situated on water beds are grown with aquatic life, usually fish. The intricate design allows for the
waste products of one biological system to serve as nutrients for another (Wahl, 2010).
Figure 14. The Aquaponic Cycle (Acquired from Worcester Roots http://www.worcesterroots.org/projects-and-
programs/youth-in-charge/)
In aquaponics water is reused through biological filtration and recirculation, this makes it a very
sustainable way for producing food. Since the fish and plants are grown together the diversity of the
biological environment allows for a great deal of biological exchange inside the system. The waste from
the fish, algae and bacteria would build up inside the tanks, and compromise the fish, however, this
waste is used to serve as fertilizer to the hydroponically grown plants. These plants are grown on a
hydroponic bed, which not only acts as an anchor for the plants but also as a filter, which rids the water
of ammonia, nitrates and phosphorous so that filtered water can be circulated back into the tanks. The
plants themselves have nitrifying bacteria in their roots, they are essential in converting atmospheric
inert nitrogen to a more reactive form, nitrates, which are then used to by the plants and enable the
nutrient cycling between the hydroponic system and the aquaculture.
Hydroponics is a way of growing plants without soil, instead growing plants directly in water, or in a
growing medium such as fine rocks. Since water is the medium for plant growth, only nutrients that are
soluble in water will be absorbed by the plant. Most minerals used by plants are soluble in water, these
include calcium, phosphates and magnesium. (Mugundhan, 2011) Very precise concentrations of these
minerals are dissolved in water, and carefully maintained, this allows for the most optimum growth of
the plant and when this is coupled with lighting effect from the greenhouse design, the yield from plants
grown this way is extremely high. The combination of hydroponically grown plants inside a biologically
integrated system linked to aquatic culture of fish is a very intricate process that allows for the
sustainable production of food.