l observed the effects of a chemical UV filter, oxybenzone, and a rising water temperature on the brightness of the bioluminescent glow, as well as the production of reactive oxygen species of dinoflagellates. Oxybenzone is a common UV filter that causes damage to coral reefs and has been found in high concentrations in the ocean. I also studied the effect temperature because greenhouse gases that have been released are being absorbed through the ocean, causing a rise in surface temperature. The dinoflagellaes I used in this experiment, Pyrocystis fusiformis, have the ability to glow bioluminescent blue when agitated in order to defend themselves against predators. I looked at the effect of these variables on the production of reactive oxygen species, or ROS, which is a toxin released by dinoflagellates when they are under stress, and the brightness of the dinoflagellate's glow. If the organism loses its ability to glow, it will also lose its defense against predators, and potentially its spot in the food chain.

To create a heated environment, I used a reptile heating pad that heats up to about 29 degrees Celsius, and placed my cultures on top of it. I introduced the Oxybenzone into the medium after dissolving it in acetone, and diluting it to a concentration of 2.0 * 10^-5..

To get a value for the brightness of the bioluminescent glow, I isolated the cultures into a dark room and then placed an air bubbler into each 100mL culture. I then set up an iPhone with the app Google Science Journal measured the brightness in exposure value, calculated by the shutter speed of the camera. I then plugged in the bubbler to cause a physical agitation and spark a glow. I found that in the control group, the brightness jumped up about 2.1 exposure values. The heated trials had no glow, and remained completely dark. The trials for oxybenzone and acetone also jumped up about 2.0 exposure values while being agitated.

In order to measure the production of ROS, I used a UV spectrophotometer to measure the presence of hydrogen peroxide. I did this by making a potassium phosphate monobasic solution as an assay. I started by calibrating the spectrophotometer to deionized water and then pipette 140 uL of the culture and 420 uL of assay into a cuvette and recorded the value at 240 nm. I found the amount of light going through for the control groups to be about 0.867, the heated culture was about -0.066, the oxybenzone cultures were about 0.057, and the acetone cultures were about 0.052. This shows that in the variable trials, more hydrogen peroxide, or ROS was produced. Throughout my experiment, I learned that the introduction of heat causes dramatic effects on dinoflagellates, however, in order to learn deeper effects of oxybenzone, future studies are needed.