OCEAN AND SEAS

OCEAN AND SEAS.

OCEANS.

ALL ABOUT OF OCEAN. The ocean covers 70 percent of Earth's surface. It contains about 1.35 billion cubic kilometers (324 million cubic miles) of water, which is about 97 percent of all the water on Earth. The ocean makes all life on Earth possible, and makes the planet appear blue when viewed from space. Earth is the only planet in our solar system that is definitely known to contain liquid water. Although the ocean is one continuous body of water, oceanographers have divided it into five principal areas: the Pacific, Atlantic, Indian, Arctic, and Southern Oceans. The Atlantic, Indian, and Pacific Oceans merge into icy waters around Antarctica..

CLIMATE. The ocean plays a vital role in climate and weather. The sun’s heat causes water to evaporate, adding moisture to the air. The oceans provide most of this evaporated water. The water vapor condenses to form clouds, which release their moisture as rain or other kinds of precipitation. All life on Earth depends on this process, called the water cycle. The atmosphere receives much of its heat from the ocean. As the sun warms the water, the ocean transfers heat to the atmosphere. In turn, the atmosphere distributes the heat around the globe. Because water absorbs and loses heat more slowly than land masses, the ocean helps balance global temperatures by absorbing heat in the summer and releasing it in the winter. Without the ocean to help regulate global temperatures, Earth’s climate would be bitterly cold..

OCEAN FORMATION. After Earth began to form about 4.6 billion years ago, it gradually separated into layers of lighter and heavier rock. The lighter rock rose and formed Earth’s crust. The heavier rock sank and formed Earth’s core and mantle. The ocean’s water came from rocks inside the newly forming Earth. As the molten rocks cooled, they released water vapor and other gases. Eventually, the water vapor condensed and covered the crust with a primitive ocean. Today, hot gases from the Earth’s interior continue to produce new water at the bottom of the ocean..

OCEAN FLOOR. Scientists began mapping the ocean floor in the 1920s. They used instruments called echo sounders, which measure water depths using sound waves. Echo sounders use sonar technology. Sonar is an acronym for SOund Navigation And Ranging. The sonar showed that the ocean floor has dramatic physical features, including huge mountains, deep canyons, steep cliffs, and wide plains. The ocean’s crust is a thin layer of volcanic rock called basalt. The ocean floor is divided into several different areas. The first is the continental shelf, the nearly flat, underwater extension of a continent. Continental shelves vary in width. They are usually wide along low-lying land, and narrow along mountainous coasts. A shelf is covered in sediment from the nearby continent. Some of the sediment is deposited by rivers and trapped by features such as natural dams. Most sediment comes from the last glacial period, or Ice Age, when the oceans receded and exposed the continental shelf. This sediment is called relict sediment..

Ocean Life Zones. From the shoreline to the deepest seafloor, the ocean teems with life. The hundreds of thousands of marine species range from microscopic algae to the largest creature to have ever lived on Earth, the blue whale. The ocean has five major life zones, each with organisms uniquely adapted to their specific marine ecosystem. The epipelagic zone (1) is the sunlit upper layer of the ocean. It reaches from the surface to about 200 meters (660 feet) deep. The epipelagic zone is also known as the photic or euphotic zone, and can exist in lakes as well as the ocean. The sunlight in the epipelagic zone allows photosynthesis to occur. Photosynthesis is the process by which some organisms convert sunlight and carbon dioxide into energy and oxygen. In the ocean, photosynthesis takes place in plants and algae. Plants such as seagrass are similar to land plants—they have roots, stems, and leaves. Algae is a type of aquatic organism that can photosynthesize sunlight. Large algae such as kelp are called seaweed..

SEAS.

ALL ABOUT OF SEAS. The sea, a vast expanse of saltwater covering Earth's surface, holds a world of wonder and mystery, teeming with diverse marine life and ecosystems. Its tides, currents, and waves shape coastlines and impact climate, making it a vital part of our planet's health and beauty..

CLIMATE. The climate of the seas is a diverse and dynamic system shaped by numerous factors. One of the most prominent influences on sea climate is latitude, with equatorial regions typically experiencing warm waters, while higher latitudes may have colder temperatures. Ocean currents play a pivotal role, redistributing heat and affecting sea surface temperatures. Seasonal variations are also present, mirroring land climates, with warmer seas in summer and cooler conditions in winter..

SEAS FORMATION. Seas, the vast expanses of saltwater that dot our planet, take shape through intricate geological processes. Most commonly, they form along continental margins where the Earth's crust sinks or subsides due to tectonic forces. This depression becomes a receptacle for seawater, giving birth to what we know as seas. Additionally, seas can arise in rift zones, where tectonic plates pull apart, creating depressions that are gradually filled with seawater, as exemplified by the Red Sea. Inland seas, such as the Baltic Sea, are formed when geological shifts isolate a portion of an ocean. Enclosed or semi-enclosed seas, like the Gulf of Mexico, emerge when landmasses partially encircle a region of the ocean. River valleys can also transform into seas when rising sea levels flood these depressions, a phenomenon observed in the Baltic Sea and Hudson Bay..

SEAS FLOOR. The sea floor, also known as the ocean floor, is the bottom of the ocean or sea. It is a diverse and complex environment comprising various features like continental shelves, abyssal plains, trenches, and underwater mountains. The sea floor's geology, ecosystems, and topography play a crucial role in Earth's processes and biodiversity..

SEAS LIFE ZONE. The sea life zones, also known as marine or oceanic zones, delineate the diverse ecological regions within the world's oceans, each distinguished by unique environmental characteristics and the specific marine life that thrives there. These zones are primarily categorized based on depth, availability of sunlight, temperature, and pressure..