[Coral-List] Parrotfish and coral

[Risk, Michael]

Hi Gene.

Your post has reminded me how little we know, and caused me to think of some early work.

An embarrassingly long time ago, we published some work on bioeroding fungi (Kendrick et al., 1982: Bull Mar Sci 32:862-867). We were able to get live cultures of fungi from several different places I happened to visit on my sabbatical (Barbados, Heron Island, Lizard Is., Raratonga). This was NOT easy, by the way...

Much to our surprise, many of the fungi turned out to be terrestrial, the sort you might find growing at the back of your fridge. We proposed a mechanism by which the fungi, which are VERY salt-tolerant (one species grows on salt fish), could sort of fall into the ocean, and then learn to bore into carbonate substrates through a combination of grazing pressure and secretion of acidic metabolic  byproducts...but of course they could have been blown in by wind.

Only problem with the modern Caribbean connection is, these eroding fungi go back at least to the early Paleozoic, and probably the PreCambrian. (In an earlier posting, I pointed out that the bioeroding fauna predates scleractinians by a few 100 million years...) There could, of course, be continuous re-infection from Africa...

Mike
________________________________________
From: coral-list-bounces at coral.aoml.noaa.gov [coral-list-bounces at coral.aoml..noaa.gov] on behalf of Eugene Shinn [eugeneshinn at mail.usf.edu]
Sent: February 24, 2017 3:19 PM
To: coral-list at coral.aoml.noaa.gov
Subject: [Coral-List] Parrotfish and coral

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.





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No Rocks, No Water, No Ecosystem (EAS)
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University of South Florida
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<eugeneshinn at mail.usf.edu>
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