Transcript introduction / background

Caribbean coral communities decline in variable environments:
can they survive in a changing climate?
Baumann
1
JH ,
Townsend
1Department
INTRODUCTION / BACKGROUND
Tropical corals are colonial organisms that rely on symbiosis
to survive. Corals are very sensitive to stress (such as rising
temperature)1,2. However, some corals cope with this stress
better than others3,4. Here we are studying the impacts of local
stress (nutrients) and global stress (temperature) on coral
communities in Belize.
1
JE ,
Aichelman
1
HE ,
Courtney
1
TA ,
Davies
1
SW ,
Lima
RESULTS
Coral communities less diverse in more variable conditions
• Used the above
parameters to divided the
Belize Mesoamerican
Barrier Reef into thermally
distinct environments
•
•
•
Fig. 4: a.) Coral species richness across site types in Belize.
B.) NMDS plot showing coral community differences between site types in Belize.
Some life history strategies handle variation
better than others
Competitive
2. Coral Surveys
Fig 2: J. Baumann completes a survey.
• Surveyed sites using
AGRRA5 methodology
• Coral diversity, abundance,
density, % cover, and
species richness calculated
FUTURE DIRECTIONS
Stress Tolerant
Generalist
Fig 3: gel of amplified ITS-2 bands.
• Analyze Coral cores and correlate with
temperature events (El Niño, etc…).
• Asses stress mechanisms of stress tolerance
using a reciprocal transplant and/or common
garden tank experiment.
We thank Dan Hoer, Lauren Speare, and Logan Buie for lab
assistance, UNC BRIC for CT scanning, and Casey Berger for
coding and data analysis. I also thank my major funding sources:
The Rufford foundation and The Department of Defense NDSEG.
Fig. 5: The four coral life history strategies as defined by Darling et al (2012)6 and their
distributions between three thermally distinct site types in Belize.
Metabarcoding reveals species-specific symbiont
communities
LITERATURE CITED
3. Symbiont genetics
• Extracted DNA from coral
samples
• Amplified ITS-2 and
sequenced
• Symbiont type identified to
sub-clade level
CONCLUSIONS
Increasing temperature and variability
correlate with decreasing coral community
variables.
Stress-tolerant and weedy corals are better
equipped to survive in the future conditions
ExtTP sites may harbor ecologically
important species and warrant further
protection.
Symbiont communities are species-specific.
“Heat tolerant” symbionts not present at
ExtTP sites.
ACKNOWLEDGEMENTS
Weedy
Fig 1: Site classification based on
SST parameters. Stars indicate
survey and sampling sites.
•
•
• What impact does environmental variability have on
coral and symbiont communities?
• How and why are some species more resilient to
stressors?
• Calculated annual
maximum temperature,
days above the bleaching
threshold, and annual
temperature variability from
sea surface temperature
records.
and K.D.
1
Castillo
of Marine Science, University of North Carolina at Chapel Hill; 2CIBIO, University of Porto, Portugal
RESEARCH QUESTIONS
METHODS
1. Site ID
2
FP ,
Fig 6: Principal component analysis of symbiont
communities present in each species.
Fig 7: Symbiont types that change
significantly with site type in S. siderea
1. Hughes TP, Baird AH, Bellwood DR, Card M, Connolly SR, et al. (2003) Climate change,
human impacts, and the resilience of coral reefs. Science 301: 929-933.
2. Hoegh-Guldberg O (2004) Coral Reefs in a Century of Rapid Environmental Change.
Symbiosis 37: 1-31.
3. Oliver T, Palumbi S (2011) Do fluctuating temperature environments elevate coral thermal
tolerance? Coral Reefs 30: 429-440.
4. Palumbi SR, Barshis DJ, Traylor-Knowles N, Bay RA (2014) Mechanisms of reef coral
resistance to future climate change. Science 344: 895-898.
5. Ginsburg R, Lang J (2003) Status of coral reefs in the western Atlantic: Results of initial
surveys, Atlantic and Gulf Rapid Reef Assessment(AGRRA) program. Atoll Research Bulletin
496.
6. Darling ES, Alvarez‐Filip L, Oliver TA, McClanahan TR, Côté IM (2012) Evaluating
life‐history strategies of reef corals from species traits. Ecology Letters 15: 1378-1386.