Rainbow nonboyant hydrothermal plume GEOTRACES study

Research cruise:
M176-2 to the Rainbow hydrothermal vent field on the Midatlantic Ridge near the Azores (Sept. 1 – Oct. 6, 2021)

Project partners:
GEOMAR Helmholtz-Centre for Ocean Research Kiel
Jacobs University Bremen (JUB)

Find the RainbowPlume cruise BLOG here:


Hydrothermal plumes form when hot solutions heated by igneous magma escape from the Earth’s crust in the deep-sea and encounter cold seawater. They are enriched in many compounds and supply the oceans with metals and nutrients.

The RainbowPlume project aims at obtaining a mechanistic and quantitative understanding of the processes that set the hydrothermal flux of trace elements and their isotopes (TEI) at the Rainbow vent field on the Mid-Atlantic Ridge near the Azores. The core of the project is research cruise M176-2 with RV Meteor, which aims at conducting detailed geochemical sampling of the hydrothermal plumes at the Rainbow site. The deep-ocean work is complimented by biological surface ocean investigations of productivity and diazotrophy.

The RainbowPlume project is part of GEOTRACES, an international study of the marine biochemical cycles of the trace elements and isotopes.

Key objectives:

  • Determining the distribution and physical and chemical speciation of TEIs, including micronutrients (e.g., Cd, Co, Cu, Fe, Mn, Mo, Ni, V, Zn, Cr), non-biologically essential elements (e.g., Al, Pb, Hg, Ti, Zr, Hf, Nb, U, W, and REE), major elements (F, Ca, Mg, Sr, K, S, Li), and a range of isotope systems (e.g., Th, Ra, Ba, Fe) in high-resolution sampling along the Rainbow Plume
  • Quantifying the fluxes of these TEIs and micronutrients to the deep ocean from the ocean crust and away from the Rainbow vent field, and assessing the role of physical and chemical speciation of TEIs for their fluxes and flux attenuation
  • Assessing the mixing and advection of these TEIs away from the Rainbow vent sites into the ocean interior, using chemical tracers and physical oceanography
  • Determining the supply of TEIs (including micronutrients) to the surface ocean from atmospheric deposition, and measure their surface ocean concentrations.
  • Exploring the relationship between macro- and micro-nutrient concentrations and fluxes, irradiance, ocean productivity, phytoplankton community composition, nutrient utilization and limitation, and diazotrophy in the North Atlantic

Chief scientist:
Prof. Dr. Eric Achterberg (GEOMAR)

JUB – Scientists involved:
Prof. Dr. Andrea Koschinsky
Dr. Sandra Pöhle (WG Koschinsky)
Lukas Klose (WG Koschinsky)
Vignesh Menon (student)