redfield: Redfield Ratio Calculator
In marelac: Tools for Aquatic Sciences

Description Usage Arguments Details Value References See Also Examples

Estimate elemental composition of biomass (or media) according to the Redfield ratio.

1 2	redfield(q, species, method = c("mol", "mass"), ratio = c(C=106, H=263, O=110, N=16, P=1))

`q`	amount of substance of that element (in mol or mass units),
`species`	The element that is given ("C", "H", "O", "N", "P"),
`method`	measurement unit ("mol" or "mass"),
`ratio`	average elemental composition.

The average elemental composition of marine plankton (Redfield ratio) is traditionally assumed to be C106 H263 O110 N16 P1 (Redfield 1934, 1963, Richards 1965). Note that while the C:N:P ratio is widely agreed there is still discussion about the average of O and H, e.g. C106 H180 O45 N16 P1 (Stumm, 1964).

Note also that there are, of course, large differences depending on species and physiological state.

A data frame with the estimated ratio of the main elements.

Redfield AC, 1934. On the proportions of organic derivations in sea water and their relation to the composition of plankton. In: James Johnstone Memorial Volume. (ed. R.J. Daniel). University Press of Liverpool, 177-192.

Redfield, AC, Ketchum, BH and Richards FA, 1963. The influence of organisms on the composition of seawater. In: Hill, MN, Editor, The Sea vol. 2, Interscience, New York (1963), pp.26-77.

Richards FA, 1965. Anoxic basins and fjords. In: Riley JP, Skirrow D. (Eds.), Chemical Oceanography, vol. 1. Academic Press, New York, 611-645. (cited in Hedges et al, 2002).

Stumm W, 1964. Discussion (Methods for the removal of phosphorus and nitrogen from sewage plant effluents by G. A. Rohlich). In Eckenfelder, WW (ed.), Advances in water pollution research. Proc. 1st Int. Conf. London 1962, volume 2, pp. 216-229. Pergamon.

Vollenweider RA, 1985. Elemental and biochemical composition of plankton biomass: some comments and explorations. Arch. Hydrobiol. 105, 11-29.

Anderson LA, 1995. On the hydrogen and oxygen content of marine plankton. Deep-Sea Res. 42, 1675-1680.

Hedges JI., Baldock JA, Gelinas Y, Lee C, Peterson ML and Wakeham SG, 2002. The biochemical and elemental compositions of marine plankton: A NMR perspective. Marine Chemistry 78, 47-63.

AtomicWeight, molvol, molweight

## Redfield ratio
redfield(1, "P")
## returns the molar Redfield ratio, rescaled to nitrogen
redfield(1, "N")
## how many mass units are related to 2 mass units (e.g. mg) P
redfield(2, "P", "mass")
redfield(c(1, 2, 3), "N", "mass")

## mass percentage of elements
x <- redfield(1, "P", "mass")
x / sum(x)

## with alternative elemental composition (Stumm, 1964)
x <- redfield(1, "P", "mass", 
              ratio = c(C = 106, H = 180, O = 45, N = 16, P = 1))
x / sum(x)

## rule of thumb for fresh mass (in mg) formed by 1 microgram P
redfield(1, "P", "mass")$C * 2 * 10 / 1000
sum(redfield(1, "P", "mass",
  ratio = c(C = 106, H = 180, O = 45, N = 16, P = 1))) * 10 / 1000