Redox control of N:P ratios in aquatic ecosystems

T. M. Quan, P. G. Falkowski

Research output: Contribution to journalArticlepeer-review

50 Scopus citations


The ratio of dissolved fixed inorganic nitrogen to soluble inorganic phosphate (N:P) in the ocean interior is relatively constant, averaging ∼16 : 1 by atoms. In contrast, the ratio of these two elements spans more than six orders of magnitude in lakes and other aquatic environments. To understand the factors influencing N:P ratios in aquatic environments, we analyzed 111 observational datasets derived from 35 water bodies, ranging from small lakes to ocean basins. Our results reveal that N:P ratios are highly correlated with the concentration of dissolved O2 below ∼100 μmol L-1. At higher concentrations of O2, N:P ratios are highly variable and not correlated with O2; however, the coefficient of variation in N:P ratios is strongly related to the size of the water body. Hence, classical Redfield ratios observed in the ocean are anomalous; this specific elemental stoichiometry emerges not only as a consequence of the elemental ratio of the sinking flux of organic matter, but also as a result of the size of the basins and their ventilation. We propose that the link between N:P ratios, basin size and oxygen levels, along with the previously determined relationship between sedimentary δ15N and oxygen, can be used to infer historical N:P ratios for any water body.

Original languageEnglish (US)
Pages (from-to)124-139
Number of pages16
Issue number2
StatePublished - Mar 2009

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Environmental Science(all)
  • Earth and Planetary Sciences(all)


Dive into the research topics of 'Redox control of N:P ratios in aquatic ecosystems'. Together they form a unique fingerprint.

Cite this