First comprehensive microplastic survey in the Baltic Sea underway

The POSEIDON, a research vessel of the ocean research institute GEOMAR in Kiel, started its expedition in Rostock and will cruise along the coast to circle the Baltic Sea once completely.

“Whether we will be able to complete the full round trip with all 50 stations, depends on the weather conditions,” says Dr. Sonja Oberbeckmann, who coordinates the expedition as chief scientist. During the cruise, the marine microbiologist from the IOW working group Environmental Microbiology is also responsible for the research focus on microplastic.

„At every station we will sample the surface waters as well as the sediment to get a comprehensive overview, where and how much microplastic is present and which types of plastic materials can be found. This makes our expedition the first microplastic survey in the Baltic Sea of such comprehensiveness,” Sonja Oberbeckmann explains.

It has been recognized since the 1970s, that so-called microplastic – small to microscopic plastic particles with a diameter smaller than 5 millimeters – accumulates in marine envi-ronments. However, only for the last decade more extensive research is being done. Many products of daily use, for instance clothes and cosmetics, contain microplastic particles, which are released into the environment via domestic waste waters.

Furthermore, these micro-sized plastic particles are formed, when larger plastic fragments break down through photo-, thermal and/or biological degradation. Due to their small size, micro-plastic can readily be ingested by a wide range of marine organisms. Not solely the inges-tion of the particles themselves, but also associated toxins might pose a threat to the marine foodweb.

Moreover, the floating particles – despite their small size – provide ma-rine microorganisms with a solid surface, which they can colonize and where they can form dense biofilms. Marine microbial communities may contain pathogenic or toxic mi-crobes, often anthropogenically introduced.

They remain unproblematic as long as they occur in the water column in low densities. Microplastic therefore poses a possible threat, if such harmful organisms accumulate on the particles as biofilm.

“So far we have no actual evidence that microplastic contributes to the accumulation of pathogens or is acting as a transport vector for such microorganisms. However, there is no doubt that the man-made factor ‘microplastic’ as an additional habitat has the po-tential to impact marine microbial communities,” Sonja Oberbeckmann states.

To better understand this impact potential, the research team will conduct experiments aboard ship, in which new sterile microplastic pellets are incubated with water and sediment samples to analyze the biofilms that develop under controlled conditions.

“The compar-ison of the experimental biofilms with those of microplastic particles isolated from the Baltic Sea at the same sampling site will provide us with additional insight into the con-ditions for and the speed of biofilm development. The experiments will also provide us with information about biofilm interaction with the environment,” Oberbeckmann ex-plains.

The microplastic research on the POSEIDON is part of the joint project MikrOMIK (http://www.io-warnemuende.de/mikromik-home.html) under the lead of IOW marine microbi-ologist Dr. Matthias Labrenz, which merges the efforts of nine major research institutions in Germany and is funded by the Leibniz Association.

The second research focus of the POSEIDON expedition also concentrates on the microbial communities of the Baltic Sea. Here, the researchers aim at a comprehensive genetic characterization of those communities, especially in areas that are frequently exposed to pollution by environmental toxins. “In the Baltic Sea, such polluted zones particularly can be found in the inflow areas of big tributaries such as the Oder, the Vistula or the Neman river,” says environmental microbiologist Dr. Christin Bennke, who also participates in the expedition and coordinates this part of the research.

„During the expedition, we will systematically sample all big river plumes to see, whether the environmental stress has an impact on the composition of the microbial communities or even leads to genetic adaptations or other responses of the organisms, which are detectable in their overall genetic fingerprint,” the IOW scientist outlines her approach.

The research is part of the European research cooperation Blueprint (http://blueprint-project.org), which focuses on microbial communities as principal drivers of marine biogeochemistry to develop new concepts of deducing the environmental status of the Baltic Sea based on biodiversity and genetic profiles of microbes in seawater samples.

*Scientific Contact:
Dr. Sonja Oberbeckmann, IOW Working Group Environmental Microbiology
sonja.oberbeckmann@io-warnemuende.de

*Press and Public Relations at IOW:
Dr. Kristin Beck | Tel.: 0381 – 5197 135 | kristin.beck@io-warnemuende.de
Dr. Barbara Hentzsch | Tel.: 0381 – 5197 102 | barbara.hentzsch@io-warnemuende.de

The IOW is a member of the Leibniz Association with currently 89 research institutes and scientific infrastructure facilities. The focus of the Leibniz Institutes ranges from natural, engineering and environmental sciences to economic, social and space sciences as well as to the humanities. The institutes are jointly financed at the state and national levels. The Leibniz Institutes employ a total of 18.100 people, of whom 9.200 are scientists. The total budget of the institutes is 1.64 billion Euros. (http://www.leibniz-association.eu)