When we looked into the ranking of the most abundant elements on Earth, we found that the composition of the Earth’s surface and the entire Earth, including the interior, is quite different. Looking at the surface, 70% of the Earth is ocean, so we think of it as a water planet, but in terms of the weight of the Earth including the interior, one third of the Earth is iron. In terms of the weight ranking including the interior, first place is iron, second place is oxygen, third place is silicon, fourth place is magnesium, and fifth place is nickel. It can also be called an iron planet.
https://chikyu-kagaku.com/2021/07/25/
If iron and oxygen are abundant on Earth, we would like to make effective use of these elements. If we think about it that way, the life activity of transporting oxygen through red blood cells, which contain iron, may be a very clever mechanism. The iron ions Fe2+ and Fe3+ are convenient for reactions such as oxidation-reduction, and are less likely to cause structural changes in proteins due to reactions, which is something that cannot be imitated by other transition metals.
https://hbh.center/03-issue_03
Also, except for special cases, iron is said to have the most stable atomic nucleus of all elements. When nuclear fusion occurs inside stars, both in space and on Earth, iron becomes stable at the point where it is created. As a result, it seems that there is a high proportion of iron. Iron is amazing.
https://www.um.u-tokyo.ac.jp/exhibition/2009Fe_description.html
When iron exists underground, it exists as iron ore, which is made up of iron oxide. Oxygen + iron. This iron ore was made by marine bacteria. They produced oxygen in the ocean through photosynthesis, which oxidized the iron in the ocean, causing the iron oxide particles to settle on the ocean floor and become iron ore.
https://www.toyaku.ac.jp/lifescience/departments/applife/knowledge/article-026.html
It seems that the iron in the ocean is carried by the wind from the desert sand, which contains iron. Iron is also found in humus, a form of decomposed organic matter, and this substance can travel up to 4,000 km on ocean currents. As iron is essential for life, there seem to be various routes for the circulation of iron.
https://www.hokudai.ac.jp/news/2020/03/4000km.html
In the first place, the geomagnetic field exists because of the magnetism of iron, and without the geomagnetic field, there would be no magnetic barrier and the solar wind would hit us directly. Without iron, photosynthesis would be impossible, which would be a major blow to ecosystems that rely on plants for food, and we wouldn’t be able to produce oxygen. Iron is amazing. The Earth is amazing.
https://www.aichi-steel.co.jp/sp_info/SPINFO/TetsuRiki-Agri/reason/index.html
