[Coral-List] Explosive growth of Sargassum in the Caribbean

[Eugene Shinn]

     As a geologist/biologist diving the Fla Keys and much of the 
Caribbean long before the coral-list, Brian LaPointe, and Marine 
Sanctuaries existed, I have watched corals diseases develop and other 
crises come and go. HoweverI do not recall a time when Sargassum growth 
exploded such as it has in the past 2 decades. Of course there were no 
satellites for observing the explosive growth back then, nevertheless we 
would have experienced abundant floating seaweed accumulating on beaches 
such as it has in the past 2 decades.During these recent decades  the 
explosive growth has been building year after year. Now the newest area 
of weed forms a belt stretching from West Africa to the Caribbean and 
beyond and it keeps enlarging. The Amazon and other rivers have often 
been blamed in the past even though it seems difficult for those waters 
to reach West Africa. Let’s see, can we blame ballast water and/or 
cruise ships? Climate Change? Upwelling? Cosmic Rays? There must be 
something out there that affects that region on a yearly basis. Whatever 
it is satellite images indicate it is coming from Africa, especially 
during our summer months. I once read some technical papers that stated 
the Amazon Rain Forrest receives its essential nutrients mainly during 
our winter months. It seems there is a this red/brown powder that 
accumulates on limbs and leaves high up in Amazon forest trees. Because 
of it some limbs even sprout rThat powder has been shown to contain 
essential nutrients. What is it? During our summer months that belt of 
powder moves northward and forms a thin soil over the prevailing 
limestone of Caribbean Islands. Some even reach the Florida Keys and 
Bermuda. It forms a thin hard laminated red/brown crust in the Florida 
Keys that has been forming for several thousand years. That crust 
contains clay minerals not native to the Keys, or Bermuda. We even have 
an agricultural area west of Miami called the Red-lands. I wonder what 
it is and how did it get there?

Of course long-time readers of the list know exactly what I am writing 
about. Just suppose that stuff gets sprinkled on the water forming a 
belt that spans the Atlantic Ocean. I wonder if it might stimulate the 
growth of a floating plant held afloat by small gas filled floats?

Why had it not affected the seaweed, and the corals, or caused red tides 
in the past?  Dr. Joe Prospero, now retired from the U. of Miami Marine 
Lab  monitored
African dust flux at Barbados starting in 1965. That  monitoring is 
on-going. There was little dust in the past when there was far less 
people/agriculture in the Schell desert of North Africa and less 
pesticides used to control Locusts outbreaks and mosquitoes. There was 
also a hundred-mile-wide lake Chad  there in 1960 that has evaporated 
down to only a few miles wide. It’s exposed lake bed, and whatever had 
accumulated in it, is now blowing across the Atlantic. Need I say more?

After all these years I keep wondering why some organization has not 
studied the situation? We at the USGS monitored and cultured live 
bacteria in the dust and noted the presence of numerous viruses in the 
late 1990s. While the military followed our work, because of bioterror 
implications, there was little interest within our organization. Only 
the US Academy of Environmental medicine appreciated the work because of 
the clear evidence of medical effects on humans, especially on Caribbean 
Islands. Trying to understand why there was so little interest in the 
projectI keep coming back to the fact that no one is  going to make 
money determining if that dust is the cause of coral, and medical 
effects. Who benefits if you can’t stop it? Of course the many thousands 
with respiratory diseases in the Caribbean and Eastern Bahamas might 
benefit but does that put any money in anyone's pocket? And what can be 
done to stop it?  Oh Well, I will continue to watch and wait. I thank 
Doug Fenner for pointing out this latest explosion of Sargassium and 
will wait for his short  reply. Gene