The name in itself evokes a bit of confusion, but simply put "bio" represents the biological aspect, "geo" represents the geological aspect, and "chemical" represents the chemical reactions that occur
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. These three aspects or factors work together to cycle matter.
A biogeochemical cycle is the pathway a nutrient takes throughout Earth's systems. These systems may include the biosphere, atmosphere, hydrosphere, and the lithosphere (geosphere). Nutrients move from one reservoir (pool) to the next, and then the next. This continuous cycle has no real beginning or end. The movement of a nutrient from one reservoir to the next is called flux. Flux is carried out over different time intervals and is termed the flux rate. Nutrients spend varying amounts of time in different reservoirs. The amount of time a nutrient spends in a given reservoir is its residence time (rt). For instance, carbon may reside in the lithosphere for millions of years, but spend less than 5 years in the atmosphere. A reservoir that receives more of a nutrient than it releases, is called a sink. A reservoir that releases more of a nutrient than it receives is called a source
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