Our lab has just published a new paper in PLoS ONE, detailing the interactions of coral and algae on the Great Barrier Reef, and uncovered just how resilient some reefs can be following coral bleaching events. The southern end of the Great Barrier Reef was exposed to extended periods of high sea surface temperatures in the end of 2006, resulting in extensive coral bleaching across the Keppel Islands throughout January 2006. Following the bleaching event, a single species of fleshy macro-algae (Lobophora) overgrew the coral skeletons, causing high rates of mortality throughout the second half of 2006. But, by February 2007, corals were rapidly recovering due to an unusual seasonal dieback of the macro-algae, and astonishing regenerative capabilities of the dominant branching Acroporid corals – almost twice the rate of offshore corals on the northern Great Barrier Reef.
What is unusual about the Keppel Islands story is threefold: first, that corals recovered within months to years (reversal of macro-algae dominated reefs often takes decades), second, recovery of the corals occurred in the absence of herbivory (traditionally assumed to be the ‘driving factor’ in macro-algal phase shifts), and third, that corals recovered through asexual (regenerative) capacities rather than reseeding of reefs by larval recruitment. Understanding the processes that drive recovery following disturbances is critical for management of coral reefs, and the Keppel Islands example shows that managing local stressors (overfishing and water quality) helps reefs bounce back from global stressors such as coral bleaching events. PLoS One is an open-access journal, so the article is free to read – click on the link below, and feel free to rate and comments on the paper. Congratulations Guillermo et al!
Guillermo Diaz-Pulido, Laurence J. McCook, Sophie Dove, Ray Berkelmans, George Roff, David I. Kline, Scarla Weeks, Richard D. Evans, David H. Williamson, Ove Hoegh-Guldberg (2009 Doom and Boom on a Resilient Reef: Climate Change, Algal Overgrowth and Coral Recovery. PLoS ONE 4(4): e5239. doi:10.1371/journal.pone.0005239