Construction and Implementation of a Bench-Top Aquaponic System as a Context for Teaching Science in Secondary Schools

Aquaponics is an integrated biological system that essentially combines a soil-less garden with an aquarium. It is important because it uses less water than commercial farming, is ecofriendly, and provides a local source of food for its practitioners. Aquaponics is also important because of its capacity to serve as an authentic teaching tool in science classrooms. This thesis is divided into three components. First we will describe the construction and implementation of our Bench-top Aquaponics System (BAS). Next, the results of an experiment that compares two methods of establishing bacteria–culture in a fishless system will be presented. Finally, the potential for use of the BAS in STEM classrooms will be discussed. The goals of this project are to (1) create an Aquaponics system that has a small ecological footprint and not take up too much room in the classroom, (2) further the current body of research on applied aquaponic systems, and (3) provide a pedagogical tool that involves students in building equipment and solving authentic problems as a gateway for learning. The BAS is assembled in 3 separate compartments, a plant tray, an aquarium, and a bacteria reservoir, with PVC piping connecting the three. It is designed around a wooden frame that is smaller than 18 ft3. This design allows for students (and teachers) to easily access and see the different compartments of the system. Many of the problems we encountered came from plumping issues related to the fountain pump or the bell siphon; these were solved using applied physics principles. Other problems we faced, including biological were solved using more consistent testing and chemical reagents to stabilize our BAS. We learned ultimately that time is the key component in establishing a bacteria colony in any aquaponic system. We also learned that establishing bacteria is the most important step in setting up a successful aquaponic system whether on a large or miniaturized scale. Some aspects of this project that need further investigation include the importance of changing out the water of the system, whether dissolved oxygen is necessary for bacteria, and how/why consistently adding bacteria may stunt the ability of a bacteria colony to form. Conclusively we have found that it is not only possible to establish such an aquaponic system that is built by students, but it is also possible to maintain it. Further research is needed to estimate the Benchtop Aquaponic System's teaching potential within STEM classrooms.