RQ {respirometry}

Calculate respiratory quotient

Description

Calculates the respiratory quotient (RQ), or ratio of CO2 produced to O2 consumed between observations. To calculate CO2 produced, either DIC or both pH and TA must be provided.

Usage

RQ(
  o2,
  o2_unit = "percent_a.s.",
  pH = NULL,
  TA = NULL,
  DIC = NULL,
  temp = 25,
  sal = 35,
  atm_pres = 1013.25
)

Arguments

o2

a numeric vector of O2 values with a length of at least 2.

o2_unit

a string describing the unit used to measure o2. Default is "percent_a.s." Options are from conv_o2.

pH

pH (total scale). Elements must align with o2 vector.

TA

total alkalinity (umol / kg). May be either a vector with length equal to o2 or a single numeric value.

DIC

dissolved inorganic carbon (umol / kg). Elements must align with o2 vector.

temp

temperature (°C). Default is 25 °C.

sal

salinity (psu). Default is 35 psu.

atm_pres

atmospheric pressure (mbar). Default is 1013.25 mbar.

Value

ratio of CO2 produced to O2 consumed.

Note

If you want a rough estimate of RQ, but only have pH measurements, TA can be estimated from salinity using guess_TA.

Author(s)

Matthew A. Birk, [e-mail]

See Also

conv_o2, guess_TA

Examples

o2_observations <- c(21, 18, 14.5, 7)
pH_observations <- c(8.05, 7.98, 7.86, 7.65)
TA_observations <- c(2222, 2219, 2208, 2214)

RQ(o2 = o2_observations, o2_unit = 'kPa', pH = pH_observations,
TA = TA_observations, temp = 20, sal = 33)

DIC_observations <- c(2222, 2250, 2284, 2355)
RQ(o2 = o2_observations, o2_unit = 'kPa', DIC = DIC_observations)

RQ(o2 = o2_observations, o2_unit = 'kPa', pH = pH_observations, TA = 2032)