Essential for marine life, nutrients like phosphate, nitrate, nitrite, ammonium, and silicate play a fundamental role. These substances are crucial for the development of phytoplankton. The entire marine food chain relies on the biomass production of phytoplankton.

Typical nutrient concentrations are up to 100 million times lower than typical salinity, which poses a significant challenge for analysts. Accurately measuring these trace levels of dissolved nutrients is a challenge that requires careful attention at every step of the analysis to avoid contamination or loss of nutrients.

Within our nutrients laboratory, diverse techniques are employed, all rooted in spectrophotometric analysis using classical chemistry principles. The microtiter technique (link to paper) stands out for its speed and suitability in processing large batches of samples with elevated nutrient concentrations, typical in mesocosm studies, rivers, or coastal systems. For more typical seawater samples, we adopt a highly sensitive yet reproducible approach utilizing robotic technology embedded in a wet chemistry analyzer (EasyChem, Systea) to automate spectrophotometric analysis.

Our well-established routine application on research vessels eliminates the need for sample preservation. Quality assurance is essential, and we ensure the accuracy of our analyses through various means, including daily calibration, examination of blanks, and running of intermittent calibration and certified reference solutions.

Leading the core facility for nutrient analysis at ICBM, the MI group examines thousands of samples annually across diverse projects. Our keen interest lies in actively contributing to research utilizing the nutrient data. We welcome inquiries from interested parties seeking more information or exploring potential collaborations. Feel free to reach out for further details.

The MI group oversees the acquisition of nutrient data from the time series station on Spiekeroog in the German Wadden Sea. Over two decades, in situ data have been systematically analyzed on the station using automatic nutrient analyzers. To enhance capabilities, a recent addition includes an automatic water collector for sampling and storing discrete water samples, facilitating comparative laboratory analysis. The MI group ensures that quality-assured data are managed and archived in data repositories.

At the Spiekeroog time series station we operate two nutrient analyzers. We determine the parameters nitrate, nitrite, phosphate and silicate, carry out the maintenance and data evaluation of these. An installed autosampler allows us to take samples of the seawater with every event, e.g. storm, change of parameters.