11th ICRS Abstract book - Nova Southeastern University

Oral Mini-Symposium 25: Predicting Reef Futures in the Context of Climate Change
25-21
Right Of Disaster: Understanding, Predicting And Accelerating The Adaptive
Response Of Reef Coral Symbioses To Climate Change
Andrew BAKER* 1,2
1 Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science,
University of Miami, Miami, FL, 2 Marine Program, Wildlife Conservation Society,
Bronx
Reef-building coral symbioses are increasingly threatened by the effects of climate
change, and it is not yet known whether these organisms will be able to adapt or
acclimatize quickly enough to avoid large-scale loss of reef ecosystems. A variety of
mechanisms have been identified by which corals, their algal symbionts, and other
microbial partners might compensate for these environmental changes. Most research to
date has focused on the ability of corals to flexibly associate with diverse algal symbionts
(“zooxanthellae” in the genus Symbiodinium) whose specific identity results in different
environmental optima for the coral host. However, the potential importance of this
mechanism is limited by: (1) the timescales over which flexibility might act; (2)
ontogenetic restrictions, environmental prerequisites and host systematic constraints on
flexibility; and (3) physiological tradeoffs of hosting different symbionts. Despite these
considerations, symbiosis flexibility remains the most promising mechanism identified to
date by which corals might survive climate change. Consequently, as we move into an era
of unavoidable climate impacts, knowledge of symbiosis flexibility might be used to
understand declines, forecast future effects, and prioritize species and areas of special
conservation. Moreover, despite the limitations on symbiosis flexibility outlined above,
artificial manipulation of symbiont communities at the larval or adult coral stages may
have conservation benefit and should be attempted. These interventions can be employed
to: (1) create stocks of thermally tolerant corals for restoration purposes; (2) protect the
largest and oldest corals on reefs of special value; and (3) create species survivorship
networks in targeted areas of special concern whose persistence may help preserve
ecosystem function. Symbiosis flexibility has probably played a critical role in the
evolution and success of reef corals, and triage-based conservation strategies that
leverage these natural adaptive mechanisms to mitigate climate change effects should be
attempted whenever possible.
25-22
Proliferation Of An Opportunistic Symbiodinium Sp. During The 2005 Eastern
Caribbean Mass Coral ‘bleaching.’
Todd LAJEUNESSE* 1,2 , Jennifer FINNEY 3 , Robin SMITH 4 , Hazel OXENFORD 3
1 Biology, Florida International University, North Miami, FL, 2 Biology, Pennsylvania
State Universtiy, University Park, 3 Center for Resource Management and Environmental
Studies, University of the West Indies, Bridgetown, Barbados, 4 Biology, Florida
International University, Miami, FL
Corals of the Eastern Caribbean underwent their worst recorded bleaching and mortality
in the fall of 2005. The resident dinoflagellate endosymbionts were examined in coral
species from Barbados during the summer before signs of stress were evident. Sampling
was repeated in early winter one month following a return to normal sea surface
temperatures, but before recovery. The reefs were revisited 5 months and two years later
to assess the state of Symbiodinium populations. A partial or complete change in the
resident population to a putatively stress-tolerant opportunist, Symbiodinium D1a,
occurred in colonies of several coral species over the course of this event. Lowabundance
resident background populations of D1a were detected using rtPCR before
signs of stress were evident and proliferated in many colonies during the late summer and
fall. The differential growth and/or persistence of this background symbiont in response
to thermal stress ‘saved’ many colonies from bleaching. Many colonies that bleached
experienced partial or total mortality in the months that followed. While the prevalence
of Symbiodinium D1a remained high months later, the symbiont populations in most
colonies reverted back to their normal symbiont species after two years. The distribution
patterns before, during and after this event clearly indicate that Symbiodinium D1a is a
weedy species generalized to numerous host taxa and opportunistic during times of
physiological stress.
25-23
A Community Change in The Symbionts Of A Scleractinian Coral Following A Natural
Bleaching Event: Field Evidence Of Acclimatization
Alison JONES* 1 , Ray BERKELMANS 2 , Madeleine VAN OPPEN 2 , Jos MIEOG 3 , William
SINCLAIR 1
1 Biosystems and Resources, Central Queensland University, Rockhampton, Australia,
2 Environmental Change and Impacts, Australian Institute of Marine Science, Townsville,
Australia, 3 Marine Benthic Ecology and Evolution, University of Groningen, Haren,
Netherlands
It has been hypothesized that reef corals can change their Symbiodinium community
populations dramatically by up-regulating low levels of more stress tolerant types in their tissue
after bleaching. In this study, we quantify the change in symbiont community in colonies of a
common reef-builder Acropora millepora after a natural bleaching event in the Keppel Islands
(Great Barrier Reef). By late February 2006 when bleaching was at its most intense, the relative
difference in bleaching susceptibility between corals predominated by C2 and D was clearly
evident, with the former bleaching white and the latter normally pigmented. The symbiont
community change in surviving colonies was dramatic (71% changed predominance from C2 to
D or C1 (n=58) however selective mortality of C2 colonies also played a substantial role in
shifting the symbiont community in the post-bleaching coral population. We suggest that this
change in symbiont community structure occurred mainly as a result of background symbionts
proliferating in recovered colonies. If these backgrounds symbionts are present in other
structurally important coral species, coral reefs may have considerably more acclimatization
potential through symbiont shuffling than previously thought.
25-24
Shifts in symbiodinium Communities Following Bleaching in The Panamic Eastern
Pacific: Insights From Quantitative Pcr
Adrienne CORREA* 1,2 , Andrew BAKER 3 , Danielle MCDONALD 3 , Peter GLYNN 3
1 Ecology, Evolution & Environmental Biology, Columbia University, New York, NY, 2 Marine
Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of
Miami, Miami, 3 Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric
Science, University of Miami, Miami, FL
The extent to which reef corals can adapt and/or acclimatize to increasing sea surface
temperatures is highly debated within climate change science. It is hypothesized that
physiological differences among the genetically diverse dinoflagellate endosymbionts of corals
(Symbiodinium spp.) may prove critical to the survival of reefs. This could occur in two ways:
(1) the differential proliferation of coral colonies that specifically host thermally tolerant
symbionts; and/or (2) shifts favoring heat tolerant Symbiodinium in colonies that flexibly host
multiple symbiont types. Some shifts in symbiont dominance have already been documented on
recently bleached reefs, within individual bleached colonies, and seasonally within healthy
colonies. These shifts may be “host-driven”, such as when differential host mortality indirectly
results in community-wide changes in Symbiodinium prevalence; or they could be symbiontdriven,
representing the outcome of ecological processes such as competition among symbionts
within hosts. We are using quantitative PCR (qPCR) to explore: (1) the prevalence of mixed
Symbiodinium communities; (2) changes in symbiont community structure; and (3) the
potential evidence for symbiont competition within a long-term (1995-2006) dataset of two
Panamanian coral species (Pocillopora damicornis and Pocillopora elegans) in the
eastern Pacific, and also within experimentally bleached colonies. This approach allows us to
explore the degree to which fine-scale changes occur between years in the average dominant
Symbiodinium clade on reefs, as well as changes in the relative abundance of Symbiodinium
clades within individual coral colonies before, during, and after bleaching. Since cryptic
diversity may function as a ‘safety net’ during times of environmental change, Symbiodinium
community dynamics, especially following disturbance, may be critical to predicting the
potential future survival trajectories of coral reefs.
233