[Coral-List] Sargassum Season and Dust

Risk, Michael riskmj at mcmaster.ca
Wed Jul 17 16:58:33 UTC 2019


Ulf,  the LAST thing this debate needs is another unsupported hypothesis.

If illegal mining were really a widespread problem, then Hg would have shown up in any of the many TE profiles already taken in the Caribbean. Many of these have been published (yeah, some by me).

We know that the Caribbean decline was well under way by 1980.

The really sad part is: Brian's results are no surprise to those who have been watching this over the years.

Mike
________________________________________
From: Coral-List [coral-list-bounces at coral.aoml.noaa.gov] on behalf of Ulf Erlingsson via Coral-List [coral-list at coral.aoml.noaa.gov]
Sent: July 17, 2019 10:29 AM
To: Pawlik, Joseph
Cc: coral-list at coral.aoml.noaa.gov
Subject: Re: [Coral-List] Sargassum Season and Dust

My two cents: Don't ignore the large scale illegal mining in the Orinoco, which pollutes the river with things like mercury and cyanide. This illegal mining has been going on since the 1990s in significant scale, but it has now accelerated, and it is now the main source of income for the dictatorship in Caracas (alongside cocaine smuggling, which also pollutes to be sure).

It is not impossible that the increase of illegal mining (mostly of gold) has grown in a general rate that is consisten with the decline of corals in the Caribbean, so I would suggest to look into that. The problem is of course to find statistics on an illegal activity, but one can use proxies, speak to the locals (the Native Americans living in the rainforest in question, notably one national park in the state of Amazonas in Venezuela), and judge the "progress" on satellite images.

Ulf Erlingsson
Lindorm, Inc.
10699 NW 123rd Street Road
Medley, FL 33178-6166


> On 2019-07-16, at 20:54 , Pawlik, Joseph via Coral-List <coral-list at coral.aoml.noaa.gov> wrote:
>
>
> Thanks for the brief review, Gene,
>
>
> The Sahara dust hypothesis is an intriguing one, both in terms of iron enrichment resulting in widespread Caribbean nutrification, and as a potential source of pathogens. My colleagues and I have included dust in some recent synthesis papers related to Caribbean reef ecosystem function (see below).
>
>
> But as I communicated to Gene a few months back, I'm having doubts about dust.
>
>
> Recent trips to the Red Sea reveal highly oligotrophic reef systems that are dumped on regularly by desert dust. Check out this video of the reefs off Egypt:
>
>
>
> https://youtu.be/DKGlOfa1clw<https://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fyoutu.be%2FDKGlOfa1clw&data=01%7C01%7Cpawlikj%40uncw.edu%7C816e7d31de284894298608d6f3e70234%7C2213678197534c75af2868a078871ebf%7C1&sdata=dUMUvCZL9B0AAc%2BiBBQJh4VKunl1oqkiQmTfVq5WRM0%3D&reserved=0> <https://youtu.be/DKGlOfa1clw%3Chttps://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fyoutu.be%2FDKGlOfa1clw&data=01%7C01%7Cpawlikj%40uncw.edu%7C816e7d31de284894298608d6f3e70234%7C2213678197534c75af2868a078871ebf%7C1&sdata=dUMUvCZL9B0AAc%2BiBBQJh4VKunl1oqkiQmTfVq5WRM0%3D&reserved=0%3E>
>
>
>
> In the water column above Red Sea reefs, there was visible trichodesmium, near daily accumulations of dust on the boat deck, but on the reefs, no seaweeds, sponges, or coral disease.
>
> What is different is that there are no river inputs to the Red Sea, and a LOT of freshwater coming into the Caribbean from the Amazon (driven N by surface currents), Orinoco, Magdelena, and Mississippi (see the vicious circle hypothesis paper, below). We've also found that the sponges on the Saudi side of the Red Sea are starving as you move offshore along a gradient of decreasing DOC, something we don't see in the Caribbean, where levels of labile DOC seem to be higher, probably because of all the seaweed.
>
>
> In short, I think river inputs (and DOC) are much more important than dust in explaining the difference between Caribbean reefs and those in other parts of the tropics.
>
>
> Any thoughts from the oceanographers at KAUST?
>
>
> Regards,
>
>
> Joe
>
>
> Pawlik, J.R., Burkepile, D.E., Vega Thurber, R. 2016. A vicious circle? Altered carbon and nutrient cycling may explain the low resilience of Caribbean coral reefs. BioScience, 66: 470-476 doi:10.1093/biosci/biw047.
>
>
>
> Pawlik, J.R., McMurray, S.E. 2020. The emerging ecological and biogeochemical importance of sponges on coral reefs. Annual Review of Marine Science, 12: 3.1-3.23
>
>
>
> Wooster, M.K., McMurray, S.E., Pawlik, J.R., Moran, X.A., Berumen, M.L. 2019. Feeding and respiration by giant barrel sponges across a gradient of food abundance in the Red Sea. Limnology and Oceanography, 64:1790-1801
>
>
>
>
> **************************************************************
>
> 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 <http://people.uncw.edu/pawlikj/index.html>
>
> PDFs: http://people.uncw.edu/pawlikj/pubs2.html <http://people.uncw.edu/pawlikj/pubs2.html>
>
> Video Channel: https://www.youtube.com/user/skndiver011 <https://www.youtube.com/user/skndiver011>
>
> **************************************************************
>
>
>
>
> ________________________________
> From: Coral-List <coral-list-bounces at coral.aoml.noaa.gov <mailto:coral-list-bounces at coral.aoml.noaa.gov>> on behalf of Eugene Shinn via Coral-List <coral-list at coral.aoml.noaa.gov <mailto:coral-list at coral.aoml.noaa.gov>>
> Sent: Monday, July 15, 2019 5:47 PM
> To: coral-list at coral.aoml.noaa.gov <mailto:coral-list at coral.aoml.noaa.gov>
> Subject: [Coral-List] Sargassum Season
>
> Melissa is correct. "There has been a lot of Sahara Dust over the same
> area where the Sargassum has proliferated.”
> Many coral-list readers will remember that I have blamed many events,
> including the demise of Caribbean corals, on microbes and toxic minerals
> in African dust. As shown by Joe Prospero at the University of Miami,
> what is often called Saharan dust is in fact soil dust originating in a
> vast area south the Sahara called the Sahel. I spent more than10 years
> devoted to the study of African dust and for several years led a USGS
> project devoted to its study. Our project included two microbiologists,
> a coral biologist who lived in the Virgin Islands and a geochemist. The
> study began with funding from NASA to hire our first microbiologist.
> Before our congressional funded project ended in 2006 over 200 live
> microbes had been identified. Viruses, including one that causes foot
> and mouth disease in cattle are many times more abundant. They remain to
> be studied. The research was initially stimulated by the demise of
> Caribbean corals, including the Florida reef tract. Disease of Acroporid
> corals peaked in 1983 the same year the sea urchin /Diadema/ began dying
> throughout the Caribbean. What led us to African dust were several peer
> reviewed scientific papers demonstrating that the Amazon rainforest
> receives most of its essential nutrients form African dust. Tree limbs
> high above flood level sprout roots to take advantage of the red
> nutrient rich soil that often coats the limbs. Air plants also thrive on
> the dust. We soon learned that red soils and hard surface crusts on most
> Caribbean islands and the Florida Keys are composed of clay minerals and
> fine-grained quartz silt. The red brown color is due to oxidized iron
> common to the millions of tons of African dust that reach this side of
> the Atlantic Ocean each year. There are no local sources of these
> minerals on Caribbean island. Most Caribbean islands surrounded by deep
> oceanic waters consist entirely of limestone constructed by corals
> including sands and mud precipitated from seawater. The Bahaman banks
> and islands cap 15,000 feet of limestone. I will refrain from boring
> readers with any more geology.
>
> What is most striking are satellite images indicating the path of this
> dust during summer months (July-November). The pattern is identical to
> the present distribution of Sargassum mats now extending from West
> Africa to the Caribbean and that periodically enters the Gulf of Mexico
> and then moves northward to cities in the northern Gulf including
> Houston and Dallas. Often these clouds of dust turn eastward and head
> back into the Atlantic where they circle the Bermuda High and settle
> over the Sargasso Sea. Creation of Red tides in the Gulf of Mexico have
> also been attributed to iron fertilization from African dust. (During
> winter months the dust clouds take a southerly rout into the Amazon
> basin) This year we had our first influx of dust in the Gulf of Mexico
> in late June. Meanwhile lake Chad in the Sahel which was about100 miles
> in diameter in 1960, has shrunk to less than 10 miles. Its huge drying
> lakebed is increasingly blowing across the Atlantic while even more is
> arriving from the Bodel depression. Dr. Joe Prospero has been publishing
> and monitoring the origin and abundance of these dust clouds since the
> 1960s.
>
> Like Melissa and many others who have experienced the dust clouds in St.
> Croix, know exactly what she is talking about. Ask any resident or
> medical doctor on Caribbean islands and they will tell you that patients
> arrive with respiratory problems when the red/hazy clouds of dust
> arrive. This is especially true for Barbados and Trinidad. Every
> sailboat owner in the Virgin Islands is familiar with the red dust they
> wash from sails and decks. Many are familiar with the red mud that
> accumulates in their water cisterns. I have collected the red mud from
> the bottom of cisterns on several islands in the Caribbean. With this
> background I like Melissa, was greatly surprised to see a paper in
> Nature attributing the Atlantic Sargassum bloom to run-off from the
> Amazon and upwelling of nutrient rich Atlantic waters. There was no
> mention of fertilization from atmospheric dust as a possible source.
> Possibly it is just another chicken or egg question. Gene
>
>
>
> --
>
>
> 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
> ---------------------------------- -----------------------------------
>
> _______________________________________________
> Coral-List mailing list
> Coral-List at coral.aoml.noaa.gov
> https://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fcoral.aoml.noaa.gov%2Fmailman%2Flistinfo%2Fcoral-list&data=01%7C01%7Cpawlikj%40uncw.edu%7C2208358f03414f99622108d70a2c845a%7C2213678197534c75af2868a078871ebf%7C1&sdata=Fdk1RPElOA2YMVMiJ8lnkemczPwFv0b2526nvS0J5QQ%3D&reserved=0 <https://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fcoral.aoml.noaa.gov%2Fmailman%2Flistinfo%2Fcoral-list&data=01%7C01%7Cpawlikj%40uncw.edu%7C2208358f03414f99622108d70a2c845a%7C2213678197534c75af2868a078871ebf%7C1&sdata=Fdk1RPElOA2YMVMiJ8lnkemczPwFv0b2526nvS0J5QQ%3D&reserved=0>
> _______________________________________________
> Coral-List mailing list
> Coral-List at coral.aoml.noaa.gov <mailto:Coral-List at coral.aoml.noaa.gov>
> https://coral.aoml.noaa.gov/mailman/listinfo/coral-list <https://coral.aoml.noaa.gov/mailman/listinfo/coral-list>
_______________________________________________
Coral-List mailing list
Coral-List at coral.aoml.noaa.gov
https://coral.aoml.noaa.gov/mailman/listinfo/coral-list


More information about the Coral-List mailing list