[Coral-List] Disappearing coral reefs

Eugene Shinn eugeneshinn at mail.usf.edu
Wed May 3 14:39:17 EDT 2017

List readers will want to read an important new publication with 
significant implications for Florida, the Caribbean, and Hawaii. The 
papers title is, /Divergence of seafloor elevation and sea level rise in 
coral reef ecosystems./ By Kimberly K. Yates David G. Zawada, Nathan A. 
Smiley and Ginger Tiling-Range. The study, published in Biogeosciences 
14, 1739-1772, 2017 < http://www.biogeosciences.net/14/1739/2017/) 
<http://www.biogeosciences.net/14/1739/2017/%29>> includes St. Thomas, 
Buck Island, and Maui, Comments here are restricted to the Florida Keys 
where I have experience diving and doing research since the 1950s. In 
this quantitative study the authors examined depths over reef areas 
determined by lead line and graduated probes from surveys conducted in 
the 1930s. That depth data is compared with recent Lidar surveys 
beginning in 2002. They also compared their data with that provided in a 
2014 Florida Fish and Wildlife habitat survey.

Using engineering based numeric adjustments for tides and local sea 
level rise the authors determined deepening of 20 to 80 cm (7,9 to 31,5 
inches) of the sea floor in reef areas that occurred during the past 
66-67 years. The paper cautiously avoids specific causes of deepening, 
other than sea level rise and erosion, but causes clearly must include 
both physical and bio erosion by parrot and other herbivorous fishes, 
boring sponges, boring algae and rock boring clams all of which can 
easily be observed by divers on reefs where corals are no longer 
growing, The paper projects erosional deepening by 2 to 8 times that 
projected by sea level rise alone by 2100. Deepening by these erosional 
processes on Maui reefs were calculated to be several times greater than 
that of all other areas examined in this study. One can conclude that 
the shores will increasingly be subjected to greater wave erosion and 
flooding even in the absence of eustatic sea level rise if corals do not 
recruit and resume growth. 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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