2.2.1 Biological & Nutrient Cycles in Aquaponic Systems
Hydroponics as well as the fauna associated inside the greenhouse is used to facilitate many intricate
biological cycles. One of the major cycles associated with the aquaponic environment is the Nitrogen
cycle. Nitrogen makes up 78% of the air we breathe in, however neither plants nor animals can make
use of nitrogen in this form (Mary S. Booth, 2005). Instead they depend on a process known as nitrogen
fixation. The key components in this process are nitrogen fixing bacteria that like in the root nodules of
plants. Both the plants and bacteria benefit from this mutualistic symbiosis. The Plant provides a niche
for the bacteria to thrive and grow, while the bacteria converts atmospheric nitrogen into ammonia
which can be absorbed by the plant. Other bacterial species such as Nitrosomonas can convert ammonia
into nitrates, these nitrates are also useful to the plants which help them to photosynthesize food. If the
nitrate concentration of the plant grow medium is too high, eutrophication will occur and decrease the
oxygen content of the aquatic environment, this is very dangerous to the marine life inside the
aquaponic system, however fungi and microaquaticorganisms convert the excess nitrates in the water
back to atmospheric nitrogen. (Carpenter, 2005)
The involvement of these bacterial species as well as this cycle points to the importance in the
homeostasis of aquaponic systems. The nitrogen cycle is one of the main drivers of nutrient recycling
inside the aquaponic environment. Waste product from the fish naturally contains Methane, Ammonia,
and Nitrates. Ammonia and especially the nitrates in this waste can be used as an ecofriendly way of
fertilizing plants, since nitrates form a large part of the raw materials used for photosynthesis. The other
main material for the plants is carbon dioxide, and like nitrogen it is cycled in the environment. The
aquatic life inside the greenhouse uses dissolved oxygen in the water to generate energy to live, this
process called respiration gives of carbon dioxide as a waste product. The plants then utilize the carbon
dioxide to begin their process of photosynthesis, which provides food for themselves and releases
oxygen to be used by the fish and restart the cycle. (Bronstein, 1995)
2.2.2 Benefits of Aquaponics
Aquaponics recycles a lot of the raw materials put into the system and makes the process very efficient.
Aquaponics uses 90% less water than traditional farming, while simultaneously producing on average six
times more yield per square foot than traditional farming (Marklin, 2013). This is partly due to the
interior homeostasis that allows production in any type of climate zone, during any time of the year.
Deserts or Tundra regions will have no effect on the plant and animal growth if the correct internal
parameters, such as lighting and heat are maintained inside the greenhouse (Marklin, 2013). Plant
growth is also drastically increased as the threat of pest is reduced as plants are grown indoors, and the
water is naturally fortified by the fish. The lighting also plays a very important role in the growth
efficiency as they are hung vertically and used to simultaneously grow two areas of plants as opposed to
one are. (Jason, 2012)
In addition to these farming benefits there are also environmental benefits to using aquaponics. Since
the process is regulated and the waste material is cycled, there is no harmful fertilizer run off into and
water sources such as water sheds and rivers. This greatly reduces the instances of water pollution that
arises as a misuse of fertilizers, this causes great damage to the aquatic life in these water bodies. (Jim,
2009) All energy used in aquaponics is electrical, this means that alternative forms of energy such as:
wind, solar and even hydroelectric can be used to power the green house. (Price, 2009). As a result
there is greater energy conservation and the use of these clean energy greatly reduces the instances of
air pollution. Convention commercial farming uses large machinery that generate large amounts of