Corals and climate change - University of Florida - Web/Baham… · Corals Adjustments Reef...

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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


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Reproduction

Climate change

Corals

Adjustments

Reef resilience


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


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


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


8 m


3 m


8 m


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


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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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Reproduction events


2-3 years of recovery

Only alleles experiencing persistent selection pressure may

attain high frequency

Reproduction

Climate change

Corals

Adjustments

Reef resilience


• 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


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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

Corals and climate change - University of Florida - Web/Baham… · Corals Adjustments Reef...

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