CLIMATE CHANGE AND CORAL REEFS

1
CLIMATE CHANGE AND CORAL REEFS
James Crabbe
2
Themes

• 1. Climate change
• 2. Coral reefs
• 3. Climate extremes
• 4. Sedimentation
• 5. Modelling coral growth and climate change
• 6. Genetic studies adaptation?
• 7. From science to conservation challenges and
  opportunities for China

3
GLOBAL WARMING
Global average temperatures (from UK Hadley
Centre)
4
Glaciers and Sea Ice are melting
The Pasterze, Austria's longest glacier, in 1875
and in 2004
5
TYPES OF REEF-BUILDING CORALS

• BRANCHING CORALS
• (Acropora palmata)
• MASSIVE CORALS
• (Diploria labyrinthiformis)

6
WHY ARE THEY IMPORTANT?

• a valuable natural resource - high productivity
• rainforests
• of the sea
• high
• biodiversity
• A food
• source for
• millions of
• people

7
WHY ARE THEY IMPORTANT?

• source of medicines -- worth billions
• coastal protection from wave erosion
• source of islands white sand beaches
  fortourist resorts
• 7 million scuba divers

8
(No Transcript)
9
Increase in Sea Surface Temperatures

• Involved in bleaching
• Involved in hurricane formation

10
Coral Bleaching

• Corals tolerate a narrow temperature range
  between 25 degrees C and 29 degrees C depending
  on location
• Corals lose their symbionts - Stark white
  appearance
• Owing to raised Sea Surface Temperatures (SSTs)
  and increased Photosynthetic Active Radiation
  (PAR).

11
World map showing levels of coral bleaching.
Source ReefBase
No bleaching Bleaching unknown Low
bleaching Medium bleaching High
bleaching
12
Waiting for a bus...
Then ..... two come along!
13
Predicted bleaching events per decade in Jamaica
Hoegh-Guldberg (1999).
14
JAMAICA Genera/species of corals
15
DISCOVERY BAY WITH BAUXITE LOADING TERMINAL
16
The reef crest in 1973, dominated by Acropora
palmata (photo P. Dunstan)
17
Coral cover at Rio Bueno
18
DEVELOPING AN ACCURATE MODEL FOR CORAL COLONY
GROWTH TO MONITOR CLIMATE-DRIVEN EXTREME EVENTS

• Exponential model
• Simple polynomial functions have been used in
  forest ecosystems
• Rational polynomial function should provide good
  fit and may produce biological insights
•  

19
HURRICANE TRACKS 1980
20
(No Transcript)
21
Recruitment/survival and storm severity
22
(No Transcript)
23
SEVERE STORMS

• NOT ONLY DESTROY BRANCHING CORALS
• SEVERELY LIMIT NON-BRANCHING CORAL RECRUITMENT,
  PROBABLY OWING TO STRESS ON REPRODUCTION AND
  CHANGES IN TOPOGRAPHY

Crabbe, M.J.C., Karaviotis, S. and Smith, D.J.
(2004) Preliminary comparison of three coral reef
sites in the Wakatobi Marine National Park (S.E.
Sulawesi, Indonesia) Estimated recruitment dates
compared with Discovery Bay, Jamaica. Bulletin
of Marine Science 74, 469-476.
24
STRESS BY SEDIMENTATION IN JAMAICA
25
VideoRay ROV
26
STRESS FROM SEDIMENT RUN-OFF IN THE INDO-PACIFIC
27
Acropora valenciennesi colony at Kaledupa reef
site, surrounded by good benthic cover. Note
tags on branches and calibration rule.
28
Acropora valenciennesi colony at Sampela reef
site, in area of high sedimentation, surrounded
by bare ground and poor benthic cover.
29
(No Transcript)
30
Comparison in estimated recruitment patterns

• Indonesia shows many lean recruitment years,
  unlike Jamaica
• Reasons Coral extraction? Bombing? Weather
  conditions?

Crabbe, M.J.C. and Smith, D.J. (2005) Coral
Reefs. 24, 437-441 Crabbe, M.J.C., Karaviotis,
S. and Smith, D.J. (2004) Bulletin of Marine
Science 74, 469-476.
31
SAMPELA built on corals
32
Can we use modelling to predict how corals will
respond to climate change ?

• Can meteorological factors be incorporated into a
  coral colony growth model?
• Data from Curaçao and Jamaica

33
Coral growth rates during study period. Maximima
and minima indicated by letters.
34
Correlation between coral growth rates and 30-day
averaged max. and min. temperatures and
precipitation
Variable with 30-day av. Maximum daily
temperature Minimum daily temperature Daily
precipitation
R2 -0.031 0.004 0.002
p-value 0.002 0.268 0.464
Crabbe, M.J.C., Walker, E.L.L. Stephenson, D.B.
2007. The impact of weather and climate extremes
on coral growth. In H. Diaz R. Murnane
(Eds.) Climate Extremes and Society. Cambridge
University Press. In the press.
35
(No Transcript)
36
Zooxanthellae clade DNA analysis Clade A group
composed of all the species descended from a
single common ancestor
Zooxanthellae
Coral Reefs
37
Adaptive bleaching hypothesis

• Bleaching may enable corals to adopt different
  classes of zooxanthellae, better suited for a new
  environment. By
• symbiont switching (a new clade from exogenous
  sources) or
• symbiont shuffling (host contains multiple
  clades and a shift in dominance occurs).

38
Community involvement !
39
SCIENCE TO CONSERVATION The Challenges

• Integrate scientific knowledge and conservation
  science into policy that directly benefits all
  the stakeholders, from Governments to local
  fisherfolk and their families.

40

• The environment is seen as part of the problem,
  not as part of the solution. This is because
  poverty and crime are seen as the key problems,
  and the government are not thinking about how the
  environment might help both those issues.

41

• Moral and practical challenges will continue to
  resonate in issues of sustainability and
  conservation. And we do not have much time. For
  people around the world who rely on coral reefs
  for their livelihoods, anthropogenic effects are
  degrading the local resource base at an alarming
  rate.

42
Time past and time future Allow but a little
consciousness T. S. Elliot, Little Gidding,
The Four Quartets
THANK YOU