The oceans and seas are known as the last unexplored regions of the world. Life in oceans and seas is very diverse and is home to a multitude of plant and animal life. Oceans and seas cover over 70% of our planet far more than that of the land!

Oceans of the World

The Earth's oceans are inter-connected. The recognized oceans are the Arctic, Atlantic, Indian, and Pacific and the newer Southern Ocean which surrounds Antarctica and extends to 60 degrees latitude. Seas (smaller oceans) are often partly enclosed by land. The largest seas are the South China Sea, the Caribbean Sea, and the Mediterranean Sea.

There is no one answer to to explain this. The saltiness of the ocean is the result of several natural influences and processes that have occured and still ouccur today. Most of the ocean's salts came from gradual processes such the breaking up of the cooled igneous rocks of the Earth's crust by weathering and erosion, the wearing down of mountains, and the dissolving action of rains and streams which transported their minerals ultimately into the sea. Some of the ocean's salts have been dissolved from rocks and sediments below its floor.

Other sources of salts include the solid and gaseous materials that escaped from the Earth's crust through volcanic vents or that originated in the atmosphere. All of these processes over time has led ot the saltiness of the seas.The saltiness or salinity of sea water varies to the melting of ice at the North and South Poles, river water flowing into the seas, evaporation, rain, snow, wind, wave motion, and ocean currents that "mixes- up " the saltwater. The saltiest water is found in the Red Sea and in the Persian Gulf, which have a salinity of about 40 o/oo because of high evapouration rates and a small inout of freshwater.

• Hard corals build by secreting calcium carbonate skeletons.
• Boring organisms such as sponges, worms, and bivalves; along with grazers such as parrotfish and sea urchins break down the coral skeletons. Borers and grazers usually attack dead coral. The resulting sediment settles into spaces in the reef.
• Coralline algae, encrusting bryozoans, and minerals cement the dead organic matter, stabilizing the reef structure.

Categories of reefs

Fringing reefs Fringing reefs border shorelines of continents and islands in tropical seas. Fringing reefs are commonly found in the South Pacific Hawaiian Islands, and parts of the Caribbean. Fringing reefs are coral reefs that grow in shallow waters and border the coast closely or are separated from it by a narrow stretch of water. Fringing reefs consist of several zones that are characterized by their depth, the structure of the reef, and its plant and animal communities.In the Caribbean most reefs are of this type.
Barrier reefs Barrier reefsare much wider and are separated from land by a lagoon which may be several kilometres wide and 10 to 70 metres deep.. These reefs grow parallel to the coast and are large and continuous. In the Caribbean Barrier reefs can be found off the east coast of Martinique and in the Grand Cul-de-Sac Marin in Guadeloupe.
Atolls Atolls are annular reefs that develop at or near the surface of the sea when islands that are surrounded by reefs subside.There are two types of atolls: deep sea atolls that rise from deep sea and those found on the continental shelf. Coral debris accumulating on the atoll rim through wave action will tend to form low-lying coral islands. There are three atolls in Belize namely Glovers Reef, Turneffe Islands and Lighthouse Reef. Glovers Reef represents one of the best and largest atoll formations in the Caribbean.

Here are some of the varieties of coral that can be found in the caribbean!

Fire Coral (Millepora spp)	Cavernous star coral	Pillar Coral
Elkhorn coral	Staghorn Coral	Brain Coral

Coral reefs are home to over 25 percent of all marine life and are among the world's most fragile and endangered ecosystems. In the last few decades, mankind has destroyed over 35 million acres of coral reefs. Reefs off of 93 countries have been damaged by human activity.

How Coral Reef Damage Can Occur

• Fishing with Explosives
  Over-fished reefs and desperate fishermen produce a deadly combination when reefs are dynamited to harvest small fish. Fisherman prepare bombs made out of materials such as potassium nitrate (a common fertilizer) to cause large explosions which kill all the fish in the surrounding area and reduce nearby coral to lifeless rubble.
• Runoff
  Water Silt from eroded soil in runoff water can block sunlight. Without sunlight, photosynthesis does not occur and reefs gradually die.
• Human Contact
  Touching Reefs, even slightly, can harm them. Boats and dropped anchors can cause severe damage to these fragile ecosystems. Frequent human contact kills the reefs over time.
• Collection and Dredging
  Removing coral to be used for construction material or sold as souvenirs also threatens coral reefs, as does the dredging and dynamiting of coral for construction in coral reef areas.
• Global warming
  Coral reefs are also threatened by global warming. When ocean temperatures get too high, coral polyps lose the symbiotic algae inside them, causing them to turn white, or "bleach," and eventually die.