[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.
Saludos,
Thomas Joaquin Goreau Arango
Thomas J. Goreau, PhD
President
Global Coral Reef Alliance
37 Pleasant Street, Cambridge MA 02139
617-864-4226
goreau at bestweb.net
http://www.globalcoral.org
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)
published
preliminary experimental results of this particular coral-algal
interaction.
While certainly high abundance of macroalgae is usually associated to
reef
degradation, especially in reefs formerly dominated by corals, this
particular
observation illustrates the complexity of mechanisms by which they
compete.
Cheers,
Guillermo
Jompa J, McCook LJ (1998) Seaweeds save the reefs?!: Sargassum canopy
decreases
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:
400-417
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