Ocean Acidification Lab

to dry for 5 days and then the pH, calcium concentration, and Kh levels were recorded for each samples. Finally, the clamshells were placed back into seawater solution to soak again and their final weights were recorded. Results : Table 1: Test subject masses. Clam – ambient Clam – treatment Initial mass (g) 0.232 0.40 Wet mass (g) May 21 0.216 0.338 Dry mass (g) May 23 0.209 0.361 Wet mass (g) May 23 0.209 0.37 Table 2: Masses of clams over a 5day period. Clam - ambient Clam - treatment Initial mass to wet mass May 21 0.232 – 0.216 = 0.016 0.40 – 0.338 = 0.062 Initial mass to dry mass may 23 0.232 – 0.209 = 0.023 0.40 – 0.361 = 0.039 Initial mass to wet mass may 23 0.232 – 0.209 = 0.023 0.40 – 0.37 = 0.03 Wet mass May 21 to dry mass May 23 0.216 – 0.209 = 0.007 0.338 – 0.361 = - 0.023 Wet mass May 21 to wet mass May 23 0.216 – 0.209 = 0.007 0.338 – 0.37 = - 0.032 Table 3: Water chemistry parameters for seawater control. pH – ambient pH – treatment Calcium – ambient Calcium – treatment KH – ambient KH - treatment Start 7.35 6.55 600 ppm – 30 drops 580 – 29 drops 14 drops – 250.6 ppm 16 drops – 286.4 ppm 1.5 hours later 7.45 6.67 540 ppm 500 – 25 drops 14 drops – 250.6 16 drops – 286.4 5 days later 7.94 7.69 520 ppm 440 ppm 14 drops 12 drops – 214.8 ppm Net change 0.59 1.14 -80 -140 0 -71.6 Table 4: Water chemistry parameters for clam treatment. pH – ambient pH – treatment Calcium – ambient Calcium – treatment KH – ambient KH - treatment Start 7.46 6.62 460 ppm 520 – 26 drops 14 drops – 250.6 ppm 14 drops – 250.6 ppm 1.5 hours later 7.47 6.58 560 ppm -28 drops 560 – 28 drops 14 drops – 250.6 ppm 16 drops -286.4

c) d) e) f) g)

Discussion: The purpose of this experiment was to test the effects of ocean acidification on skeletons of corals and shells. After several days of testing it was found that the clamshells gained mass over time in seawater, whereas, in clam solution the clam loss mass. In addition, it was measured that the pH of the clam treatment was lower than the pH of the clam ambient and the same for the seawater ambient and treatment. However, the difference in pH between seawater ambient and treatment versus clam ambient and treatment is that the clam ambient and treatment are slightly higher than the seawaters. Following after, it was found that the calcium concentration in both the seawater ambient and treatment decreased over the 5-day period. Whereas, the clam ambient and treatment solutions initially increased within the first 1.5 hours and then proceeded to decrease at the 5 th day. Finally, the Kh for each solution was found, the Kh for seawater ambient remain unchanged over the course of the 5 days. On the contrary, the Kh for seawater treatment and clam ambient both remain unchanged after 1.5 hours and then decreased by the 5 th day. For the clam treatment the Kh initially increased after 1.5 hours but then decreased by the 5 th day. Next, there were several t-Test ran in order to determine the p values for both seawater and clam, ambient and treatment. The p value for the net change in clam ambient and clam treatment mass was 0.31843554, which is above 0.05 indicating there is not enough evidence to reject the null hypothesis. Failing to reject the null hypothesis, means that there is not a significant change in clam mass within a few days, however it is still possible that over a course of several days or even weeks, there could be a significant change in mass.