[Coral-List] Repeat Bleaching of a Central Pacific Reef over the past Six Decades

[Anne Cohen]

Dear Colleagues

Our open access paper "Repeat Bleaching of a Central Pacific Reef over 
the past Six Decades" is published and available here: 
https://www.nature.com/articles/s42003-018-0183-7

The paper connects formation of coral skeletal "stress bands" with 
prolonged, bleaching-induced starvation by tracking individual coral 
colonies on Jarvis Island, central equatorial Pacific, before, during 
and after the 2015 bleaching event.  We then use skeletal stress bands 
to reconstruct a history of bleaching of a coral reef that experiences 
extreme levels of thermal stress every 3-7 years.

The earliest evidence of bleaching in long skeletal cores extracted from 
big old colonies is ~1912.   And we found that since 1960, Jarvis's 
coral community has bleached 10 times, sometimes severely.  Within the 
context of the last 6 decades, the 2015 event appears to have been the 
most catastrophic on record for Jarvis Island.

One cool discovery was some of the///Porites/ colonies that bleached and 
appeared to have died in the 2015 El Nino, had no visible evidence of 
live tissue on the surface or in cores, and were overgrown by algae,  
revived within a year (photo below).   CAT scans of skeletal cores 
extracted from those colonies revealed that the same coral polyps that 
were building the skeleton before the bleaching occurred, continued to 
build the skeleton after the bleaching, in other words, the corallite 
tracks were continuous through the stress band and mortality scar. This 
suggests to us that polyps, or perhaps cells?, taking refuge deep inside 
the skeleton, revived and continued to grow and accrete skeleton once 
ocean conditions returned to normal.

Please let us know if you have any problems accessing the paper

Sincerely,

Hannah and Anne, on behalf of all authors.

-- 
Anne L. Cohen
Tenured Scientist
Woods Hole Oceanographic Institution
Cohen Lab 118
Mailstop #23
Woods Hole
MA 02543
Office 508 289 2958 Lab 508 289 3857
https://web.whoi.edu/cohen/