国家地理:Coral Reefs 岌岌可危的珊瑚礁

The waves of these azure seas hide an abundant treasure. Below the waves, coral reefs provide a habitat for teeming life, a life with a kaleidoscope of color.
In oceans around the world, clear and well-circulating waters encourage corals to anchor and grow. Despite their plant or stone like appearance, corals are actually animals. They come in many colorful forms and textures.
Starting as tiny cylindrical polyps just a couple of millimeters in diameter, they grow about half an inch a year and can become several feet in diameter. Corals form reefs as successive generations build on the skeletal remains of older generations. Reefs can be hundreds of feet wide and stretch for miles.
The greatest collection of reefs is located off the northeast coast of Australia, the Great Barrier Reef. This collection of reefs encompasses 135,000 square miles.
Thousands of species of reef fish，mollusks， sea stars and other creatures inhabit coral reefs. The reef system's spinygrottos offer refuge and feeding grounds for a variety of aquatic life.
In spring, this Caribbean reef plays host to the fanatic mating of fish. A male yellow head garfish is left alone to tender fertilized eggs he carries in his mouth. He spits them out from time to time in order to aerate them over the 5-day gestation period.
In this aquatic community, unusual relationships develop. A cleaning station thrives around this coral head, often patronized by the tiger grouper. Tiny gobies fearlessly enter the tiger's mouth to feed on dead tissue and parasites. But just as the reef fosters life, it can harbor danger. Lurking on the fringes of this Caribbean reef, the barracuda is a fierce predator equipped with razor-sharp teeth. Although they do hunt in groups, sometimes adults branch off and prowl for food on their own. This small ballyhoo fish is a mere snack for this hungry barracuda.
Coral reefs have been evolving for about 500 million years, but these days they are under threat. Global warming, pollution and overfishing have contributed to their decline. Earnest efforts are under way to protect the world's reefs and restore them. Artificial reefs created from sunken ships and other man-made objects have shown some short-term promise. But man's impact on the environment continues to make the future of coral reefs uncertain.
1. azure: adj.
having a bright blue colour like the sky
2. teeming: adj.
full of people, animals etc that are all moving around
3. polyp: n. 珊瑚虫
a very simple sea animal that has a body like a tube
4. skeletal: adj.
connected with the skeleton of a person or an animal
5. Great Barrier Reef: n. 大堡礁
The largest coral reef in the world, about 2,011 km (1,250 mi) long, off the northeast coast of Australia. Its vividly colored banks are known for their exotic fish and crustaceans.
6. mollusk: n. 软体动物
a type of sea or land animal that has a soft body covered by a hard shell
7. spiny: adj.
(of animals or plants) having sharp points like needles
8. grotto: n.
A grotto is a small cave with interesting or attractively shaped rocks.
9. garfish: n. 长嘴硬鳞鱼
10. gestation: n.
the process by which a child or young animal develops inside its mother's body before birth, or the period of time when this happens
11. tiger grouper: n. 老虎斑
12. goby: n. 虾虎鱼
13. barracuda: n. 梭鱼
14. branch off: v.
to diverge from the main way, road, topic, etc
15. prowl: v.
if an animal prowls, it moves around an area quietly, especially because it is hunting another animal
16. ballyhoo: n. 巴西鱵