Ocean, a geographical term, is the floorboard of the widest water body on the earth. The earth's surface is divided into huge interconnected water bodies by the mainland, which are called oceans. The central part of the ocean is called ocean, and the marginal part is called sea. They communicate with each other and form a unified water body. The total ocean area on the earth is about 360 million square kilometers, accounting for 7 1% of the earth's surface area, with an average water depth of about 3795 meters. The ocean contains more than1350 million cubic kilometers of water, accounting for about 97% of the total water of the earth, and only 2% is available for human consumption. The four oceans of the earth are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean and the Arctic Ocean, and most of them are bounded by land and seabed topographic lines. Today, only 5% of the seabed has been explored, and 95% of the seabed is unknown. The ocean covers more than 70% of the earth's surface and is the main driving force of weather and climate. Slight fluctuations in ocean temperature may lead to drastic changes in global weather and climate.
The role of the ocean:
The ocean has a huge biological system, which produces a lot of oxygen for the earth. Rich in marine biological resources, protein is the largest supply base. There are huge mineral resources in the ocean, and almost all the minerals found on land are in the ocean. There are inexhaustible marine chemicals and marine energy resources in the ocean, including a large number of chemicals and fresh water contained in seawater, as well as abundant power, water and thermal energy resources.
Causes of marine pollution:
1. Land-based pollution: the ocean and rivers enter the ocean. Applying chemical pesticides to coastal farmland, dumping and stacking garbage and wastes on beaches will also cause pollution damage to the environment.
2. Ship pollution: the ships on board discharge oil or other harmful substances into the sea for various reasons. Ship pollution mainly refers to the pollution caused by ships to the surrounding water environment and atmospheric environment during navigation, port call and cargo loading and unloading.
3. Maritime accidents: ships run aground, hit rocks, collide, blowout, oil pipeline leakage, etc.
4. Ocean dumping: a treatment method of dumping wastes into the ocean to reduce land environmental pollution. Use ships, planes, platforms or other vehicles to dispose of wastes or other harmful substances into the sea. It also includes the abandonment of ships, planes, platforms and other floating tools.
5. Coastal engineering construction: Some coastal engineering constructions have changed the natural characteristics of the coast, tidal flat and subtidal zone and their subsoil, and destroyed the ecological balance of the ocean and coastal landscape.
Measures to protect the ocean:
1. Establish marine nature reserves: the establishment of marine nature reserves can preserve rich natural resources and marine natural background, protect the original appearance and state of the ocean, and protect the original characteristics of species from loss; It can protect, restore, develop, introduce and propagate biological resources, preserve the diversity of biological species, and eliminate and reduce man-made adverse effects.
2. Sewage discharge control: the discharge of domestic sewage and industrial wastewater will bring a lot of bacteria and toxic substances to the ocean, leading to eutrophication of seawater. In order to improve the marine environment, we must pay attention to the emission problem.
3. It is forbidden to over-exploit the ocean: over-exploitation such as land reclamation and energy exploitation will destroy the habitat of living things and make them face the threat of extinction. Overfishing and indiscriminate killing will also lead to a sharp decline in the number of species.
4. Develop marine science and technology: strengthen scientific research on biodiversity protection and marine environmental pollution control, and provide technical support for marine biological protection.
5. Reduce noise pollution: According to the World Wide Web report, in the past 100 years, marine noise has become more and more serious, such as propellers and sonar. All kinds of noises are produced in the ocean, which interferes with the normal activities of marine life. Therefore, it is necessary to make the ocean "quiet" and reduce the harmful effects on marine life.