The application of nanobubble
technology for enhanced yields in
aquaculture production system
Henk Stander
Division of Aquaculture, Department of Animal Sciences,
Stellenbosch University
T
he metabolic rates of fish can be
severely affected by the concentration
of oxygen in a rearing environment.
Suppressed dissolved oxygen levels
leads to decreased respiration and feeding
activity that slows fish growth rates. It can
also lead to disease and fungal infections. If
correctly applied, oxygen supplementation
ensures that fish and seafood farmers can
achieve the highest possible survival rates
under optimum breeding conditions to boost
yields and profits.
The amount of any gas that can be held
in solution by water depends upon the
temperature and atmospheric pressure. It
is worth noting that whereas one litre of air
contains about 200 ml of oxygen, one litre
of water contains about 10 ml. Dissolved
oxygen concentration may also be expressed
as a percentage of the saturation value. The
amount of oxygen (as mgl -1 ) that gives 100%
saturation (ASV- Air Saturation Value) is given
by the equation:
AgriKultuur |AgriCulture
100% ASV = 468/31.6 T
Where T is temperature in °C.
It is also worth noting that although the
capacity of water to hold oxygen in solution
decreases with rising temperature, the oxygen
needs of fish increases with temperature.
Dissolved oxygen concentrations may
show daily fluctuations that reflect the
photosynthetic activity of aquatic plants in
nature.
Water as a chemical compound:
Water is a transparent, tasteless, odourless,
and nearly colourless chemical substance,
which is the main constituent of Earth’s
streams, lakes, and oceans, and the fluids
of most living organisms. It is vital for all
known forms of life, even though it provides
no calories or organic nutrients. Its chemical
formula is H 2 O, meaning that each of its
molecules contains one oxygen and two
hydrogen atoms connected by covalent
bonds. Water is the name of the liquid state
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