Drivers and biogeochemical implications of global C∶N∶P stoichiometric deviations in marine ecosystems

The cycling patterns of marine carbon (C), nitrogen (N), and phosphorus (P) nutrients are changing in the context of global change, raising the question of whether the classical Redfield ratio (C∶N∶P = 106∶16∶1) is still universally applicable. Liu et al.(2025) compiled nearly 50 years (1971—2020) of global data, including approximately 50,000 planktonic particulate samples and about 380,000 observations of dissolved constituents in seawater, and conducted a systematic analysis of marine ecological stoichiometry. The results show that marine stoichiometric ratios deviate markedly from the traditional Redfield ratio on both spatial and temporal scales, while showing a consistent global pattern. For example, in different ocean basins, the C∶P and N∶P ratios in both planktonic particulate matter and dissolved pools are generally higher than the Redfield ratio. In contrast, the C∶N ratio has remained relatively stable, indicating a highly stable coupling relationship between carbon and nitrogen metabolism in the plankton. However, the global C∶P and N∶P ratios have exhibited a clear interdecadal decline since 2007, which further indicates that changes in terrestrial nutrient inputs and adjustments in community structure are reshaping marine nutrient limitation patterns. In conclusion, these findings suggest that marine ecological stoichiometry is undergoing a transition, shifting from a steady state to a new dynamic equilibrium. Therefore, further research should focus on biological, biogeochemical, and physical processes that govern stoichiometry and integrate these processes into Earth system models to improve predictions of carbon sinks and climate feedback in marine ecosystems.