A Five‐stage Evolution of Earth's Phosphorus Cycle

Abstract

AbstractPhosphorus (P) is a key biological nutrient and probably the ultimate limiter of marine productivity during Earth history. In recent years, a wealth of new knowledge has revolutionized our understanding of the global P cycle, yet its long‐term evolution remains incompletely documented. In this paper, we review the effects of three major controlling factors on the long‐term evolution of the global P cycle, i.e., tectonics, marine redox conditions, and bio‐evolution, on the basis of which a five‐stage model is proposed: Stage I (>∼2.4 Ga), tectonic‐lithogenic‐controlled P cycling; Stage II (∼2.4 Ga to 635 Ma), low‐efficiency biotic P cycling; Stage III (∼635 Ma to 380 Ma), transitional biotic P cycling; Stage IV (∼380 Ma to near‐modern), high‐efficiency biotic P cycling; and Stage V (Anthropocene), human‐influenced P cycling. This model implies that the earlier‐proposed Ediacaran reorganization of the marine P cycle may represent only the start of a ∼250–Myr–long transition of the Earth's P cycle (Stage III) between the low‐efficiency biotic mode of the Proterozoic (Stage II) and the high‐efficiency biotic mode of the Phanerozoic (Stage IV). The development of biologically‐driven, high‐efficiency P cycling may have been a key factor for the increasing frequency and volume of phosphorite deposits since the late Neoproterozoic.