ABSTRACT
During evolution, all living organisms experienced the action of the Earth’s magnetic field (MF) (also called geomagnetic field, GMF), which is a natural component of the environment. GMF is steadily acting on living systems, and influences many biological processes. There are significant local differences in the strength and direction of the GMF. For instance, at the surface of the Earth, the vertical component is maximal at the magnetic pole, amounting to about 67 µT and is zero at the magnetic equator. The horizontal component is maximal at the magnetic equator, about 33 µT, and is zero at the magnetic poles (Kobayashi et al., 2004). The MF strength at the Earth’s surface ranges from less than 30 µT in an area including most of South America and South Africa (the so-called south Atlantic anomaly) to almost 70 µT around the magnetic poles in northern Canada and southern Australia and in part of Siberia (Maffei, 2014; Occhipinti et al., 2014; Bertea et al., 2015). Most of the magnetic field observed at the Earth’s surface has an internal origin. It is mainly produced by the dynamo action of turbulent flows in the fluid metallic outer core of the planet, while little is due to external magnetic fields located in the ionosphere and the magnetosphere (Qamili et al., 2013). The GMF, through the magnetosphere, protects 90the Earth, together with its biosphere, from the solar wind deflecting most of its charged particles (Maffei, 2014).
