Title

Spatial and Temporal Dynamics of Arabian Gulf Coral Assemblages (U.A.E.) in Response to Temperature-Forcing

Event Name/Location

10th International Coral Reef Symposium, Okinawa, Japan, June 28-July 2, 2004

Document Type

Conference Proceeding

Publication Date

6-2004

Abstract

We analyzed spatial and temporal patterns of coral communities in the southeastern Arabian Gulf (Abu Dhabi, Dubai, Sharjah) in response to temperature variability in one of the most extreme coral environments. We used IKONOS and Aster satellite imagery combined with 8 years of ecological monitoring data (line transects and photo-squares) and sea-surface temperature data (CoADS, HadISST1, NCAR). Analysis of SST confirms that the area is subjected to recurrent and cyclic temperature anomalies. We explore whether unusually low or high temperatures are the main forcing factor of coral mortality and whether links to ENSO via the Indian Ocean Zonal Mode/Dipole exist. Temperature extremes occur more frequently in the western area between Qatar and Abu Dhabi than in the eastern area between Abu Dhabi and Musandam. The spatial expression of coral assemblages near Jebel Ali (Dubai) on IKONOS imagery is consistent with what would be predicted if reef development was repeatedly ‘reset’ on a decadal time-scale by recurring episodes of coral mass mortality induced by severe positive or negative SST anomalies. Furthermore, a combination of remotely-sensed habitat mapping and bathymetric digital elevation model analysis revealed no evidence of any reefal framework development, suggesting that the cycle of temperature-induced mortality has been operating for a considerable time. We therefore suggest that the environment in the entire southeastern Arabian Gulf has not been conducive to biohermal framework production and that all coral areas have been subject to frequent mortality episodes. Increased global temperatures are likely to increase the frequency of extreme positive SST excursions and indeed the area has experienced bleaching events in 1996, 1998, and 2002, which is the fastest recurrence rate recorded on any reef system. While some evidence for phenotypic adaptation was observed (reduced bleaching in Acropora), further degradation of the system is expected.

Comments

page 174

ORCID ID

B-8552-2013 F-8807-2011

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