5 Zones of the Ocean in Order

In this 5 zones of the ocean in order post we have briefly explained about ocean definition, 5 zones of ocean ecosystem in order, benthic organisms and benthic organisms zones of ocean ecosystem.

Communities vary in their physical and chemical conditions, and the organisms that live in each have specific strategies that allow them to survive. The boundaries of the various zones of ocean ecosystem are defined by their physical characteristics, such as temperature, depth, and light penetration.

5 Zones of the Ocean in Order

Marine Environmental zones

5 Zones of the Ocean in Order

Intertidal zone

At the boundary between land and sea is the shallow intertidal zone. This zones of ocean ecosystem is defined by the tidal changes of sea level along the shoreline. The intertidal zones of ocean ecosystem is a thin strip of area that is exposed to air when the tide is low and is under water when the tide is high.

Splash zone

Above this zones of ocean ecosystem is the splash zone. This area is never under water but is exposed to the salt spray of the waves. Below the intertidal zone is the inner shelf. It is always under water and is the area where light can penetrate into the water.

Photic zone

The combination of the splash, intertidal, and inner shelf zones make up the photic zones of ocean ecosystem. This area is where light intensity is great enough for photosynthesis to occur. The depth of a photic zone varies depending upon the clarity of the water, but usually is about 50 to 100 meters

Dysphotic zone

Below the photic zones of ocean ecosystem is the dysphotic zone, where light can be measured, sometimes as deeply as a kilometer down, but is too faint to support photosynthesis.

Aphotic zone

From the lower boundary of this zones of ocean ecosystem and extending all the way to the bottom is the aphotic zone, where no light ever passes and animals have evolved to take advantage of other sources of food. One such environment is hydrothermal vent communities.

Outer Shelf, Bathyal Zone, Abyssal Zone, Hadal Zones: From the top of the aphotic zone to the edge of the continental shelf is the outer shelf. As you move farther away from the shelf, there are three more zones of ocean ecosystem identified by their depth.

The bathyal zone is where the continental shelf drops down to the deep ocean. The abyssal zone refers to the abyssal plains of the deep ocean floor. The hadal zone is in the deep ocean trenches.

Benthic organisms

Marine organisms can be divided into two major groups depending upon where they live. Benthic organisms are those that live on the ocean floor. Some are permanently attached, such as corals, while others move along the bottom, such as rays. Benthic plants and animals inhabit distinct seafloor habitats.

The shallow-bottom habitat that extends from the shore to the edge of the continental shelf supports mollusks, polychaete worms, and attached algae and sponges.

The continental slope and beyond make up the benthic zones of ocean ecosystem, which includes the deepest part of the ocean floor. It is sparsely populated with deposit feeders and filter feeders such as the pycnogonid sea spiders and stalked crinoids

Pelagic organisms

Organisms that live up in the water column are called pelagic. Among the pelagic organisms, there are plankton (which move along with the ocean currents), including phytoplankton and zooplankton. There are also organisms called nekton that are able to swim against the flow of currents. Most fish, for example, are nektonic organisms.

Plankton is the dominant life and food source of the ocean. Phytoplankton, which carries on photosynthesis near the water surface, provides food for grazing zooplankton and the fish life it supports. The deep water and bottom life forms depend on a rain of organic matter from above.

Neritic zone

Finally, areas of the pelagic water column are also divided into sections. The neritic zones of ocean ecosystem is the near shore ocean environment, which occurs over the continental shelf. Most photosynthetic life (life that uses light energy to convert carbon dioxide and water into food), such as phytoplankton and floating sargassum, is located in this region.

Zooplankton, which is the floating creatures ranging from microscopic diatoms to a small fishes and shrimp, also live here. Many species of whales, like the gigantic blue and humpback whales, feed almost entirely on the tiny zooplankton. These whales force seawater through baleen plates (combs of bony material that form in the place of teeth) to filter out the tiny sea creatures.

Oceanic zone

The oceanic zones of ocean ecosystem is comprised of all the other pelagic areas in the ocean. It extends from 200 meters deep all the way down to the bottom of the ocean, which can be thousands of meters. All these divisions and subdivisions help scientists study the organisms that inhabit the oceans of the world.

Further Readings