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Today the Marine Science Interns ventured out to the site of the Mari Boeing, which was a freighter that ran aground on Bermuda’s north reefs in 1978, the day after Christmas! The vessel was salvaged through blasting causing a damage area estimated to be 0.44 km2 (Smith, 1985). There were very few corals that survived this process. Long-term monitoring of the grounding scar has shown reef recovery to take around 100 years (Anderson et al. 2001).
Armed with transect tapes, vernier calipers and quadrats the interns headed out to see how the reef was recovering. Each diver was responsible for completely measuring all of the recruits in three quadrats along the transect line, placed on random numbers. They recorded the length and width of colonies, or if circular in shape, their total diameter.
Back in the lab the interns were busy putting over a hundred recorded corals into Excel spreadsheets to look at their size distributions. The interns also looked at the total number of broadcaster and brooding colonies. The most common species per meter squared was the Mustard Hill Coral followed by the Golf Ball Coral. Both of these species are brooders, meaning they exhibit internal fertilization and release an already fertilized planulae larvae.
The interns investigated the concept of 'ecological succession'. This is a process in which a community progressively changes itself until a stable community is formed. The interns decided that the scar is still in the stages of early succession.
The interns hypothesized that, due to these corals undergoing internal fertilization they may be able to quickly colonize disturbed sites. What was interesting in their short survey was that size wise, the Diploria colonies were on the larger end of the size distribution. Although there are less of the broadcasting coral species, they are currently larger at the site. Only time will tell how the scar will continue to recover.
Here are the notes from the interns:
Notes from Miles: I found it difficult to measure the coral as the waves would push me back and forth, which was also annoying. I did learn the difference between Brooders and Broadcasters and that after there is reef destruction many brooders settle first then they are over taken by the broadcasters, like the Brain corals.
Notes from Eliza: Today we looked at the baby coral that have grown since the crash. The corals that have grown are mostly brooding coral, meaning that fertilization takes place internally. There are also some broadcasting coral, but not nearly as many.