The Earth is a similarly closed system, with chemical reactions that occur in soil affecting chemical reactions that occur in skies and seas.
Chemistry is destiny.
Phosphorus also plays a key role in the cycles of such biologically essential elements as nitrogen, oxygen and sulfur. Because of analytical limitations, little was known about phosphorus cycling until recently. The new technologies and methods allow scientists to characterize phosphorus compounds in water and soil, estimate how fast phosphate cycles through natural reservoirs, estimate long-term phosphorus burial in the oceans through geologic time, pinpoint phosphorus sources in different ecosystems, determine fluctuations in phosphate concentrations at certain times and places, and study the effects of phosphorus pollution in estuaries and lakes. In recent years, AGU meetings, traditionally devoted to geology and geophysics, have increasingly included biology-related topics. It also attempts to evaluate human impact on the system.