[Coral-List] Barrel sponge bleaching
clive.wilkinson at rrrc.org.au
Mon Apr 30 02:23:00 EDT 2012
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The images labelled 'Barrel sponge disease' of Xestospongia muta certainly appears like it is a disease of the cyanobacterial symbionts and probably not of the sponge cells. These sponges have a thin surface layer of cyanobacteria, probably all enclosed within sponge amoebocytes (or cyanocytes). It appears that the 'disease' has affected just the symbionts and not the sponge as the diver was able to ensure that the sponge tissue was still intact.. These cyanobacteria would provide a small amount of additional energy to these large sponges, but could be critical for the development of juveniles as the cyanobacteria are carried in the larvae.
There are other sponges in the Caribbean that have such symbionts (usually a brown to red colouration in the outer tissue); were any other sponges showing any 'bleaching'?
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