Glacier flour in Disko Bay

Today, the research vessel Maria S. Merian sets sail. Its destination: the large fjords of Greenland and Iceland. Among other things, Oldenburg scientists want to investigate how harmful algal blooms develop - using state-of-the-art marine technology.

The journey begins in Nuuk, the capital of Greenland. On board are scientists from the Institute of Chemistry and Biology of the Marine Environment (ICBM) at the University of Oldenburg, the Alfred Wegener Institute for Polar and Marine Research Bremerhaven (AWI) and the Woods Hole Oceanographic Institution (WHOI).

The research vessel's first stops: the Uummannaq Fjord, 590 kilometres north of the Arctic Circle, and Disko Bay to the south. These are Arctic fjord systems, known for their strong glacier activity and characterised by meltwater input.

The scientists are investigating the interaction between oceanographic, bio-geochemical and bio-optical environmental properties. They want to investigate plankton species with toxic properties - and understand how harmful algal blooms develop. To do this, they use molecular and mass spectrometric marine techniques.

Light is crucial for the growth of algae - a key topic of the Marine Sensor Systems working group led by Oldenburg university lecturer Prof Dr Oliver Zielinski, who is deputy leader of the expedition. "We use hyperspectral radiometers to record the light distribution in the water column in high resolution. We also record bio-optical influences such as the input of yellow substances and the finest glacier flour," explains the marine researcher. The aim of the investigations is to model the underwater light field in northern latitudes as accurately as possible. "We are thus making a contribution to ecosystem modelling, which is of central importance for climate research," says Zielinski.

Zielinski is also investigating fluorescent fingerprints of dissolved organic material - brought in partly by glacier water and partly by local marine decomposition products. The team led by Bremerhaven expert Prof. Dr Boris Koch is analysing the geochemical composition of this material.

After visiting Disko Bay, the Maria S. Merian will sail to the southern tip of Greenland. It then sets course for Iceland. Here, in the fjords, comparative studies are on the programme. "We want to better understand the Arctic coastal ecosystems. To this end, we are comparing the biogeochemical, optical and oceanographic properties as well as the distribution of toxic plankton species," explains Zielinski. The expedition ends on 10 August in Reykjavik.