11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 25: Predicting Reef Futures in the Context of Climate Change
25.1149
Using Global Circulation Models And Optimized Bleaching Thresholds To Assess
The Future Of Reefs
Ruben VAN HOOIDONK* 1 , Matthew HUBER 1
1 Earth and Atmospheric Sciences, Purdue University, West-Lafayette, IN
Global, thermally induced bleaching is projected to increase in frequency due to
anthropogenic climate change. The predicted-time to widespread bleaching and
subsequent mortality is strongly influenced by the thresholds used and the uncertainties
surrounding these thresholds. Therefore there is a need to optimize techniques that
predict bleaching and their local thresholds. Using the Peirce Skill Score we can establish
the predictive techniques skill or accuracy, and we can also find a local threshold value
that objectively maximizes the accuracy of the technique at any given location. We use
these optimized thresholds in combination with several SRES scenarios in Global
Circulation Models to assess the likelihood of bleaching at all reefs worldwide in next
century and beyond. And with the measured skill we can quantify the uncertainty in our
predictions of bleaching and the possible implications of uncertainties in global warming
rates in climate models used in the IPCC report.
25.1150
Species Susceptibility To Bleaching And Disease Before, During, And After The
2005 Caribbean Warm Water Event On Deep And Mid-Depth Reefs Of The Us
Virgin Islands
Jacqulyn CALNAN* 1
1 University of the Virgin Islands, St. Thomas, Virgin Islands (U.S.)
During the months of September to December 2005, the northeastern Antilles
experienced an unprecedented warm water event that had a dramatic impact on the health
of coral in this region of the Caribbean. Annual monitoring of coral health since 2001
has allowed for the examination of species susceptibility to bleaching and disease over
four time periods; “pre bleaching”, “bleaching,” “recovery” and “post bleaching.”
Bleaching was severe for a number of common coral species during the event, most
specifically those in the genus Montastraea as well as for Agaricia agaricites. A cause
for concern is that many corals continued to show an above normal prevalence of
bleaching into the “post bleaching” (6-12 months) period. Colpophyllia natans,
Montastraea annularis, Porites porites, Siderastrea siderea, and Diploria strigosa
appeared slower to recover than other species such as Agaricia agaricites which showed
no signs of bleaching six months following the event. Although all common corals
species showed greater than 70% bleaching during this event, there very few incidences
of disease observed until the “recovery” period (2-5 months later). During this period,
coral diseases reached unprecedented levels at many of the sampling sites. White plague
was the most common disease following the bleaching event and affected primarily
Montastraea franksi (22% prevalence). Siderestrea siderea was also frequently affected
by disease, largely due to a high prevalence of dark spots disease in the post bleaching
period. Overall, prevalence of partial mortality on common coral species increased from
only 7% to 80% in the months following the bleaching. Species specific responses to
thermal related stresses are therefore important to understanding and predicting the future
trajectories of coral reefs.
25.1151
Environmental Correlates Of Symbiodinium Population Clade Identity
Thomas OLIVER* 1 , Kevin ARRIGO 2 , Stephen PALUMBI 1
1 Hopkins Marine Station, Stanford University, Pacific Grove, CA, 2 Geophysics, Stanford
University, Stanford, CA
Recent studies have shown that the genetic identity of a reef coral's obligate endosymbionts,
dinoflagellates in the genus Symbiodinium, determines in part that coral’s likelihood of resisting
temperature increases. If this effect is common, we may be able to better understand a given
reef’s likelihood of resisting temperature increase based in part on the composition of its
Symbiodinium community. By correlating reefs with documented Symbiodinium community
compositions to a range of environmental variables we can potentially predict areas more likely
to house symbionts that better resist thermal stress. We review 41 published papers that
genotyped wild Symbiodinium, at 110 sites, and correlated the observed Symbiodinium
community compositions at each site to the site’s Sea Surface Temperature (SST), Chl-A
compostion, cloud-cover corrected photosynthetically active radiation (PAR), turbidity, degree
heating weeks, and bleaching history. Bleaching history was reconstructed using the ReefBase
database of bleaching events, and all other variables were derived from satellite observations.
Frequencies of the resistant Symbiodinium clades A and D showed significant positive linear
correlations with annual mean and maximum SST, as well as annual mean PAR. Multiple
linear regression models return corrected R2s from 0.44-0.79, depending on the genus of corals
examined, with Poccillopora’s Symbiodinium community having the strongest environmental
correlations. From these models, we have produced global maps with predicted proportions of
Symbiodinium clades A-D, given an area’s environmental characteristics.
25.1152
Global Warming And Caribbean Coral Reefs Collapse: The Case Of Star Corals
(Montastraea Annularis And M. Faveolata) in Puerto Rico.
Edwin HERNANDEZ-DELGADO* 1 , Raisa HERNANDEZ 1
1 Biology, Universtity of Puerto Rico, San Juan, Puerto Rico
A catastrophic warming event occurred during 2005 through the northeastern Caribbean Sea
that caused a mass coral bleaching event in Puerto Rico that was followed by an unprecedented
mass mortality of star coral species complex (Montastraea annularis and M. faveolata), among
other species. It resulted in a severe net physiological fragmentation of large coral colonies.
Permanent photo-stations were established in 4-6 m deep reef terraces dominated by
Montastraea spp. at four sites in Culebra Island, Puerto Rico. Digital photography was used to
document changes in benthic community structure before (2005) and after (2007) this event. All
coral colonies bleached during 2005. Mass coral mortality caused a 60 to 95% decline in %
living tissue cover in both species. No significant difference in % living tissue cover loss was
documented among sites. Abundant physiological tissue fragments were formed in each colony,
typically ranging from just below 1 to 105 cm2, but mostly in mean sizes below 10 cm2. There
was no significant difference in mean fragment size among sites. Fragment density was
significantly higher (p