Phosphorus as an integral component of global marine biogeochemistry

Phosphorus (P) is essential for life, but most of the global surface ocean is P depleted, which can limit marine productivity and affect ecosystem structure. Over recent decades, a wealth of new knowledge has revolutionized our understanding of the marine P cycle. With a revised residence time (~10–20 kyr) that is similar to nitrate and a growing awareness that P transformations are under tight and elaborate microbial control, the classic textbook version of a tectonically slow and biogeochemically simple marine P cycle has become outdated. P moves throughout the world’s oceans with a higher level of complexity than has ever been appreciated before, including a vast, yet poorly understood, P redox cycle. Here, we illustrate an oceanographically integral view of marine P by reviewing recent advances in the coupled cycles of P with carbon, nitrogen and metals in marine systems. Through this lens, P takes on a more dynamic and connected role in marine biogeochemistry than previously acknowledged, which points to unclear yet profound potential consequences for marine ecosystems, particularly under anthropogenic influence.