[Coral-List] Szmant 2002: Great review on nutrient enrichment on coral reefs (Gene Shinn)

[Eugene Shinn]

Hi Joseph, Bleaching and black band disease did originate mainly in 1986 
and 1987. However those were not the beginning of the end. The beginning 
of the end had started much earlier in the late 1970s. Harold Hudson, 
who was part of our USGS lab on Fisher Island, began using a siphoning 
device to remove black bands from large heads at Looe Key in 1986. He 
also made many measurement of the rate of BB spread, which was many cm 
per summer.
      I had begun taking annual photographs of /a cervirornis/ and 
/palmata/ at both Grecian rocks and Carysfort in1960.
Coral disease (not bleaching) began to be noticeable in the late 1970s. 
However the peak year of /Acroporid /death was 1983. The same thing 
happened at San Salvador as noted by the director and several 
researchers at the Finger Lakes research laboratory located there. As a 
result a nearby dive resort that catered to underwater photographers 
went bust and closed its doors. The principally A /cervicornis/ reef 
(known locally as telephone pole reef) died over a period of about 3 
months. I dove on the shallow reef in 1984 and the dead staghorn was 
still standing. I was with Phil Dustan at the time. Phil and I also 
visited a site off the north end of the island where there was a stand 
of large elkhorn corals. They were in growth position but entirely dead. 
About a year later I visited nearby Rum Cay with Bob Halley. All the 
/Acroporids /there were dead. Locals told us the /Acroporids/ had died 
in 1983. If you check with old timers in the islands you will find it 
was true throughout the Caribbean. Of Course dive shop operators were 
not advertising that fact at the time. Not good for business.
     As you know I have continued to take annual photographs of the 
Grecian and Carysfort site until 2016. Coral demise has continued until 
the present. In the 1990s we began an extensive program of 
high-resolution mapping. The work was prepared by Barbara Lidz and can 
be read at https://pubs.usgs.gov/pp/2007/1751/
Especially note the figure showing sediment thickness of the Florida 
Reef. It is based on Hundreds of km of high-resolution seismic profiles 
and numerous cores. As the map shows the thickness of the Holocene along 
the tract known as the main reef is less than 2 m thick. (In some places 
there is no Holocene….just bare Pleistocene with lots of gorgonians and 
sponges). Because of water depth along this tract it has been underwater 
at least 6,000 years. So why is it that the main reef line adjacent to 
Gulfstream waters remains so poorly developed or not developed at all? 
As I have pointed out many times the slowest growing coral out there 
should have outpaced the well-documented rate of rise in sea level over 
the past 6,000 years.
     Unfortunately anything having to do with coral has become highly 
politicized. For example, Lauren Toth recently examined and performed 
around 190 carbon 14 analyses on the reef cores we have been drilling 
for the past 30 years. From the rates of accretion derived from these 
dated corals she determined that uniform reef accretion rates have been 
touch-and-go for the past approximately 3,000 years. Her paper has now 
been turned down by three different journals. No one wants to believe 
her fact-based conclusions. The data in fact agrees well with the known 
thickness of the outer reef line in the Keys.

Phil Dustan also has classic photos showing the demise of the lush A. 
palmata reef that existed seaward of the Carysfort lighthouse. There is 
noting but rubble there now (being chewed up by parrot fish). In 
conclusion, what became noticeable to divers in the late 1970s has 
continued until today. The C14 data show growth rates slowed down or 
ceased about 3,000 years ago when rising sea level created tidal passes 
that allowed inimical waters from Florida Bay and Hawk channel to 
periodically flow over the main reef tract.As Conrad Neumann one 
published----“the reefs were shot in the back by their own lagoons.” Gene



On 5/7/18 8:27 AM, Pawlik, Joseph wrote:
> Hi Gene and list,
>
> Was the peak year for Caribbean coral demise in 1983?
>
> Zlatarski and the Halas did videos of Grecian and Dry Rocks reefs in 1987, capturing the beginning of the end for reefs in the Key Largo Area -- check out these videos (prepare to be depressed).
>
> https://youtu.be/LIbmsHmuxWk
>
> https://youtu.be/QV-XJZdPbk0
>
> In 1987, things were still very healthy, but the narration indicates that diseased patches were observed.
>
> Is there any agreement on the span of demise of Acropora in the Caribbean?  For the northern Keys, I would suggest that it's closer to 1988-89, but I'd like confirmation of that by those who were there and monitoring the reefs.
>
> Joe
>
> **************************************************************
> Joseph R. Pawlik
> Frank Hawkins Kenan Distinguished Professor of Marine Biology
> Dept. of Biology and Marine Biology
> UNCW Center for Marine Science
> 5600 Marvin K Moss Lane
> Wilmington, NC  28409
> Office:(910)962-2377; Cell:(910)232-3579
> Website:http://people.uncw.edu/pawlikj/index.html
> PDFs:http://people.uncw.edu/pawlikj/pubs2.html
> Video Channel:https://www.youtube.com/user/skndiver011
> **************************************************************
>
>
> -----Original Message-----
> From:coral-list-bounces at coral.aoml.noaa.gov  <coral-list-bounces at coral.aoml.noaa.gov>  On Behalf Of Eugene Shinn
> Sent: Thursday, May 3, 2018 12:54 PM
> To:coral-list at coral.aoml.noaa.gov
> Subject: Re: [Coral-List] Szmant 2002: Great review on nutrient enrichment on coral reefs (Gene Shinn)
>
> John, I agree the Szmant 2002 paper on nutrient enrichment is a classic.
> It was one of several papers consulted while we were developing our African dust hypothesis. At the time it was already known that African dust supplied the nutrients that stimulate Amazon rain forest growth.
> Thus, African dust also seemed a viable explanation for benthic turf algal blooms and demise of coral reefs around isolated Caribbean islands with small human populations. It was noted early on that the peak year of coral demise throughout the Caribbean was centered around 1983. That was also the peak year of increased dust flux in the Atlantic. During this period of time our USGS research revealed tidal pumping and offshore seepage of nutrient rich ground water. Also at that time many researchers were finding offshore surface waters contained insufficient amounts of nutrients to readily explain benthic turf algal blooms, Thus, seepage of nutrient rich ground water (enriched by anthropogenic sewage
> nutrients) combined with sedimentation of atmospheric dust elements might explain turf algal blooms and at the same time explain the relative lack of dissolved nutrients in the overlying water column.
>
> So where are we now? For sure the demise of corals reefs continues throughout the Caribbean and especially in Florida. It seems likely increasing human population in the Keys and continued African dust flux (enhanced by climate change) is ongoing. African dust nutrients are now increasingly recognized as a stimulus for phytoplankton blooms in mid Atlantic surface waters. Many studies have also shown the dust transports viable bacteria and fungi along with toxic elements like mercury and arsenic in addition to pesticides. And now we have sunscreens containing Oxybenzone to contend with. It is increasingly difficult to remain optimistic. Gene
>
> See: Shinn, E.A., Smith, G.W., Prospero, J.M., Betzer, P., Hayes, M.L., Garrison, V., Barber, R.T., 2000, African dust and the demise of Caribbean coral reefs: Geological Research Letters, v. 27, p. 3129-3032.
>
> Also seehttps://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fcoastal.er.usgs.gov%2Fafrican_dust%2Fgallery.html&data=01%7C01%7Cpawlikj%40uncw.edu%7Cb7c8df1161b8417497ae08d5b1c38c02%7C2213678197534c75af2868a078871ebf%7C1&sdata=h4vJogAotNbVB9wmetx64b0FyuGlQllvSLlOAJnYtQs%3D&reserved=0
>

-- 


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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