Saturday, September 10, 2011

Teaching with Aquaponics

     Nature is an amazing system of balances between the chemical makeup of our planet and various forms of life.  Aquaponics is an amazing way to teach children about one of these systems through hands on learning and observation.
     In nature the decomposition and conversion of organic matter into nitrogen and other nutrients provides plants with the materials they need to produce their own food.  We all depend on plants to survive.  Without them at the base of the food chain we would not have a means of converting raw material to food we can process.  Aquaponics displays this process of conversion right before your eyes. 
     When you feed the fish of an aquaponic system they produce waste.  Ammonia is excreted through gills and in urine, and solid waste is produced from undigested and uneaten food.  Ammonia is a form of nitrogen, the most used nutrient by plants.  It is unavailable for use, however, because plants cannot absorb N in the ammonia form.  This is where the beneficial bacteria come into play.  Nitrosomonas sp. oxidize ammonia as they utilize it for growth, which converts ammonia into nitrite.  Nitrite, another form of nitrogen, is still not available for uptake by plants, though.  From here, Nitrobacter sp. convert the nitrites into nitrates.  Nitrate is a form of N that is very available to plants.  Now that there is a form of N that can be utilized by plants, they use the nitrates and filter the water for the fish.
     Aquaponics can be used to teach children about life in several ways.  Watching fish in a system displays the cycle of life in animals.  As the fish are provided the right environment and are fed they grow and, eventually, die.  While some may find it morbid to consider death a lesson for children, it is an inescapable aspect of life that is better coped with when understood.  Aquaponics also teaches us about the balance found in nature.  The fish rely on the plants to filter their water and, in some cases, provide food.  In turn, plants rely on the fish for the nutrients they need to survive and thrive.  It is also a great way to teach children about plants, how they grow, how to cultivate them, and how important they are to us.  A more advanced look at aquaponics would reveal lessons in chemistry and biology.  But we'll keep it simple today.
20 gallon desktop aquaponic system

     Getting into aquaponics needs not be a costly venture.  A tabletop system can be constructed for a relatively low price out of a fish aquarium and other inexpensive, readily available materials.  The added benefit is that it is easier to observe the fish in these glass tanks as opposed to the tanks used for larger systems.  And the ability to keep the system inside on a table or desk allows for more observation.
     Whether or not you have kids that you'd like to teach about life a tabletop aquaponic system is an amazing thing to see working.  Fish can be fun to watch swimming around and lettuce or herbs can easily be produced for cooking at home.  I encourage anyone who thinks they don't have the time, money, or space for aquaponics to consider putting one of these systems together.  It's a great introduction to aquaponics and can't be beat as far as cost goes.


  1. Anyone still interested in using aquaponics for education? I teach HS Biology and will be installing a 110 gallon system in the greenhouse attached to my classroom. I want to use it to teach most of my curriculum. Chime in if you want to discuss this.

  2. I am interested in how people successfully teach this topic at the high school level as I am doing the same in a biology class.