11th ICRS Abstract book - Nova Southeastern University

Oral Mini-Symposium 25: Predicting Reef Futures in the Context of Climate Change
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The Future Of Specific Symbioses Within The Reef Coral Pocillopra in The Eastern
Pacific: Investigating The Impacts Of Thermal Anomalies in Western Mexico
Mark WARNER* 1 , Todd LAJEUNESSE 2 , Hector REYES-BONILLA 3 , Matt
ASCHAFFENBURG 1 , Mike MCGINLEY 1 , Robin SMITH 4 , Tye PETTAY 4
1 University of Delaware, Lewes, DE, 2 Pennsylvania State University, University Park,
PA, 3 University of Southern Baja California, La Paz, Mexico, 4 Florida International
University, Miami, FL
Many sources have pointed to the endosymbiotic dinoflagellates within the genus
Symbiodinium as a primary cellular target of damage during coral bleaching. However,
the genetic and physiological diversity of these symbionts, coupled with the fact that
some corals may harbor multiple symbiont types, has led to the idea that such plasticity
could provide an axis for acclimatization or adaptation to climate change if corals can
retain and/or acquire thermally tolerant algae. In particular, it is thought that symbionts
within the “D” lineage may serve this role, yet our knowledge of the ecological
distribution and physiological detail of this and other groups of Symbiodinium is largely
incomplete. The eastern Pacific provides an excellent venue to test these ideas of
symbiont change and coral resilience, as it encompasses regions that have been
differentially impacted by thermal anomalies and coral bleaching. Here we present the
initial findings of a three year study that is investigating the distribution of “C” and “D”
Symbiodinium within the coral Pocillopora in several regions of western Mexico. In
addition, the impact of short-term thermal stress experiments on the photobiology, as well
as long-term analysis of bleaching recovery, coral growth and fitness in Pocillopora
harboring dominant populations of either “C” or “D” Symbiodinium in the southern
Gulf of California will be presented. Initial results from experimental bleaching suggest
that D1 symbionts may possess a slightly higher degree of tolerance to elevated
temperature and/or light as compared to type C1b-c algae, yet significant damage to
photosystem II can result. The long-term implications for recovery and response to future
warming events in the northeastern Pacific will be addressed.
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Annual Summer Mass Bleaching Of A Multi-Species Coral Community in
American Samoa
Douglas FENNER* 1 , Scott HERON 2
1 Marine & Wildlife Resources, American Samoa Government, Pago Pago, American
Samoa, 2 Coral Reef Watch, NOAA, Townsville, Australia
Widespread annual summer mass coral bleaching has been predicted to begin in about
30-50 years, due to increasing global temperatures. Annual mass bleaching has been
reported for two individual coral species, one in the Mediterranean and one in Florida,
but this study is the first known annual bleaching report for a multi-species coral
community. Bleaching levels have been recorded in two back-reef pools on Tutuila,
American Samoa on a biweekly to monthly basis since late 2003. Mass bleaching of
several species has occurred in all four summers during this period. Most Acropora,
one of two species of Millepora, and one small area of Porties cylindrica have
repeatedly bleached but little mortality has been observed so far. During this period,
there was little or no bleaching on the reef slopes. The back-reef pools have limited
circulation, and get hotter on sunny summer days than the adjacent ocean, with sea
surface temperature (SST) reaching about 32°C in these pools. The two summers
previous to the start of recording were reported to have bleaching on reef slopes. About
50% of all staghorns in the pools were dead at the start of observations, which likely were
caused by the more intense bleaching in those 2 years. This suggests that bleaching has
occurred every summer for at least 6 years in a row. The record of the intensity of
bleaching in the pools over the 4 years follows SST’s quite closely. This appears to be
the first detailed record of the time course of repeated multi-species bleaching available.
Ongoing annual mass bleaching of a multi-species community provides a window into
the future and an opportunity for examining the effects on corals of climate change.
25-40
Bleaching Damage And Recovery Potential Of Coral Reefs in Dubai, Uae
John BURT 1,2 , Andrew BAUMAN* 3 , Aaron BARTHOLOMEW 4 , Peter SALE 5,6
1 Natural Science and Public Health, Zayed University, Dubai, United Arab Emirates,
2 Department of Biological Sciences, University of Windsor, Windsor Ontario, Canada,
3 International Network on Water, Environment and Health, United Nations University, Dubai,
United Arab Emirates, 4 Department of Biology and Chemistry, American University of Sharjah,
Sharjah, United Arab Emirates, 5 Department of Biological Sciences, University of Windsor,
Windsor, ON, Canada, 6 International Network on Water, Environment and Health, United
Nations University, Windsor, Canada
Documenting long-term changes to coral reef communities following large-scale bleaching
events is necessary for predicting changes to coral community composition and their recovery
potential to climate change. Such information is necessary to successfully predict how
bleaching events may affect the composition and recovery potential of coral communities. In
the Arabian Gulf increasing frequencies of elevated sea surface temperatures (1996, 1998, and
2002) have caused extensive coral reef mortality in Dubai United Arab Emirate. Here, we
surveyed coral communities within Dubai, examining the composition of the coral assemblages
present in 2007, and compared this with information on coral community composition from
1996. We characterized five distinct coral communities in 2007 and compared with previously
published accounts of the same communities. In 1996, extensive coral mortality in Dubai,
primarily affected Acropora dominated communities, reducing their abundance by almost 90%.
Our research showed that within the same areas, Acropora communities had nearly doubled in
abundance, from 22% to 42%. Despite this strong recovery of Acropora communities, both
Faviid and Poritid assemblages, which only suffered negligible mortality in 1996, dominated
remaining communities. However, minimal change in percent coral cover of both Faviid and
Poritid between 1996 and 2007 suggested assemblages were shifting towards Acropora
dominated pre-bleaching communities. We also investigated the recovery potential of coral
communities by surveying coral recruitment. Recruitment densities were consistently low
throughout coral assemblages, with community composition highly dependent on the
surrounding adult communities. However, the prevalence of relatively fast growing Acropora
juveniles throughout communities indicated that recovery of Acropora dominated communities
was occurring. This study shows that despite recurring mass coral bleaching events, coral
communities throughout Dubai are able to rapidly recover suggesting that these assemblages
may be acclimatized to the extreme conditions found throughout the Arabian Gulf.
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Can Symbiont Diversity Help Coral Reefs Survive Climate Change?
Marissa BASKETT* 1 , Steven GAINES 2 , Roger NISBET 2
1 National Center for Ecological Analysis and Snythesis, University of California, Santa
Barbara, Santa Barbara, CA, 2 Ecology, Evolution and Marine Biology, University of California,
Santa Barbara, Santa Barbara, CA
Given climate change, thermal stress-related mass coral bleaching events present one of the
greatest anthropogenic threats to coral reefs. While corals and their symbiotic algae may
respond to future temperatures through adaptation and shifts in community compositions, the
climate may change too rapidly for coral response. Here we develop a model of coral and
symbiont ecological dynamics and symbiont evolutionary dynamics. Model results without
variation in symbiont thermal tolerance predict coral reef collapse within decades under
multiple future climate scenarios, consistent with previous threshold-based predictions.
However, model results with genetic or community-level variation in symbiont thermal
tolerance can predict coral reef persistence into the next century, provided low enough
greenhouse gas emissions occur. Therefore, the level of greenhouse gas emissions will have a
significant effect on the future of coral reefs, and accounting for biodiversity and biological
dynamics is vital to estimating the size of this effect.
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