Phosphorus cycling

Ecosystems have long been shaped by phosphorus limitation. We need to better understand how natural and human-caused shifts in the phosphorus cycle disrupt the Earth system.

From Dutch painters to ocean sediments, Caroline Slomp discusses the role vivianite plays in the distribution of phosphorus, an essential nutrient for life.

Nature Geoscience spoke with Dr Shlomit Sharoni, an ocean biogeochemist at Massachusetts Institute of Technology, and Dr Kelly Andersen, a tropical ecologist at Nanyang Technological University about the interplay between phosphorous cycling and the ecosystems they study.

A review of aqueous phosphorus availability on the Earth’s early surface suggests a range of phosphorus sources supplied the prebiotic Earth, but that phosphorus availability declined as life evolved and altered geochemical cycling.

Marine phosphate levels and biological productivity were lowest during the early Phanerozoic when seafloor weathering rates were high and continental weathering rates were muted, according to a statistical model of coupled elemental cycles.

Recycling of sedimentary phosphorus driven by increasing oceanic sulfide availability contributed to the persistent oxygenation of Earth’s atmosphere, according to analysis of Archean drill-core samples and biogeochemical modelling

Increased volcanism-related phosphorus delivery to the Late Ordovician ocean helps explain widespread cooling and eutrophication-driven extinctions, as shown by a biogeochemical model incorporating volcanic ash phosphorus and carbon isotope records.

Early Neoproterozoic marine productivity fell due to nutrient drawdown following a switch from an iron-rich to a sulfide-rich ocean, according to records of phosphorus geochemistry measured from sedimentary sections in North China.

Phosphorus remobilized from seafloor sediments due to a reduced influx of iron-oxide from land led to widespread anoxia during the end-Permian mass extinction, according to palaeoredox and phosphorus speciation proxy records from Svalbard.

The oxygenation of the Earth's deep oceans is often thought to have triggered the evolution of simple animals. A review article proposes that instead, the evolution of animal life set off a series of biogeochemical feedbacks that promoted the oxygenation of the deep sea.

Production and consumption of dissolved organic phosphorus in the surface ocean is controlled by the interplay between phosphate and iron stress, according to global analyses of the distribution of marine nutrients.

Ecosystem modelling suggests that a range of growth conditions and ecological selection of phytoplankton explain global patterns of C:N:P ratios in marine organic matter.

Phosphorus plays a dynamic and complex role in marine biogeochemistry, which is closely connected to carbon, nitrogen and metal cycling, according to a literature synthesis on recent advances in understandings of the marine phosphorus cycle.

Upward fluxes have been thought to dominate nutrient replenishment at the ocean surface. A numerical model reveals that lateral transfer is an important source of phosphorus and nitrogen for all five subtropical gyres.

Photosynthetic microbes, collectively termed phytoplankton, are responsible for the vast majority of primary production in marine waters. A synthesis of the latest research suggests that two broad nutrient limitation regimes — characterized by nitrogen and iron limitation, respectively — dictate phytoplankton abundance and activity in the global ocean.

The elemental composition of marine organic matter is used to infer a variety of oceanic ecosystem processes. A compilation of observational data suggests that elemental ratios differ substantially from the Redfield ratio, but exhibit a clear latitudinal trend.

About half of the current available phosphorus in agricultural soil globally is derived from anthropogenic sources, according to country-scale simulations of phosphorus dynamics between 1950 and 2017.

Plant-available phosphorus declines in paddy soils as atmospheric CO₂ increases, according to long-term free air carbon dioxide enrichment experiments of rice plants.

Lakes preferentially retain phosphorous over nitrogen, amplifying the imbalance of nutrient cycles caused by anthropogenic inputs, according to analyses of more than 5,000 lakes globally.

Spatial patterns in the phosphorus and nitrogen limitation in natural terrestrial ecosystems are reported from analysis of a global database of the resorption efficiency of nutrients by leaves.

Phosphorus limitation can significantly reduce the response of the Amazon forest to CO₂ fertilization, according to ecosystem-model ensemble simulations of a free-air CO₂ enrichment experiment.

Nutrient limitation of plant growth can reduce net plant productivity. Model projections indicate that productivity declines when nitrogen and phosphorus limitations are considered, turning terrestrial ecosystems into a net source of CO₂ by 2100.