[Coral-List] two questions for coral listers

John Bruno jbruno at unc.edu
Thu Nov 8 14:40:41 EST 2007

First, is anyone aware of an example (preferably published) where  
macroalgae have alleviated some stress or otherwise benefitted corals  
in terms of growth, survival, etc?  I have heard people talk about  
observing that shading by macroalgae can reduce bleaching and  
bleaching-related mortality, but don't recall seeing any studies on  
this and have not been able to dig any up using various search engines.

Second, is anyone aware of an example in which after herbivore  
populations were replenished (either naturally or via management)  
macroalgal cover/biomass remained "high"?  This question really gets  
at whether "phase shifts" to macroalgal dominance are "permanent  
states" or simply responses to the removal of top down control.   
Every example I can think of clearly indicates that once herbivores  
return (e.g., Diadema to the north coast of Jamaica ala Edmunds and  
Carpenter 2001, Carpenter and Edmunds 2006) macroalge immediately  
return to formerly very low cover and abundance (which also suggests  
that top down rather than bottom up forces were the primary cause of  
the change in macroalgal cover in the first place).

Thanks for any examples, ideas or advise you might have.


John Bruno, Ph.D.
Associate Professor
Department of Marine Science
The University of North Carolina at Chapel Hill
Chapel Hill, NC 27599-330
jbruno at unc.edu

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