[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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