Aquaponic Garden Building (Mark Yaney)
Author: Mark Yaney
NGSS Engineering Standards:
MS-LS1-6. Construct a scientific explanation based on evidence for the role of photosynthesis in the cycling of matter and flow of energy into and out of organisms. [Clarification Statement: Emphasis is on tracing movement of matter and flow of energy.] [Assessment Boundary: Assessment does not include the biochemical mechanisms of photosynthesis.]
MS-LS1-7. Develop a model to describe how food is rearranged through chemical reactions forming new molecules that support growth and/or release energy as this matter moves through an organism. [Clarification Statement: Emphasis is on describing that molecules are broken apart and put back together and that in this process, energy is released.] [Assessment Boundary: Assessment does not include details of the chemical reactions for photosynthesis or respiration.]
MS-LS2-1. Analyze and interpret data to provide evidence for the effects of resource availability on organisms and populations of organisms in an ecosystem. [Clarification Statement: Emphasis is on cause and effect relationships between resources and growth of individual organisms and the numbers of organisms in ecosystems during periods of abundant and scarce resources.]
MS-LS2-3. Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem. [Clarification Statement: Emphasis is on describing the conservation of matter and flow of energy into and out of various ecosystems, and on defining the boundaries of the system.] [Assessment Boundary: Assessment does not include the use of chemical reactions to describe the processes.]
MS-LS2-4. Construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations. [Clarification Statement: Emphasis is on recognizing patterns in data and making warranted inferences about changes in populations, and on evaluating empirical evidence supporting arguments about changes to ecosystems.]
Materials Needed
Fish
Dechlorinated Water
Tank
Fish Food
Plant Seeds
Submersible Pump
Net Pots
Gravel or grow stones
A foam "raft" to hold the net pots
or
A tray to hold the net pots
Paint to make the upper sides of the tank opaque
Electrical source for the submersible pump
Below is a somewhat more sophisticated system
Aquaponics Explanation
Aquaponics is a method of farming which generally involves a culture of fish providing nutrients to plants, the roots of which are submerged only in water. There is no soil to provide nutrients. Instead, the effluent from the fish provides vital nutrients, especially nitrogen which would normally be fixed by bacterial in the soil, then available to the plants.
Aquaponics consists of two main parts, with the aquaculture part for raising aquatic animals and the hydroponics part for growing plants. Aquatic effluents, resulting from uneaten feed or raising animals like fish, accumulate in water due to the closed-system recirculation of most aquaculture systems. The effluent-rich water becomes toxic to the aquatic animal in high concentrations but this contains nutrients essential for plant growth. Although consisting primarily of these two parts, aquaponics systems are usually grouped into several components or subsystems responsible for the effective removal of solid wastes, for adding bases to neutralize acids, or for maintaining water oxygenation (Wikipedia).
Depicted to the left is a somewhat large scale operation, which is capable of producing lots of food. There are smaller scale versions which can be achieved, and fashioned at home. Common aquariums and water pumps, with fresh water aquarium fish (Markapeida).
Procedure to build your own
Use a water tight storage bin for your tank, or an aquarium if you have one. Take the lid and drill out holes in it that are 2mm smaller than the rims of your net pots, and hang the pots in the lid. Make sure at that at least the top 1/3 of your "tank" is opaque, as light will cause parasitic algae to grow on the roots of your plants. Fill the bin just below where the bottoms of the net pots extend when the lid is replaced. Add fish slowly, by acclimatizing them slowly to the temperature in the tank (leave them int their container for 15 minutes before emptying them into the tank. Once the fish are inside, fill your net pots with your stones and sprinkle in the seed seeds (having soaked the seeds beforehand). Place tank near a light source. Wait. Wait some more. Feed fish every day. Partially change aquarium water every week or 2, depending upon the algal growth. It will be pretty obvious, as the fish will swim near the top of the tank looking for oxygen. Harvest food when it is ready. Voila!
AS A TEACHING TOOL
There is the obvious engineering tie in of building something. Brainstorming, planning, drawing, testing and constructing are all part of the process, but there's also the engineering system of the nutrient cycle. The students input the fish food, and all is cycled back around. At some point, the students may figure out ways to grow the kinds of plants that can actually feed the fish and close the loop.
In the image below, the water which has been cleaned by the plant roots is pumped back into the aquarium. As the fish metabolize their food, they nitrify the water for the plants, eliminating the need for artificial fertilizers.
Take a moment to watch the time lapse video below of an aquaponics kit available through direct from Back to the Roots, or via Amazon for about sixty bucks. It comes with everything except fish, and water, but it does come with a three dollar Petco coupon for a betta veil tail, which is about three bucks at Petco. Grow figure.
