Ecological impact of magnetotactic bacteria across redox gradients in the Baltic Sea (BALTICMAGX)

趋磁细菌生活在含氧水和硫化水之间的趋化层过渡带的海洋和湖泊环境中。在这里，它们在化学传感和它们在细胞内矿化的纳米级铁磁性晶体(称为磁小体)的帮助下，沿着组成趋化层的各种化学层移动。趋磁细菌是一类种类繁多的水生细菌，然而，到目前为止，只有少数研究讨论了它们在远洋环境中的生态重要性。最近在巴文湖和黑海的研究表明，远洋趋磁细菌可能会以聚磷酸盐的形式积累大量的磷酸盐。对于黑海，研究表明，它们可能穿梭在亚氧水团中，在上层积累磷酸盐，并在深处释放磷酸盐。这种从地表水中抽出的磷酸盐正在防止富营养化，这可能是黑海处于低营养状态的原因之一。波罗的海的一项初步调查显示，在这里，也可以在深层硫化物盆地的水柱中发现趋磁细菌。该项目旨在描述和量化这些趋磁细菌的种群，并揭示它们对波罗的海磷循环的可能影响。

Magnetotactic bacteria live in marine and limnic environments in the chemocline transition zone between oxygenated and sulfidic waters. Here, they move along the various chemical horizons that make up the chemocline, with the aid of chemical sensing and the nanometer-sized ferromagnetic crystals that they mineralize within their cell, called magnetosomes. Magnetotactic bacteria are a diverse and abundant group of aquatic bacteria, however, only a few studies have so far addressed their ecological importance in pelagic environments. Recent studies in Lake Pavin and the Black Sea revealed that pelagic magnetotactic bacteria may accumulate large amounts of phosphatein the form of polyphosphate . For the Black Sea, it was shown, that they may shuttle within the suboxic water masses accumulating phosphate at the upper zone and releasing it at depth. This pumping of phosphate away from surface waters is preventing eutrophication and may be a reason for the oligotrophic state of the Black Sea. A preliminary survey in the Baltic Sea revealed that also here magnetotactic bacteria can be found in the water columns of the deep sulfidic basins. This project aims to describe and quantify these populations of magnetotactic bacteria and to reveal their possible influence on phosphorus cycling in the Baltic Sea.