Cited by 1,412Marine and coastal ecosystemsAquatic Ecosystems and Phytoplankton DynamicsOceanographic and Atmospheric Processes

Redfield revisited: Variability of C:N: P in marine microalgae and its biochemical basis

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Geider, Richard, La Roche, Julie·2002·European Journal of Phycology

Abstract

A compilation of data on the elemental composition of marine phytoplankton from published studies was used to determine the range of C:N:P. The N:P ratio of algae and cyanobacteria is very plastic in nutrient-limited cells, ranging from <5 mol N:mol P when phosphate is available greatly in excess of nitrate or ammonium to <100 mol N:mol P when inorganic N is present greatly in excess of P. Under optimal nutrient-replete growth conditions, the cellular N:P ratio is somewhat more constrained, ranging from 5 to 19 mol N:mol P, with most observations below the Redfield ratio of 16. Limited data indicate that the critical N:P that marks the transition between N- and P-limitation of phytoplankton growth lies in the range 20–50 mol N:mol P, considerably in excess of the Redfield ratio. Biochemical composition can be used to constrain the critical N:P. Although the biochemical data do not preclude the critical N:P from being as high as 50, the typical biochemical composition of nutrient-replete algae and cyanobacteria suggests that the critical N:P is more likely to lie in the range between 15 and 30. Despite the observation that the overall average N:P composition of marine particulate matter closely approximates the Redfield ratio of 16, there are significant local variations with a range from 5 to 34. Consistent with the culture studies, lowest values of N:P are associated with nitrate- and phosphate-replete conditions. The highest values of N:P are observed in oligotrophic waters and are within the range of critical N:P observed in cultures, but are not so high as to necessarily invoke P-limitation. The C:N ratio is also plastic. The average C:N ratios of nutrientreplete phytoplankton cultures, oceanic particulate matter and inorganic N and C draw-down are slightly greater than the Redfield ratio of 6.6. Neither the analysis of laboratory C:N:P data nor a more theoretical approach based on the relative abundance of the major biochemical molecules in the phytoplankton can support the contention that the Redfield N:P reflects a physiological or biochemical constraint on the elemental composition of primary production.

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Authors
Geider, R., & La Roche, J.
Affiliations
University of Essex (GB)
Venue
European Journal of Phycology
Published
2002-03
Volume
37
Issue
1
Pages
1-17
ISSN
  • 0967-0262 (ISSN-L)
  • 1469-4433
OpenAlex
W2060313313
Cited by
1,412
References
75
Citations by year
2026: 57 · 2025: 60 · 2024: 65 · 2023: 99 · 2022: 90 · 2021: 100 · 2020: 79 · 2019: 73 · 2018: 82 · 2017: 86 · 2016: 69 · 2015: 79 · 2014: 75 · 2013: 61 · 2012: 61
FWCI
18.50
Type
journal article
Language
en
Open access
Licence
other-oa
Locations
  • European Journal of Phycology (publishedVersion)
  • Helmholtz Centre for Ocean Research Kiel (GEOMAR) (acceptedVersion, other-oa)
Funders
Natural Environment Research Council
Topics
  • Physical Sciences › Earth and Planetary Sciences › Oceanography › Marine and coastal ecosystems
  • Physical Sciences › Environmental Science › Environmental Chemistry › Aquatic Ecosystems and Phytoplankton Dynamics
  • Physical Sciences › Earth and Planetary Sciences › Oceanography › Oceanographic and Atmospheric Processes
Keywords
Redfield ratio, C:N:P stoichiometry, marine phytoplankton, cyanobacteria, N:P ratio, nutrient limitation, nitrogen limitation, phosphorus limitation, C/N ratio, oligotrophic waters, particulate matter, biochemical composition

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