Aquaponics Education in the CommunityThomas Halpenny

Melissa BadeENSTU 403Spring 2017

Introduction        Food deserts and droughts are growing issues in the world today. These problems are being compounded by standard farming practices that are proving to be ineffective at meeting the demands of a growing world population1. Aquaponics is a method of growing food that combines hydroponics and aquaculture in a closed loop system, and is intended to grow terrestrial plants and fish at an accelerated rate for human consumption. While aquaponics can grow food in food deserts, and has been proven to be a water-efficient way to produce organic food and fish, the public is not fully aware of the concept. Since young people are future consumers and scientists, our capstone project is intended to increase awareness of aquaponics, specifically in schools. We are working with Both Company Aquaponics for our capstone. Both Co.’s mission is to eliminate worldwide thirst and hunger using aquaponics to help society approach a sustainable future. In order to accomplish this, we created educational curricula for UC Santa Cruz for the aquaponics system already in place on their campus. In addition, we designed the curricula for use at the middle school level.

BackgroundAquaponics is a combination of

hydroponics and aquaculture2. Hydroponics is traditionally a closed loop system intended to grow food in a water efficient manner without using soil. Aquaculture is breeding fish for food. Aquaponics is a marriage of the two farming methods by using worms and bacteria in symbiosis with the plants to provide the nutrients necessary to fertilize plants. These worms function as a biological filter that survive off the fish waste, releasing nitrates and nitrites. Unlike hydroponics, aquaponics does not add chemicals or pesticides to the water because such additives are toxic to living creatures. If these additives were used in a system, then the fish would be contaminated, and through bioaccumulation, the humans that eat the fish would be as well. Therefore, any food or fish raised in an aquaponics system is completely organic.

There are four stages to the aquaponics cycle (Figure 1). The first is the fish food, which is in pellet form. In keeping with the organic nature of the system, these pellets must be organic,

1 Rigby, Dan, Phil Woodhouse, Trevor Young, and Michael Burton. 2001. “Constructing a Farm Level Indicator of Sustainable Agricultural Practice.” Ecological Economics 39 (3): 463–78.

2 Rakocy, James E., Michael P. Masser, and Thomas M. Losordo. 2006. “Recirculating Aquaculture Tank Production Systems: Aquaponics—integrating Fish and Plant Culture.” SRAC Publication 454: 1–16.

Figure 1 The basic four stage aquaponics cycle. Note the power and sun inputs.

Source: ecolifeconservation.org/aquaponics/.

but that is the only requirement. In addition to pellets, the nutrient rich water flowing through piping that connects each part of the system allows algae to grow. Once the algae has grown to a certain point, the fast flowing water will dislodge it, and carry it down to the fish tank for a fish to eat. In aquaponics, worms are used for filtering water but they can also be washed down the system to the fish pond adding to the diet of the fish. The second stage is the fish. In the system cycle, the fish live their lives, contributing their waste to the water in the pond. This waste is mainly ammonia, but also has; effluence (pee and poop), magnesium, iron, and potassium. These materials function as nutrients for worms, which are common red worms (Eisenia foetida), in the third stage. The third stage is the worms and bacteria, known as Vermiculture. In this stage, bacteria process the fish waste into nitrates. The bacteria live on the surface of the growing media, and in the digestive systems of the worms. There are two types of bacteria that are involved in this process. The first is Nitrosomonas spp, which take in the ammonia, convert it into nitrites, and then release it. Then the second type, Nitrobacter spp, take in the nitrites and release them as nitrates, which then flow back out into the system. Besides the ammonia, the worms digest effluence and release it into the water as a worm tea. After the worms have processed the fish waste, it is pumped into the fourth and final stage, which is the plants. Plants have an easier time taking nitrates up through their roots and processing them than they do with ammonia. This means that the nitrate laden water saves the plant's energy that would be used in processing ammonia, and allows them to devote that energy to growth. By taking these nutrients up through their roots, the plants strip the nutrients from the water, thereby filtering it for the fish before it is pumped back into the pond3.

This cycle conserves water through constant reuse. The value of aquaponics systems is that they can be constructed inside a warehouse, a shed, or a living room, and this freedom of location removes the water loss to the environment through evaporation that is common in traditional agriculture4. As California is entering a drought, adopting sustainable practices such as aquaponics is vital to conserving the valuable drinking water available to people. Despite its value, aquaponics is not a common practice in the US. In 2010, there were an estimated 800 to 1200 systems in the USA5. While this number is growing, and aquaponics is becoming more prevalent in school curricula, most of the US population does not have access to an aquaponics system, and is not aware of aquaponics as a practice.

Approaches: For our project, there were two approaches we could have taken for education about

aquaponics. The first approach was to set up an interactive website with information about the working of aquaponics and additional links to useful websites. The second approach we considered was to create a PowerPoint that could be presented to groups of people. We decided to take the second approach because it would work better for what we are trying to accomplish. The benefits of having a PowerPoint is that we can change and adapt it to the audience we were

3 Bernstein, Sylvia. Aquaponic gardening: a step-by-step guide to raising vegetables and fish together. New society publishers, 2011.

4 Goodman, Elisha R. (Elisha Renee). 2011. “Aquaponics : Community and Economic Development.” Thesis, Massachusetts Institute of Technology.

5 Love, David C., Jillian P. Fry, Laura Genello, Elizabeth S. Hill, J. Adam Frederick, Ximin Li, and Ken Semmens. 2014. “An International Survey of Aquaponics Practitioners.” PLOS ONE 9 (7): e102662.

presenting to. We could also interact with our audience and answer their questions, thereby demonstrating in person how the system works.    

Project Goals:The goals of our project are to raise awareness about aquaponics and what it is, as well as

the science behind it. This, in turn, will teach middle school and college students about how a relatively unknown agricultural practice works as well as the benefits of the system to communities. We sought to present aquaponics to the community to make them aware that there is an alternative to traditional farming, that it can benefit the community, and that it is environmentally friendly and sustainable. Also, we made it a major point that aquaponics can be implemented almost anywhere including inner cities. We hope that by providing this information we will create an interest in youth and in college students so they will go on to further this field of study, and encourage support from older community members.  

Project Description:For our project, our community partner, Janna, supplied us with fact sheets covering the

information she wanted us to use as a foundation for our project. Using these sheets, we created a basic PowerPoint that we refined into a presentation that can be presented in a classroom setting, or at a community event. For a college level course, we created class activities that provided practice in technical aspects of monitoring an aquaponics system, such as water testing and assembling a five-gallon aquaponics system. To create these activities, we looked at activities that our own college classes used, and followed their formatting, but we created our own content. For students, we designed a three-hour lecture using activities to facilitate the PowerPoint. Without the activities, the PowerPoint functions as a general overview of aquaponics for non-science audiences. To evaluate the effectiveness of our curricula, we wrote two sets of pre and post-tests to determine what they knew before and after the presentation. We tested this program at a community event for hOURbank to evaluate its effectiveness.

ResultsWe created two different curricula

units to be used for either college or middle school. These units include two different pre and post surveys depending on which audience it is. However, the speaking points for the two are different and the activities are to be used in a college class alone. We tested our middle school curricula on the hOURbank of Monterey County (Figure 2). In a class made up of sixteen people from the ages of forty to ninety years, we gave a one hour presentation of our PowerPoint. On a scale of one to five, we had these people self-evaluate their knowledge of aquaponics before and after the presentation. We then averaged the total rankings of the Pre-tests and Post-tests together.

Figure 2: The hOURbank presentation. Photo credit: Janna Ratzlaff

Given that an average knowledge is a rank of 3, what we found was that the average response had a lower than average knowledge of aquaponics before we presented, with a rank of 2.3 on the pretest. This number showed a noticeable increase on the post-test with a ranking of 3.5 (Figure 3).

To evaluate what the audience learned from our presentation, the second part of our pre-and post-tests asked how aquaponics worked. On the pre-test, we saw that out of the fifteen people, four had a correct description of the aquaponics cycle. Following the presentation, there were twelve correct answers (Figure 4).

Evaluation

Our project was limited by our access to our population of interest. We had intended to present this in a class at UC Santa Cruz, but we were unable to obtain a classroom within the semester we developed this curriculum. Given that our presentations were to a

small group of fifteen people, we would have liked to gather data from a larger audience. Age was a limiting factor in our presentations as well. The hOURbank group was between the ages of 40 and 90, therefore we know this curriculum can facilitate learning in that age group, but this material needs to be tested on collegiate and high school students before it can be considered truly effective. However, based on the trends identified above, the presentation is a successful way to raise awareness of aquaponics and the science behind it.

RecommendationTo test this curriculum further, it would be good for future capstone students to present it

to different age groups. We had an issue with our audience answering our questions with specific information, so we recommend that future presenters refine the pre-tests and post-tests to be more specific about technical details to reduce misunderstandings on the part of the audience. Finally, we highly recommend presenting to larger groups than were available to us.

Pre-test Post-test0

2

4

6

8

10

12

14

How does aquaponics work?

Figure 4 Right answers on the pre-test compared to the right answers on the post-test on how aquaponics works.

Pre-test Post-test1

1.52

2.53

3.54

4.55

Self Evaluation of Knowledge

Figure 3 Pre-test compared to post-test averages of knowledge respondents had before the presentation. 1-5 self-evaluation scale.

ConclusionAquaponics is a sustainable farming method that can be used to benefit communities and

economies, as well as address social issues. However, the problem is that people are not familiar with it, and there is no mainstream method of teaching them. Based on our data, our project has the potential be used to address the lack of material for teaching about aquaponics. Further presentations should be conducted to test it on different audiences to examine its effectiveness at teaching the ideas behind aquaponics.