[Coral-List] Algae canopies

Thomas Goreau goreau at bestweb.net
Sun Nov 11 12:59:25 EST 2007

Estimado Guillermo,

Thanks. I have seen this also in Seychelles, Mauritius, and Fiji with  
corals still alive under seasonal blooms of Sargassum driven by rainy  
season increases in  land-based nutrient sources (note that these  
annual changes are due to seasonally varying nutrients, and probably  
not to seasonal variations in herbivores), but an amazing amount of  
corals survive under Sargassum as long as it does not stay around too  
long! In this case you, Jamal, and Larry McCook are right that they  
will suffer less bleaching mortality.  This is like the only survivor  
of the Mont Pelee eruption being a prisoner in the deepest dungeon!   
Once Sargassum cover becomes permanent, as you can see happening  
where the land based nutrient sources are increasing, then hardly any  
coral can survive. But Sargassum is the morphological exception, not  
the rule, and most algae that grow over corals really kill them stone  
dead pretty quickly. I'm working with Jamaludin Jompa in a few weeks  
and will discuss this with him further.

Thomas Joaquin Goreau Arango

Thomas J. Goreau, PhD
Global Coral Reef Alliance
37 Pleasant Street, Cambridge MA 02139
goreau at bestweb.net

Message: 1
Date: Sat, 10 Nov 2007 08:43:29 -0500
From: guillermo.diaz at unimagdalena.edu.co
Subject: Re: [Coral-List] two questions for coral listers
To: John Bruno <jbruno at unc.edu>
Cc: coral-list at coral.aoml.noaa.gov
Message-ID: <20071110084329.j5qb04x6quosg0co at mail.unimagdalena.edu.co>
Content-Type: text/plain;	charset=ISO-8859-1;	format="flowed"

Dear John,

Inshore coral reefs of the Great Barrier Reef have dense stands of  
the brown
seaweed Sargassum during the austral summer. During the coral  
bleaching of
1998, we observed that shading by Sargassum canopy protected corals from
beaching. Jompa & McCook (1998) and McCook, Jompa & myself (2001)  
preliminary experimental results of this particular coral-algal  
While certainly high abundance of macroalgae is usually associated to  
degradation, especially in reefs formerly dominated by corals, this  
observation illustrates the complexity of mechanisms by which they  


Jompa J, McCook LJ (1998) Seaweeds save the reefs?!: Sargassum canopy
coral bleaching on inshore reefs. Reef Res 8: 5.

McCook LJ, Jompa J, Diaz-Pulido G (2001) Competition between corals and
algae on
coral reefs: a review of evidence and mechanisms. Coral Reefs 19:  

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