Surveying Coral Reefs

by Michele Felberg

Michele Feldberg (upper) and Wendy Whitcombe swim a transect on Guam. Photo by Jim Haw.

Stepping off the plane in the airport in Guam, I was greeted with a familiar humidity. I felt just as if I had come home to Houston. But my first two dives proved that Guam is a whole new world. We set off to Double Reef to go on our first dive, where buddy teams would set 100 m transect lines and perform a substrate survey. The purpose of this assay was to acclimate my classmates and myself to the new ecosystems we would be performing further research on during our time in Guam and then Palau.

Plunging into the 86-degree Fahrenheit water, my buddy Wendy Whitcombe and I began our descent to the reef below us. It was a bit of a challenge to maintain buoyancy as I no longer was wearing my 7-millimeter wetsuit that I wore while learning to dive at the Wrigley Institute off Catalina Island. Wendy and I set out on a course of 225 degrees, carefully laying out the line on towers and plateaus of delicate Porites Coral.

Spider Conch shell on a reef in Guam. Photo by Jim Haw.

It was interesting to see the difference in corals between Double Reef and Tumon Bay, where we went snorkeling the first day. Although there is heavy coral coverage in both areas, in Tumon Bay it was almost only acropora. In Double Reef, there was a much higher diversity of corals, with just as much coverage. This shows the importance of studying diversity as a means of ecosystem health and to evaluate other influences (i.e. runoff, pollution, and other anthropogenic effects) that contribute to the growth or destruction of reefs. While performing the survey, I also noted that there was a plethora of small fish darting in and out of the corals. I realized that performing invertebrate counts for our second dive that day was going to be difficult because of the hectic reef ecosystem.

After the appropriate surface interval time, we jumped back into the waters at Gun Beach to perform a second substrate assay as well as an invertebrate count of urchins, sea cucumbers, giant clams, and spider conchs. This entailed counting the number of invertebrates within every 20 m on the transect line, within 1 m to each side of the line we laid out. The added task of invertebrate counts meant that Wendy and I had to be much more meticulous about our efforts. I realized just how crucial it is to be alert yet thorough in counting, as urchins hid under corals and spider conchs blended in with the bottom.

Michele Feldberg (center) joins other USC students on the surface following a dive on Guam. Photo by Tom Carr.

Even after the first two dives, I felt that my eyes had been opened to the importance of gathering data in the underwater environment. In order to truly learn and monitor the coral reef systems, it is crucial to understand why certain species flourish, such as the acropora in Tumon Bay, and how to gauge diversity and general ecosystem health by means of counts and observational records.

Michele Felberg is entering her junior year at USC Dornsife, where she is getting her B.S. in environmental studies and a minor in economics. Michele has had a lifetime of passion for the environment and hopes to continue down a marine ecosystem research career path.

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