Why is the ocean layers

The neritic zone is from low tide mark and slopes gradually downward to the edge of the seaward side of the continental shelf.

Some sunlight penetrates to the seabed here. The oceanic zone is the entire rest of the ocean from the bottom edge of the neritic zone, where sunlight does not reach the bottom. Skip to main content. Oceans and Coastal Environments. Search for:. Layers of the Ocean In , two men in a specially designed submarine called the Trieste descended into a submarine trench called the Challenger Deep 10, meters. Licenses and Attributions. This zone extends from 1, meters 3, feet down to 4, meters 13, feet.

Here the only visible light is that produced by the creatures themselves. The water pressure at this depth is immense, reaching 5, pounds per square inch. In spite of the pressure, a surprisingly large number of creatures can be found here. Sperm whales can dive down to this level in search of food. Most of the animals that live at these depths are black or red in color due to the lack of light. Abyssopelagic Zone - The next layer is called the abyssopelagic zone, also known as the abyssal zone or simply as the abyss.

It extends from 4, meters 13, feet to 6, meters 19, feet. The name comes from a Greek word meaning "no bottom". The water temperature is near freezing, and there is no light at all. Very few creatures can be found at these crushing depths. Most of these are invertebrates such as basket stars and tiny squids.

Three-quarters of the ocean floor lies within this zone. The deepest fish ever discovered was found in the Puerto Rico Trench at a depth of 27, feet 8, meters.

Hadalpelagic Zone - Beyond the abyssopelagic zone lies the forbidding hadalpelagic zone. Impact of Attending Conferences Donate. Search Search for:. Main Points The ocean has three main layers: the surface ocean, which is generally warm, and the deep ocean, which is colder and more dense than the surface ocean, and the seafloor sediments.

The thermocline separates the surface from the deep ocean. Due to density differences, the surface and deep ocean layers do not easily mix. This means that the gases dissolved in surface seawater, such as CO 2 , also get mixed into deep seawater on longer timescales. The seafloor is made up of 4 main types of sediments: Biogenic, Lithogenic, Hydrogenous, and Cosmogenic. Biogenic sediments are very important, and include both siliceous and carbonaceous sediments made up of the hard parts of marine organisms.

Carbonaceous sediments are those that contain calcite, or calcium carbonate CaCO 3. Hypothetical cross section of a continental shelf to ocean transect with different layers of the ocean showing timescales on which different layers of the ocean mix completely, along with how long it takes for the biosphere to take in CO 2 from the atmosphere, and how long it takes for CO 2 that is buried on the seafloor to be part of the rock record.

Blue whale not to scale. Ocean temperature profile within the mid-latitude regions. The area where temperature changes from the surface ocean to the deep ocean is called the thermocline. Image modified from NOAA. Mixing of the Surface and Deep Oceans Because the surface and deep ocean layers are of very different densities due to salt content and temperature , these layers of the ocean do not mix easily.

Seafloor Sediments Seafloor sediments are sediments that can be found at the bottom of the seafloor that are still in contact with seawater. Major types of seafloor sediments and their distribution on the seafloor. Siliceous ooze and carbonate ooze are both types of biogenic sediments.

Terrigenous Sediments Terrigenous sediments are those that are derived from the Earth, mostly from the continents themselves. Clay Very small particles of sediment that settle onto the seafloor are considered clay. Biogenic Sediments A radiolarian, an example of a siliceous microfossil.

Hydrogenous Sediments Hydrogenous sediments are ocean sediments that are formed in place from chemical reactions with the surrounding seawater. Share this: Twitter Facebook. Like this: Like Loading Loading Comments Email Required Name Required Website.