Takatoshi AKAI

23-1 JOCV/KWS

Malindi Marine National Park

Outline

• Desertification in ocean

• Cause of coral whitening phenomenon

• Case Study 1: Great Barrier Reef

• Case Study 2: Ishigaki Island

• Solution and conclusion

Desertification in ocean

• If there are several kinds of corals exist, the place has maintaining good eco-system.

• However, some beautiful coral places changing color into white, and looks like desert.

• Its not only loss of beautiful spot, but also loss of eco-system in entire ocean.

HealthHealthyy

CoralCoral

Dead Dead (Whitening(Whitening

))CoralCoral

Healthy coral & Whitening coral

Healthy coral (up) & Whitening coral (down)

Cause①： Environmental Pollution

• Coral whitening is caused by loss of zooxanthella.

• Zooxanthella and coral have relationship of mutualism (symbiosis / parasitism).

• Loss of zooxanthella is caused by stress to coral.

Ex: increase acid in water⇒⇒ocean disposal of wastes⇒build new structure

on the sea WithWithzooxanthellazooxanthella

WithoutWithoutzooxanthella zooxanthella

Cause②： Changing water quality and temperature

1. Once outbreak plankton,It cause red/blue/white or green tide.

2. Those tide block sun light,So coral can not photosynthesis.

3. Zooxanthella left coral to seekooxanthella left coral to seek sunlight to photosynthesis.sunlight to photosynthesis.Also, if the ↑ they remove.℃Also, if the ↑ they remove.℃

4. Without zooxanthella, coral cannot get oxygen and dead. Maintain only lime part.

No light, no oxygen.

I'm choking!I cannot breathe.

Cause③：White Syndrome• Different from “left of Zooxanthella”, ooxanthella”,

there is a kind of disease, which makes there is a kind of disease, which makes coral white.coral white.

• It called “White Syndrome”

• However, the cause and solution are not found yet.

Case Study 1: Great Barrier Reef• Great Barrier Reef has 400 kinds of corals and listed in World

Heritage in UNESCO.• Since 2006, corals in Great Barrier Reef start to become white.Cause:

↑① water temperature due to global warming, and water increased acid.②Global warming led “el Nino phenomenon” to make heavy rain.③Heavy rain brings earth and sand from land, also sometimes

chemicals.Now: Great Barrier Reef is getting smaller each year. Australian government regulate to protect it, but not effective.

Case Study 2: Ishigaki Island 1• Since 2007, the number of white coral increased. • Ishigaki Island is one of the most famous diving spot in Japan

Cause: ①Tourist without manner between 1980 to 2000 increased.

They break or stamp on the coral reef and killed them.

Journey to Revive: The number of coral decreased dramatically, but people in Ishigaki and

NGO/NPO worked hard to revive coral reef. They opposed to stop development and declamation of ocean in Ishigaki. Due to their effort, tourist without manner has decreased dramatically and development on Ishigaki area has post phoned.

Case Study 2: Ishigaki Island 2New problem: Recently, caused by global warming, the ocean

current has changed and brought garbage dumped in foreign country.

Ocean is connected to the world, so people have to aware to stop dumping in the sea.

That will effect and help to stop coral whitening.

Solution and Conclusion

• Be well-mannered. ⇒Do not dump garbage into ocean.

• To stop global warming. ⇒Practice “3R”.

• To think and learn about ocean. ⇒Ocean is only one. ⇒Ocean is connected

to the world. ⇒Ocean is for everyone.