Earlier this year I (ESR 5, Alina) spent my secondment to the Mediterranean Institute of Oceanography (MIO) on a GEOTRACES cruise crossing the South Pacific Ocean (SO 289)! More than 30 scientists were on board RV Sonne investigating biogeochemical cycling of trace metals in the marine environment. We spend almost two months at sea sampling more than 40 profiles, to provide high resolution full water column observations on Hg speciation. I was performing onboard measurements for total mercury and dissolved gaseous mercury and incubation experiments using species-specific enriched isotopes. It was the first time on such a big ship and doing onboard measurements.

Our cruise started in Valparaiso, Chile, and led us to New Caledonia crossing many interesting features such as the productive upwelling/ oxygen minimum zone off Chile and the East Pacific rise.

Since I am used to working in the coastal environment, where I am applying similar methods under very different conditions, everything was new and interesting. My experience on the ship was great, as was working with so many other passionate scientists from different fields. I am very happy to have had the opportunity to participate. It helped me to extend my horizon and was an excellent learning experience. If you are interested to read more about the work on Hg on the cruise I recommend the “Ocean blog” which has been released during the cruise. It can be found here: https://www.oceanblogs.org/geotraces/2022/04/04/mercury-in-the-south-pacific-ocean/