Microbial diversity in
Aquaponics Systems
Henk Stander
Aquaculture Division, Department of Animal Sciences, Faculty of AgriSciences,
University of Stellenbosch
T
he word “aquaponics” comes from two
separate words, which are combined.
The first word is “aqua”, which of
course, means water, but in this case,
the “aqua” is from another compound word
“aquaculture” (the production or raising of fish
as a livelihood). The second word is “ponics”,
which is Latin for work, and comes from its
use in “hydroponics” (working, at growing
plants in water, hydro).
Aquaponics refers to any system that
combines conventional aquaculture with
hydroponics in a symbiotic environment.
In normal aquaculture, excretions from the
animals being raised can accumulate in the
water, increasing toxicity. In an aquaponics
system, water from an aquaculture system
is fed to a hydroponic system where the
by-products are broken down by nitrifying
bacteria initially into nitrites and subsequently
into nitrates that are utilized by the plants as
nutrients. The water is then recirculated back
AgriKultuur |AgriCulture
to the aquaculture system.
Aquaponics systems are recirculating
aquaculture systems that incorporate the
production of plants without soil. Intensive
recirculating systems are designed to raise
large quantities of fish in relatively small
volumes of water by treating the water to
remove toxic waste products and then reusing
it. In the process of reusing the water many
times, non-toxic nutrients and organic matter
accumulate. These metabolic by-products
need not to be wasted if they are channelled
into secondary crops that have economic
value or in some way benefit the primary
fish production system. Systems that grow
additional crops by utilizing by-products
from the production of the primary species
are referred to as integrated systems. If the
secondary crops are aquatic or terrestrial
plants grown in conjunction with fish, this
integrated system is referred to as an
aquaponics system.
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