NPP Lab Report
Collaborators: Julianne Rodgers, Logan Shytle, Christina Filippini. The entire class compiled their individual group data in order to create the class data.
Introduction:
"Primary Production is the rate of accumulation of biomass. Gross primary production (GPP) is the total amount of energy produced by vegetation; some of that energy is used for cellular respiration i.e. for the growth and development of the plant" (Hakim). The Net Primary Productivity is the amount left over after cellular respiration. In other words, NPP is the rate at which an ecosystem accumulates energy or biomass, excluding the energy it uses for the process of respiration. This typically corresponds to the rate of photosynthesis, minus respiration by the photo synthesizers. The NPP of an ecosystem is calculated by subtracting the Gross Primary Productivity (GPP) and the Respiration (R):
NPP= GPP-R.
The Net Primary Productivity of an ecosystem is important to know because a change in NPP can lead to a change in vegetation growth. Ecosystems with a high NPP can support more life and biodiversity because there is more energy being produced at the first tropic level, allowing for more energy to be passed along to the next tropic level than an ecosystem with a low NPP would. For example, tropical rain forests and marshes have high NPP levels which yield 15,000 kcal/m^2/year and 12,000 kcal/m^2/year respectively (rcn.com). This high level of NPP can be contributed the wide range and variety of plants photosynthesizing in the ecosystems. In this lab, radish seeds previously used in the "LD-50 Lab" that had germinated the best were planted and left to grow. Considering this lab was conducted in a temperate climate different from the climate of tropical rain forests and marshes, the NPP will not be as high as it would be in a different climate.
After the seeds were planted, left to grow, and then harvested, they were left to dry. This ideally would yield a more accurate mass of the radishes without the weight of water altering the result.
NPP= GPP-R.
The Net Primary Productivity of an ecosystem is important to know because a change in NPP can lead to a change in vegetation growth. Ecosystems with a high NPP can support more life and biodiversity because there is more energy being produced at the first tropic level, allowing for more energy to be passed along to the next tropic level than an ecosystem with a low NPP would. For example, tropical rain forests and marshes have high NPP levels which yield 15,000 kcal/m^2/year and 12,000 kcal/m^2/year respectively (rcn.com). This high level of NPP can be contributed the wide range and variety of plants photosynthesizing in the ecosystems. In this lab, radish seeds previously used in the "LD-50 Lab" that had germinated the best were planted and left to grow. Considering this lab was conducted in a temperate climate different from the climate of tropical rain forests and marshes, the NPP will not be as high as it would be in a different climate.
After the seeds were planted, left to grow, and then harvested, they were left to dry. This ideally would yield a more accurate mass of the radishes without the weight of water altering the result.
Hypothesis:
If the Net Primary Productivity of the radish seeds is calculated, then the NPP will be found to be less than .006 g/cm^2/day.
Parts of the Experiment:
Independent Variable: No independent variable
Dependent Variable: The growth of the radishes
Controlled Variables: Type of soil, the type of plants, amount of water, the time they grew, the area of the space the radishes were planted in.
Experimental Group: All the radish plants from the different groups
Control Group: No control group
Dependent Variable: The growth of the radishes
Controlled Variables: Type of soil, the type of plants, amount of water, the time they grew, the area of the space the radishes were planted in.
Experimental Group: All the radish plants from the different groups
Control Group: No control group
Materials:
- Radish seeds
- Soil
- Empty juice/ milk carton
- Water
- Scale
- Ruler
Method:
1. Fill the empty carton with soil
2. Pick out the best germinated radish seeds from the "LD-50 Lab"
3. Weigh the seeds
4. Be sure to record the mass of the seeds and the number planted
5. Measure the area of the plot of soil in square cm
6. Plant the seeds, do not burry them too deep into the soil
7. Allow the seeds to grow for a few weeks.
8. Carefully pull the plants out of the soil
9. Measure the mass of the plants and record
10. Allow the plants to dry out for a couple days
11. Measure and record the mass
2. Pick out the best germinated radish seeds from the "LD-50 Lab"
3. Weigh the seeds
4. Be sure to record the mass of the seeds and the number planted
5. Measure the area of the plot of soil in square cm
6. Plant the seeds, do not burry them too deep into the soil
7. Allow the seeds to grow for a few weeks.
8. Carefully pull the plants out of the soil
9. Measure the mass of the plants and record
10. Allow the plants to dry out for a couple days
11. Measure and record the mass
Data:
Area of the soil plot: 180cm^2
The plants grew for 27 days
Average Change in Mass: 1.2 grams
Number of Plants total: 69
NPP (in g/cm^2): 2.469 X 10^-4 g/cm^2/day
NPP (in average g/ plant): 6.44 X 10^-4 g/plant
The plants grew for 27 days
Average Change in Mass: 1.2 grams
Number of Plants total: 69
NPP (in g/cm^2): 2.469 X 10^-4 g/cm^2/day
NPP (in average g/ plant): 6.44 X 10^-4 g/plant
Data Analysis:
The data can only be analyzed to a certain extent given that there is neither an independent variable nor control group to compare the results to. The Net Primary Productivity of the radish seeds was found in terms of grams per square centimeter by taking the average of the seven different masses(1.2) and dividing it by the area of the soil plot (180), then dividing it by 27 days. In order to find the NPP in terms of the average gram per plant, the average mass (1.2) was divided by the total number of plants (69). The data inconclusive as to whether the NPP of these radishes is a high or low NPP. The NPP per gram per plant was greater than the NPP per gram per square centimeter. This means that given the area, more energy was produced per plant rather than per square centimeter. If there had been more radish seeds planted within the same area, the NPP per gram per square centimeter would have increased.
Conclusion:
The Net Primary Productivity of the radish seeds was 2.469 X 10^-4 g/cm^2/day or 6.44 X 10^-4 g/plant. The NPP can vary due to a variety of changing factors. According to umich.edu, "climate and nutrients control primary productivity. Areas that are warm and wet generally are more productive". This statement makes sense considering that tropical rain forests, which have warm, wet climates, are more productive than deserts that are only dry and warm or the tundra where it is dry and cold. Additionally the amount of water available, the amount of sunlight the plant receives, and the amount of space it has to grow can affect the productivity. If there is a sufficient amount of water, sunlight and space available to the plant then the plant will have high productivity. This is because plants make their energy through photosynthesis. Therefore the more water, carbon dioxide and sunlight available for the plant, the more it will taken in, thus yielding a higher amount of biomass products such as glucose and oxygen. If there is not a sufficient amount of water, sunlight and space available to the plant, then the plant will have a low productivity. If a plant does not have enough water, carbon dioxide, and sunlight, it will not be very productive.
Net Primary Productivity is important to know about in order to protect ecosystems. If the NPP decreases, that means there is less energy being put into the ecosystem beginning at the first trophic level. This smaller amount of energy available in the first trophic level will have a chain effect and cause problems and disrupt the higher trophic levels. A higher NPP also means that more carbon dioxide is being taken out of the atmosphere, which is beneficial to the environment and the earth. Protecting ecosystems such as tropic rainforests, that yield a high level of productivity every year, will in the long term not only be beneficial for that specific local ecosystem but the entire planet.
Net Primary Productivity is important to know about in order to protect ecosystems. If the NPP decreases, that means there is less energy being put into the ecosystem beginning at the first trophic level. This smaller amount of energy available in the first trophic level will have a chain effect and cause problems and disrupt the higher trophic levels. A higher NPP also means that more carbon dioxide is being taken out of the atmosphere, which is beneficial to the environment and the earth. Protecting ecosystems such as tropic rainforests, that yield a high level of productivity every year, will in the long term not only be beneficial for that specific local ecosystem but the entire planet.
Citations:
Hakim.
"Gross and Net Primary Production." The Earth's Energy Balance.
Abdulhakim Abdi, 10 Nov. 2012. Web. 10 Mar. 2015.
http://www.hakimabdi.com/20121110/gross-and-net-primary-production/.
"The Flow of Energy: Primary Production." The Flow of Energy: Primary Production. University of Michigan, n.d. Web. 12 Mar. 2015. <http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/energyflow/energyflow.html>.
"Ecosystem Productivity." Ecosystem Productivity. N.p., 11 Feb. 2011. Web. 12 Mar. 2015. <http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/N/NetProductivity.html>.
"The Flow of Energy: Primary Production." The Flow of Energy: Primary Production. University of Michigan, n.d. Web. 12 Mar. 2015. <http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/energyflow/energyflow.html>.
"Ecosystem Productivity." Ecosystem Productivity. N.p., 11 Feb. 2011. Web. 12 Mar. 2015. <http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/N/NetProductivity.html>.