[Coral-List] Sargassum fluitans proliferation in the Lesser Antilles

Arlo H. Hemphill arlo at arlohemphill.com
Wed Aug 10 16:18:06 EDT 2011

Dear Jean-Philippe and All,

Atlantic Pelagic Sargassum is generally dominated by two holopelagic  
species, both Sargassum fluitans and S. natans.  The two are easily  
distinguished by looking for a pin-like stipe at the base of the air  
bladders on S. natans.  Six other species of Sargassum may also  
potentially be present in pelagic mats, but those species are not  
holopelagic.  The habitat, while it remains offshore, is extremely  
important as a juvenile fish nursery and also for juvenile sea  
turtles.  Thus it's appearance offshore during hatching season may  
perhaps be a bit of a blessing for the turtles, although I do  
understand it can be a major mess when it washes ashore.  I am curious  
as to whether there is an actual increase in pelagic biomass as  
opposed to a change in prevailing winds or currents?  Sargassum often  
forms sizeable mats in both the Gulf of Mexico and the Sargasso Sea,  
and it quite commonly washes up on beaches of Florida and Bermuda as  
you are describing.  Does anyone have any data on what might be  
happening offshore - ie. biomass increase vs change in oceanographic  
conditions?  We've had a strange weather year with the storms and  
heat, so my inclination would be to look at physical oceanography first.



Arlo H. Hemphill
Marina, California

202.746.3484 (m)
E-mail: arlo at arlohemphill.com
Skype: arlohemp
Twitter: arlohemphill

Conservation * Exploration * Communications

Date: Tue, 09 Aug 2011 12:30:47 -0400
From: OMMM Association <ommm at wanadoo.fr>
Subject: [Coral-List] Sargassum fluitans proliferation in the Lesser
To: coral-list at coral.aoml.noaa.gov
Message-ID: <4E4160B7.5070700 at wanadoo.fr>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Dear all

Since May, 2011, a huge amount of pelagic sargassum piles up along the
coast of Martinique and Guadeloupe in the Lesser Antilles, and might
affect probably all the islands in the area.
Tons of algae enter the bays and cover the beaches. This accumulation of
floating sargassum can also extends at the surface of the water for tens
of meters in semi closed area, causing environmental problems to very
coastal communities.

We have not seen any comments since this began in May. The algae still
accumulates and cause management problems for local authorities. This is
also the marine turtles' nesting period, what has an incidence on local
decision to remove the algae accumulated on the beaches. Those algae
decomposed and toxic gaz might be produced, as H2S, which is quite low
from the measures that have been done at the moment (0-3 ppm).

Is there any information we could share on the origin of this
proliferation of pelagic sargassum in the area?
Who else in the Lesser Antilles or elsewhere face the same problem?

We do airplane survey and fly over the coastal area to detect piles of
sargassum away offshore looking at possible trajectories.

We are interested in any satellite images that could detect those  

Jean-Philippe Mar?chal

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