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4/3/2014
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Corals and climate change
Robert van Woesik, Ph.D.
Department of Biological SciencesFlorida Institute of Technology
Photos: T. Nakamura
Photos: T. Nakamuravan Woesik
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NASA NASA image
NASA
NASA
Reproduction
Climate change
Corals
Adjustments
Reef resilience
Corals and climate change
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Reproduction
Climate change
Corals
Adjustments
Reef resilience
Corals and climate change
A coral’s life cycle
Broadcasters
Brooders
Wallace (1999) Staghorn corals of the world
Egg and sperm bundles
Photo: P. Harrison
Hermaphrodites
Photo: P. Harrison
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Photo: P. Harrison Photo: P. Harrison
Photo: P. Harrison
Yossi Loya and Kazuhiko Sakai (2008)
Proc Royal Soc B 275: 2335-2345
Males-> Females
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Synchronous spawning of hundreds of coral species on the Great Barrier Reef (Harrison et al. 1984) Why mass spawning?
What is the long-term advantage (i.e., the adaptive significance) of mass spawning?
Spawning occurs during calm seasons
van Woesik
Hypothesis: there is a strong relationship between synchronous spawning and calm seasons
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van Woesik
Hypothesis: there is a strong relationship between synchronous spawning and calm seasons
van Woesik
<6 m s-1
Global analysis – Tropical Microwave Imager (TMI) data, randomly selected pixel in reef vicinity, for each month (from
1999 to 2007)
• Great Barrier Reef (latitude 19oS)
• Okinawa (26oN)
• Palau (7oN)
• Kenya (3oS)
• Galápagos (0o)
• Ningaloo (21oS)
• Florida Keys (24oS)
Global analysisSpawning period = -1.9773+1.4773*x; 0.95 Conf.Int.
1 2 3 4 5 6 7 8
Duration when average winds < 6 ms-1 (months)
0
1
2
3
4
5
6
7
8
9
10
Sp
aw
nin
g p
eri
od
(m
on
ths)
van Woesik (2010) Proc Royal Soc 277: 715-722
adj. R2 = 0.809, p = 0.005
GBR
PalauOkinawa
Kenya
Galapagos
Florida Keys
Western Australia
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Repercussions:
Mass spawning during seasonally calm periods agrees with genetic evidence of local retention.
… most recruitment is local (10s km), but there is also, albeit infrequent, connectivity over large distances.
Cowen et al 2006. Science 311: 522-527
Reproduction
Climate change
Corals
Adjustments
Reef resilience
Corals and climate change
primary polyp
0.5 mm
S. pistillata
20 cm
Photos Y. Loya
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van Woesik
Darwin’s dilemma
How do coral reefs thrive in low nutrient environments?
Photo: O. Hoegh-Guldberg
Translocates 78-97% of total net carbon fixed to coral host
Recycles nutrients
Sunlight
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van Woesik
Symbiosis
Darwin’s dilemma: how do coral reefs thrive in low nutrient environments?
van Woesik
Sustainability – a model system with over 245
million years of success
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Ries 2011 Nature Climate Change 1: 294-295
Barnes & Lough. 1993. J E M B E 167: 91-108
Ong et al 2012
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Light attenuation
0
20
40
60
80
100
120
0 10 20
Depth (m)
Lig
ht
inte
nsi
ty (
%) …
.
30 cm
30 cm
Light resource
Surface area
Sunlig
ht
Large light resource
30 cm
30 cm
Low-lightHigh-light
Porites sillimaniani
Light intensity
van Woesik
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Darwin 1842 Darwin 1842
Tim
e
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Veron 2009
Persistence of coral reefs
1) Natural beauty and diversity
2) Coral reefs are important physical structures
3) Corals reefs supply goods and services to humans
Global Climate Change
Climate change
D. Wagner
Global warming is:
… the unusually rapid increase in Earth’s average surface temperature over the past century primarily because of the release of greenhouse gases by people that are burning fossil fuels.
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http://www.youtube.com/watch?v=6yiTZm0y1YA
https://www.ipcc.ch/report/ar5/index.shtml
1552 pages
Jean Baptiste Joseph Fourier : March 21, 1768-May 16, 1830
Joseph Fourier’s argument was the earth's atmosphere acted like the glass of a hot-house
Arrhenius (1896): ‘On the influence of carbonic acid in the
air upon the temperature on the
ground’,Philosophical
Magazine 1896(41): 237-76).
Svante August Arrhenius,
Feb 19, 1859- Oct 2, 1927
Broeker (1979) Fate of fossil fuel carbon
dioxide and the global carbon budget. Science
Vol 206: 409-418
CO2 - rate of change !
“The rate of change is 100 times faster than anything seen in the past hundreds of millennia” Nature (2006) 442: 978-980
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Increase in CO2
• Rise in air temperature
• Rise in ocean temperature
• Decrease in ocean pH
• Melting of ice caps (on land) = sea-level rise
Reproduction
Climate change
Corals
Adjustments
Reef resilience
Corals and climate change
Webster et al 2005. Science Santer et al 2006. PNAS 103: 13905-13910
Tropical Atlantic
Tropical Pacific
Last 20 years –average increase of 0.5oC
van Woesik IPCC 2007
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Present location of reefsPresent Region > 18°C (64oF)
Thriving Acropora cervicornispopulations off Ft. Lauderdale after 4000-year hiatus
Bill Precht
van Woesik van Woesik
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Normal temperatures
Light Reactions
H2O
O2
Light
Dark Reactions
CO2
Organic C
O2 O2*O2 O2*
Oxidative DAMAGE
BLEACHING
Dark Reactions
CO2
Organic C
Active Oxygen
Photosynthesis
Slide: Hoegh-Guldberg
Symbiotic dysfunction
Southern Japan, 1998
Starvation
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2 months 3 months
5 months
6 months
7 months
Favia favus
More bleaching and coral death in shallow habitats than in deep habitats
15 m
8 m
~ 20% Photosynthetic Active Radiation
3 m
More bleaching and coral death in shallow habitats than in deep habitats
8 m
~ 20% Photosynthetic Active Radiation
3 m
More bleaching and coral death in shallow habitats than in deep habitats
8 m
~ 20% Photosynthetic Active Radiation
3 m
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van Woesik et al 2012 Ecology and Evol
van Woesik
Clear reciprocity between temperature & light
Corals experience light & temperature in a similar manner
TemperatureLight
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van Woesik
Clear reciprocity between temperature & light
Corals experience light & temperature in a similar manner
TemperatureLight
Florida’s coral reefs
van Woesik van Woesik
2005, 69-day composite temperature map
Totugas
Lower KeysMiddle Keys
Upper Keys
Biscayne
transition
Broward
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E. Muller photo. September 2005
Species/Colonies Bleached Within Zones
(Keys)
% Species
Bleached
% Colonies
Bleached
Inshore 47% 39%
Mid Channel 75% 55%
Forereef 66% 44%
Minor to moderate bleaching in the Florida Keys occurred in 2005, 2007, 2008, 2009, and 2010.
Wagner, Kramer, van Woesik et al (2010) Marine Ecology Progress Series 408: 65-78
Global projections
Villanni & Vecchi (2012) Nature Climate Change 2: 604-607
RCPs= Representative Concentration Pathways, named after possible radiative forcing values in the year 2100, relative to pre-industrial values (+2.6, +4.5, +6.0, and +8.5 W/m2, respectively)
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Caribbean is a disease hotspot
Coral reef
Coral-disease occurrence
8%
66%
van WoesikDiseases : over 30 diseases described, only 3 with a specific
pathogen… (in 25 years of research)
Black-band
White-band
White-plague
Yellow-band
White-poxPhoto byG. Burnham.
White-plaguePhoto byS. Miller.
Photos by
E.C. Peters.
Are diseases increasing?
Muller and van Woesik (2008) Coral Reefs 27: 191-195
Compromised-host hypothesis
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Do the fishes care?
Yes! Fishes aggregate around reef-building corals
Munday et al 2008. Fish & Fisheries 9: 261-285
Another issue
Rising atmospheric CO2 concentrations over the past two centuries have led to greater CO2
uptake by the oceans.
NOAA image
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IPCC 2013
Fine & Tchernov (2007) Science 315: 1811
Ries 2011 Nature Climate Change 1: 294-295 Ries 2011 Nature Climate Change 1: 294-295
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Perforate Imperforate
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Message:
The higher the cover of live corals the greater the chance of reef growth.
Intergovernmental Panel Climate Change 2013
Intergovernmental Panel Climate Change 2013
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The Republic of the Marshall Islands
Parts of Majuro are only 30 cm above sea level
March 5, 2014 (King Tides)
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Tim
e
Tim
e
More Storms?Global storms 150 years
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Tropical storms
Before After
Foster et al 2013. PLoS One
van Woesik
Before Bonnie
After Bonnie... .
..
.
..
HurricaneBonnie 2004
van Woesik
Before Bonnie
After Bonnie... .
..
.
..
HurricaneBonnie 2004
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6/20/05 7/10/05 7/30/05 8/19/05 9/8/05 9/28/05 10/18/05
2005 Temperature stress
Average
Bleaching Threshold
starts at 29.5oC
In-situ water temperaturesMid-channel -Hens & Chickens-10 feet
Reef Margin-Mollasses reef- 20 feet
Katrina
In-situ temp data fromHarold Hudson
RitaDennis
Surveys
max
In-s
itu t
emp
(C
)
P. J. Webster et al., Science 309, 1844 -1846 (2005)
Global time series for 1970-2004
P. J. Webster et al., Science 309, 1844 -1846 (2005)
Intensity of hurricanes Saffir-Simpson scale (categories 1 to 5)
Ruíz, Escaleante y Iglesias Prieto en Preparación.
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October 22, 2005Hurricane Wilma, 2005
Coral Reefs
• Protect the coastline
• Biodiversity hotspots
• Recreation & tourism
• Fishing grounds….
Reproduction
Climate change
Corals
Adjustments
Reef resilience
Corals and climate change
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Will refuges save reefs?
• Where are the refuges?• Deep reefs?
• Habitats that experience low temperatures?
• Habitats that experience strong currents?
Where are the refuges??
Can corals adapt?
Do corals have the ability to rapidly evolve tolerance to changes in ocean temperature that are likely by the end of the current century?
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Driving question
Which coral populations are destined to
become the ‘winners’ and which populations
are destined to become the ‘losers’?
Loya Y, Sakai K, Yamazato K, Nakano Y, Sambali H, van Woesik R (2001) Ecology Letters 4: 122-131
Hierarchy of tolerance
• Leptastrea - Cyphastrea spp. (Encrusting)
• Goniastrea aspera (Encrusting -Massive)
• Porites lutea (Massive)
• Porites cylindrica (Branching)
• Acropora spp. (Branching
• Pocillopora damicornis (Branching)
• Millepora intricata (Branching)
T
o
l
e
r
a
n
c
e
High
Low
Differential reproduction isat the ‘heart’ of adaptation
adaptation involves differential-reproductive rates on different individuals within populations.
Thermal event filter
Annual reproduction (recombination) –
biannual in tropics
10 years of recovery
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Thermal event filter
Reproduction events
Thermal event filter
2-3 years of recovery
Only alleles experiencing persistent selection pressure may
attain high frequency
Reproduction
Climate change
Corals
Adjustments
Reef resilience
Corals and climate change
• Conservation and sustainable use
• Halt and reverse pollution
• Watershed management
• Protect biodiversity & connectivity
• Prevent over-fishing
• Increase stability of desirable states
Resilience-based management
GBRMPA
1900 2000 2100 2200
Year
“Resilience threshold”
Sea temperatures• reduce rate & magnitude of change
Reef condition
Increase resilience• Refugia
• Water quality
• Biodiversity
• Connectivity
Resilience - a framework for
management response to climate change
GBRMPA
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1960 1980 2000 2020
Coral cover (proxy for condition)
Recommendations
1. Establish and strictly enforce networks of Marine Protected Areas that include No-Take Areas.
2. Control terrestrial discharge on coral reefs (from rivers and
local sources).
3. Need regional and global action to reduce effects of climate change.
“Degraded reefs will not keep up”
“Healthy reefs may keep up with sea level rise”
Resilient systems are self-sustaining!
Reproduction
Climate change
Corals
Adjustments
Reef resilience
Corals and climate change
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1900 2000 2100 2200
0
2
4
Glo
bal
tem
pera
ture
ch
an
ge (
°C
)
3
1
Unmitigated emissions 750 ppm stabilisation 550 ppm stabilisation
Hadley Centre for Climate Prediction and Research
The degree to which global warming changes life on Earth depends on our decisions Conclusions
• Projected changes in climate may drive temperature and seawater chemistry to levels outside the envelope of modern reef experience.
• Some reef organisms will adapt to climate change more than others – some will be winners, while others will be losers.
• Local connectivity suggests that local protection and management will lead to local benefits. Action and protection may buy time for adaptation.
Selective pressure
Evolve toward synchronization
Ancient Most derived
Evolution of the system
van Woesik (2010) Proc Royal Soc 277: 715-722
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