# co2_add: Calculate CO2 to add to water In respirometry: Tools for Conducting and Analyzing Respirometry Experiments

## Description

Calculates the moles of CO2 gas to be added to a volume of seawater to achieve the desired pCO2. Useful for ocean acidification experiments where CO2 treatments are desired.

## Usage

 ```1 2``` ```co2_add(goal_pco2, start_pH, vol, temp = 25, sal = 35, TA = NULL, atm_pres = 1013.25) ```

## Arguments

 `goal_pco2` the desired pCO2 in the water (uatm). `start_pH` pH of the water before CO2 is added (total scale). `vol` volume of the water (liter). `temp` temperature (°C). Default is 25 °C. `sal` salinity (psu). Default is 35 psu. If `sal` < 26 psu, then `TA` must be provided. `TA` (optional) total alkalinity (umol / kg). If undefined TA is estimated from salinity using `guess_TA`. `atm_pres` atmospheric pressure (mbar). Default is 1013.25 mbar.

## Value

moles of CO2 gas to be added to the seawater.

## Note

It is assumed that all of the CO2 added dissolves and remains in solution. This can be achieved (almost completely) by bubbling CO2 according to Jokiel et al. 2014.

## Author(s)

Matthew A. Birk, [email protected]

## References

Jokiel PL, Bahr KD, Rodgers KS. 2014. Low-cost, high-flow mesocosm system for simulating ocean acidification with CO2 gas. Limnol Oceanogr Methods. 12:313–322.

`co2_rate`, `flush_carb`, `carb`, `peri_pump`
 ```1 2 3``` ```# I want the 50 L reservoir to have a pCO2 = 1000 uatm. It currently has a pH of 7.88. # How many moles of CO2 gas should be added to the water to reach my desired pCO2? co2_add(goal_pco2 = 1000, start_pH = 7.88, vol = 50) ```