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THE PREDICTED EFFECTS OF GLOBAL WARMING AND CLIMATE CHANGE ON RYEGRASS

Frank Jiang, Danielle Karacsony, Sophie Lederer, Brian Li,

Rachel Mumma, Roma Patel, Jacklyn Pezzato, Kelsey Schroeder

Advisor: Dr. Arun Srivastava Assistant: Gillian Bradley

ABSTRACT As global warming becomes an increasingly salient problem, its effects must be analyzed from different perspectives. One of the least understood environmental relationships is that between atmospheric carbon dioxide, temperature, and plant biomass. Plants are a necessary recycler of carbon dioxide, so if their growth is accelerated due to global warming, they may be able to remove carbon dioxide from the atmosphere at a faster rate. While studies have initially concluded that elevated carbon dioxide levels indeed facilitate photosynthesis and thus yield greater plant growth, most studies agree that significant uncertainty remains. This lies in the role temperature may play in stunting the terrestrial carbon storage efficiency of soil. As such, a new experiment in which temperature and carbon dioxide levels were manipulated on ryegrass was developed. Height of plant growth, carbon-nitrogen soil ratios, and other qualitative characteristics were recorded. Results showed that higher temperatures yielded better plant growth, though this might have also been because of variable light settings or water intake. Carbon dioxide, on the other hand, led to grass with overall greater biomass but less height. These conclusions have several interpretations, so further research is necessary to refine current knowledge on this subject. For instance, if all variables but temperature are controlled, its effects on carbon storage efficiency will be more accurately measured. Other variables, including light and water, can also be better controlled for more precision. With such future steps, the relationship between plant biomass and its environment will be clarified and fully understood. INTRODUCTION Climate change is a natural periodic process. Ice Ages are followed by warmer interglacial periods as the Earth alternates between hot and cold cycles. However, recent global warming has progressed at an unprecedented rate—accelerating so fast, in fact, that many species have been unable to adapt to the rapid change in conditions (1). As this occurs, entire ecosystems may be irreparably changed.

While atmospheric carbon dioxide (CO2) has fluctuated throughout geological time, it has increased recently due to anthropogenic factors, including consumption of fossil fuel and deforestation. CO2 partial pressure has increased from 27 Pa to 35 Pa since the onset of the industrial revolution 140 years ago, and is expected to rise to 70 Pa by the end of the century (23). While the existence of climate change is not a problem in itself, the rate at which the Earth’s temperature is shifting is. The carbon cycle, a fundamental and natural process, plays a vital role in this change because it is based on the movement of carbon from inorganic to organic molecules, manifesting primarily as carbon dioxide in the atmosphere. Carbon dioxide has an

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important property that other major components of air, such as oxygen (O2) and nitrogen (N2), do not. CO2 is a greenhouse gas and thus absorbs heat. Therefore, as the concentration of atmospheric CO2 continues to increase, there will be a subsequent increase in temperature around the world (2).

Estimates have shown that by 2050 there will be an overall increase in global temperature

of approximately 2.8०C, or 5०F (3). While this may appear trivial, the profound impact of variations in atmospheric conditions is actually the preeminent threat to biodiversity (4). In fact, studies have shown that all species may not be able to adapt to a changing environment (5). In addition, previous literature suggests that atmospheric carbon dioxide levels will rise from 400 parts per million (ppm) today to 625 ppm by 2050 (6). This dramatic increase in carbon dioxide levels will have many adverse effects on the global climate as well as the species that inhabit it. For instance, plants have already begun to adapt to hotter conditions by utilizing C4 photosynthesis, a process that requires less water and can thrive in harsh conditions (7).

Such adaptations will soon be necessary. As carbon dioxide emissions collect in the

Earth’s atmosphere, a “greenhouse effect” will be created. Trapped heat will cause an increase in global temperature (8), and much of the ocean will absorb additional carbon dioxide, raising the acidity and temperature of the water (9) and elevating the sea level from melting ice caps. In turn, coastal erosion will occur and directly impact nearby inhabitants, who will become more susceptible to damage from storm waves. Warmer temperatures will also increase the amount of water vapor in the lower atmosphere, resulting in a more humid environment and unpredictable weather patterns.

In order to understand global warming, the carbon cycle itself must first be understood.

There are numerous factors in the carbon cycle, including the air-sea gas exchange, decomposition of organisms, and the carbon stored in the soil, ocean sediments, and fossils (Fig. 1) (10, 11, 12). The two most significant processes in the carbon cycle, however, are photosynthesis and respiration. During respiration, organisms take in oxygen and release carbon dioxide. The released carbon is recycled during photosynthesis and returns to its organic state (13). Plants then use carbon dioxide to create simple glucose and other biological components according to the following equation:

6CO2 + 6H2O + light → C6H12O6 + 6O2

Fig. 1 The carbon cycle. An essential natural process that begins as animals respire and release CO2. Exploitation of fossil fuels also releases CO2. Plants take in the CO2 and exchange it for O2, though recently the cycle has destabilized with deforestation and other anthropogenic problems.

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The relationship between photosynthesis and carbon is intricate. A greater amount of carbon dioxide in the atmosphere has been shown to improve plants’ ability to perform photosynthesis (14). Photosynthesis is the ultimate source of biomass in plants, as the sugars produced become the organic molecules the plant needs to grow (15). Through photosynthesis, light energy converts carbon dioxide into the chemical energy contained in carbohydrates and other biological components (16).

A plant must also take in nutrients from the soil, and therefore the composition of the soil

is very important to plant growth. By determining how much the composition of the soil changed over time, one may determine how much of what nutrients the plant used during its growth. Three important nutrients in determining the rate of plant growth include potassium, phosphorus, and nitrogen. While not directly involved in plant structure, potassium takes an active role in many biochemical functions, including but not limited to cell division and resistance to disease. Phosphorus, another vital mineral, plays an important role in energy storage and chemical transfer within the plant. Finally, nitrogen, in the form of nitrates, is a necessary component for plant growth. Found in assorted plant structures, adequate levels of nitrogen are needed for healthy plants and increased yields (17).

However, with increased amounts of carbon dioxide in the atmosphere, the amount of carbon the earth’s ecosystem takes in could increase. Carbon sequestration might also be limited by the availability of nitrogen in the soil. Therefore, the carbon-nitrogen ratio of the soil has important ramifications for the terrestrial ecosystem productivity, atmospheric carbon dioxide concentration, and the resulting feedbacks on climate as carbon uptake by vegetation exceeds carbon loss from the soil. Plant nitrogen productivity is defined as how much a plant's growth depends on the amount of internal nitrogen and as the increase in a plant's dry biomass per unit time and per unit plant nitrogen content. Efficient use of nitrogen during photosynthesis has been shown to lead to higher plant productivity (18). Gross plant productivity is equivalent to the photosynthetic rate, or the CO2 assimilation rate. Nevertheless, net productivity must take plant respiration into account (19).

There is also an ongoing debate about whether plants, in the forest or grasslands, are

likely to become a net carbon source or sink as a result of increasing temperature, higher concentrations of atmospheric CO2, or other environmental variables by 2050. These uncertainties are mainly attributed to the spatial consistency of measured biomass productivity and how plants’ structure and dynamics change over time. Recent studies by Amazon Forests Inventory Network (RAINFOR: 20) suggested that the average rate of biomass growth was stimulated by environmental changes with a significant increase in turnover rates (21). However, in another study at La Selva, Costa Rica, researchers found that growth rate decreased and similar trends are reported from Panama and Malaysia (22).

High biomass indicates high glucose production, so calculations can be made regarding

the rate of carbon dioxide uptake to determine how additional carbon dioxide in the atmosphere will affect plant growth (23). This increase in glucose resulting from an increase in CO2 elongates the carbon cycle by decreasing the amount of carbon dioxide in the atmosphere. Previous literature by Hughes and Benemann (24) describes observations that conclude that over ten times more CO2 is fixed by plants into biomass and annually released by decomposers and

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food chains than is emitted by the burning of fossil fuels. With approximately half of the carbon circulating the Earth because of mankind, gaining the ability to fixate it would be effective in decreasing the greenhouse gases in the atmosphere.

However, not all of the carbon released is accounted for each year, causing a shift in the

stability of the cycle. With increasing industrialization, humans burn fossil fuels for energy, and tons of carbon dioxide are released into the atmosphere each year. An increased amount of carbon dioxide in the air will dissolve more readily into the surface water of the ocean and become fixed in plants’ biomass. This increase alone results in a facilitation of photosynthesis, storing more carbon in terrestrial carbon sinks. However, since temperatures will also rise as part of the climate change process, plant maintenance and soil respiration rates will increase as well, reducing terrestrial carbon storage efficiency. Because of such uncertainty, it is clear that further investigation into the relationship between plant biomass and global warming is necessary.

Two different methods exist for measuring the biomass in plants, wet and dry. To

measure the dry biomass of a plant, the water inside the plant must first be evaporated so that only the organic matter is left. According to Hickman and Pitelka (25), the organic material represents the energy allocation in the plant, and obtaining the mass of different parts of the plant distinguishes the tissues in the plant that require the most energy. On the other hand, the wet weight is a good indicator of both the amount of water the plant contains and the degree of turgor pressure in the plant. The change from wet weight to dry weight indicates how tolerant of stress the plant is, with smaller cells being more tolerant of low water potential (26).

As plants are often subjected to periods of soil and atmospheric water shortage, they have

developed complex responses, ranging from drought-avoidance to stress-resistance. Chaves et al. (27) have studied alterations in nitrogen and carbon metabolism and concluded that they lead to changes in the root to blade ratio and the temporary accumulation of reserves. In addition, plants may regulate carbon metabolism through processes other than photosynthesis, an important defense mechanism in the absence of water.

Biomass measurement is easily possible on a small scale through an invasive method, but

a method that is less destructive for larger scales is greatly preferred. Recent novel methods to determine biomass on a larger scale have included 3D quadrat, plate meter, and visual estimation (28). These are methods that can be implemented if this experiment is carried out on a wider scale.

Beyond just measuring biomass, it is also necessary to determine the carbon-nitrogen

content of soil. As mentioned before, this poses many different ramifications to growth. For example, carbon sequestration can help growth, but higher temperatures usually signify respiration and less carbon intake. At the same time, Haney et al. (29) has shown that strong carbon-nitrogen ratios can lead to more productive and efficient growth. As such, if environmental conditions can be shown to greatly affect soil conditions, this can lead to new insights in plant growth.

Höglind et al. (30) have begun such investigations by attempting to model future and

past-based global scenarios. Assorted climate models were tested on two different grass types,

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with the conclusion that there would be a projected increase in grass yield with rising temperatures in the future. However, the exact impacts of global climate change on the environment remains unclear.

The purpose of this experiment was thus to analyze the effects of global warming on plant growth through the study of ryegrass under various conditions. Increased carbon dioxide levels and raised temperatures were used in order to compare the growth of plants under present-day conditions to that of plants in 2050. If plant photosynthesis is dependent on CO2 concentration, greater CO2 concentration will cause greater plant growth. In addition, if increased temperature decreases the ability of the plant to take in carbon dioxide by increasing soil respiration levels, lower temperature will be most beneficial to plant growth. A consensus could not be reached over whether or not a lower temperature or higher CO2 levels would be more beneficial to the plant, though the study should establish such conclusions. MATERIALS AND METHODS Initial Preparation Germination of Gulf Annual Ryegrass (Lolium multiflorum Lam.)

In order to begin experimentation, seeds first had to be germinated (Fig. 2). One liter of Miracle-Gro Organic Choice Garden Soil® was poured into four EZ foil® casserole pans (11 ¾ .mbn, m.mn in. X 9 ¼ in. X 1 ½ in.) each. Six grams of ryegrass seeds were spread evenly across the surface of the soil before being covered with an additional five hundred mL of soil. Five hundred mL of water was then added to each tray for moisture.

All four trays were placed in a growth chamber (Fig. 3) for seven days with no light at

32°C. While in the chambers, the trays were rotated from top to bottom for even heat distribution and watered as needed to keep the soil moist. Variable conditions were not enforced at this stage

Fig. 2 Three of the four trays used in growing ryegrass

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to encourage even germination. Furthermore, as plant biomass is dependent upon photosynthesis, conditions and light are meaningless until the grass has grown.

Preparation of Containers As the seeds germinated, plastic containers were prepared for future testing. Two of the plastic containers were modified to allow the injection of CO2. A Bunsen burner was used to heat one end of a gold connector. Once hot, the connector was pressed into a container and a perfectly fitted hole was melted into the plastic (Fig. 4). After both of the gold connectors were securely fitted in their respective holes, the tubing for the carbon dioxide had to be attached. The plastic tubing inside the container was heated and fused to the gold connector. This process for attaching the tubes was performed twice per container. It was done once to connect the outside tubing with the pressurized CO2 gas cylinder and once for the tubing inside the box. Experimentation Experimental Setup After germination occurred, grass growth was observed. In the four trays prepared, there was a slight variation in the density of the grass - the two trays with lower carbon dioxide levels, regardless of temperature, grew denser than the others.

Fig. 3 Growth chamber with trays of grass Fig. 4 Gold connector hold burned into plastic

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To compensate for this variation, each tray was cut in half. Then the trays with sparse growth were paired with trays situated in low carbon dioxide levels (Fig. 5). This allowed for an equal distribution of grass. To ensure accurate simulations of the four different environments (Fig. 6), each plastic container was covered and taped shut. The high CO2 plots were pumped to 625 ppm with a carbon dioxide tank. The high temperature plots were placed in a growth chamber. The low temperature and low carbon dioxide conditions were both set to room levels. To further model each environment, 50 mL of water were added inside the plastic container to create a moderate level of humidity for the grass in the aluminum tray. A thermometer was placed in each container to monitor temperature (Fig. 7).

Fig. 6 Chart of four different environments and their respective conditions

Conditions Low Temperature (room) High Temperature (29°C)

Low CO2 (room) Tray 1- Present Conditions Tray 2

High CO2 (625 ppm) Tray 3 Tray 4- 2050 Conditions

Fig. 7 Final set-up of container with water and thermometer

Fig. 5 Recombined tray of grass from two trays

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Data Collection

Data, such as height and other salient qualitative observations, were collected every other day. To calculate the average height of each tray, ten random blades of grass were measured. On the seventh day in the controlled environment, grass samples were taken to determine the biomass and soil content. Biomass was measured for both aboveground and belowground, providing an overall biomass. This process was begun by removing a 5.5 x 6.25 cm plot of grass and soil from each of the four conditions represented. Excess soil was as gently removed from the plot of grass as possible by hand. To ensure that most of the soil was being removed, the grass was washed and then lightly dried with cool air so that the water inside the grass did not evaporate. This process allowed for maximum soil removal (Fig. 8).

Fig. 8 Separation of grass from the high CO2, low-temperature environment and soil by hand

Since the roots and the blades of the grass needed to be measured for biomass separately,

each shoot of grass was cut directly at the soil line. The wet mass of each component was taken. The roots and blades were then placed in an oven for one hour to allow for the evaporation of water from the grass before the mass was taken again, this time yielding the dry biomass.

The soil that had been removed from each plot was tested for phosphorus, nitrate, pH, and potassium, using a Soil Test Kit by Luster Leaf Products, Inc. To test for phosphorus, a solution of soil and phosphorus extractant, containing molybdate, was created to form a phosphor-molybdate compound. A reducing agent which included stannous chloride was added as an indicator of the amount of phosphorus present in the soil. Nitrogen, in the form of nitrate, was tested for by utilizing cadmium, a component of a nitrate-reducing agent that produces a red dye through a diazotization reaction, meant to indicate the amount of nitrate present in the soil. Barium sulfate and a pH testing solution created a mixture for determining the acidity of the soil.

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In testing for potassium, the soil was made alkaline, and the potassium reacted with a sodium tetra phenyl boron solution to form a precipitate. The resulting cloudiness of the solution indicated how much potassium was present in the soil (Fig. 9).

Fig. 9 Different soil tests (pH, phosphorus, nitrate, and potassium from top left to bottom right)

with charts for concentration analysis

In addition, the carbon-nitrogen ratio was tested using the Solvita gel system. Clumps and wood chips were removed from the soil, and containers were filled up approximately halfway with soil. The soil was then allowed to stand for one hour before the carbon dioxide and ammonia probes were placed inside and the caps screwed on for four hours. The color of the strips at the end of the four hours indicated the respective concentrations (Fig. 10).

Fig. 10 Carbon dioxide and ammonia probes, along with CO2 chart for color analysis

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RESULTS

Qualitative observations of grass color and relative density were made every time the height of the grass was measured. Both of the high temperature plots were very green throughout the experiment. The low CO2 plot was the densest of all the plots, and the high CO2 plot was the least dense. The low temperature plots were yellow-green and maintained medium densities, but the high CO2 plot was slightly denser than the low CO2.

Fig. 11 Height of grass over time

The heights of the grass in the low CO2 plots grew much taller than the grass in the high CO2 plots (Fig. 11). In general, they exhibited increased height and growth rates compared to the high CO2 plots, though there may be some sampling error due to the fact that only ten randomly selected blades of grass were selected. The high temperature, low CO2 grass was much taller than its high CO2 counterpart, indicating that the level of CO2 in the environment does have an effect on the length of the grass blades. Separate analysis of the low temperature grass heights leads to the same conclusion.

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Fig. 12 Wet biomass of grasses

The wet biomasses of the samples in each set of conditions shows that most of the wet biomass resides in the blades (the above-ground portion of the grass), instead of in the roots (Fig. 12). The wet biomasses of the two low temperature plots show very similar results regarding wet biomass. However, the high temperature plots contrast each other in a way that allows conclusions to be drawn about the effect of CO2 on biomass. The high temperature, low CO2 plot had the greatest wet biomass by far. In fact, its total wet biomass almost doubled that of each of the other samples. The high temperature low CO2 plot appears to have grown the best overall when looking at the heights and the wet biomass. The opposite is true for the high temperature, high CO2 plot. However, this dramatically changes when the dry biomass is taken into account.

Fig. 13 Dry biomass of grasses

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The dry biomass is effectively a measurement of the total tissue in the plant. The dry biomass data (Fig. 13) is an extremely dramatic change from the wet biomass data. First of all, the majority of the mass seems to reside in the roots when the dry biomass is taken instead of in the blades like when the wet biomass was taken. This indicates that most of the grass’s water weight resides in the blades and that most of the grass’s tissue is contained in the roots. Also, the high temperature, high CO2 sample went from having the most wet biomass to having the least when the water was removed. Conversely, the high temperature, high CO2 sample had the greatest dry biomass by far even though it had the lowest wet biomass. Therefore, this data suggests that high CO2 levels have a significant effect on the dry biomass of the grass in that high CO2 levels lead to an increase in plant tissue.

Fig. 14 Percentage of water in biomass

It is evident that high temperature and high CO2 has the lowest percentage of water by biomass (Fig. 14) and that high temperature and low CO2 has the highest percentage. This explains why there was such a drastic change from the wet biomass graph to the dry biomass graph. The two low temperature plots had very similar percentages of water, which explains why both their dry and wet biomasses do not differ from each other much.

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Fig. 15 Soil testing results

1 - low CO2, low temp

2 - low CO2, high temp

3 - high CO2, low temp

4 - high CO2, high temp

Initial Testing pH Potassium Nitrate Phosphorus CO2 Ammonia

Slightly acidic High-medium Medium High-medium 8 (minimal) 5 (minimal)

Slightly acidic High-medium Medium High-medium 8 5

Slightly acidic High-medium Medium High-medium 8 5

Slightly acidic High-medium Medium High-medium 8 5

Test Day 2 pH Potassium Nitrate Phosphorus

slightly acidic high-medium low high-medium

neutral high-medium medium-low high-medium

slightly acidic high-medium low high-medium

slightly acidic medium-low low high-medium

Test Day 3 (Final Day) pH Potassium Nitrate Phosphorus CO2 Ammonia

neutral medium low high-medium 8 5

neutral medium low high-medium 8 5

neutral medium low high-medium 7.5 (a bit more) 5

neutral medium-low low high-medium 7.5 (a bit more) 5

After the two days of soil testing (Fig. 15), results were compiled and compared. Significant changes occurred in pH, potassium level, carbon dioxide level, and amount of nitrates, though the pH change may be attributable to carbon’s buffering effect. After the first testing day, three of the four trays proved to be slightly acidic, but after two more days of growth, all four trays changed back to neutral. In addition, three of the four trays decreased in potassium levels from medium-high to medium. The amount of nitrates also decreased, most likely suggesting that it was used up as the grass grew (nitrogen and potassium are essential for plant growth). Furthermore, while ammonia levels remained constant, the high CO2 plots wound up increasing slightly in soil carbon content, suggesting that the carbon wound up being sequestered as expected. CONCLUSION

Initially, the grass that grew in the low carbon dioxide and high temperature environment was observed to be sublime in terms of both height and color after two days of exposure. However, after the dry biomass was calculated, it became apparent that the grass in this environment had one of the least total biomasses. As a result of the significant difference between the dry and wet biomasses, the grass growing in the low temperature and high carbon dioxide conditions was the least stress-tolerant of the grasses in terms of water potential.

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The initial hypothesis was both supported and refuted. The “green” growth, or the growth

of the blade, was the highest when the CO2 levels were low. However, the total biomass was the greatest in conditions with high CO2 levels. Most of the carbon dioxide must have gone to the soil and roots since the blade growth in conditions with high CO2 levels was not apparent. With greater amounts of carbon dioxide in the roots, a more intricate support system grew. In turn, this root system would provide long term annual stability to prevent the grass from dying. Pineapple, cacti, and other plants growing in high temperatures undergo similar stress-resistant techniques to survive in harsh climates using C4 photosynthesis.

While high amounts of CO2 did not lead to ideal grass in terms height, density, or

appearance as expected, it did lead to an overall increase in dry biomass when temperature was held constant. However, the reason why the grass blades’ mass decreased in high carbon dioxide environments remains unknown. In order to further understand this topic, the experiment must be modified to account for specific variables since the current experiment did not present justification.

During soil testing, there were several salient factors which changed significantly. The

pH levels went from slightly acidic to neutral in all conditions, though this might have been because of carbon’s buffering effect as it was gradually sequestered over time. Furthermore, both potassium and nitrate levels decreased as the two were likely used for plant growth. Thus, these changes in soil content were relatively expected but still helped to yield insights as to plant development.

On a wider scale, an increase in CO2 in the atmosphere would lead to fewer plants with a

high amount of wet biomass in blades of grass. Since these blades are responsible for photosynthesis, the amount of oxygen released from plants into the atmosphere would significantly decrease. Furthermore, since root biomass increased in the high CO2 and high temperature environment and roots undergo respiration, the above implications are further emphasized. These factors, combined with deforestation, could quickly worsen in a vicious circle of climate change, making the reparation process much harder. Limitations

Although we attempted to design a controlled and accurate experiment, several possible sources of error may have affected our results. After germination, the “high temperature” samples were grown in a growth chamber, while the “low temperature” samples were grown in an isolated room. The light in the growth chamber was more powerful than the light in the isolated room, and within the growth chamber, the top shelf and bottom shelf experienced different light intensities. Measured at 500 nm, the light in the isolated room was 172 nW, the light on the top shelf of the growth chamber was 305 nW, and the light on the bottom shelf of the growth chamber measured 218 nW. For this reason, the “high temperature, low CO2” sample was exposed to considerably more light than the other samples, potentially explaining why this sample was the most dense and green. Additionally, the white walls of the growth chamber may have reflected more light than the darker beige walls of the isolated room, exposing the “high temperature” samples to more intense light and thus extra room for growth.

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Our first measurement involved the height of the grass in each tray. So as to avoid too

invasive a procedure, we chose to measure the height of six random blades in each sample. Although this method did allow the grass to grow regularly without any change, it also may have affected our results. It is possible that taller-than-average grass blades were selected in one sample while shorter-than-average blades were measured in another. Because of this sampling error, the height of a particular sample may have been misrepresented by the data collected. However, this likely is not very significant.

Our second measurement, biomass, presented possible sources of error as well. When

extracting a sample to measure, we used a constant area, but the volume of our sample may have differed as the depth of each tray varied slightly. This would result in a slightly inaccurate comparison of the biomasses of each sample. A random patch of grass for each biomass measurement was chosen as well, and it is possible that the selected patch for each tray was not the best representation of ryegrass growth in that sample. Furthermore, when separating the roots from the blades, some contamination or accidental mixing may have occurred and skewed the results. This could have led to an uneven ratio between the root and blade mass. Some soil also may have been included in our biomass measurements since the grass is hard to completely clean and separate. Future Direction For future experiments, the effect of different lighting on plant growth could be tested to ensure greater precision. Another variable that could be investigated further is the amount of water given to each plot of grass. The grass in this experiment was watered as needed to maintain a relatively consistent moisture level. This ensured that water would not limit the growth of the grass nor add another variable to the experiment. For instance, the higher temperature plots might have been given more water over the course of the experiment and allowed them to grow at a faster rate. Therefore, a future experiment could add water and lighting as additional variables alongside temperature and CO2. ACKNOWLEDGEMENTS

The authors of this study would first and foremost like to thank Dr. Srivastava for his patient suggestions, wise thoughts, and detailed explanations. We simply could not have had a better mentor. We would also like to thank Gillian Bradley for her unending kindness and helpful comments. Further thanks go to Dr. Miyamoto and the Governor’s School in the Sciences staff for putting together such an amazing experience. And last but definitely not least, our thanks go to the Governor’s School Scholars themselves, for without them we could not have met such an incredible group of inspiring people. REFERENCES 1. [US EPA] United States Environmental Protection Agency. 2012 June 14. Climate Change

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