Calculate dissolved oxygen saturation

Calculates the dissolved oxygen concentration in equilibrium with the atmosphere from water temperature, barometric pressure, and salinity. This is the DO.sat quantity commonly required by stream metabolism models.

Usage

calc_O2sat(
  temp_water,
  atmo_press,
  units = "atm",
  salinity = 0,
  out_units = "mg/L"
)

Arguments

temp_water

Numeric vector. Water temperature in degrees Celsius.

atmo_press

Numeric vector. Barometric pressure at the site.

units

Character string. Units of atmo_press. See convert_pressure() for accepted pressure units. Defaults to "atm".

salinity

Numeric vector. Salinity in parts per thousand. Defaults to freshwater (0).

out_units

Character string. Output concentration units, either "mg/L" (the default) or "umol/L".

Value

Numeric vector of dissolved oxygen saturation in the requested units.

Details

The calculation uses the Benson and Krause umol/kg fit reported by Garcia and Gordon (1992), applies a vapor-pressure correction for non-standard barometric pressure, and converts from mass-based concentration to a volume basis with a salinity-aware density correction.

References

Garcia, H.E., and Gordon, L.I. (1992). Oxygen solubility in seawater: better fitting equations. Limnology and Oceanography, 37(6), 1307-1312.

See also

calc_CO2sat(), calc_CH4sat(), calc_N2Osat(), calc_N2sat(), calc_Arsat()

Examples

calc_O2sat(temp_water = 15, atmo_press = 1, units = "atm")
#> [1] 10.08393

calc_O2sat(
  temp_water = c(5, 15, 25),
  atmo_press = c(101.2, 100.8, 100.5),
  units = "kPa"
)
#> [1] 12.754349 10.030790  8.193632

# Return micromoles per liter instead of mg/L
calc_O2sat(temp_water = 15, atmo_press = 1, out_units = "umol/L")
#> [1] 315.1347