Polyphosphate as an Integral Component of Global Phosphorus Cycling through Earth’s History

Polyphosphate (polyP), a condensed linear form of orthophosphate
residues, is functionally versatile phosphorus (P) polymer that has
persisted since prebiotic Earth. Long treated as a cellular biochemical
curiosity, it remains systematically overlooked in global P budgets
and Earth system models. In this review, we compile the first global-scale
synthesis of environmental occurrence, biological regulation, and
ecosystem functions of polyP across terrestrial, freshwater, marine,
and engineered systems. Integrating 568 environmental observations
and over 3000 microbial genomes, we unveil that polyP is a quantitatively
significant and phylogenetically widespread component of global P
cycling, often comprising 5–40% of total phosphorus in major
ecosystems. We synthesize current understanding of how microbial taxa,
including bacterial or archaeal polyP-accumulating organisms and arbuscular
mycorrhizal fungi, mediate polyP turnover and interact with carbon/nitrogen
cocycling under fluctuating redox, nutrient, and climatic conditions.
Our quantitative assessment reveals that global polyP stocks in soils,
sediments, and wastewater systems form a substantial, yet previously
unaccounted, reservoir of recoverable and climate-sensitive P. The
omission of polyP from existing models creates systematic blind spots
in understanding P bioavailability, retention, cycling, and sustainability.
Integrating polyP into the global P narrative is essential for advancing
new frontiers in climate-smart biogeochemical forecasts, circular
nutrient management, and long-term water-energy-food ecosystem security
under global climate change.