|TEAM||MERCURY & TRACE METALS|
|Project name||Knowledge and technology transfer to investigate marine mercury contamination|
|Principal Investigator 1||Susanne Fietz||Stellenbosch University (SU)|
|Principal Investigator 2||Lynwill Martin||South African Weather Service (SAWS)|
|Principal Investigator 3||Lars-Eric Heimbuerger||CNRS-MIO|
Onboard MERCURY & TRACE METALS team members:
|Susanne Fietz||PI and Onboard Team Leader||SU|
|David Amptmeijer||PhD||GMOS, Europe|
|Sonja Gindorf||PhD||GMOS, Europe|
|Lide Janse van Vuuren||MSc||SU|
More about their research:
Mercury is a natural element and its biogeochemical cycle is heavily altered by anthropogenic activities. Over the past two decades, it became clear that processes in seawater are largely responsible for the conversion from inorganic mercury to the bioaccumulative neurotoxin methylmercury, which accumulates up marine food chains. This is of special concern as globally the main pathway of human exposure to methylmercury is via the consumption of seafood.
The #SCALEwin22 expedition is extremely valuable to better understand mercury dynamics in the Southern Ocean. Observations from this region are rare, especially observations during winter. Sonja and David are both doctoral students within the “Global Mercury Observation and Training Network in Support of the Minamata Convention”, a Marie-Curie training network involving several institutions all over Europe. Together with the TraceEx team from Stellenbosch University: Susanne (Senior Lecturer at the Department of Earth Sciences), Lide, Kayla, Caspar, Liam, and Jared, water and ice core samples will be taken, for mercury speciation and dissolved trace metals.
In the water and ice, we are sampling for oxygen and deuterium isotopes, different dissolved organic matter parameters, and persistent organic pollutants to relate mercury biogeochemistry to different anthropogenic and environmental factors. Moreover, we sample for genes that are relevant in mercury (de-)methylation (see purging process below).
All our samples and work onboard are following trace metal clean protocols. Trace metal sampling in itself is tricky! We take a wide range of measures to keep our samples uncontaminated: we wear protective gloves, sleeves, and coveralls, and all our work happens in a metal-clean container.
During this voyage, the project also aims to transfer important skills to improve our understanding of the mercury cycle to South Africa. This project thus trains young researchers, transfers analytical skills, and provides data for an improved understanding of mercury cycling.
More about the sampling:
Gaseous mercury will be measured in the atmosphere during the transect as well as total, dissolved gaseous, and methyl-mercury (see video and image below) in the ocean. In addition, we will sample frazil ice, unconsolidated and consolidated ice for the mercury content. The assessment of the mercury levels is accompanied by measurements of the phytoplankton and microbial community structure and also other trace metals in our collaborative work.
Scan this QR code below with your smartphone’s camera (or click on the image) to view the water sampling process.
VIDEO: CTD (Conductivity, Temperature, and Depth) deployment and recovery with GoFlo tubes. This is the process of collecting water samples at specific depths. After recovery, the water-filled GoFlo tubes are removed from the frame (filled with water collected from a specific depth) and moved to the trace metal testing clean lab.
Purging is the process of measuring methylmercury in water. In the image below, David (GMOS programme) and Casper (SAWS) are setting up for purging a methylmercury sample.
In this video: The purging process. One methylmercury species are outgassed and other species are left behind.
Text supplied by Susanne Fietz (PI and onboard team leader) and Sonja Gindorf. Images supplied by Susanne Fietz, Sonja Gindorf and Kurt Martin (SAPRI Trainee).
Featured Image: L-R: CTD recovery; postgrads working in the clean lab; Susanne carrying GoFlo tube to clean lab, after recovery; tubes being stored in the clean lab.
Anche Louw, Antarctic Legacy of South Africa, 20 July 2022