Work on the project included:
* Two field campaigns to the Hooghly estuary (India) during pre-monsoon and monsoon seasons.
* Estuary water, suspended sediment and bed load sediment samples were collected along a 120 km transect along the estuary, targeting a wide range in salinity and pH.
* Developing several analytical protocols (adapted to unique sample matrices) for sample treatment and preparation, Ni column chromatography and Ni isotope analysis using a double spike technique
* The methodology was successfully transferred from the initial laboratory at the Institute for Planetary Materials at Okayama University, Japan, to the national infrastructure facility at the Museum of Natural History in Stockholm, Sweden
* Developing robust analytical technique for measurement of trace metal concentrations in estuarine waters, a notoriously challenging sample matrix
* Setting up batch reaction experiments to investigate the behaviour of Ni and Ni isotopes during ferrihydrite formation (coprecipitation and adsorption experiments) mimicking pelagic sedimentation on the seafloor
* 250 samples were collected from 125 separate experimental conditions testing effect of varying concentrations of Ni and other elements, pH and equilibration time
* This work package has already resulted in one publication, and a minimum of one more is expected within the next year.
* Results show that coprecipitation yields the same Ni isotopic fractionation regardless of Si concentration in the solution (Figure 1 attached), whereas adsorption is highly sensitive to Si content. This has implications for the Ni sink in the marine environment where the presence os Si varies greatly with hydrothermal vent input.
* Sample processing and analysis: the project has resulted in over ten thousand data points for Ni isotopes, major-, minor-, and trace element compositions, TEM-, Raman-, IR-, and XRD spectra in a large variety of geological sample matrices (fresh waters, estuary waters, seawaters, suspended sediments, bedload sediments, iron oxides).
The results are currently being synthesised and prepared for publications in peer reviewed journals, and have been presented at two conferences.
