[Coral-List] Why we are failing to repair coral reefs

Eugene Shinn eugeneshinn at mail.usf.edu
Thu Nov 6 11:03:46 EST 2014

With all the concerns about saving coral reefs I was surprised no one 
picked up on the thread of Martin Moe's recent posting concerning tire 
rubber. Using old tires for artificial reefs blossomed in the early 
1970s but their use quickly subsided when various chemicals in the 
artificial rubber were found to be toxic. NOAA supported experimentation 
with tires as reefs. Their FLAIR project consisted of dozens of tires 
bound together and placed in about 25 ft of water in what was then 
Biscayne National Monument. At the end of the project I observed and 
filmed the collection of tropical fish it had harbored. What was most 
noticeable was that although small fish hid in the tires little if 
anything grew on the rubber it self. In time it became apparent toxic 
components leaching from the tires prevents encrustation by marine 
organisms. Tire reefs soon when out of favor. Clearly tire rubber was 
not good for the reef environment so it is no wonder that the black 
rubber powder produced by the abrasion of tire tread (as pointed out by 
Martin) has the potential to be highly toxic. As he pointed out, rain 
flushes the chemical mix into surrounding waters. This is increasingly 
likely in the Florida Keys for three reasons:

1.) There is only one main highway connecting the keys. Highway US1 is 
close to the water on most of the keys. Bridges of course pass over the 

2) The chemicals in the rubber powder if not going directly into 
surrounding water, enters the porous limestone and ground water. Even 
where there are storm drains the water ultimately drains into the saline 
groundwater, which in most cases is anoxic, contains ammonia and 
hydrogen sulfide. This all makes for a potentially toxic mix that is no 
more than a foot or two below the surface over about 75 percent of the 
Keys. That's right, 75 percent of the Florida Keys surface area is only 
one meter or less above present sea level. In all cases due to tidal 
pumping and higher Gulf side sea level net movement of ground water is 
toward the Atlantic. Movement through the limestone amounts to roughly 
2-meters per day!

3) Auto and boat trailer traffic on that single asphalt artery is 
bumper-to-bumper during much of the year and increasing each year. Multi 
wheel tractor-trailers deliver goods to Key West throughout the night 
when auto traffic subsides. Clearly a lot of rubber powder is being 
produced and flushed into the surrounding sea or ground water that in 
turn flushes into near shore Atlantic waters. It is little wonder that 
Martin Moe has such difficulty rearing sensitive urchin eggs and larvae 
in seawater collected near his laboratory. Meanwhile people keep 
flooding into the Florida Keys and loving 'em to death. Determining 
toxicity and amount looks like a good study for some one to attempt.  Gene



No Rocks, No Water, No Ecosystem (EAS)
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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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