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BALTICMAGX: *Ökologische Auswirkungen von magnetotaktischen Bakterien in Redoxgradienten in der Ostsee (BALTICMAGX)"

01.11.2024 - 31.10.2027
Project manager:
Prof. Dr. Heide Schulz-Vogt
DFG - Deutsche Forschungsgemeinschaft

Magnetotactic bacteria live in marine and limnic environments in the chemocline transition zone between oxygenated and sulfidic waters. Here, they maintain and alter their position along the various chemical horizons that make up the chemocline, with the aid of chemical sensing and the nano-sized ferromagnetic crystals that they mineralize within their cell, called magnetosomes. There is great diversity in magnetotactic bacteria's cellular and magnetosome morphology. Optical and scanning electron microscopy has shown that bacteria with magnetosomes exhibit coccoid, spirillum, vibrio, and basilicas morphologies. Metagenome and 16s rDNA analysis on enriched magnetotactic bacteria populations have shown the presence of bacterial genera, Nitrospirae, OP3 and α-, β-, and δ-proteobacteria. Magnetotactic bacteria are a complex group of marine bacteria. However, the extent of the diversity across the marine pelagic chemocline is still poorly understood. It is still unknown the specific metabolic requirements of magnetotactic bacteria and whether they change between different species. However, the difficulty of culturing pelagic magnetotactic bacteria compared to the relative ease of maintaining magnetotactic bacterial populations in sediment cores. Together with the evolution of magnetosomes to increase directional swimming ability it has been suggested that magnetotactic bacteria may utilize the oxidation potential from the upper and lower chemocline. Alongside iron-rich magnetosomes, some magnetotactic bacteria have shown the presence of phosphorous-rich inclusions when imaged with energy-dispersive X-ray analysis. These phosphorous-rich inclusions were determined to be composed of polyphosphate, which has also been detected in other species of bacteria that experience fluctuating oxidation environments. Considering the presence of polyphosphate in magnetotactic bacteria and their increased vertical swimming efficiency, they may play a significant role in phosphorus transport. It Is important to understand the influence of phosphorous transport by magnetotactic bacteria in areas like the Baltic Sea, which is eutrophic by anthropogenic inputs of phosphorous and other excess resources which contribute to expanding oxygen minimum zones.