Experimental Design in the Coral Reefs

 Photo Credits: Mario Gaitan

The faculty-led project (FLP) in Bocas del Toro was the second time I conducted research in a coral reef, but the first time with equipment and techniques.  Back when I was a young, aspiring, but not yet studying, ecologist, I jumped at every opportunity to learn.  One of those was the Young Naturalists Competition for seventh grade and up directed by the American Museum of Natural History.  My family was taking a trip to Hawaii the summer before my junior year of high school and I decided to twist it into a “research trip.”  I took pictures with my underwater disposable camera of coral on two healthy reefs and one reef covered in invasive algae, a major problem for Hawaiian reefs.  At home, I identified all the coral and assessed biodiversity using the Shannon-Wiener Index.  The comments given to me by AMNH were to standardize the plot size in each of the reefs and develop a more experimental component to future studies.

            At Bocas del Toro, I was able to achieve both of these, through the FLP with Alain Duran.  In order to study why there was so little macroalgae on the coral reefs in this area even though there were few fish, we surveyed Pete’s Reef along eight, 30-m transects.  Every two meters, we laid a one-by-one meter plot in which to take our measurements.  We measured rugosity, which indicates the variation in height of the coral, by laying down a one-meter chain along the top of the coral and seeing how long it is.  Macroalgae grow better in areas with lower rugosity.  After, we counted all the large and small sea urchins, which eat the algae, in the plot.  Alain took two pictures in the center of the plot in 0.25-by-0.25 plots.  We estimated the coral, sponge, and algae cover within these plots.  Our study found that there was less macroalgae in areas with less rugosity, meaning they were flatter, and in areas with more small sea urchins, but there was more macroalgae in areas with more large sea urchins. 

            This experiment taught me how to do experimental design in coral reef!  I learned about many techniques that I did not think possible, such as writing underwater.  Swimming and avoiding fire coral and sea urchins, while laying out plots and taking measurements was a challenge.  I am more experienced with difficulties, such as rain and heat, while doing terrestrial field work.  This FLP gave me the unique opportunity to experience how an experiment is designed and conducted underwater.

Ariek Barakat Norford

Franklin and Marshall College