A Scientific Investigation by Coral Bleaching A Scientific Investigation by Sherrie Engram Matthew Grambow Emily Jeng Adam Rynalski Johanna Said

Last Week: We tested our tank’s temperature, salinity, zooxanthellae density, chlorophyll concentration, and protein concentration.

Last Week’s Data: Class Control Tank: -Salinity: 34ppt -Temperature: 25°C Group One Tank (We’re #1): -Original Salinity: 42ppt -Our original salinity was above the class control salinity, so we removed 1.5L seawater and added 1.5L freshwater to equalize. -Modified Salinity: 34ppt

Zooxanthellae Density We took two samples of three polyps each, homogenized them in two milliliters of seawater, and calculated the zoox density based on the averages of the two results. To calculate the zoox counts, three group members each performed five counts, using the hemocytometer. We then averaged all thirty counts from both sample to create the Average Zooxanthellae Counts value. Average polyp weight: .0295g Average Zooxanthellae Counts: 31.7 Average Zooxanthellae Density: 5.38 x 10^8 zoox/g

Chlorophyll Concentration Sample 1‘s Absorbance was: 665= .075 647= .022 630= .035 Sample 2’s Absorbance was: 665= .033 647= .015 630= .038 We found the Ca of Sample 1 to be .852. The Ca of Sample 2 was .364. The total concentration of chlorophyll a in µg/ml of sample 1 was 2.4. The total concentration of chlorophyll a in µg/ml of sample 2 was 1.03. The average concentration of chlorophyll of the two samples was 3.42 µg/ml.

Protein Concentration Data BSA A1 A2 Avg. A mg/ml 0.378 0.399 0.3885 0.5 0.627 0.644 0.6355 0.75 0.94 0.914 0.927 1 1.25 1.211 1.2305 1.477 1.415 1.446

Standard Protein Curve

Protein Concentration Data Residual line equation: y=1.0137x + 0.1799 Polyp absorbance: 0.568 Protein Concentration: 23.13 mg protein/g wet wt

Our Experiment Null Hypothesis: Temperature will have no effect on coral bleaching. Alternate Hypothesis: If the temperature of the seawater is raised, it will induce coral bleaching.

Experimental Design We plan to raise the temperature in the tank from 25°C to 31°C over three weeks. Every week, we will measure the zooxanthellae density, chlorophyll concentration, and protein concentration. Our class control tank will be kept at 25°C for the extent of the experiment. Both tanks will be kept in equivalent salinity and light conditions. Both coral samples will have equivalent masses.

Our Experiment At the end of last class we attempted to raise the temperature of our tank to 28°C, using one heater. On Thursday, we found that the temperature of the tank had decreased to 24°C. To assist in the water temperature control we added another water heater and set both heaters to 27°C.

T E C H N I C A L DIFFICULTIES!!! After adding the second water heater to the tank, severe overheating occurred in our tank. The temperature in the tank, estimated to be about 33 degrees Celsius, killed 100% of our coral.

What’s Next? As a result of this setback, we plan to restart the experiment. Today we are planning to set the temperature to 28 degrees Celsius using only one water heater. We plan to closely monitor the temperature and the coral’s response to this temperature throughout the week.