What is bio-geochemical cycle research?

　The bio-geochemical cycle of carbon is one of the most important research theme. This is because carbon dioxide in the atmosphere has a greenhouse effect. The history of the terrestrial carbon cycle is also the history of climate change. It shows where and how much carbon is stored, as well as where it is moving and how fast it is doing so. The carbon in fossils lying dormant in the crust is released into the atmosphere as carbon dioxide, and part of it is stored in the ocean, used by living things, and returned to the atmosphere again. This kind of material circulation influenced by biological activity is called the bio-geochemical cycle.

   A bio-geochemical cycle can be conceived for all elements other than carbon. The nitrogen cycle, phosphorus cycle, sulfur cycle…among these is the iodine cycle. In bio-geochemical cycle research, if the carbon cycle occupies the top rung, followed by nitrogen, phosphorus, and sulfur. The iodine cycle would follow (this is my personal opinion) .