The Ocean Floor

Metal-microbe interactions in hydrothermal plumes and its role for hydrothermal element fluxes and bioproductivity

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Project Description

This project aims at disentangling the complex interactions between hydrothermally derived trace metals and their role in supporting microbial productivity and elemental fluxes into the ocean. It will focus on the following hypotheses: Dissolved organic matter (DOM) protects hydrothermally derived metals from precipitation, thus allowing long-distance transport and fertilization of the deep ocean and supporting photosynthesis in surface oceans. Pelagic microorganisms grow on multiple dissolved and particulate reduced compounds emitted from hydrothermal vents, and this biomass affects deep-sea food webs. These microorganisms are able to actively mitigate metal bioavailability and toxicity by producing metal-binding organic ligands. To verify these hypotheses, the PhD student will participate in research cruises to diverse shallow and deep sea hydrothermal vent sites such as mid-ocean ridge systems and volcanic arcs to investigate these processes in the field by sampling hydrothermal fluids, plumes and associated microorganisms. Home-lab work will include the analysis of trace metal speciation including determination of metal redox forms and organic complexation as well as the analysis of microbial communities structure and function using microscopic, omics and statistical approaches. Metal-binding DOM will be identified and evaluated in its role for metal mobility and bioavailability from the hydrothermal source along the plume to the open ocean. Incubation experiments will be conducted to further investigate the impact of identified key species on organic ligand production and metal cycling/detoxification. Data derived from these projects will support modeling approaches to quantify the role of hydrothermal venting for elemental fluxes and bioproductivity in the ocean.

Further Reading

• Sander, S. and Koschinsky, A. (2011): Metal flux from hydrothermal vents increased by organic complexation. Progress article, Nature Geoscience 4, 145-150. doi: 10.1038/ngeo1088
• Klevenz, V., Sander, S., Perner, M., and Koschinsky, A. (2012): Amelioration of free copper by hydrothermal vent microbes as a response to high copper concentrations. Chemistry and Ecology. doi: 10.1080/02757540.2012.666531
• Ardyna, M., Lacour, L., Sergi, S., d’Ovidio, F., Sallée, J.-B., Rembauville, M., Blain, S., Tagliabue, A., Schlitzer, R., Jeandel, C., Arrigo, K.R., Claustre, H. (2019): Hydrothermal vents trigger massive phytoplankton blooms in the Southern Ocean. Nat. Commun. 10(1), 2451, doi: 10.1038/s41467-019-09973-6
• Schine, C.M.S., Alderkamp, A.-C., van Dijken, G., Gerringa, L.J.A., Sergi, S., Laan, P., van Haren, H., van de Poll, W.H., Arrigo, K.R. (2021): Massive Southern Ocean phytoplankton bloom fed by iron of possible hydrothermal origin. Nat. Commun., doi: 10.1038/s41467-021-21339-5
• Hansen, C.T., Kleint, C., Böhnke, S., Klose, L., Adam-Beyer, N., Sass, K., Zitoun, R., Sander, S.G., Indenbirken, D., Dittmar, T., Koschinsky, A. & Perner, M. (2022): Impact of high Fe-concentrations on microbial community structure and dissolved organics in hydrothermal plumes: an experimental study. Sci Rep 12, 20723. doi: 10.1038/s41598-022-25320-0
• Dede, B., Hansen, C.T., Neuholz, R., Schnetger, B., Kleint, C., Walker, S., Bach, W., Amann, R., Meyerdierks, A. (2022) Niche differentiation of sulfur-oxidizing bacteria (SUP05) in submarine hydrothermal plumes. ISME J., 1–12, doi: 10.1038/s41396-022-01195-x.

Modalities

The doctoral project will be supervised by Andrea Koschinsky (Constructor University, Bremen) and Anke Meyerdiercks (MPI for Marine Microbiology, Bremen) and will be located within the working group “Marine Geochemistry” (CU, Bremen). The remuneration corresponds to pay group TVöD 13 with 75% of the weekly working hours. 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: Charlotte Kleint (MARUM) and Thorsten Dittmar (UOL).

Main Tasks

• Scientific research in the field of:
  Marine Biogeochemistry
• Analysis of:
  hydrothermal fluid and plume samples for trace metals and microbial communities as well as their interactions; field work and lab experiments
• 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 sciences, geochemistry, biochemistry or microbiology

Further questions?

Questions about the project can be addressed to Andrea Koschinsky ([Bitte aktivieren Sie Javascript]) or Anke Meyerdiercks ([Bitte aktivieren Sie Javascript]).