Trace element analysis of seawater and phytoplankton. Trace elements (e.g. Fe, Mn, Co, Cu, Zn, Mo) in seawater strongly influence the growth of phytoplankton. To understand the cycle of trace elements as well as the influence of trace elements on phytoplankton growth, the concentration of the mentioned elements in seawater and phytoplankton can be analyzed via the coupling of a SeaFast system to an inductively coupled plasma mass spectrometer (ICP-MS, Element2).

SeaFast System (Elemental Scientific). Picture: D. Wilhelms-Dick
Element 2 ICP-MS. Picture: D- Wilhelms-Dick

The SeaFast System eliminates matrix components such as Na, Mg, Ca, and Cl via a chelating resin and preconcentrates the samples by a factor of 20. After elution of the concentrated trace metals from the column into the ICP-MS nebulizer, trace element concentrations in the lower nM L-1 range can be precisely and accurately assessed.

Trace element concentrations (in nM L-1) of different seawater samples and a seawater reference standard (NASS-6). D. Wilhelms-Dick

Trace element analysis of phytoplankton cells. Using a high resolution ICP-MS of NuInstruments (figure 4D), trace metal concentrations (Fe, Co, Zn, Cd, Mn, Mo, Cu) of phytoplankton cells can be quantified.

ICP-MS Attom Nu Instruments. Picture: D. Wilhelms-Dick

Determination and characterization of trace metals and their natural ligands via voltammetry. The working group EcoTrace has got three voltammeters. The 757 VA Computrace voltammeter from Metrohm is a small, compact system to analyse seawater trace metal concentrations. The EC Epsilon Potentiostat from Bioanalytical Systems is characterized by a comparably higher sensitivity. Using the latter, we can determine the chemical speciation of iron as well as the concentration of humic acid-like substances.

Voltammeter Computrace. Photo: C. Völkner
Voltammeter Bioanalytical Systems. Photo: C. Völkner

In addition to this, we carry out our incubation experiments with isolates from the Southern Ocean in a 2 °C cold room and have access to various analytical tools.



Contact seafast and ICP-MS:

Dr. Dorothee Wilhelms-Dick

Contact voltammetry:

Christian Völkner

Christian Völkner. Photo: G. Nehrke (Photo: Alfred-Wegener-Institut)