Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals. These corals are unable to move and clusters with other corals so they form colonies. Coral reefs vary in size, type and location and they are very sensitive organisms. They want clear and hot waters. That’s why all coral reefs are located in the tropical places.
Today coral reefs are endangered by human. The greatest treat are the fishermen. Many coral reefs in South China Sea are endangered and this has to stop. Look at these great photos of the 10 largest coral reefs and lets increase the awareness to help coral reefs.
Great Barrier Reef, Australia
Length: 1,553 miles (2,500 km)
Location: Coral Sea near Australia

Image by eutrophication&hypoxia via Flickr

Image by Richard Ling via Flickr
Red Sea Coral Reef
Length: 1,180 miles (1,900 km)
Location: Red Sea near Israel, Egypt and Djibouti

Image by Derek Keats via Flickr

Image by Dmytro Kochetov via Flickr
New Caledonia Barrier Reef
Length: 932 miles (1,500 km)
Location: Pacific Ocean near New Caledonia

The Mesoamerican Barrier Reef
Length: 585 miles (943 km)
Location: Atlantic Ocean near Mexico, Belize, Guatemala and Honduras

Photo by Tony Rath

By U.S. Geological Survey (USGS) [Public domain], via Wikimedia Commons
Florida Reef
Length: 200 miles (322 km)
Location: Atlantic Ocean and Gulf of Mexico near Florida

Image by Rafael Robayna via Flickr
Andros Coral Reef
Length: 124 miles (200 km)
Location: Bahamas between the islands of Andros and Nassau

Zhongsha Islands (Macclesfield Bank)
Length: 50 miles (81 km)
Location: South China Sea

Credit: Hughes et al. Current Biology
Saya De Malha
Area: 15,444 square miles (40,000 sq km)
Location: Indian Ocean

Great Chagos Bank
Area: 4,633 square miles (12,000 sq km)
Location: The Maldives

Image by faiyu Shafyq via Flickr
Reed Bank
Area: 3,423 square miles (8,866 sq km)
Location: South China Sea, claimed by the Philippines

Image by Storm Crypt via Flickr
