Do Ocimum basilicum have a higher chlorophyll concentration when integrated in an aquaponics system or when growing under typical conditions?
Written By: Katie Keung Dylan Douglas-Brown Fahad Paryani Sahaj Bhimani Design: ASPECT 1 - Our initial question for this project was ‘Do Ocimum basilicum have a higher chlorophyll concentration when integrated in an aquaponics system or when growing under typical conditions?’ This question would hopefully provides insight into the specific advantages of aquaponic integration. Our independent variable was whether the Ocimum basilicum was integrated in the aquaponic system and exposed to waste from the Carassius auratus or planted in the control growth bed. Our dependent variable was the chlorophyll concentration in the leaves of the Ocimum basilicum. ASPECT 2 - To control the environment and exclude any other factors that could possibly affect chlorophyll concentration, we imposed several controls upon our aquaponic and natural growth systems. We controlled the following variables: the wattage of the light source, the type of soil in which Ocimum basilicum was grown, the time at which chlorophyll concentration was calculated, the size of the Ocimum basilicum inserted into the spectrophotometer, and the placement of seeds within the two grow beds. ASPECT 3 - We analyzed the chlorophyll concentration of Ocimum basilicum by placing a 1 cm2 * 1 cm2 piece of the Ocimum basilicum in a spectrophotometer. The Ocimum basilicum was analyzed at three different wavelengths: 630 nm, 645 nm, and 665 nm. These three wavelengths are where chlorophyll pigments spike and were the easiest points at which to measure concentration. The chlorophyll analysis was done every 14 days on three plant samples and the average chlorophyll concentrations between those three samples was produced. Weekly images were taken of the aquaponic system and the Ocimum basilicum. The diagram below illustrates our initial building goals for our aquaponic system. We adjusted this diagram to reflect barriers that were imposed by monetary resources, time permitted to assemble the structure, and the stability issues that arose during construction. The images following the diagrams are of the actual aquaponic system, prior to seed germination. Data Collection and Processing: ASPECT 1 - Date pH Ammonia (NH4) Nitrate (NO3) Nitrite (NO2) 1/19/17 5.5 3.0 harmful 0 1 1/23/17 5.5 6.0 danger 0.5 10 1/24/17 5.5 3.0 harmful 0.5 10 1/27/17 5.0 1.0 stress 10 2 2/1/17 5.0 3.0 harmful 5 2 2/15/17 5.5 3.0 harmful 5 2 3/1/17 6.0 1.0 stress 5 2 3/15/17 6.5 0.5 normal 5 2 3/29/17 6.5 0.5 normal 5 2 Group 1 (Aquaponic) Growth of Ocimum basilicum Date Absorption at 630 (nm) Absorption at 645 (nm) Absorption at 665 (nm) Chlorophyll a Concentration(mg/g) Chlorophyll b Concentration (mg/g) 2/1/17 0.02 0.05 0.07 0.744 1.03 2/15/17 0.02 0.06 0.10 1.08 0.721 3/1/17 0.03 0.06 0.12 1.10 0.625 3/15/17 0.03 0.09 0.13 1.22 0.550 3/29/17 0.04 0.12 0.15 1.25 0.53 Group 2 (Control Group) Growth of Ocimum basilicum Date Absorption at 630 (nm) Absorption at 645 (nm) Absorption at 665 (nm) Chlorophyll a Concentration(mg/g) Chlorophyll b Concentration(mg/g) 2/1/17 0.01 0.03 0.05 0.539 0.360 2/15/17 0.02 0.03 0.05 0.538 0.360 3/1/17 0.02 0.02 0.05 0.538 0.371 3/15/17 0.03 0.02 0.04 0.540 0.380 3/29/17 0.02 0.02 0.05 0.548 0.362 ASPECT 2/3 - We collected a variety of different sources to help support our hypothesis and includes; chlorophyll a and b concentration, pH level, ammonia concentration, nitrate concentration, and nitrite concentration. When we first began the project there was large fluctuation in the concentration of the various compounds making the water conditions horrible for the fish, but over the course of eight weeks the levels slowly began to stabilize into optimal conditions. In addition, the chlorophyll a concentration for both groups began at relatively same levels and as time progressed the aquaponic chlorophyll a concentration jumped from 0.744 mg/g to 1.25 mg/g indicating a healthy growth among the Ocimum basilicum population in the aquaponic system. The control group’s chlorophyll a concentration remained relatively at 0.540 mg/g. Group’s 1 chlorophyll b concentration started off at a high concentration indicating its stress due to the horrible conditions in the water due to low pH levels and dangerous levels of ammonia in the water. However, as the weeks progressed the chlorophyll b concentration went from 1.03 mg/g to 0.53 mg/g. Conclusion and Evaluation: ASPECT 1 - It can be concluded that when integrated into an aquaponics system, Ocimum basilicum’s chlorophyll A concentration is higher than when growing under typical conditions. Chlorophyll A is the main chemical utilized in absorbing light energy for photosynthetic processes; therefore higher concentration would indicate elevated need for absorption, likely due to more rapid photosynthesis. We found that chlorophyll B concentration was elevated initially in the aquaponic system, yet it began to level out as we controlled ammonia levels in our water. High levels of chlorophyll B insinuate that a plant is experiencing high levels of stress, which would correlate with our elevated ammonia levels in the first weeks of our research. Our data supports our conclusion; the chlorophyll concentrations of the Ocimum basilicum growing under typical conditions were lower than those of the Ocimum basilicum integrated in the aquaponics system. ASPECT 2 - While our data did support our pre-testing research, there were some limitations and weaknesses within our study. One limitation was simply the amount of time allowed to collect data; as will all studies, a longer period of research and more data collection allows for a smaller margin of error and more accurate values. Another limitation was the environment in which our experiment took place. Unfortunately, we had no control over other students tampering with the system, as we found “foreign objects” in our aquarium several times. We attempted to control temperature of our systems, but as we had no authority over the heating/ventilation in the school building, fluctuations were out of our hands. A final weakness could’ve been the usage of only one species of fish in our aquarium, as most industrial aquaponic systems are constructed over a body of water harboring an entire ecosystem. ASPECT 3 - In the future, we should plant the seeds further in advance to allow for germination to occur prior to the start of experimentation. This will allow the pants to be fully incorporated into each of the respective growing conditions as well as allowing the plants to be larger and have leaves that can be analyzed rather than disrupting entire plants in the beginning of our experimentation. We could also extend the length of our data collection period to lessen our margin of error. To control the environment, we could possibly move the testing area to a lab setting (which is slightly unrealistic) or move the testing environment to an outdoor area which would mimic natural fluctuations in temperature that would affect industrial aquaponic systems. If we wanted to devote even more research to the influence of aquaponic integration on chlorophyll concentration, we could construct an apparatus that could float on a nearby body of water, to allow exposure to waste from an entire ecosystem.
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Essential knowledge 1.A.2: Natural selection acts on phenotypic variations in populations.
Essential knowledge 3.E.2: Animals have nervous systems that detect external and internal signals, transmit and integrate information, and produce responses.
Essential knowledge 4.A.5: Communities are composed of populations of organisms that interact in complex ways.
Science Practice 5: The student can perform data analysis and evaluation of evidence.
This image depicts the nitrogen cycle in our system. This image depicts the carbon cycle in our system. This image depicts energy flow in our system.
Comments about data:Now we are beginning to see a trend in our data. The Ocimum basilicum in the aquaponic setup is experiencing an increase in the chlorophyll a concentration which is an indication that the aquaponic setup is getting more out of this system than the control. The chlorophyll b concentration dropped in the aquaponic setup, but that is not a bad indicator because often times chlorophyll b is used in time of stress. By seeing a decrease in chlorophyll b it is essentially saying the aquaponic environment is a better setup than our control.
What has been going well?
We are now starting to see growth in our Ocimum basilicum in both of our groups which is a good sign our aquaponic is working. In addition, ammonia levels have dropped from dangerous conditions to more stable conditions in our fish tank. We were able to begin collecting data on the Ocimum basilicum and analyzed its absorption rates at various frequency. What has not been going well and what adjustment has been made? Our filter broke on 2/13/17 and the clarity of the water began to worsen. We quickly brought a new filter to replace the broken one and it is now in place and working. We were experiencing difficulties with growing the Ocimum basilicum , but found that our light system was causing the water to evaporate before it was fully used to its full potential. We turned the lights off in the morning, but in 5th period we turn it back on for photosynthesis to complete. SYSTEM UPDATE:
January 30th Aquatic System Water Conditions: pH - 5.5 NO2/NO3 - 5/10 Ammonia - 0.5 (safe) February 2nd Aquatic System Water Conditions: pH - 5.5 NO2/NO3 - 5/10 Ammonia - (stress)
The first example of net productivity is occurring in the basin where our Ocimum basilicum is planted (Noted with a red circle). Net productivity is equal to gross productivity minus respiration. In our plant based system the Ocimum basilicum creates oxygen and this represents the idea of gross production (Represented with a blue arrow). However, the plants uses energy to create glucose for itself, and that energy comes from the oxygen plants intake through cellular respiration (Represented with an orange arrow). The net productivity is simply the difference between the amount of oxygen produced and used by the Ocimum basilicum. Most plants produce more than enough oxygen for itself and the overall net productivity of it is a positive net growth which means Ocimum basilicum is producing more oxygen then its consuming (Represented with a black arrow). Initial and Current Nitrogen & Hydrogen Levels:
Above is an annotated diagram of the initial setup of the aquaponic system. Let it be noted that the tubing that connects the grow bed to the aquarium is not currently connected- these two will be attached once the Ocimum basilicum have germinated and are ready to transplant.
The producer arrows are pointing to the Ocimum basilicum, while the consumer are pointing to the Carrasius auratus. 1. Hypothesis (include scientific names of organisms): If Ocimum basilicum is integrated into an aquaponic system, then it will have a higher chlorophyll concentration than Ocimum basilici grown in a system without aquaponic integration. 2. Literature Review (based on Annotated Bibliography) that supports your hypothesis The following information supports our hypothesis that the Ocimum basilicum will have higher chlorophyll concentration, as it is receiving increased nutritional material. “In an aquaponic system, water from an aquaculture system is fed to a hydroponic system where the by-products are broken down by nitrification bacteria into nitrates and nitrites, which are utilized by the plants as nutrients.” Zajdband, A. D. (2011). Integrated Agri-Aquaculture Systems. Sustainable Agriculture Reviews Genetics, Biofuels and Local Farming Systems, 87-127. doi:10.1007/978-94-007-1521-9_4 This source allowed us validate our assertion that look chlorophyll concentration is a representative value that can show efficiency of photosynthesis. Behrenfeld, M. J., & Falkowski, P. G. (1997). Photosynthetic rates derived from satellite-based chlorophyll concentration. Limnology and Oceanography, 42(1), 1-20. doi:10.4319/lo.1997.42.1.0001 3. Independent variable (with units) The independent variable in this study is whether or not the Ocimum basilicum is integrated in the aquaponic system and being exposed to waste from the Carassius auratus. 4. Dependent variable (with units) The dependent variable in this study is chlorophyll concentration in the leaves of the Ocimum basilicum, presented in the units of mg/L. 5. Control variables (at least 3) There are several control variables in this study, including but not limited to: light source, type of soil in which Ocimum basilicum is grown, and time at which chlorophyll concentration is calculated. 6. Experimental Group The experimental group is the system containing Ocimum basilicum that is integrated in the aquaponic system. Its chlorophyll concentration averages will show the effects of Carassius auratus waste on ability to effectively photosynthesize. 7. Control Group The control group is the system containing Ocimum basilicum that is not integrated in the aquaponic system. It requires daily watering, to account for this difference. It will be comparable with chlorophyll concentration in plants exposed to Carassius auratus waste. 8. What unexpected challenges have you encountered thus far? The main challenge we have had so far is the construction of the system outside of the location that the experiment would be conducted. This required the transportation of the Carassius auratus; we hypothesize that this excessive stress caused two of the twelve fish to die shortly after transportation. 9. How will you know your experiment is a success? We will know that our experiment is a success if we are able to collect sound numerical data regarding chlorophyll concentration. While our data may not run parallel with our hypothesis, the ability to collect data over the entire 12 week experimental period, and keep both the Carassius auratus and Ocimum basilicum alive will display a successful experiment. 10. How your experiment addresses Energy Dynamics: Our experiment addresses Energy Dynamics by attempting to measure the effects of energy being transferred from the Carassius auratus waste to the Ocimum basilicum. The methodology of our experiment also mindful of Energy Dynamics, as it accounts for the fact that energy is lost through photosynthesis and cellular respiration, as these processes never have a perfect 100% yield of energy and is often lost as metabolic heat. The methodology accounts for this by including two energy inputs- food and light. |
AuthorsKatie Keung |