The earth's oceans are all connected to one another. The same water is circulated throughout them all. The oceans cover more than seventy percent of the surface of the earth.  Until the year 2000, there were four recognized oceans: The Pacific, Atlantic, Indian, and Arctic. In the spring of 2000, there was a a new ocean delemited, the Southern Ocean. This new ocean surrounds Antarctica. There are also many seas (smaller branches of an ocean). Seas are often partly enclosed by land. The largest seas are the South China Sea, the Caribbean Sea, and the Mediterranean Sea.

The oceans serve many functions, including the natural regulation of our weather and temperature. They moderate the earth's temperature by absorbing incoming solar radiation (stored as heat energy). The always-moving ocean currents distribute this heat energy around the globe, heating surrounding landmasses and air during winter and cooling it down during summer.

Many people treat the oceans as if they were inexhaustible, in terms of what they produce, as well as what our oceans can absorb. We can’t continue with bad practices like overfishing. Fish species are very valuable and contribute to the world's food supply and economy of many nations. Up to 30 million people rely directly on fishery for employment. Fish and seafood products are globally traded and generate billions of dollars. Thousands of fish, sea animals and plants live in our seas and oceans, and thye form a critical element in earth's natural foodchains. To preserve these often unique marine species, we have to halt large scale dumping of industrial waste into our oceans and rivers.

Another important part of the oceans are coral reefs. For many people in developing countries, coral reefs offer food (fish and crustaceans) and an income from fishery and tourism. More important, coral reefs are also the habitat of thousands unique animal and plant species. The reefs provide food and shelter and thier exclusive breeding grounds to reproduce. Coral reefs are one of the most important parts of our oceans.  Even though reefs take only 0,25% of the seas, a quarter of all fish species depend on them.

Due to polluting and overfishing, many species are in danger of extinction, and our coral reefs, wetlands, and kelp forests are disappearing.

Valuable fish stocks are threatened by overfishing. Two-third of Europe’s fish stocks are estimated to be overexploited, and 24% of the world's total fisheries are already overexploited. Humans are taking far more fish out of the oceans than can be replaced by nature.
Numerous independent scientific studies have shown high concentrations of plastics waste, blocking the guts of as much as 177 marine species. Almost 80% of pollution to this marine environment comes from land-based sources, such as runoff pollution. Runoff pollution includes many small sources, like septic tanks, cars, trucks and boats, plus larger sources such as farms, ranches and forest areas. Some water pollution actually starts as air pollution, which settles into waterways and oceans. Another dangerous pollution to our oceans happens when ships leak oil. Even today there are still up to two dozen oiltanker-disasters happening every year. These are a big threat to plants and animals in the oceans. Acid rain is another threat. Pollution originating from land goes up into the air and then rains back down into the oceans, poisoning marine life.

Lakes

Rivers

Oceans

Groundwater

Only 0,6% of the world’s oceans are protected, compared to nearly 13% of our planet’s land areas.
It’s very difficult to protect the oceans and seas, because they don’t belong to any single nation and no nation has sovereignty over an entire sea or ocean. We need international cooperation to effectively protect our oceans. By ageeing to designate an ocean or see as an MPA, Marine Protected Area, we can protect it internationally.  Once a sea is appointed as an MPA, fishing can be severely restricted and even totally banned in the designated marine area.

Tourism could be another solution for areas where people depend on fishery. Responsible and sustainable tourism can form an alternative source of income for these local people.

Oceana

Reefkeeper

Ocean Conservancy

Living Oceans

Ocean Watch 

Reef Relief 

Marine Protected Areas