Bubbles Protocol: The Effect of Carbon Dioxide on Sea Water
Introduction: Carbon is emitted into the environment very regularly and has increased with the dawning of civilization and industrialization. With the rise of industrialization also came a rise in the acidity levels of the ocean. From the time between 1751 to 1994, the pH of the ocean increased by 26% in acidity. Since the ocean is a major carbon sink, it absorbs a lot of carbon daily, taking in more than one million metric tons of carbon dioxide. As an essential component, its acidity level must be maintained. This also applies to marine organisms because carbon is necessary for them to build their shells and skeletons. It is also a necessary intake for plants to photosynthesize so that they could produce their energy and other byproducts (such as sugar and oxygen). However, with the excessive amount of carbon emission into the atmosphere, other factors are being affected. Carbon is released into the atmosphere through the burning of fossil fuels and the destruction of main carbon sinks. A major carbon sink is the ocean, which absorbs carbon dioxide in three processes. It starts with the the absorption of CO2, then it bonds with water molecules to form carbonic acid. It then moves on to separate the carbonic acid into hydrogen ions and bicarbonates which increases the acidity of the ocean.
The maintenance of the acidity level of the ocean is important for all marine plants and animals. This procedure serves to test the effects of carbon dioxide on water. When carbon dioxide is added into a beaker of ocean water and separate beakers of cold, hot and room temperature tap water, calcium carbonate will be formed and broken apart and the pH of the ocean water will turn more acidic than that of the different temperatures water.
Methods and Materials: In order to view the effects of carbon on the acidity level of water, carbon dioxide was added as a treatment to both distilled and ocean water. This was done by adding 100 mL of saltwater to a 500 mL beaker and then using a transfer pipette to add 1 mL of universal indicator. A white sheet of paper was then placed under the beaker to record the initial color of the pH of the water. After recording the pH, a piece of cling wrap was stretched onto the top of the beaker to completely cover it and a straw was poked through the film. The beaker remains over the white sheet of paper as someone breathes into the beaker through the straw for two minutes (in 30 second intervals) and the change in color of the water is recorded. The color data that was recorded was then converted into numbers and plotted on a graph. These steps were repeated for the room temperature tap water, hot saltwater and cold saltwater experimental conditions with the addition of placing the cold saltwater beaker in ice for 3 minutes and placing the hot saltwater beaker on a hotplate for 3 minutes. This procedure was repeated in the five groups for the one class, each representing a trial.
Conclusion: According to the results in Table 1, the pH of the different types of water starts to decrease after a 30 second exposure to CO2. The graph illustrates the decrease of the pH of the control variables and the experimental variables. It shows that the control variable (sea water) decreases to a pH of 6.5 after 1 minute and remains at that same pH for the remainder of the observation. It also shows that the cold water variable also decreased to a pH of 6.5 but at a much slower rate. The hot water proved to be the most resistant to changes in pH by CO2 in that its pH only decreased by .5 and remained at a neutral pH level of 7.0 for the remainder of the observation. The data show that the room temperature tap water was the most susceptible to changes in pH by CO2 in that its pH continuously decreased until it reached a pH level of 6.0, relatively more acidic than the other variables.This proves the hypothesis that the control variable will turn more acidic than the other variables in that it was the room temperature variable that was most affected and changed by the exposure to CO2. The data does not support this hypothesis as evidenced by the greater decrease of pH in the room temperature variable than that of the control variable and other variables. Overall, this experiment has revealed that CO2 does affect the pH of water, making it more acidic and contributing to ocean acidification.
Shells Protocol: The Effect of Ocean Acidity on CaCo3 Shells
Introduction: The ocean makes up approximately 71% of earths surface and is the home to numerous organisms, some of which have yet to be discovered. However, due to the decrease of pH in the ocean the organisms residing in the ocean are put in danger. These changes in the acidity of the ocean are mainly due to high amounts of carbon that is constantly and increasingly being emitted into the atmosphere. With the great surface the ocean takes up, it acts as a major carbon sink and absorbs 9.3 billion tons of CO2 per year. This harms not only the ocean but also the marine organisms, specifically shelled organisms. Shelled organisms create their shells through the secretion of calcium carbonate (CaCO3). These shells serve as a protection against many threats to the sea creature but it may not be effective against the harm done by ocean acidification. With the rise of the pH level comes the possible endangerment or extinction of these species and many more. Acidity levels that are higher than usual for these creatures can cause the weakening, degradation and destruction of these shells which make these creatures more vulnerable and easier to attack. It will also reduce the availability of carbonate ions which will prevent these organisms from building their shells and skeletons. This would lead to a sudden decrease in their population which will greatly affect the food chain of the ocean.
The purpose of this procedure serves to examine and observe the effect of acidity on CaCo3 shells to apply it to much greater concepts such as the effect of ocean acidification on marine life as a whole. When shells are placed in a solution with a pH level of 0-6, the shell will disintegrate and become weakened by the acidity. In contrast, if it is placed in a solution with a relatively neutral pH level, or one that is the same as their natural environment, then no harm will be done to the shell. If a shell is placed in an acidic solution such as vinegar, then the shells will dissolve.
Methods and Materials: The untreated shells were first removed from their bags and labeled "E" for experimental and "C" for control with a sharpie. The initial observations of the shells characteristics were then recorded into the data table and then placed on a measuring scale to record the starting mass of both shells. After the initial data was recorded, 150 mL of vinegar was poured into a 500 mL beaker and 150 mL of salt water was poured into a second 500 mL beaker. The pH of the salt water and the vinegar where then tested using pH strips and the color was then recorded after the strips were exposed to the liquids. Next, the untreated shells were added into the beakers at the same time with the control shell "C" placed into the salt water beaker and the experimental shell "E" placed into the beaker of vinegar. The timer was also set for 30 minutes and started at the same time that the shells were placed into the solutions. After 15 minutes had passed since the shells were placed into the beakers, the observations of what was happening to the shells in the different solutions were observed and recorded into the data table. While the untreated shells were being treated, the pre-treated shells (marked "L" for low exposure and "H" for high exposure) were taken from their bag and observed. Their initial masses, which were found on the bag they came in, were recorded and their final mass was taken before the observations. The difference of the masses between the pre-treated shells were then calculated and the the data was recorded. Once the 30 minutes passed for the untreated shells they were removed with tweezers and dried off with paper towels. The recently treated shells were then massed and the difference was calculated and recorded, along with any changes in the characteristics of the shells. The strength of the shells were then tested by placing Biology textbooks on top of the shells and increasing the weight incrementally by adding one book at a time. The data from the procedure was recorded and compared to make conclusions.
Conclusion: According to the results recorded in the table, acidity has a negative effect on CaCO3 shells. It shows that exposure to liquids with high levels of acidity causes the degradation of the shells. With a first glance, it would have been simple to conclude that the longer the shells are exposed to vinegar, the greater the damage to the shell and the greater the loss in mass. However, based on the data of the High Exposure shell, this conclusion is made invalid in that its 720 minute exposure to vinegar didn't have such a drastic effect as the 30 minute exposure of the Experimental shell. Furthermore, the amount of weight needed to crush the "H" shell was the same weight needed to crush the "L" shell. There could have been other factors such as a mutation in the "H" shell that caused it to be more resistant to low pH levels but it can not be known for sure in this procedure. Based on this information, it can be concluded that high levels of acidity (ocean acidification) causes CaCO3 shells to dissolve and disintegrate to a certain degree, thus proving the hypothesis that increasing the acidity of the environment in which marine organisms live in (ocean acidification) is harmful and damaging.