Title

Taphonomic Alteration of Branching Coral Skeletons Following a Mass Mortality Event in the Arabian Gulf (Dubai, UAE)

Event Name/Location

9th International Coral Reef Symposium, Bali, Indonesia, October 23-27, 2000

Document Type

Conference Proceeding

Publication Date

10-2000

Abstract

In the aftermath of a coral mass mortality in the southern Arabian Gulf (Dubai, UAE), taphonomic alteration in death assemblages of the coral genus Acropora were investigated. Between May and August 1996, sea-surface temperatures in the study area were elevated by 2 degrees above average which lead to widespread coral death in an area previously covered in dense Acropora growth. In November 1999, samples of dead Acropora corals were taken and compared to samples of the same species collected in October 1995, when still alive. Early constructive (encrustation, cementation) and destructive (micro- and macroboring, grazing) diagenetic processes and their influence on framework formation were studied. A sequence of encrustation was found: after death, the skeletons were rapidly colonized by a layer of bivalves (Chama spp.) which were later replaced by coralline red algae and other bivalves, particular Spondylus spp. This latter encrustation added significantly to the carbonate mass of the branches. The earliest destructive processes were associated with sea-urchin grazing, which led to erosion of external structures. Later, boring by clionid sponges and boring bivalves caused dissolution and ensuing mechanical weakening of the skeletons. Three years after the mass mortality, the constructive processes were volumetrically still more important than destructive processes. The latter, however, are expected to become increasing important with time.

Comments

page 254

ORCID ID

F-8807-2011

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