Calculate the biological fluorescence index (BIX)

The biological fluorescence index (BIX) is calculated by dividing the fluorescence at excitation 310 nm and emission at 380 nm (ex = 310, em = 380) by that at excitation 310 nm and emission at 430 nm (ex = 310, em = 430).

Usage

eem_biological_index(eem, verbose = TRUE)

Arguments

eem: An object of class eemlist.
verbose: Logical determining if additional messages should be printed.

Value

An object of class eemlist.

A data frame containing the biological index (BIX) for each eem.

Interpolation

Different excitation and emission wavelengths are often used to measure EEMs. Hence, it is possible to have mismatchs between measured wavelengths and wavelengths used to calculate specific metrics. In these circumstances, EEMs are interpolated using the interp2 function from the parcma library. A message warning the user will be prompted if data interpolation is performed.

References

Huguet, A., Vacher, L., Relexans, S., Saubusse, S., Froidefond, J. M., & Parlanti, E. (2009). Properties of fluorescent dissolved organic matter in the Gironde Estuary. Organic Geochemistry, 40(6), 706-719.

doi:10.1016/j.orggeochem.2009.03.002

Examples

file <- system.file("extdata/cary/scans_day_1/", package = "eemR")
eem <- eem_read(file, import_function = "cary")

eem_biological_index(eem)
#>    sample       bix
#> 1    nano 2.6812045
#> 2 sample1 0.7062640
#> 3 sample2 0.8535423
#> 4 sample3 0.4867927