o2.at.sat {LakeMetabolizer}

Calculates the equilibrium saturation concentration of oxygen in water at the supplied conditions

Description

Used to calculate the equilibrium concentration of oxygen in water. The equilibration concentration of oxygen in water varies with both temperature, salinity, and the partial pressure of oxygen in contact with the water (calculated from supplied elevation or barometric pressure).

Usage

o2.at.sat(ts.data, baro, altitude = 0, salinity = 0, model = "garcia-benson")

o2.at.sat.base(
  temp,
  baro,
  altitude = 0,
  salinity = rep(0, length(temp)),
  model = "garcia-benson"
)

Arguments

ts.data

Object of class data.frame with two named columns “datetime” and “wtr” (water temp in deg C).

baro

barometric pressure in millibars.

altitude

a numeric value indicating the elevation above mean sea level in meters. Defaults to mean sea level. An alternative to supplying barometric pressure.

salinity

a numeric vector of salinity in PSU. Defaults to zero. Length must be one or equal to length of temperature.

model

the empirical model to be used. "garcia-benson", "garcia", "weiss" and "benson" are the available options. "garcia-benson" is our current recommendation. The models correspond to the like-named references described below, where both "garcia" and "garcia-benson" are from Garcia & Gordon (1992).

temp

a numeric vector of water temperature in degrees Celsius.

Details

DO solubility is converted from mL/L to mg/L by multiplying by 1.42905, per USGS memo 2011.03. Corrections for vapor pressure are made according to barometric pressure as in Equations 2&3 of USGS memos 81.11 and 81.15. When barometric pressure is not supplied, it is estimated from altitude by the barometric formula as in Colt (2012).

Value

The equilibration concentration at the supplied conditions in mg/L of oxygen.

Author(s)

Luke A Winslow

References

Colt, John. 1 - Solubility of Atmospheric Gases in Freshwater. In Computation of Dissolved Gas Concentration in Water as Functions of Temperature, Salinity and Pressure (Second Edition), edited by John Colt, 1-71. London: Elsevier, 2012. http://www.sciencedirect.com/science/article/pii/B9780124159167000012.

Garcia, H., and L. Gordon (1992), Oxygen solubility in seawater: Better fitting equations, Limnol. Oceanogr., 37(6).

Benson, B. B. & Krause, D. (1984). The concentration and isotopic fractionation of oxygen dissolved in freshwater and seawater in equilibrium with the atmosphere. Limnology and Oceanography, 29(3), 620-632. doi:10.4319/lo.1984.29.3.0620

Staehr, Peter A., Darren Bade, Matthew C. Van de Bogert, Gregory R. Koch, Craig Williamson, Paul Hanson, Jonathan J. Cole, and Tim Kratz. Lake Metabolism and the Diel Oxygen Technique: State of the Science. Limnology and Oceanography: Methods 8, no. 11 (November 1, 2010): 628-44. doi:10.4319/lom.2010.8.0628

USGS. New Tables of Dissolved Oxygen Saturation Values. Quality of Water Branch, 1981. http://water.usgs.gov/admin/memo/QW/qw81.11.html.

USGS. New Tables of Dissolved Oxygen Saturation Values; Amendment of Quality of Water Technical Memorandum No. 81.11. Quality of Water Branch, 1981. http://water.usgs.gov/admin/memo/QW/qw81.15.html.

USGS. Change to Solubility Equations for Oxygen in Water. Technical Memorandum 2011.03. USGS Office of Water Quality, 2011.

Weiss, R. (1970). The solubility of nitrogen, oxygen and argon in water and seawater. Deep Sea Research and Oceanographic Abstracts, 17(4), 721-735. doi:10.1016/0011-7471(70)90037-9

See Also

water.density, o2.at.sat.base

Examples

temp.range = 1:25
sal.range = 1:25

par(mfrow=c(1,2))
plot(temp.range, o2.at.sat.base(temp.range), xlab='Temperature (C)',
ylab='Oxygen Saturation (mg/L)')
plot(o2.at.sat.base(rep(20,25), salinity=sal.range), xlab='Salinity (PSU)', ylab='')