CAUSES OF GAS BUBBLE DISEASE
From: Nancy Lightowler nlightowler@lbaop.org
To: aqua-l@killick.ifmt.nf.ca
Sent: February 23, 2000
QUESTION:
I always thought that gas bubble disease was caused by nitrogen. But
recently I read that supersaturation of water from plants (photosynthesis)
can also cause the disease? Can anyone explain?
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COMMENTS 1:
Nitrogen is the more common cause of gas bubble disease but we
do see it with oxygen on occasion. I once had a catfish fingerling
pond with dissolved oxygen levels constantly above 15 mg/l for
12-14 days caused by a dense green-algae bloom (Closterium sp).
These fish had small gas bubbles visible in their fins and were
beginning to die. We ran our well and knocked the DO level down
to 8 ppm (near saturation in this case) and they recovered. In live-
haul trucks where oxygen is used to transport fish for long
distances this oxygen super saturation can also occur if the tanks
have no vents to let the excess gas out. Any time you heat water
in a closed system with gases present you run the risk of gas
saturation in the outflow. Sometimes we find well heads with small
leaks in the system and air is pulled in like a venturi effect and
then
pumped under pressure causing gas saturation. I hope this
answers some of your question. Of course deep wells are
particular suspects for nitrogen saturation as are waters released
from dams near the bottom of a reservoir.
This publication deals with solving gas saturation problems in
channel catfish hatcheries that use deep well water:
http://agpublications.tamu.edu/pubs/efish/191fs.pdf
Jim Steeby
Area Extension Agent/Aquaculture
Mississippi State University Extension Service
P.O.BOX 239
Belzoni, MS 39038, USA
Tel. +601 247 2915
Fax +601 247 3823
email:jsteeby@ext.msstate.edu
http://www2.msstate.edu/~jas17/index.html
http://www.msstate.edu/dept/tcnwac
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COMMENTS 2:
Nitrogen is generally the suspect gas in supersaturation. Oxygen, if
moderately supersatured, does not seem to cause problems because it
is a gas that the fishes body can utilise. When it is present in such
large
amounts, that it surpasses what a fish can handle (greater than 125%
as per Noga, 1996), the same pathologies can result. I hope this somewhat
simplistic explanation is helpful.
F. Carl Uhland, DVM
Faculté de Médecine Vétérinaire
Université de Montréal
3200 rue Sicotte
Saint-Hyancinthe (Québec) J2S 7C6
Tel. 450 773 8521 (ext. 8317)
Fax 450 778 8116
uhlandf@MEDVET.UMontreal.CA
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COMMENTS 3:
My impression is that gas bubble disease can be caused by a variety of
gases, if the water is oversaturated or supersaturated with any of
them.
A common problem is air getting sucked into water supply lines,
taking the total gas saturation above 100%. When it gets to around 110%
many organisms show symptoms. More sensitive ones show them at various
points in between.
Will Borgeson
wdborgeson@ucdavis.edu
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COMMENTS 4:
It is more common for gas bubble disease to be caused by nitrogen,
however it can also occur with oxygen if the oxygen levels are very
high, or if the concentration suddenly increases in the water.
Howard
Dryden Aqua Ltd
Butlerfield, Bonnyrigg,
Edinburgh EH19 3JQ, Scotland, UK
Tel. + 44(0187) 58 22222
Fax +44 (0187) 58 22229
e-mail howard@DrydenAqua.com
e-mail sale@DrydenAqua.com
http://www.DrydenAqua.com
http://www.ozone.co.uk
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COMMENTS 5:
GBD is normally caused by nitrogen because of the greater proportion of
N2 in the atmosphere (air) compared with O2... animals obviously
metabolise O2, so its not usually a problem. Also N2 is less soluble than
O2. Plants obviously do produce O2 but I have never seen it in large
enough quantities to cause serious supersaturation problems (ie >107%).
Interestingly sometimes GBD does occur during fish transport where high
levels of O2 are used, and couple this with high CO2 can cause problems
for fish. Saying all of this I remember during some of my PhD having
a gas equilibration column near a window with algae growing in it and
doing respiratory experiments looking at water and blood gases of fish and
seeing changes in both water and blood PO2 as the sun came out...however
we are talking perhaps changes of upto about 5 mm Hg.
Dr. Mark Powell
Lecturer,
School of Aquaculture
University of Tasmania,
Locked Bag 1-370
Launceston, Tasmania, Australia 7250
Tel. +61 3 63243813
Fax +61 3 63243804
e-mail: Mark.Powell@utas.edu.au
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COMMENTS 6:
Gas bubble disease is caused by an excess of gases (supersaturation). It
just so happens that nitrogen is the largest gaseous component in water
that is in equilibrium with the atmosphere. For this reason it has been
traditionally identified as the main causal factor in gas bubble
disease. However if any single gaseous component becomes supersaturated to
the point where the total gas pressure of the water is beyond what the
particular species will tolerate, it makes little difference what the
individual components of gas are. So yes, photosynthesis can cause gas
bubble disease, as can large reductions in pressure or increases in
temperature.
Gintas Kamaitis,
Aquaculture Innovations Inc., Consulting Services
gkamaitis@sympatico.ca
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COMMENTS 7:
It's total gas pressure in the tissue. In the case of large fish,
the hemoglobin system controls the O2 partial pressure except in the
rays of the fins were the diffusion rate from the water can control.
In the case of larval fish, the O2 diffuses through them so fast that
the partial pressures in the tissue are almost the same as the water
and you can kill them with gas bubble disease.
Dallas E. Weaver, Ph.D.
deweaver@gte.net
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COMMENTS 8:
The bubble disease occurred in your fish, may be caused by
supersaturation of oxygen. We have experienced this in glass eel and
grouper fry culture in indoor recirculating systems under a missing
control of oxygen controller and air suction in the inlet of a pump.
Dr. Kuo-Feng Tseng
Department of Aquaculture,
National Taiwan Ocean University,
Keelung, 202, Taiwan, R.O.C.
e-mail: kftseng@ntou66.ntou.edu.tw
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COMMENTS 9:
In 1975 I was involved in the research by the USEPA on gas bubble
disease in the Columbia River. We studied individual gas components, ie,
oxygen and nitrogen and their effects on fish.
Two references: Nebeker, AV, AK Hauck, and FD Baker. 1979.
Temperature and oxygen/nitrogen gas rations affect fish survival in
air-supersaturated water.
(pp. 299-303. In: Water Research, vol 13. Pergamon Press, UK).
Nebeker, AV, GR Bouck and DG Stevens. 1976. Carbon dioxide and
oygen/nitrogen rations as factors affecting salmon survival in
air-supersaturated water. (Trans. Amer. Fish. Soc. 105: 425-9)
In short, the findings were:
CO2 gas at levels from 1.7-22.0 mg/l did not affect survival of
salmonids held in constant gas supersaturated water levels.
We also experimented with the N2/O2 ratios and found that mortalities
decreased significantly when the ratio of O2/N2 was increased
(increase in O2, decrease in N2) at a constant total percent saturation.
However, much more extensive and severe signs and lesions of gas bubble
disease appear at high O2/N2 ratios. Also, although oxygen appeared to
play a significant role in the formation of external emphysema, death
occurs sooner with low O2/N2,
indicating that nitrogen is the more lethal of the two gases. The
final
conclusion was that total gas saturation is a more important
consideration than individual gas levels, since fish mortalities from gas
bubble disease will not occur unless the total dissolved gas saturation
exceeds 100%, regardless of O2/N2 ratios.
Kent Hauck
Fish Pathologist
agmain.khauck@state.ut.us
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COMMENTS 10:
Gas supersaturation can also occur when cold water is heated in a closed
heat exchanger. I learned this the hard way! I had no way of
measuring total dissolved gasses or dissolved N, but oxygen
supersaturation was confirmed through Winkler titration. The simple
solution was to allow water to trickle over plastic media before entering
the head tank.
Water 'spread out' over the media, allowing plenty of surface area
for
gas exchange. I also kept water in the head tank rolling with lots of
airstones. Problem solved.
Laurel Ramseyer
lramseye@clam.mi.nmfs.gov