# RQ: Calculate respiratory quotient In respirometry: Tools for Conducting and Analyzing Respirometry Experiments

## 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

 ```1 2``` ```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, [email protected]

`conv_o2`, `guess_TA`

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11``` ```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) ```

### Example output

```[1] 0.960987 1.097911 1.006876
[1] 0.9440819 0.9826159 0.9575688
[1] 1.227301 1.619191 1.096923
```

respirometry documentation built on Aug. 13, 2018, 9:04 a.m.