Summary of Abstract Submission

Abstract Submission No. IO50-03-0049PresentationPoster

EFFECT OF ENVIRONMENTAL STRESS ON SCLERACTINIAN CORALS OF MAURITIUS: A FIELD- AND LAB- BASED PERSPECTIVE.

Sushma Mattan-Moorgawa*1, Ranjeet Bhagooli1, Soonil DDV Rughooputh2

1 Faculty of Ocean Studies, University of Mauritius, Mauritius
2 Faculty of Science, University of Mauritius, Mauritius

ABSTRACT :

The island of Mauritius is surrounded by 150 km of fringing reefs except with breaks on the southern and western coasts. Though its coral reefs have escaped the major 1998 bleaching event, recent records of coral bleaching and mortality have increased mostly due to climate-induced thermal stress and other anthropogenic pressures. This study aimed to assess the effects of environmental stressors, thermal and chemical, on the photo-physiology, mortality and recovery of selected scleractinian corals of Mauritius, by means of field observations and laboratory investigations using coral cell aggregates as a miniaturized model. Field observations made during a bleaching event in 2009 indicated that the tabular corals A. cytherea and A. hyacynthus were most susceptible to thermal stress compared to P. eydouxi and Fungia sp., which were among the most robust. In a comparison between the pre-bleaching and post-bleaching physiology of these corals, a pre-disposition or susceptibility of the Acroporids to elevated sea surface temperature was noted. Thermal stress experiments on coral cell aggregates under laboratory conditions revealed that higher temperatures, 28˚C and 31˚C, tended to have negative effect on the density of coral cell aggregates mostly in A. muricata as compared to P. damicornis. A combination of thermal stress and crude sponge or ascidian extracts had an increased negative effect on the coral cell aggregates, with ascidian D. molle being most toxic to coral cell aggregates in all corals. The study suggest possible implications for the ecological and chemical interactions of coral reefs in the wake of a warming ocean.