11th ICRS Abstract book - Nova Southeastern University

12-1
Past Frequencies Of Thermal Anomalies Determine Extent Of Coral Bleaching
Diane THOMPSON* 1 , Robert VAN WOESIK 1
1 Biological Sciences, Florida Institute of Technology, Melbourne, FL
Coral bleaching events have increased in the past few decades due to an increase in the
frequency, severity and spatial scale of anomalous sea-surface temperature (SST) events.
These coral bleaching events are expected to become even more frequent as SSTs
continue to rise. Yet, the frequency of past anomalous SSTs may influence coral
acclimatization and adaptation. The objective of this study was to determine whether the
frequency of anomalous SST events in the past influences the ability of corals to resist
bleaching. We hypothesize that corals at sites that have experienced frequent anomalous
SSTs over the last three centuries will be able to resist bleaching during contemporary
regional thermal stress events. Wavelet analysis of coral stable oxygen isotope records
was used to determine significant interannual and decadal variability at 17 reef locations.
Interpolation was then used to determine the probability of interannual and decadal
variability throughout the Pacific and Indian Oceans and the Red Sea. The difference
between these probabilities was used as the predictive variable, as less bleaching is
expected at sites with high-frequency variability (high interannual and low decadal). A
global meta-analysis categorically defined bleaching severity at each site during the peak
of the 1997-98 event as either: 1) no, 2) low, 3) medium or 4) high bleaching. We show
that sites that experienced no or low bleaching had a significantly higher difference
between the interannual and decadal modes. Therefore, corals at sites that had
experienced frequent thermal anomalies in the past were more likely to resist bleaching
during contemporary thermal events. Based on the frequency of past thermal events, reef
corals in the Pacific Ocean may be more likely to resist bleaching during future climate
change-associated anomalies compared with corals in the Indian Ocean and Red Sea.
12-2
Corals in Hot Water: Physiological Responses Of porites Lobata in A Diurnally
Fluctuation Environment
Daniel BARSHIS* 1,2 , Jonathon STILLMAN 3 , Ruth GATES 1 , Robert TOONEN 1 , Lance
SMITH 4 , Charles BIRKELAND 4
1 Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, HI,
2 Department of Zoology, University of Hawaii at Manoa, Honolulu, 3 Romberg Tiburon
Center for Environmental Studies, San Francisco State University, Tiburon, CA,
4 Department of Zoology, University of Hawaii at Manoa, Honolulu, HI
The Ofu back reef in the National Park of American Samoa hosts a wide variety of corals
that withstand mean temperatures (up to 30oC) and daily fluctuations (3-4oC) greater
than most coral reef habitats. Despite these known stressors, back reef corals appear
healthy, exhibiting limited bleaching despite high levels of environmental fluctuation.
We hypothesized that frequent exposure to the fluctuating environment of the Ofu back
reef enhances the corals ability to cope with environmental stress. Samples from 4
source colonies of Porites lobata from the back reef and 4 colonies from the neighboring
forereef were cross and back transplanted to each source location. Transplants were
sampled every 24 hrs for 5 days following transplantation (n=40). Heat shock protein 70
(Hsp70), ubiquitin-conjugated proteins, manganese superoxide dismutase (MnSOD), and
4-Hydroxynonenal (4-HNE) protein levels were analyzed by Western blot for each
sample. Ubiquitinated protein levels were higher in back reef source colonies for all
transplants and all days (p