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The role of lateral transport in enhancing carbon fluxes to the ocean floor

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Project Description

Lateral carbon fluxes account for substiatnial, but largely unquantified portions of deep-sea carbon flux. Lateral export is a potential pathway of rapid carbon sequestration in the deep sea, but may also, following resuspension, re-introduce previously buried materials to oxygenated water masses, subjecting them to further degradation. Lateral transport of organic materials also has the potential to impact sedimentary paleoclimate archives recorded in organic biomarker proxies. In spite of its global significance and potenital impact on deep-sea carbon sequestration and sediementary records, factors controlling lateral transport as well as the composition, age and reactivity of laterally transported organic matter remain poorly constrained. This project aims at 1) detecting laterally transported carbon in nepheloid layers and relating it to potential mobilization mechanisms like interal waves and tides, 2) characterizing the composition and age of laterally transported carbon in the water column, and 3) quantifying laterally supplied relative to vertically exported carbon in diverse deep-sea settings. A combination of in-situ observations in the water column and geochemical methods (organic geochemistry, isotopes, radiocarbon) with ocean observations (optical, current and geophysical masurments) and laboratory experiments will be used. Continental margin systems with different oceanographic and productivity regimes will be investigated and compared with the goal of generating mechanistic understanding and budgeting the contribution of lateral transport to carbon sequestration.

Further Reading

• Rogge, A., et al. (2023), Carbon dioxide sink in the Arctic Ocean from cross-shelf transport of dense Barents Sea water, Nature Geoscience, 16(1), 82-88, doi:10.1038/s41561-022-01069-z.
• Magill, C. R., B. Ausín, P. Wenk, C. McIntyre, L. Skinner, A. Martínez-García, D. A. Hodell, G. H. Haug, W. Kenney, and T. I. Eglinton (2018), Transient hydrodynamic effects influence organic carbon signatures in marine sediments, Nature Communications, 9(1), 4690, doi:10.1038/s41467-018-06973-w.

Modalities

The doctoral project will be supervised by Gesine Mollenhauer (AWI) and Elda Miramontes (University of Bremen). Depending on the personal expertise of the doctoral candidate, it will be supervised within the working group “Marine Geochemistry” (Bremerhaven) or the working group “Sedimentology” (Bremen). The remuneration corresponds to pay group TVöD 13 with 75% of the weekly working hours if based at AWI or pay group TV-L 13 with 75% of the weekly working hours if based at the University of Bremen. The positions is for a fixed-term period of 4 years, starting January 1st 2026 the earliest and until at most December 31, 2029 (according to § 2 WissZeitVG) with the aim of obtaining a doctorate.

The project mentoring team also includes: Morten Iversen (AWI).

Main Tasks

• Scientific research in the field of:
  Marine Organic Geochemistry / Marine Biogeochemistry / Marine Microbiology
  
  
• Analysis of:
  Molecular and isotopic (¹⁴C) composition of particles and sediments, geophysical datasets (multibeam and Parasound data) and oceanographic data (CTD, current measurements)
• Writing of scientific publications
• Participation in ship expeditions
• Participation in international conferences

Formal Requirements:

Completed scientific university degree (Master/University diploma or comparable) in Marine Geosciences, Oceanography, or a related discipline.

Further questions?

Questions about the project can be addressed to Gesine Mollenhauer ([Bitte aktivieren Sie Javascript]) or Elda Miramontes ([Bitte aktivieren Sie Javascript]).