1. Hypothesis:
If the nitrate levels are increased in the clay pebbles then the increased post-photosynthetic output of dissolved oxygen will lower ammonia levels in the tank as well as increase Spinacia oleracea growth.
2. Literature Review (based on Annotated Bibliography) that supports your hypothesis
Estimating productivity and efficiency of energy transfer
In the Blok's work Maximum Plant Uptakes for Water, Nutrients, and Oxygen Are Not Always Met by Irrigation Rate and Distribution in Water-based Cultivation Systems , he explains how by using a media-filled growing bed the plants yield higher growth due the frequent transfer of water from the tank to the growing bed. He explains how it maximizes the amount of nutrient received by the plants, which he explains to increase the photosynthetic output of oxygen. Hypothetically, if the plant receiving a constant flow of along with additional nutrients (ammonia that follows the nitrogen cycle and produces a form of nitrogen that could be used by the plant) then the growth rate Spinacia oleracea (spinach) would be much greater than spinach in a normal system The dissolved oxygen from the plant will hopefully create a basic, if not then a more acidic environment, and result in the fish producing feces with lower ammonia levels.
a. Text from the article
Growing on rooting media other than soils in situ -i.e., substrate-based growing- allows for higher yields than soil-based growing as transport rates of water, nutrients, and oxygen in substrate surpass those in soil. Possibly water-based growing allows for even higher yields as transport rates of water and nutrients in water surpass those in substrate, even though the transport of oxygen may be more complex. Transport rates can only limit growth when they are below a rate corresponding to maximum plant uptake. Our first objective was to compare Chrysanthemum growth performance for three water-based growing systems with different irrigation. We compared; multi-point irrigation into a pond (DeepFlow); one-point irrigation resulting in a thin film of running water (NutrientFlow) and multi-point irrigation as droplets through air (Aeroponic). Second objective was to compare press pots as propagation medium with nutrient solution as propagation medium. The comparison included DeepFlow water-rooted cuttings with either the stem 1 cm into the nutrient solution or with the stem 1 cm above the nutrient solution. Measurements included fresh weight, dry weight, length, water supply, nutrient supply, and oxygen levels. To account for differences in radiation sum received, crop performance was evaluated with Radiation Use Efficiency (RUE) expressed as dry weight over sum of Photosynthetically Active Radiation. The reference, DeepFlow with substrate-based propagation, showed the highest RUE, even while the oxygen supply provided by irrigation was potentially growth limiting. DeepFlow with water-based propagation showed 15–17% lower RUEs than the reference. NutrientFlow showed 8% lower RUE than the reference, in combination with potentially limiting irrigation supply of nutrients and oxygen. Aeroponic showed RUE levels similar to the reference and Aeroponic had non-limiting irrigation supply of water, nutrients, and oxygen. Water-based propagation affected the subsequent cultivation in the DeepFlow negatively compared to substrate-based propagation. Water-based propagation resulted in frequent transient discolorations after transplanting in all cultivation systems, indicating a factor, other than irrigation supply of water, nutrients, and oxygen, influencing plant uptake. Plant uptake rates for water, nutrients, and oxygen are offered as a more fundamental way to compare and improve growing systems.
b. APA citation
Blok, Chris, Jackson, Brian, Guo, Xianfeng (2017).Maximum Plant Uptakes for Water, Nutrients, and Oxygen Are Not Always Met by Irrigation Rate and Distribution in Water-based Cultivation Systems. International Journal of Environmental Research and Public Health, 11(4), 4427–4440. http://doi.org/10.3389/fpls.2017.00562
3. Independent variable (with units)
The addition of 1/2 cup/ 2 oz. of Hershey Dark Cocoa powder to one 1 lb. of clay pebbles (growing media)
4. Dependent variable (with units)
The Spinacia oleracea dissolved oxygen output (post-photosynthesis)
5. Control variables:
- Tanks filled with 10 gallons of water from the same sink
- Media-filled growing bed 4.5'' x 7.5'' x 3.5''
- clay pebbles
- 12 Spinacia oleracea (spinach) seeds (6 seeds per growing bed)
- Bell Siphon system
- number of Oreochromis aureus (Blue Tilapia) per tank
6. Control Group
The control group contains a 10 gallon tanks, a metal plank 10"x10", a plastic Media-filled growing bed 4.5'' x 7.5'' x 3.5'' filled with
1 lbs. of Aquaponic clay pebbles, and one bell siphon. In the tank, both air pump for 10 gallons is placed in the water of the tank along with a pond pump that pumps 48 gallons per hour.
7. Experimental Group
The experiment groups growing bed contains a mixed media of 1 lbs. of Aquaponic clay pebbles and 2 oz. of Hershey's Dark Cocoa. Beside the media, the dimensions and materials are the same as the control group.
8. What unexpected challenges have you encountered thus far?
I've encountered shipment problems with my tilapia due to unexpected freezing temperatures. I have not had any issues with aquaponic system itself nor the bell siphon and other aquarium necessities (water pump, air pump, etc.)
9. How will you know your experiment is a success?
If my experiment was successful, then Oreochromis aureus growth (weight in grams) will not be impeded and if the growth of the experimental system exceeds the growth of the controlled systems plant growth or if the fish die due to too high levels of dissolved oxygen as well as an too acidic pH levels in their water.
10. How your experiment addresses Energy Dynamics:
My experiment addresses Energy Dynamics as the photosynthetic outputs are amplified by the addition of Dark cocoa, which has a high nitric oxide level. The additional nitric oxide adds and oxygen trapped in the clay pebbles react to form nitrite and quickens the nitrogen cycle as the process of nitrification is no longer necessary, The energy conversion occurs in both primary (spinach) and secondary consumers (blue tilapia) (ex: oxygen and glucose are converted to chemical energy during cellular respiration), or in the waste products (ex: faeces) of the secondary consumers . During respiration, energy is produced by the mitochondria, so the the cells of the spinach can performs its daily functions. Subsequently, glucose is converted to ATP in different pathways, such as glycolysis, citric cycle electron transport chain, etc. As a result, heat, energy, is lost as an effect and the bell syphon transfer the photosynthetic outputs by the bell syphon. Energy is lost by faeces because food must be digest, which is a body function that requires energy to be converted to ATP. Subsequently, the faeces releases ammonia in to the water and the water is pumped back to the spinach in the growing bed; the cycle repeats. In the experiment, I must find the biomass; (dry mass of spinach/wet mass of spinach)x100. I would also find the net biomass; all the biomasses added together. By taking the biomas, I will know how much the plant has grown.
11. Take and post a “before” picture of your set up
Note: Post further below.
12. Compare 1st day and 1st week (Day #1 & Day #5) chemical H2O readings (NO2, NO3, NH3 pH etc.)
As a reminder the standards/objective that this experiment should address are as follows:
Your experimental design will need to include:
accounting and budgeting, measuring biomass, calculating unit conversions in simple equations