1. Coral Reefs: Biodiversity and
Beauty at Risk
Dr. Mark McGinley
Professor, Head of Science Unit
Core Curriculum and General Education Office
Lingnan University
markmcginley@ln.edu.hk

2. Planet Earth

3. Planet Earth??

4. What’s down there?

5. Coral Reefs
Footage by Josh Jensen, Undersea Productions

10. 10
What is a Coral?

13. 13
Coral Polyps

14. Coral Asexual Reproduction

15. 15

16. 16
Coral Skeleton

17. Branching Corals

18. Brain and Boulder Corals

19. Plate and Table Corals

20. Terrestrial Environment is Dominated
by Plants

21. But These Are All Animals.
Where Are All of the Plants???

24. 24
Types of Coral Reefs- Atolls

25. Types of Coral Reefs- Barrier Reef

26. Coral Reefs
Thickest reef about 1.5 km thick!

27. Coral Wall

28. Big Things Built By Humans

29. Largest “Biogenic” Structure
Great Barrier Reef

30. Coral Reef Distribution

45. Lionfish

46. Lionfish- Caribbean Sea

47. Parrotfishes

48. Parrotfish Sleeping

49. Parrotfish “beak”

50. Parrotfish “eliminating wastes”

51. Biogenic Sand

52. Stoplight Parrotfish

53. Great Barracuda

54. Barracuda with “cleaners”

55. Cleaner Shrimp

56. Cleaning Stations

57. Cleaner Wrasse

58. Relationship Between “Cleaner” and
“Client”
• Originally, thought to be
a mutualistic
relationship
– Both partners benefit
• Cleaner gets food
• Client is cleaned of
parasites
• After further study,
scientists realize that
this system is much
more complicated
– Sometimes the cleaner
eats the parasites and
other times it bites the
client fish and removes
scales, skin, etc.!!
– “Cheaters!”

59. What Would You Do?

60. What Should a Client Fish do if a
Cleaner Fish Takes a Bite Out of
Them??

61. Client Fish can be Smart!!
• They remember when a
cleaner fish bites them
rather than cleaning
them and respond by
• Not returning to that
cleaning station
• Not allowing that
individual fish clean them
any more
• Try to punish “cheaters”

62. Clients Can Learn!!

63. Cleaner Fish Can Be Pretty Smart Too
• Whether a cleaner will
“cheat” or not depends
on who is watching
– Less likely to “cheat” if
other potential client
fish are watching
– More likely to “cheat” if
there are no potential
client fish around.

64. Benefits of Coral Reefs
• Coral reefs provide
233 billion HKD to
1,300 Billion HKD of
goods and services
each year
– WWF & SI

65. Benefits of Coral Reefs
Fisheries
• About one billion people
depend, at least partially,
on coral reefs for food
and income from fishing.
• Reefs can yield around
15 tonnes of fish and
other seafood per square
kilometre each year.
– WWF

66. Benefits of Coral Reefs
Shoreline Protection

67. Benefits of Coral Reefs
Tourism
• Florida Keys 23
billion HKD annually
• Australia’s Great
Barrier Reef
generates well over
7 billion HKD per
year.
– WWF

68. Benefits of Coral Reefs
Medicines
• Treatments for cardiovascular diseases, ulcers,
leukemia, lymphoma, and skin cancer, based
on from chemicals in reef plants and animals.
• More than half of all new cancer drug
research focuses on marine organisms.
– bioprospecting
• Coral’s unique skeletal structure has been
used to make bone-grafting materials.
• Coral Reef Alliance

69. Benefits of Coral Reefs
Intrinsic Value
Although coral reefs cover <1% of Earth’s surface and <2% of ocean
bottom, 25% of ocean species depend on coral reefs!

70. Coral Reefs At Risk
(Now)

71. Coral Reefs At Risk
(projected 2050)

72. Reefs at Risk- Caribbean Sea

73. Reef Decline in Caribbean Sea

74. Threats to Reefs
Over Fishing

75. Threats to Reefs: Over Fishing

76. Threats to Coral Reefs
Dynamite fishing

77. Threats to Coral Reefs
Pollution and Siltation

78. Threats to Coral Reefs
Coral Diseases

79. African Dust Hypothesis

80. Coral Bleaching

81. Coral Bleaching

82. Coral Bleaching Mechanism

83. Coral Bleaching RISK

84. Threats to Reefs
Ocean Acidification

85. Ocean Acidification Mechanism

86. Future of Coral Reefs??

87. Learn More
• Corals and Coral Reef: Smithsonian National
Museum of Natural History
– http://ocean.si.edu/corals-and-coral-reefs
• Coral Reefs: WWF
– http://wwf.panda.org/about_our_earth/blue_planet/
coasts/coral_reefs/
• What Are Coral Reefs?: NOAA
– http://www.coris.noaa.gov/about/what_are/
• Coral Reefs 101: Coral Reef Alliance
– http://coral.org/coral-reefs-101/

88. Thank You!!