This type of cycle of atoms between living and non-living things is known as a biogeochemical cycle. All of the atoms that are building blocks of living things are a part of biogeochemical cycles. The most common of these are the carbon and nitrogen cycles. The carbon cycle is nature's way of reusing carbon atoms, which travel from the atmosphere into organisms in the Earth and then back into the atmosphere over and over again. Most carbon is stored in rocks and sediments, while the rest is stored in the ocean, atmosphere, and living organisms. Respiration, excretion, and decomposition release the carbon back into the atmosphere or soil, continuing the cycle. The ocean plays a critical role in carbon storage, as it holds about 50 times more carbon than the atmosphere.