solO2: Solubility of oxygen in fresh- and seawater

In denis-chabot/fishMO2: Calculate and Plot SMR, O2crit and SDA, and convert between oxygen units

Description

Calculates the amount of oxygen that dissolves in water according to temperature, salinity and atmospheric pressure, when water and air are in equilibrium (100% saturation). Different oxygen units are allowed. Solubility can be calculated per liter (common in physiology) or per kg (common in oceanography) of water.

Usage

solO2(
  t,
  s = 0,
  o2Unit = c("mg", "ml", "umol"),
  waterUnit = c("l", "kg"),
  p = 101.325,
  author = c("Garcia", "Benson")
)

Arguments

t	A vector of temperature values in degrees Celsius
s	A vector of salinity values
o2Unit	The desired oxygen units for solubility calculation (mg, ml, µmol)
waterUnit	Unit of water used for solubility calculation (liters or kg)
p	Total gas pressure above the water body (kPa)
author	Equations from 2 authors can be used, Garcia or Benson (see references)

Details

Different units of oxygen concentration are allowed, different units for quantity of water (1 liter or one kg), and equations from different two authors are allowed. If total gas pressure is not 101.325, solubility will be calculated for the pressure requested by the user.

The equations provided by García and Gordon (1992) are used by default, they are supposedly the best available for seawater below 5 °C. Equations of Benson and Krause (1980, 1984) are provided for comparison with the results from DOTABLES program at http://water.usgs.gov/software/DOTABLES/. For T varying from 0 to 15°C, P from 99 to 102 kPa, S=0 and 28 and values rounded to 2 decimals, author set to "Benson", results match what DOTABLES does.

Value

Solubility value(s) of oxygen for requested temperatures and salinities, in desired oxygen and water units, adjusted to pressure requested by user.

Warnings

It is assumed that vectors t and s have the same length, or that one of the two is a constant value. This is not checked in the present version, the user must make sure it is the case.

Author(s)

Denis Chabot

References

Benson B. B. and Krause D. Jr. (1980) The concentration and isotopic fractionation of gases dissolved in freshwater in equilibrium with the atmosphere. 1. Oxygen. Limnology and Oceanography, 25, 662-671.

Benson B. B. and Krause D. Jr. (1984) The concentration and isotopic fractionation of oxygen dissolved in freshwater and seawater in equilibrium with the atmosphere. Limnology and Oceanography, 29, 620-632.

García, H. E. and Gordon, L.I. (1992) Oxygen solubility in seawater: better fitting equations. Limnology and Oceanography 37, 1307-1312.

Examples

solO2(t=5, s=28, o2Unit="mg")
# should give 10.5928 mg O2 per liter

# to compute % saturation

obsDO = 8 # observed DO in mg per liter
Sol = solO2(t=10, s=28, o2Unit="mg")
sat = obsDO / Sol * 100
sat

denis-chabot/fishMO2 documentation built on July 16, 2020, 1:53 a.m.