lateral flux, where the first probably results from wave-induced shelf resuspension of organic-poor material, which underwent minimal remineralization and induced scavenging, while the latter derives from the conveyance of large amount of land-derived organic matter, which undergoes remineralization, therefore input of 234Th to the water column.

Original languageEnglish
Article number104713
JournalDeep-Sea Research Part II: Topical Studies in Oceanography
Volume171
DOIs
StatePublished - Jan 2020

Bibliographical note

Funding Information:
We are grateful to the Council for Higher Education in Israel and the Mediterranean Sea Research Centre of Israel (MERCI), the Wolfson Foundation, the North American Friends of IOLR and Bar-Ilan University (BIU) for funding the construction and maintenance of DeepLev. We owe gratitude to a lot of people, who contributed to the success of DeepLev deployment. This includes the IOLR departments of electronic, sea operations and marine physics and the engineers of the machine shop at BIU. Special thanks to the captain and crew of R/V Bat Galim, who did a great job in the deployment and recovery of the mooring and attached devices. Special thanks to K. Weiss and Y. Zakon for the MC-ICPMS analyses of 230Th. Lastly, we want to thank the anonymous reviewers for their very helpful comments and to Annie Sacio for proof-reading the manuscript. This project was supported by the Israeli Ministries of Energy and Environmental Protection under tdhe framework of the National Monitoring Program for Israeli Mediterranean Waters and by the Israel Science Foundation grant ISF 25/2014.

Funding Information:
We are grateful to the Council for Higher Education in Israel and the Mediterranean Sea Research Centre of Israel (MERCI), the Wolfson Foundation, the North American Friends of IOLR and Bar-Ilan University (BIU) for funding the construction and maintenance of DeepLev. We owe gratitude to a lot of people, who contributed to the success of DeepLev deployment. This includes the IOLR departments of electronic, sea operations and marine physics and the engineers of the machine shop at BIU. Special thanks to the captain and crew of R/V Bat Galim, who did a great job in the deployment and recovery of the mooring and attached devices. Special thanks to K. Weiss and Y. Zakon for the MC-ICPMS analyses of 230 Th. Lastly, we want to thank the anonymous reviewers for their very helpful comments and to Annie Sacio for proof-reading the manuscript. This project was supported by the Israeli Ministries of Energy and Environmental Protection under tdhe framework of the National Monitoring Program for Israeli Mediterranean Waters and by the Israel Science Foundation grant ISF 25/2014 . Appendix A

Publisher Copyright:
© 2019 Elsevier Ltd

Keywords

  • C export
  • DeepLev
  • Levantine basin
  • Sediment traps
  • Th

ASJC Scopus subject areas

  • Oceanography

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