This is a basic function with no inputs. It prints to the console the units
that can be used in the functions `convert_DO()`

, `convert_MR()`

,
`convert_rate()`

, and `convert_rate.ft()`

.

`unit_args()`

A print out to the console of accepted units

Note that some oxygen unit conversions require temperature (`t`

), salinity
(`S`

), and atmospheric pressure (`P`

) to be specified.

Note the difference between percent air saturation (`%Air`

), where air
saturated water is ~100%, and percent oxygen saturation (`%Oxy`

), where air
saturated water is ~20.946% *oxygen* saturated. In other words, `%Oxy = %Air x 0.20946`

.

For most units a fuzzy string matching algorithm is used to accept different
formatting styles. For example, `"mg/l"`

, `"mg/L"`

, `"mgL-1"`

, `"mg l-1"`

,
`"mg.l-1"`

are all parsed the same.

`convert_DO()`

`from`

and `to`

:Oxygen concentration units. Should use SI units (`L`

or `kg`

) for the
denominator.

Do *NOT* require `t`

, `S`

and `P`

for conversions:

`"mg/L"`

,`"ug/L"`

,`"mol/L"`

,`"mmol/L"`

,`"umol/L"`

,`"nmol/L"`

,`"pmol/L"`

Require `t`

, `S`

and `P`

for conversions:

`"uL/L"`

,`"mL/L"`

,`"mm3/L"`

,`"cm3/L"`

,`"mg/kg"`

,`"ug/kg"`

,`"mol/kg"`

,`"mmol/kg"`

,`"umol/kg"`

,`"nmol/kg"`

,`"pmol/kg"`

,`"uL/kg"`

,`"mL/kg"`

,`"ppm"`

(i.e. parts per million, equivalent to`mg/kg`

).

Percentage saturations (require `t`

, `S`

and `P`

):

`"%Air"`

(i.e. % Air Saturation), `"%Oxy"`

(i.e. % Oxygen Saturation)

Pressure units (require `t`

, `S`

and `P`

):

`"Torr"`

, `"hPa"`

, `"kPa"`

, `"mmHg"`

, `"inHg"`

Combining units for `output.unit`

in `convert_rate()`

and
`convert_rate.ft()`

, or for use in `convert_MR()`

, must follow these
orders:

Absolute rates:

`Oxygen/Time`

e.g.`"mg/s"`

,`"umol/min"`

,`"mL/h"`

Mass-specific rates:

`Oxygen/Time/Mass`

e.g.`"mg/s/ug"`

,`"umol/min/g"`

,`"mL/h/kg"`

Area-specific rates:

`Oxygen/Time/Area`

e.g.`"mg/s/mm2"`

,`"umol/min/cm2"`

,`"mL/h/m2"`

**Oxygen amount units:**

`"ug"`

,`"mg"`

,`"pmol"`

,`"nmol"`

,`"umol"`

,`"mmol"`

,`"mol"`

,`"uL"`

,`"mL"`

,`"mm3"`

,`"cm3"`

Note `"mm3"`

and `"cm3"`

(i.e. `cc`

) are used in some older publications.
These are equivalent to `"uL"`

and `"mL"`

respectively.

**Time units:**

`"sec"`

,`"min"`

,`"hour"`

,`"day"`

**Mass units for mass-specific rates:**

`"ug"`

,`"mg"`

,`"g"`

,`"kg"`

**Area units for area-specific rates:**

`"mm2"`

,`"cm2"`

,`"m2"`

,`"km2"`

```
# Run the function:
unit_args()
#> Note: A string-matching algorithm is used to identify units.
#> Example 1: These are recognised as the same: 'mg/L', 'mg/l', 'mg L-1', 'mg per litre', 'mg.L-1'
#> Example 2: These are recognised as the same: 'Hour', 'hr', 'h'
#>
#> # Input Units # --------------------------------------
#> Oxygen concentration units should use SI units (`L` or `kg`) for the denominator.
#>
#> Oxygen Concentration or Pressure Units - Do not require t, S and P
#> [1] "mg/L" "ug/L" "mol/L" "mmol/L" "umol/L" "nmol/L" "pmol/L"
#> Oxygen Concentration or Pressure Units - Require t, S and P
#> [1] "uL/L" "mL/L" "mm3/L" "cm3/L" "cc/L" "mg/kg" "ug/kg" "ppm" "mol/kg" "mmol/kg" "umol/kg" "nmol/kg" "pmol/kg" "uL/kg" "mL/kg" "%Air" "%Oxy" "Torr" "hPa" "kPa" "mmHg" "inHg"
#>
#> Volume units for use in flow rates in calc_rate.ft and convert_rate.ft
#> (e.g. as in 'ml/min', 'L/s', etc.)
#> [1] "uL" "mL" "L"
#>
#> Time units (for 'time.unit' or as part of 'flowrate.unit')
#> [1] "sec" "min" "hour" "day"
#>
#> Mass units
#> [1] "ug" "mg" "g" "kg"
#>
#> Area units
#> [1] "mm2" "cm2" "m2" "km2"
#>
#> # Metabolic Rate Units # -----------------------------
#> For use in 'convert_rate', 'convert_rate.ft', 'convert_MR'
#>
#> Must be in correct order:
#> Absolute rates: Oxygen/Time e.g. 'mg/sec', 'umol/min', 'mL/h'
#> Mass-specific rates: Oxygen/Time/Mass e.g. 'mg/sec/ug', 'umol/min/g', 'mL/h/kg'
#> Area-specific rates: Oxygen/Time/Area e.g. 'mg/sec/mm2', 'umol/min/cm2', 'mL/h/m2'
#>
#> Output Oxygen amount units
#> [1] "ug" "mg" "pmol" "nmol" "umol" "mmol" "mol" "uL" "mL" "mm3" "cm3"
#>
#> Output Time units
#> [1] "sec" "min" "hour" "day"
#>
#> Output Mass units for mass-specific rates
#> [1] "ug" "mg" "g" "kg"
#>
#> Output Area units for surface area-specific rates
#> [1] "mm2" "cm2" "m2" "km2"
```