[Coral-List] Ideal Temperatures for Coral growth, reproduction, and thermal lethal limits.

Kuffner, Ilsa ikuffner at usgs.gov
Wed Sep 10 16:09:59 EDT 2014

Coral List,

For those of you interested in this topic, my colleagues and I just
published a paper on ocean temperatures in the Florida Keys:

Kuffner IB, Lidz BH, Hudson JH, Anderson JS (In press) A century of ocean
warming on Florida Keys coral reefs: Historic in situ observations. *Estuaries
and Coasts*.

Available open access:

Our analysis shows that late-summer water temperatures on the upper Florida
Keys reef tract were warmer by about 1 degree Celsius (nearly 2 degrees
Fahrenheit) in the last several decades compared to a century earlier.

We compared water temperatures during multiple-decade-long periods a
century apart at two of Florida’s historic offshore lighthouses – Fowey
Rocks Light, off Miami, and Carysfort Reef Light, off Key Largo. The first
period included data from 1879 to 1912, while the second period spanned
from 1991 to 2012.

Our paper shows that corals on the outer-reef tract are now regularly
experiencing temperatures above 29 C (84.2 F) during July, August and
September; average monthly temperatures that were infrequently reached 120
years ago (see Figure 3 in the paper).

Underwater temperatures at a third area, a mid-shore patch reef off
Islamorada, Florida were also monitored from 1975 to 2007. We found that
the temperature increase measured during this recent 32-year period was as
large as that measured at the lighthouses between the two periods a century
apart – meaning that all of the net warming since the late 1800s can be
accounted for by the recent warming since the 1970s.

Sincerely, the authors:

Ilsa Kuffner

Barbara Lidz

Harold Hudson

Jeffery Anderson

P.s. Though not included in our study, average temperature at Fowey Rocks
this August was 30.6 C (87 F) and has resulted in a Keys-wide bleaching
event. See press release for photos of the bleaching from September 7 near
Molasses Reef:


Ilsa B. Kuffner, Ph.D.
St. Petersburg Coastal & Marine Science Center
600 4th Street South
St. Petersburg, FL 33701

Email: ikuffner at usgs.gov
Tel: (727) 502-8048
Fax: (727) 502-8001


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