Coral Bleaching and Mortality Thresholds in the SE Gulf: Highest in the World
Bleaching is a stress reaction in corals, during which the symbiosis between corals and the algae (zooxanthellae) living in the coral cells breaks down. As a result, zooxanthellae are expelled, and the coral appears pale or even white (Fig. 6.1; Baker et al. 2008). The link between environmental variables and coral bleaching has been well-established in a variety of studies and synthesized in several places (Phinney et al. 2006; Baker et al. 2008; van Oppen and Lough 2009). Large-scale and region-wide bleaching events, such as occur in the Gulf, have been clearly linked to unusually high temperatures and the accumulation of heat stress in corals. Other drivers, such as UV and water acidity can have compounding effects (Baker et al. 2008) and bleaching can also be caused by these factors alone, or other local drivers such as unusually cold temperatures (Saxby et al. 2003; Lajeunesse et al. 2007). However, it is heat stress that has been demonstrated as the most reliable predictor and defined time-integrated bleaching thresholds exist for various regions of the Indo-Pacific and the Caribbean (Berkelmans 2002a, b; Manzello et al. 2007; Berkelmans 2009).
KeywordsHeat Stress Great Barrier Reef Average Daily Temperature Bleaching Event Gulf Region
Early phases of the monitoring project were funded by the WWF/EWF/Dolphin project and then sponsored by Abu Dhabi EAD, Qatar Gas, Qatar Ministry of Environment and NCRI at NSU. We thank R. Al-Mubarak, F. Launay, M. Chandler for support during that project.
- Berkelmans R (2002b) Reply comment: time-integrated thermal bleaching thresholds of reefs and their variation on the Great Barrier Reef. Mar Ecol Prog Ser 237:309–310Google Scholar
- Birkeland C, Craig P, Fenner D, Smith L, Kiene WE, Riegl B (2009) Geologic setting and ecological functioning of coral reefs in American Samoa. In: Riegl B, Dodge RE (eds) Coral reefs of the USA. Springer, Dordrecht, pp 741–765Google Scholar
- Dunne RP (2002) Comment: comment on Berkelmans (2002) ‘Time-integrated thermal bleaching thresholds of reefs and their variation on the Great Barrier Reef’. Mar Ecol Prog Ser 237:307–308Google Scholar
- George JD, John DM (1999) High sea temperatures along the coast of Abu Dhabi (UAE), Arabian Gulf – their impact upon corals and macroalgae. Reef Encount 25:21–23Google Scholar
- George JD, John DM (2000) The effects of the recent prolonged high seawater temperatures on the coral reefs of Abu Dhabi (UAE). Proc Int Symp Extent Coral Bleaching: 28–29Google Scholar
- Maynard JA, Turner PJ, Anthony KRN, Baird AH, Berkelmans R, Eakin CM, Johnson J, Marshall PA, Packer GR, Rea A, Willis BL (2008b) ReefTemp: an interactive monitoring system for coral bleaching using high-resolution SST and improved stress predictors. Geophys Res Lett 35:L05603. doi: 10.1029/2007GL032175 CrossRefGoogle Scholar
- Podesta GP, Glynn PW (2001) The 1997–98 El Nino event in Panama and Galapagos: an update on thermal stress indices relative to coral bleaching. Bull Mar Sci 69:43–59Google Scholar
- Riegl B, Purkis S (2009) Model of coral population response to accelerated bleaching and mass mortality in a changing climate. Ecol Modell 220:192–208Google Scholar
- Van Oppen MJH, Lough JM (2009) Coral bleaching. Patterns, processes, causes and consequences. Springer, Berlin, 178ppGoogle Scholar