Net primary productivity
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Introduction: (I had to study for the SAT so this will be completed later)
Collaborators: Logan, Logan, Maggie, Amber The purpose of this lab is to be able to determine primary productivity, which is a measure of the amount of photosynthesis that an ecosystem undergoes and this contributes to gross primary productivity. The gross primary productivity is the measure of the total amount of chemical energy created from the sunlight an area receive. Through cellular respiration, the producers must also use some of the glucose made to create ATP. If you take the GPP, and subtract the glucose used to create ATP, then, what is left if the net primary productivity. The net primary productivity is the remaining chemical energy that is available to the consumers in that ecosystem. Most importantly, it allows scientist to analyze the factors that affect the production potential of plants, including climate change, soil moisture. Ultimately, the NPP can be used to determine how healthy that ecosystem is and how much biomass it is putting out. In the lab, the problem being addressed is "What is the NPP of radishes," which can be calculated by dividing the biomass of the radishes by the area of the opening of the container by the amount of days the radishes was allowed to grow. Hypothesis:The net primary productivity of a radish seed will be less than .0025. Materials: Germinated seeds from LD-50 lab Soil Water Cut open plastic two-liter bottle Paper towels Digital scale Parts of the Experiment: There is no independent variable. The dependent variable is the growth of the radishes. There is no control group. The experimental group consists of the plots of radishes. The controlled variables are the amount of sunlight, the amount of water, the soil used, the number of days the radishes were grown, and the temperature. Methods: 1. Select the best germinated seeds from your LD-50 lab. 2. Take the mass of the seeds. 3. Record the mass of the seeds and how many are planted. 4. Fill the two-liter bottle with soil and plant the seeds. 5. Measure the area of the plot of soil in cm². 6. Cover the seeds with a wet paper towel to contain the moisture. 7. Allow the seeds to grow for a couple weeks. 8. After a few weeks, dig the plants out of the soil. 9. Measure the mass of the seeds and record the data. 10. Allow the plants to dry out for a few days. 11. Measure the mass of the plants again and record. Data: Area of the soil plot- 180cm2 Days planted- 27 days NPP= Average/180, Answer/27 NPP= 2.45x10-4 Data Analysis: The experimental procedures in this lab did not include a control group nor a independent variable, thus leaving no specific variable that manipulated a certain affect. The NPP of the radishes was calculated using the 69 total plants and 7 masses of each group's plants. The calculated grams per cm^2 per day was 2.45X10^-4 g/cm/day. By finding the average mass of the plants, dividing it by the number of days the plants grew, the NPP could be determined. Similar to the last, the average of the grams per plant per day was 6.44X10^-4g/plant/day. Conclusions: The calculations proved the experiment to heed the hypothesis stated that the NPP of the radishes would potentially be less than .0025. The NPP actually turned out to be quite a miniscule number. In an indoor setting, the sun was not used as the energy source for the plants, and that groups were responsible for watering their plants every other day, which could have resulted in a significantly lower NPP. In order for photosynthesis to take place, plants need to capture and store solar energy, collect water, and have a constant source of CO2. Some of these factors influencing plant productivity can simply not be replicated in an classroom. Just as the many factors that could have resulted in an experimental error, NPP is also affected by too many environmental factors to be scaled down to such a simple model of complex processes that go on in ecosystems, such as the carbon cycle. Plants can help the environment, by taking carbon out of the air and releasing oxygen throughout the processes of respiration and photosynthesis. This interaction clearly identifies the importance of NPP as a basis in the sustainability of an ecosystem. Therefore, understanding the primary productivity of an ecosystem should be important to every human being. This information would be important to scientists, especially environmentalist, and environmental organizations that advocate ecological balance by sustaining high levels of energy input in an ecosystem. Citations: "Net Primary Productivity." Net Primary Productivity. N.p., n.d. Web. 16 Mar. 2015. |