2810 Revis editoriales 2011

2810 DISSOLVED GAS SUPERSATURATION*
2810 A. Introduction
Water can become supersaturated with atmospheric gases by
various means, heating and air entrainment in spilled or pumped
water being the most common. The primary sign of gas super-
saturation is the formation of bubbles on submerged surfaces or
within the vascular systems and tissues of aquatic organisms.
Gas supersaturation can limit aquatic life and interfere with
water treatment processes. Levels of supersaturation lethal to
aquatic organisms have been found in springs, rivers, wells,
lakes, estuaries, and seawater. Gas supersaturation can be pro-
duced in pumped or processed water intended for drinking, fish
hatchery supply, and laboratory bioassays. Seasonal and other
temporal variations in supersaturation may occur in surface
waters as a result of solar heating and photosynthesis. Because
the rate of equilibration may be slow, supersaturation may persist
in flowing water for days and excessive dissolved gas levels thus
may persist far from the source of supersaturation.
Gas bubbles form only when the total dissolved gas pressure
is greater than the sum of compensating pressures. Compensat-
ing pressures include water, barometric and, for organisms,
tissue or blood pressure. The total dissolved gas pressure is equal
to the sum of the partial pressures of all the dissolved gases,
including water vapor. Typically, only nitrogen, oxygen, argon,
carbon dioxide, and water vapor pressures need to be considered
in most natural waters. Gas bubble disease, of fish or other
aquatic organisms, is a result of excessive uncompensated gas
pressure. A single supersaturated gas such as oxygen or nitrogen
may not necessarily result in gas bubble disease because bubble
formation depends largely on total dissolved gas pressure. The
degree of gas saturation should be described in terms of pres-
sures rather than concentration or volume units.
2810 B. Direct-Sensing Membrane-Diffusion Method
1. General Discussion
a. Principle: This method requires an instrument with a variable
length of “gas permeable” tubing, connected to a pressure-measur-
ing device. Dimethyl silicone rubber tubing often is used because it
is highly permeable to dissolved gases, including water vapor. At
steady state, the gauge pressure inside the tubing is equal to the
difference in gas pressure (⌬P) between the total dissolved gas
pressure and the ambient barometric pressure. When the water is in
equilibrium with the atmosphere, ⌬Pequals zero. If ⌬Pis greater
than zero, the water is supersaturated. Conversely, if ⌬Pis negative
the water is undersaturated.
b. Working range: The working range of this method depends
on the pressure-sensing device used, but typically will range
from ⫺150 to ⫹600 mm Hg. Dissolved solids in wastewater will
not interfere with this method. The practical depth range for
these instruments is 1 to 10 m.
2. Apparatus
Several types of membrane-diffusion instruments are available
commercially.* Alternatively, construct a unit from commer-
cially available parts. Several units have been described, includ-
ing a direct-reading instrument using pressure transducers and a
digital readout,
1
an on-line unit that can activate an alarm sys-
tem,
2
and an early model of the Weiss saturometer.
3
Each of
these units has specific advantages and limitations; the instru-
ment of choice will depend on the specific application. All these
instruments are portable so that data collection is completed in
the field.
Test the instrument for leaks according to the manufacturer’s
recommendation. Even a very small leak, difficult to detect and
locate, will result in useless data. Calibrate the pressure-measuring
device with a mercury manometer or certified pressure gauge. If a
manometer is used, include fresh mercury that flows freely in the
tubing. An alternative method for directly testing membrane-diffu-
sion instruments in a small, closed chamber where induced ⌬P
levels can be compared against observed ⌬Plevels is available.
2
Van Slyke-Neill
4
or gas chromatography methods
1
are inap-
propriate for calibration but they may be used to verify results.
These methods measure individual gas concentrations and re-
quire further conversion to ⌬Por partial pressure and suffer from
sampling and sample handling problems.
5–7
3. Procedure
At the start of each day, test the instrument for leaks and recali-
brate. At a monitoring site, completely submerge the sensing ele-
ment in the water, preferably below the hydrostatic compensation
depth. This is the depth where the hydrostatic and total gas pressures
are equal and as a result, bubbles will not form on the tubing.
Bubble formation on the silicone rubber tubing seriously reduces
accuracy. Compute hydrostatic compensation depth
5
as follows:
Z⫽⌬P
73.42
* Approved by Standard Methods Committee, 2010. Editorial revisions, 2011.
Joint Task Group: 20th Edition—John E. Colt (chair), Larry E. Fidler, John O.
Jensen, John W. Sweeney, Barnaby J. Watten.
* Common Sensing, Clark Fork, ID; Eco Enterprises, Seattle, WA; Novatech,
Vancouver, BC, Canada; and Sweeney Aquametrics, Stony Creek, CT.
1

where:
Z⫽hydrostatic compensation depth, m, and
⌬P⫽pressure difference between total dissolved gas pressure
and the ambient barometric pressure, mm Hg.
The factor 73.42 is the hydrostatic pressure of fresh water at
20°C expressed in terms of mm Hg/m water depth. Because the
variation of hydrostatic pressure with temperature and salinity is
small, this equation can be used for all natural waters.
Dislodge formed bubbles on the tubing by gently striking the
instrument or moving the instrument rapidly in the water. Move-
ment of water across the silicone rubber tubing also facilitates
establishing the equilibrium between gas pressure in the water
and in the tubing.
Operate the instrument “bubble free” until a stable ⌬Pis
observed. This may take from 5 to 30 min, depending on the ⌬P,
water temperature, water flow, and geometry of the system. The
time response of the membrane-diffusion method is shown in
Figure 2810:1 for “bubble-free” and “bubble” conditions.
If the instrument is used in heavily contaminated water con-
taining oil or other organic compounds, clean the silicone tubing
with a mild detergent according to the manufacturer’s instruc-
tions. Silicone rubber tubing has been used in uncontaminated
natural water for at least eight years without being adversely
affected by attached algal growth.
2
The tubing can be damaged
by abrasive grit, diatoms, biting aquatic organisms, certain or-
ganic compounds, and strong acids.
2
Obtain the barometric pressure with each measurement by
using a laboratory mercury barometer, a calibrated portable
barometer, or pressure transducer. Barometric pressures reported
by weather agencies (or airports) are corrected to sea level and
are unusable.
4. Calculation
a. Total gas pressure: Preferably report total gas pressure as
⌬P.
2,6,8
Express pressure as millimeters of mercury.
Total gas pressure also has been reported as a percentage of
local barometric pressure:
TGP % ⫽
冋
P
b
⫹⌬P
P
b
册
⫻100
where:
P
b
⫽true local barometric pressure, mm Hg.
The reporting of total gas pressure as a percentage is not
encouraged.
8
b. Component gas pressures: When information on compo-
nent gas supersaturation is needed, express data as partial pres-
sures, differential pressures, or percent saturation.
5,8
This re-
quires additional measurements of dissolved oxygen, tempera-
ture, and salinity† at the monitoring site. In a mixture of gases in
a given volume, the partial pressure of a gas is the pressure that
this gas would exert if it were the only gas present.
1) Oxygen partial pressure—Calculate partial pressure of ox-
ygen as follows:
P
O
2
⫽DO
␤
O
2
⫻0.5318
where:
P
O
2
⫽partial pressure of dissolved oxygen, mm Hg,
␤
O
2
⫽Bunsen coefficient for oxygen (Table 2810:I), L/(L 䡠atm), and
DO ⫽measured concentration of oxygen, mg/L.
Bunsen coefficients for marine waters are available.
5
The
factor 0.5318 equals 760/(1000 K), where Kis the ratio of
molecular weight to molecular volume for oxygen gas.
5
2) Nitrogen partial pressure—Estimate the partial pressure of
nitrogen by subtracting the partial pressures of oxygen and water
vapor from the total gas pressure.
P
N
2
⫽P
b
⫹⌬P⫺P
O
2
⫺P
H
2
O
where:
P
H
2
O
⫽vapor pressure of water in mm Hg from Table 2810:II.
This term includes a small contribution from argon and any
other gases present, including carbon dioxide and methane. The
partial pressure of carbon dioxide is negligible in natural waters
of pH ⬎7.0.
3) Nitrogen:oxygen partial pressure ratio—The ratio of the
partial pressure of nitrogen to the partial pressure of oxygen
(N
2
:O
2
) characterizes the relative contribution of the two gases
to the total dissolved gas pressure. In water in equilibrium with
air, this ratio is 3.77.
c. Differential pressures: The differential pressure of a gas is
the difference between the partial pressures of that gas in water
and air. The oxygen differential pressure may be calculated as
⌬P
O
2
⫽P
O
2
⫺0.20946(P
b
⫺P
H
2
O
)
and the nitrogen differential pressure as
⌬P
N
2
⫽⌬P⫺⌬P
O
2
† Methods for these variables may be found in Sections 4500-O, 2550, and 2520,
respectively.
Figure 2810:1 Time response for the membrane-diffusion method.
DISSOLVED GAS SUPERSATURATION (2810)/Membrane-Diffusion Method
2
DISSOLVED GAS SUPERSATURATION (2810)/Membrane-Diffusion Method

d. Percent of saturation: In older literature, supersaturation
values have been reported as percent saturation. This method of
reporting component gases is discouraged but can be calculated
as follows:
N
2
(%) ⫽
冋
P
N
2
0.7902 (P
b
⫺P
H
2
O
)
册
⫻100
O
2
共%兲⫽
冋
P
O
2
0.20946(P
b
⫺P
H
2
O
)
册
⫻100
The following relationships are useful conversions:
TGP(%) ⫽0.20946 O
2
(%) ⫹0.7902 N
2
(%)
⌬P⫽0.20946
冋
O
2
(%)
100 ⫺1
册
[P
b
⫺P
H
2
O
]
⫹0.7902
冋
N
2
(%)
100 ⫺1
册
[P
b
⫺P
H
2
O
]
⌬P⫽DO
␤
O
2
(0.5318)(1 ⫹N
2
:O
2
)⫺(P
b
⫺P
H
2
O
)
Use care with these relationships with older data because both
TGP(%) and N
2
(%) have been differently defined.
5
TABLE 2810:I. BUNSEN COEFFICIENT FOR OXYGEN IN FRESH WATER
Temperature
°C
Bunsen Coefficient at Given Temperature (to nearest 0.1°C)
L real gas at STP/(L 䡠atmosphere)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
0 0.04914 0.04901 0.04887 0.04873 0.04860 0.04847 0.04833 0.04820 0.04807 0.04793
1 0.04780 0.04767 0.04754 0.04741 0.04728 0.04716 0.04703 0.04680 0.04678 0.04665
2 0.04653 0.04640 0.04628 0.04615 0.04603 0.04591 0.04579 0.04567 0.04555 0.04543
3 0.04531 0.04519 0.04507 0.04495 0.04484 0.04472 0.04460 0.04449 0.04437 0.04426
4 0.04414 0.04403 0.04392 0.04381 0.04369 0.04358 0.04347 0.04336 0.04325 0.04314
5 0.04303 0.04292 0.04282 0.04271 0.04260 0.04250 0.04239 0.04229 0.04218 0.04206
6 0.04197 0.04187 0.04177 0.04166 0.04156 0.04146 0.04136 0.04126 0.04116 0.04106
7 0.04096 0.04086 0.04076 0.04066 0.04056 0.04047 0.04037 0.04027 0.04018 0.04008
8 0.03999 0.03989 0.03980 0.03971 0.03961 0.03952 0.03943 0.03933 0.03924 0.03915
9 0.03906 0.03897 0.03888 0.03879 0.03870 0.03861 0.03852 0.03843 0.03835 0.03826
10 0.03817 0.03809 0.03800 0.03791 0.03783 0.03774 0.03766 0.03757 0.03749 0.03741
11 0.03732 0.03724 0.03716 0.03707 0.03699 0.03691 0.03683 0.03675 0.03667 0.03659
12 0.03651 0.03643 0.03635 0.03627 0.03619 0.03611 0.03604 0.03596 0.03588 0.03581
13 0.03573 0.03565 0.03558 0.03550 0.03543 0.03535 0.03528 0.03520 0.03513 0.03505
14 0.03498 0.03491 0.03448 0.03476 0.03469 0.03462 0.03455 0.03448 0.03441 0.03433
15 0.03426 0.03419 0.03412 0.03406 0.03399 0.03392 0.03385 0.03378 0.03371 0.03364
16 0.03358 0.03351 0.03344 0.03338 0.03331 0.03324 0.03318 0.03311 0.03305 0.03298
17 0.03292 0.03285 0.03279 0.03272 0.03266 0.03260 0.03253 0.03247 0.03241 0.03235
18 0.03228 0.03222 0.03216 0.03210 0.03204 0.03198 0.03192 0.03186 0.03180 0.03174
19 0.03168 0.03162 0.03156 0.03150 0.03144 0.03138 0.03132 0.03126 0.03121 0.03115
20 0.03109 0.03103 0.03098 0.03092 0.03086 0.03081 0.03075 0.03070 0.03064 0.03059
21 0.03053 0.03048 0.03042 0.03037 0.03031 0.03026 0.03020 0.03015 0.03010 0.03004
22 0.02999 0.02994 0.02989 0.02983 0.02978 0.02973 0.02968 0.02963 0.02958 0.02952
23 0.02947 0.02942 0.02937 0.02932 0.02927 0.02922 0.02917 0.02912 0.02907 0.02902
24 0.02897 0.02893 0.02888 0.02883 0.02878 0.02873 0.02868 0.02864 0.02859 0.02854
25 0.02850 0.02845 0.02840 0.02835 0.02831 0.02826 0.02822 0.02817 0.02812 0.02808
26 0.02803 0.02799 0.02794 0.02790 0.02785 0.02781 0.02777 0.02772 0.02768 0.02763
27 0.02759 0.02755 0.02750 0.02746 0.02742 0.02737 0.02733 0.02729 0.02725 0.02720
28 0.02716 0.02712 0.02708 0.02704 0.02700 0.02695 0.02691 0.02687 0.02683 0.02679
29 0.02675 0.02671 0.02667 0.02663 0.02659 0.02655 0.02651 0.02647 0.02643 0.02639
30 0.02635 0.02632 0.02628 0.02624 0.02620 0.02616 0.02612 0.02609 0.02605 0.02601
31 0.02597 0.02594 0.02590 0.02586 0.02582 0.02579 0.02575 0.02571 0.02568 0.02564
32 0.02561 0.02557 0.02553 0.02550 0.02546 0.02543 0.02539 0.02536 0.02532 0.02529
33 0.02525 0.02522 0.02518 0.02515 0.02511 0.02508 0.02504 0.02501 0.02498 0.02494
34 0.02491 0.02488 0.02484 0.02481 0.02478 0.02474 0.02471 0.02468 0.02465 0.02461
35 0.02458 0.02455 0.02452 0.02448 0.02445 0.02442 0.02439 0.02436 0.02433 0.02429
36 0.02426 0.02423 0.02420 0.02417 0.02414 0.02411 0.02408 0.02405 0.02402 0.02399
37 0.02396 0.02393 0.02390 0.02387 0.02384 0.02381 0.02378 0.02375 0.02372 0.02369
38 0.02366 0.02363 0.02360 0.02358 0.02355 0.02352 0.02349 0.02346 0.02343 0.02341
39 0.02338 0.02335 0.02332 0.02329 0.02327 0.02324 0.02321 0.02318 0.02316 0.02313
40 0.02310 0.02308 0.02305 0.02302 0.02300 0.02297 0.02294 0.02292 0.02289 0.02286
Based on Benson and Krause.
9,10
␤ ⫽9.9902 ⫻10
⫺4
[exp(9.7265 ⫺5.26895 ⫻10
3
/T⫹1.00417 ⫻10
6
/T
2
)], where T⫽273.15 ⫹°C.
DISSOLVED GAS SUPERSATURATION (2810)/Membrane-Diffusion Method
3
DISSOLVED GAS SUPERSATURATION (2810)/Membrane-Diffusion Method

5. Quality Control
The quality control practices considered to be an integral part
of each method are summarized in Tables 2020:I and II.
The precision of the membrane-diffusion method depends
primarily on the pressure-sensing instrument. For an experienced
operator it is approximately ⫾1 to 2 mm Hg with an accuracy of
⫾3to5mmHg.
3,6
Air leaks, bubble formation, biofilm devel-
opment, incomplete equilibration, or condensation produce neg-
ative errors while direct water leaks can result in positive errors
in submersible units.
For accurate work, measure water temperature to the nearest
⫾0.1°C.
6. Reporting of Results
In reporting results, include the following data:
• Sensor depth, m,
• Barometric pressure, mm Hg,
• Water temperature, °C,
• Dissolved oxygen, mm Hg or mg/L,
• Salinity, g/kg, and
•⌬P,mmHg.
If component gas information is needed add:
• Partial pressure of oxygen, mm Hg,
• Partial pressure of nitrogen, mm Hg, and
TABLE 2810:II. VAPOR PRESSURE OF FRESH WATER
Temperature
°C
Vapor Pressure at Given Temperature (to nearest 0.1°C)
mm Hg
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
0 4.58 4.61 4.64 4.68 4.71 4.75 4.78 4.82 4.85 4.89
1 4.92 4.96 4.99 5.03 5.07 5.10 5.14 5.18 5.21 5.25
2 5.29 5.33 5.36 5.40 5.44 5.48 5.52 5.56 5.60 5.64
3 5.68 5.72 5.76 5.80 5.84 5.88 5.92 5.97 6.01 6.05
4 6.09 6.14 6.18 6.22 6.27 6.31 6.36 6.40 6.44 6.49
5 6.54 6.58 6.63 6.67 6.72 6.77 6.81 6.86 6.91 6.96
6 7.01 7.05 7.10 7.15 7.20 7.25 7.30 7.35 7.40 7.45
7 7.51 7.56 7.61 7.66 7.71 7.77 7.82 7.87 7.93 7.98
8 8.04 8.09 8.15 8.20 8.26 8.31 8.37 8.43 8.48 8.54
9 8.60 8.66 8.72 8.87 8.84 8.89 8.95 9.02 9.08 9.14
10 9.20 9.26 9.32 9.39 9.45 9.51 9.58 9.64 9.70 9.77
11 9.83 9.90 9.97 10.03 10.10 10.17 10.23 10.30 10.37 10.44
12 10.51 10.58 10.65 10.72 10.76 10.86 10.93 11.00 11.07 11.15
13 11.22 11.29 11.37 11.44 11.52 11.59 11.67 11.74 11.82 11.90
14 11.98 12.05 12.13 12.21 12.29 12.37 12.45 12.53 12.61 12.69
15 12.78 12.86 12.94 13.05 13.11 13.19 13.28 13.36 13.45 13.54
16 13.62 13.71 13.80 13.89 13.97 14.06 14.15 14.24 14.33 14.43
17 14.52 14.61 14.70 14.80 14.89 14.98 15.08 15.17 15.27 15.37
18 15.46 15.56 15.66 15.76 15.86 15.96 16.06 16.16 16.26 16.36
19 16.46 16.57 16.67 16.77 16.88 16.98 17.09 17.20 17.30 17.41
20 17.52 17.63 17.74 17.85 17.96 18.07 18.18 18.29 18.41 18.52
21 18.64 18.75 18.87 18.98 19.10 19.22 19.33 19.45 19.57 19.69
22 19.81 19.93 20.05 20.48 20.60 20.42 20.55 20.67 20.80 20.93
23 21.05 21.18 21.31 21.44 21.57 21.70 21.83 21.96 22.09 22.23
24 22.36 22.50 22.63 22.77 22.90 23.04 23.18 23.32 23.46 23.60
25 23.74 23.88 24.03 24.17 24.31 24.46 24.60 24.75 24.90 25.04
26 25.19 25.34 25.49 25.64 25.80 25.95 26.10 26.26 26.41 26.57
27 26.72 26.88 27.04 27.20 27.36 27.52 27.68 27.84 28.00 28.17
28 28.33 28.50 28.66 28.83 29.00 29.17 29.34 29.51 29.68 29.85
29 30.03 30.80 30.37 30.55 30.73 30.91 31.08 31.26 31.44 31.62
30 31.81 31.99 32.17 32.36 32.54 32.73 32.92 33.11 33.30 33.49
31 33.68 33.87 34.06 34.26 34.45 34.65 34.85 35.05 35.24 35.44
32 35.65 35.85 36.05 36.25 36.46 36.67 36.87 37.08 37.29 37.50
33 37.71 37.92 38.14 38.35 38.57 38.78 39.00 39.22 39.44 39.66
34 39.88 40.10 40.33 40.55 40.78 41.01 41.23 41.46 41.69 41.92
35 42.16 42.39 42.63 42.86 43.10 43.34 43.58 43.82 44.06 44.30
36 44.55 44.79 45.04 45.28 45.53 45.78 46.03 46.29 46.54 46.79
37 47.05 47.31 47.56 47.82 48.08 48.35 48.61 48.87 49.14 49.41
38 49.67 49.94 50.21 50.49 50.76 51.03 51.31 51.59 51.87 52.14
39 52.43 52.71 52.99 53.28 53.56 53.85 54.14 54.43 54.72 55.01
40 55.31 55.60 55.90 56.20 56.50 56.80 57.10 57.41 57.71 58.02
Based on an equation presented by Green and Carritt.
11
This equation is cumbersome to use. The following equation
9
is adequate for most applications:
P
H
2
O
⫽760[exp(11.8571 ⫺3,840.70/T⫺216,961/T
2
)], where T⫽273.15 ⫹°C.
5
DISSOLVED GAS SUPERSATURATION (2810)/Membrane-Diffusion Method
4
DISSOLVED GAS SUPERSATURATION (2810)/Membrane-Diffusion Method

• Nitrogen:oxygen partial pressure ratio
or
•⌬P
O
2
, mm Hg, and
•⌬P
N
2
,mmHg.
7. Interpretation of Results
The biological effects of dissolved gas supersaturation depend on the
species, age, depth in water column, length of exposure, temperature,
and nitrogen:oxygen partial pressure ratio.
12
Safe limits generally are
segregated into wild/natural circumstances, where behavior and hydro-
static pressure can modify the exposure by horizontal and vertical
movements away from dangers, and captive environments such as
aquaria, hatcheries, or laboratories, where conditions not only preclude
escape but also include other significant stresses. Of these two realms,
captive circumstances are more likely to cause illness or mortality from
gas bubble disease and will do so sooner and at the lower ⌬Plevels.
In wild/natural circumstances, the limit of safe levels of gas
supersaturation depends on the depth available to the species
and/or species behavior, but this limit usually occurs at a ⌬P
between 50 and 150 mm Hg. Under captive conditions, the ⌬P
should be as close to zero as possible. For sensitive species and
life stages, sublethal and lethal effects have been observed at ⌬P
of 10 to 50 mm Hg.
13
8. References
1. D’AOUST, B.G., R. WHITE &H.SIEBOLD. 1975. Direct measurement
of total dissolved gas partial pressure. Undersea Biomed. Res.
2:141.
2. BOUCK, G.R. 1982. Gasometer: an inexpensive device for continu-
ous monitoring of dissolved gases and supersaturation. Trans. Amer.
Fish. Soc. 111:505.
3. FICKEISEN, D.H., M.J. SCHNEIDER & J.C. MONTGOMERY. 1975. A
comparative evaluation of the Weiss saturometer. Trans. Amer.
Fish. Soc. 104:816.
4. BEININGEN, K.T. 1973. A Manual for Measuring Dissolved Ox-
ygen and Nitrogen Gas Concentrations in Water with the Van
Slyke-Neill Apparatus. Fish Commission of Oregon, Portland.
5. COLT, J. 1984. Computation of dissolved gas concentrations in water
as functions of temperature, salinity, and pressure. Spec. Publ. 14,
American Fisheries Soc., Bethesda, Md.
6. D’AOUST, B.G. & M.J.R. CLARK. 1980. Analysis of supersaturated
air in natural waters and reservoirs. Trans. Amer. Fish. Soc. 109:
708.
7. PIRIE, W.R. & W.A. HUBBERT. 1977. Assumptions in statistical
analysis. Trans. Amer. Fish. Soc. 106:646.
8. COLT, J. 1983. The computation and reporting of dissolved gas
levels. Water Res. 17:841.
9. BENSON,B.B.&D.KRAUSE. 1980. The concentration and isotopic
fractionation in freshwater in equilibrium with the atmosphere. 1.
Oxygen. Limnol. Oceanogr. 25:662.
10. BENSON,B.B.&D.KRAUSE. 1984. The concentration and isotopic
fractionation of oxygen dissolved in freshwater and seawater in
equilibrium with the atmosphere. Limnol. Oceanogr. 29:620.
11. GREEN, E.J. & D.E. CARRITT. 1967. New tables for oxygen saturation
of seawater. J. Mar. Res. 25:140.
12. WEITKAMP, D.E. & M. KATZ. 1980. A review of dissolved gas
supersaturation literature. Trans. Amer. Fish. Soc. 109:659.
13. COLT, J. 1986. The impact of gas supersaturation on the design
and operation of aquatic culture systems. Aquacult. Eng. 5:49.
DISSOLVED GAS SUPERSATURATION (2810)/Membrane-Diffusion Method
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DISSOLVED GAS SUPERSATURATION (2810)/Membrane-Diffusion Method