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

趋磁细菌生活在含氧和含硫沃茨之间的化学跃层过渡带的海洋和湖沼环境中。在这里，它们沿着构成化学跃层的各种化学视界移动，借助化学传感和它们在细胞内矿化的纳米大小的铁磁晶体，称为磁小体。趋磁细菌是一组多样性和丰富的水生细菌，然而，到目前为止，只有少数研究涉及到它们在远洋环境中的生态重要性。最近在帕文湖和黑海的研究表明，浮游趋磁细菌可能以聚磷酸盐的形式积累大量的磷酸盐。对于黑海，它被证明，他们可能穿梭在亚氧水团积累磷酸盐在上层区，并释放它在深度。这种将磷酸盐从表面沃茨中抽走的做法防止了富营养化，可能是黑海贫营养状态的一个原因。在波罗的海的初步调查显示，在这里也可以在深海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.