sulfide (H 2 S) can “poison” the electrodes, decreasing the
response to oxygen concentrations. In more recent years,
a luminescent technique has become commercially available using a sensor called an optode with a membrane
impregnated with a dye which emits red light frequencies
when excited by a blue laser. Both the intensity and duration (lifetime) of the fluorescence signal are affected by
temperature and are quenched by DO in a linear response
at low to mid saturation levels. Because of this, temperature
measurements of high precision are required. This method
has a number of advantages, including less interference
from H 2 S and biofouling and greater sensitivity under low
DO conditions since oxygen concentration decreases the
fluorescence response, so the strongest signal occurs under
anoxic conditions. However, at high saturation values, the
response is more complex and requires a complex polynomial relationship between DO, temperature, and the fluorescence signal. The dye can degrade over time and so
requires membrane replacement at set intervals (Mitchell,
2006; YSI, 2009). Some sensors measure the intensity,
while others measure the lifetime of the emitted signal.
Summary
Dissolved oxygen (DO) is the amount of elemental oxygen
(Chemical symbol O 2 , molecular wt 31.99 g/mol) dissolved
in fresh or salt waters. It is measured as mg/L or ml/L for
environmental regulatory purposes but is usually measured
in uMol for chemical and oceanographic studies. The maximum amount of DO in water at equilibrium with the atmosphere (100 % saturation) depends on the atmospheric
pressure (partial pressure) of oxygen and the temperature
and salinity of the water. As temperature and salinity
increase, dissolved oxygen saturation decreases, while
increases in atmospheric pressure increase saturation concentration. Dissolved oxygen concentration is not conservative and is strongly affected by biological processes
such as photosynthesis and respiration.
Bibliography
APHA American Public Health Association, 2005. Standard
Methods for the Examination of Water and Wastewater,
21st edn. Washington, DC: American Public Health Association,
American Water Works Association, and Water Environment
Federation, pp. 4–136. 137.
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.
Broenkow, W. W., and Cline, J. D., 1969. Colorimetric determination of dissolved oxygen at low concentration. Limnology and
Oceanography, 14, 450–454.
Carpenter, J. H., 1965. The Chesapeake Bay Institute technique for
the Winkler dissolved oxygen method. Limnology and Oceanography, 10, 141–143.
Clark, H. A., 1959. Patent no. 2913386.
Eutech Instruments Pte Ltd., 1997. Tech-tips16. Dissolved oxygen
electrodes. Accessed May 30, 2013 from: http://www.
eutechinst.com/tips/do/04.pdf.
García, H. E., and Gordon, L. I., 1992. Oxygen solubility in sea
water: better fitting equations. Limnology and Oceanography,
37, 1307–1312.
Lewis, M. E., 2006. Dissolved oxygen: U.S. Geological Survey
Techniques of Water-Resources Investigations, book 9,
chap. A6., sec. 6.2, June 2006, Accessed May 16, 2013 from:
http://water.usgs.gov/owq/FieldManual/Chapter6/6.2_contents.
html.
Mitchell, T. O., 2006. Luminescence Based Measurement of Dissolved
Oxygen in Natural Waters. Loveland, CO: HACH©Environmental. Accessed May 16, 2013 from: http://www.
hachhydromet.com/web/ott_hach.nsf/id/pa_white_papers.html.
Strickland, J. D. H., and Parsons, T. R., 1968. Determination of
dissolved oxygen. In A Practical Handbook of Seawater
Analysis. Fisheries Research Board of Canada, Bulletin,
167, pp. 71–75.
Thierry, V., Gilbert, D., Kobayashi, T., and Schmid, C., 2013.
Processing Argo OXYGEN data at the DAC level. Version 1.3,
January, 2013. available from the International Argo Program.
(http://www.argo.ucsd.edu, http://argo.jcommops.org), Accessed
May 21, 2013 from: http://www.argodatamgt.org/content/download/16300/106561/file/ARGO_oxygen_proposition_v1p3.pdf.
UNESCO, 1981. Background papers and supporting data on the
International Equation of State of Seawater 1980. UNESCO
Technical Papers in Marine Science, 38, 192.
U.S. Geological Survey, 1981. Water quality – new tables of
dissolved oxygen saturation values: Quality of Water
Branch Technical Memorandum 81.11. Accessed May 21, 2013
from: http://water.usgs.gov/admin/memo/QW/qw81.11.html.
U.S. Geological Survey, 2011. Change to solubility equations for
oxygen in water: Office of Water Quality Technical Memorandum 2011.03. Accessed May 21, 2013 from http://water.usgs.
gov/admin/memo/QW/qw11.03.pdf.
U.S. Geological Survey, 2013. DO Tables: on line software.
Accessed May 21, 2013 from: http://water.usgs.gov/software/
lists/geochemical.
Weiss, R. F., 1970. The solubility of nitrogen, oxygen and argon in
water and seawater. Deep-Sea Research, 17, 721–735.
White, A. F., Peterson, M. L., and Solbau, R. D., 1990. Measurement and interpretation of low levels of dissolved oxygen in
ground water. Ground Water, 28, 584–590.
Winkler, L. W., 1888. Die bestimmung des in wasser gelösten
sauerstoffen. Berichte der Deutschen chemischen gesellschaft,
21, 2843–2855.
Wong, G. T. F., and Kuo-Yuan, L., 2009. Winkler’s method overestimates dissolved oxygen in seawater: iodate interference and its
oceanographic implications. Marine Chemistry, 115, 86–91.
YSI Inc., 2009. The Dissolved Oxygen Handbook: A Practical
Guide to Dissolved Oxygen Measurements. W39 0909
76 pp. Available at http://blog.ysi.com/definitive-dissolved-oxygen-handbook.
Cross-references
Aerobic Environments
Anaerobic Environments
Ecological Monitoring
Estuarine Total Ecosystem Metabolism
Eutrophication
Halocline
Microbial Degradation
Oxygen Depletion
Water Quality
Well-Mixed Estuary
DISSOLVED OXYGEN
203
response to oxygen concentrations. In more recent years,
a luminescent technique has become commercially available using a sensor called an optode with a membrane
impregnated with a dye which emits red light frequencies
when excited by a blue laser. Both the intensity and duration (lifetime) of the fluorescence signal are affected by
temperature and are quenched by DO in a linear response
at low to mid saturation levels. Because of this, temperature
measurements of high precision are required. This method
has a number of advantages, including less interference
from H 2 S and biofouling and greater sensitivity under low
DO conditions since oxygen concentration decreases the
fluorescence response, so the strongest signal occurs under
anoxic conditions. However, at high saturation values, the
response is more complex and requires a complex polynomial relationship between DO, temperature, and the fluorescence signal. The dye can degrade over time and so
requires membrane replacement at set intervals (Mitchell,
2006; YSI, 2009). Some sensors measure the intensity,
while others measure the lifetime of the emitted signal.
Summary
Dissolved oxygen (DO) is the amount of elemental oxygen
(Chemical symbol O 2 , molecular wt 31.99 g/mol) dissolved
in fresh or salt waters. It is measured as mg/L or ml/L for
environmental regulatory purposes but is usually measured
in uMol for chemical and oceanographic studies. The maximum amount of DO in water at equilibrium with the atmosphere (100 % saturation) depends on the atmospheric
pressure (partial pressure) of oxygen and the temperature
and salinity of the water. As temperature and salinity
increase, dissolved oxygen saturation decreases, while
increases in atmospheric pressure increase saturation concentration. Dissolved oxygen concentration is not conservative and is strongly affected by biological processes
such as photosynthesis and respiration.
Bibliography
APHA American Public Health Association, 2005. Standard
Methods for the Examination of Water and Wastewater,
21st edn. Washington, DC: American Public Health Association,
American Water Works Association, and Water Environment
Federation, pp. 4–136. 137.
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.
Broenkow, W. W., and Cline, J. D., 1969. Colorimetric determination of dissolved oxygen at low concentration. Limnology and
Oceanography, 14, 450–454.
Carpenter, J. H., 1965. The Chesapeake Bay Institute technique for
the Winkler dissolved oxygen method. Limnology and Oceanography, 10, 141–143.
Clark, H. A., 1959. Patent no. 2913386.
Eutech Instruments Pte Ltd., 1997. Tech-tips16. Dissolved oxygen
electrodes. Accessed May 30, 2013 from: http://www.
eutechinst.com/tips/do/04.pdf.
García, H. E., and Gordon, L. I., 1992. Oxygen solubility in sea
water: better fitting equations. Limnology and Oceanography,
37, 1307–1312.
Lewis, M. E., 2006. Dissolved oxygen: U.S. Geological Survey
Techniques of Water-Resources Investigations, book 9,
chap. A6., sec. 6.2, June 2006, Accessed May 16, 2013 from:
http://water.usgs.gov/owq/FieldManual/Chapter6/6.2_contents.
html.
Mitchell, T. O., 2006. Luminescence Based Measurement of Dissolved
Oxygen in Natural Waters. Loveland, CO: HACH©Environmental. Accessed May 16, 2013 from: http://www.
hachhydromet.com/web/ott_hach.nsf/id/pa_white_papers.html.
Strickland, J. D. H., and Parsons, T. R., 1968. Determination of
dissolved oxygen. In A Practical Handbook of Seawater
Analysis. Fisheries Research Board of Canada, Bulletin,
167, pp. 71–75.
Thierry, V., Gilbert, D., Kobayashi, T., and Schmid, C., 2013.
Processing Argo OXYGEN data at the DAC level. Version 1.3,
January, 2013. available from the International Argo Program.
(http://www.argo.ucsd.edu, http://argo.jcommops.org), Accessed
May 21, 2013 from: http://www.argodatamgt.org/content/download/16300/106561/file/ARGO_oxygen_proposition_v1p3.pdf.
UNESCO, 1981. Background papers and supporting data on the
International Equation of State of Seawater 1980. UNESCO
Technical Papers in Marine Science, 38, 192.
U.S. Geological Survey, 1981. Water quality – new tables of
dissolved oxygen saturation values: Quality of Water
Branch Technical Memorandum 81.11. Accessed May 21, 2013
from: http://water.usgs.gov/admin/memo/QW/qw81.11.html.
U.S. Geological Survey, 2011. Change to solubility equations for
oxygen in water: Office of Water Quality Technical Memorandum 2011.03. Accessed May 21, 2013 from http://water.usgs.
gov/admin/memo/QW/qw11.03.pdf.
U.S. Geological Survey, 2013. DO Tables: on line software.
Accessed May 21, 2013 from: http://water.usgs.gov/software/
lists/geochemical.
Weiss, R. F., 1970. The solubility of nitrogen, oxygen and argon in
water and seawater. Deep-Sea Research, 17, 721–735.
White, A. F., Peterson, M. L., and Solbau, R. D., 1990. Measurement and interpretation of low levels of dissolved oxygen in
ground water. Ground Water, 28, 584–590.
Winkler, L. W., 1888. Die bestimmung des in wasser gelösten
sauerstoffen. Berichte der Deutschen chemischen gesellschaft,
21, 2843–2855.
Wong, G. T. F., and Kuo-Yuan, L., 2009. Winkler’s method overestimates dissolved oxygen in seawater: iodate interference and its
oceanographic implications. Marine Chemistry, 115, 86–91.
YSI Inc., 2009. The Dissolved Oxygen Handbook: A Practical
Guide to Dissolved Oxygen Measurements. W39 0909
76 pp. Available at http://blog.ysi.com/definitive-dissolved-oxygen-handbook.
Cross-references
Aerobic Environments
Anaerobic Environments
Ecological Monitoring
Estuarine Total Ecosystem Metabolism
Eutrophication
Halocline
Microbial Degradation
Oxygen Depletion
Water Quality
Well-Mixed Estuary
DISSOLVED OXYGEN
203