Bacteria associated with the coral Echinopora lamellosa (Esper 1795) in the Indian Ocean - Zanzibar Region

Abstract

Infectious diseases are now known to have major effects on the structure and function of coral reef ecosystems throughout the world. The number of recognized coral diseases has increased dramatically. The problem was first recognized in the Caribbean in the early 1970’s but has now been reported to affect coral communities worldwide. There is little information regarding bacteria associated with diseased corals in the Indian Ocean. However, one of the most common disease signs observed is a rapid loss of tissue leaving exposed white skeleton in contact with compromised tissue, followed by necrosis. These signs have been referred to as white plague in the Caribbean. Similar signs have been observed in the Indo-Pacific and are referred to as white syndrome. The pathogens associated with these disease signs depend on the species and geographic location of the corals. In the Caribbean, the disease was associated with Aurantimonas coralicida and in the Red Sea with Thalassomonas loyaeana , both newly described species. During exploratory surveys in the reefs near Zanzibar in the Indian Ocean, mucus samples were collected from healthy and apparently diseased Echinopora lamellosa (with signs of white syndrome) colonies. Samples were plated on two solid media: GASW (a nonspecific medium) and TCBS ( Vibrio selective medium). Growth on TCBS was only found with diseased samples. Culturable isolates were characterized using metabolic profiling. A relatively high prevalence of Class Gamma Proteobacteria was found with diseased samples compared with healthy samples and Vibrio species were well represented in diseased samples. Keywords: Disease, coral reef, echinopora, Indian Ocean, white syndrome