[Coral-List] Parrotfish and coral

Eugene Shinn eugeneshinn at mail.usf.edu
Fri Feb 24 15:19:30 EST 2017

Thanks Quinton, Doug Fenner asked the same valid question. You both 
asked that if the dust blew in from the east why did the /Diadema/ 
disease start in the southwester Caribbean. When African dust enters the 
Caribbean it often blankets the entire Caribbean in essentially a single 
day. There is greater water circulation in the eastern Bahamas because 
the deeper Atlantic waters first enter the Caribbean through the 
Windward Islands. At the same time circulation and water volume is 
reduced in the southwestern Caribbean near Panama where the disease was 
first noticed. Our oceanographer just showed me an animated drifter 
simulation that shows the area off Panama has a persistent gyre. This 
indicates that anything in the water is more likely to have an effect 
because it stays in that area longer. Of course there is also the 
possibility that dying /Diadema/ were not noticed as quickly in more 
remote parts of the Caribbean. A map by Roberts (1977) explaining 
dispersal of fish and coral larvae down current clearly showed overall 
water movement in the Caribbean is from east to west eventually becoming 
the gulf stream. His map also shows the gyre off eastern Panama where 
the /Diadema/ disease was first noticed.I wondered why if the disease 
originated in Panama how did it end up migrating eastward against the 
prevailing current to reach the Windward Islands? We were also aware 
that /Acropora/ disease and death in the eastern Bahamas such as around 
San Salvador Island was essentially synchronous with /Diadema /disease 
throughout the Caribbean. Seafan disease (caused by a soil fungus 
/Aspergillus/) also occurred almost simultaneously throughout the 
Caribbean in 1983. Did they all come from ballast water from ships 
moving through the Panama Canal as was commonly thought?It is a good 
question. I suppose ones bias determines which hypothesis one accepts 
since no one seems to have concrete evidence either way.

During the several years we researched the problem (two microbiologists, 
one coral biologist, and one geochemist) we realized our bias went 
against the agendas of several large Government agencies. They included 
1. Dept. of Commerce Marine sanctuary, 2. Environmental Protection 
Agency, 3. Center for disease control, and 4. Department of Agriculture. 
African dust was something that none of these agencies could do anything 
about. Desertization of the Sahel was happening causing an increase in 
dust flux across the Atlantic. Lake Chad was drying up and pesticides 
banned in the US were (and still are) in use in the Sahel while 
satellite images, and monitoring on the island of Barbados, clearly 
showed dust flux to the Caribbean and eastern US was increasing. Dust 
flux at Barbados spiked in 1973, peaked again in 1983, and again in 
1997. Our concerns with coral reef demise soon morphed into a project 
related to human health. Asthma had increased 17-fold in the eastern 
Caribbean since 1970, especially in the Windward Islands) and that soon 
led to concerns (and modest funding) about dust being used as a carrier 
for bioweapons. We learned from Russian defector Ken Alibek that the 
Soviets had manufactured hundreds of tons of weaponized anthrax 
(/Bacillus anthraces)./We knew the dust contained other species of 
/Bacillus/ suggesting that the bad one could also make it across the 
Atlantic. But that’s another story. My bias toward the dust hypothesis 
remains mainly because all the other hypothesizes proposed don’t seem to 
work well everywhere in the Caribbean and the diseases happened before 
significant coral bleaching began in the Caribbean. Gene

*Roberts, C. M., Connectivity and management of Caribbean coral reefs. 
Science, 278, 1,454-1,457 1977.


No Rocks, No Water, No Ecosystem (EAS)
------------------------------------ -----------------------------------
E. A. Shinn, Courtesy Professor
University of South Florida
College of Marine Science Room 221A
140 Seventh Avenue South
St. Petersburg, FL 33701
<eugeneshinn at mail.usf.edu>
Tel 727 553-1158
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