title: Doom and boom on a resilient reef: climate change, algal overgrowth and coral recovery.
abstract: BACKGROUND
  Coral reefs around the world are experiencing large-scale degradation, largely due to global climate change, overfishing, diseases and eutrophication. Climate change models suggest increasing frequency and severity of warming-induced coral bleaching events, with consequent increases in coral mortality and algal overgrowth. Critically, the recovery of damaged reefs will depend on the reversibility of seaweed blooms, generally considered to depend on grazing of the seaweed, and replenishment of corals by larvae that successfully recruit to damaged reefs. These processes usually take years to decades to bring a reef back to coral dominance.
  
  
  RESULTS
  In 2006, mass bleaching of corals on inshore reefs of the Great Barrier Reef caused high coral mortality. Here we show that this coral mortality was followed by an unprecedented bloom of a single species of unpalatable seaweed (Lobophora variegata), colonizing dead coral skeletons, but that corals on these reefs recovered dramatically, in less than a year. Unexpectedly, this rapid reversal did not involve reestablishment of corals by recruitment of coral larvae, as often assumed, but depended on several ecological mechanisms previously underestimated.
  
  
  CONCLUSIONS
  These mechanisms of ecological recovery included rapid regeneration rates of remnant coral tissue, very high competitive ability of the corals allowing them to out-compete the seaweed, a natural seasonal decline in the particular species of dominant seaweed, and an effective marine protected area system. Our study provides a key example of the doom and boom of a highly resilient reef, and new insights into the variability and mechanisms of reef resilience under rapid climate change.
authors.affiliation: Centre for Marine Studies and Australian Research Council Centre of Excellence for Coral Reef Studies, The University of Queensland, St Lucia, Brisbane, Queensland, Australia. g.diazpulido@uq.edu.au
authors.forename: Guillermo
authors.initials: G
authors.lastname: Diaz-Pulido
authors.forename: Laurence J
authors.initials: LJ
authors.lastname: McCook
authors.forename: Sophie
authors.initials: S
authors.lastname: Dove
authors.forename: Ray
authors.initials: R
authors.lastname: Berkelmans
authors.forename: George
authors.initials: G
authors.lastname: Roff
authors.forename: David I
authors.initials: DI
authors.lastname: Kline
authors.forename: Scarla
authors.initials: S
authors.lastname: Weeks
authors.forename: Richard D
authors.initials: RD
authors.lastname: Evans
authors.forename: David H
authors.initials: DH
authors.lastname: Williamson
authors.forename: Ove
authors.initials: O
authors.lastname: Hoegh-Guldberg
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000254:growth & development*; D002980:Climate; D056890:Eukaryota / Q000254:growth & development*