[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
water.
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
--
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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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