abyssThe near-freezing layer from 4,000 to 6,000 meters down. The name is from a Greek word for bottomless. It is also called the abyssal zone.
bioluminescenceLight that a living thing gives off. A firefly is bioluminescent, and so are many animals of the deep ocean.
hadal zoneThe deepest zone, below 6,000 meters, in the trenches. It runs down to the lowest point of the ocean, and living things have been found even there.
marine snowSpecks of dead matter sinking from the waters above. Many animals of the deep feed on it. Some flakes drift down for weeks before they land on the bottom.
midnight zoneThe always-dark layer from 1,000 to 4,000 meters down. The only light is the glow of the animals themselves. Sperm whales can dive this deep to find food.
photosynthesisThe way algae and plants use light to build food. In the ocean it is not possible below about 200 meters, where too little sunlight is left.
sea floorThe ground at the very bottom of the ocean. Seabed, ocean floor and ocean bottom are other names for it.
Show all 36 terms (29 more)
The five zones, continued
sunlight zoneThe top layer, from the surface to about 200 meters. Enough light reaches it for plants and algae to grow. Its scientific name is the epipelagic zone.
trenchA seabed ditch far deeper than the floor around it. Trenches can be thousands of kilometers long. Most lie around the Pacific Ocean, and the Mariana Trench is the deepest.
twilight zoneFaintly lit middle waters: 200 meters down to 1,000. The sunlight here is very faint, too faint for photosynthesis.
water columnA top-to-bottom slice of the water at one spot. It runs from the surface to the sea floor. Temperature, saltiness and light are measured at each depth of it.
water pressureThe squeeze of all the water lying overhead. It grows with depth. In the Mariana Trench the water above weighs over 8 tons on each square inch.
Names and divisions 12
abyssopelagic zoneThe scientists' name for the abyss. Most of the deep ocean floor, about three parts in four, lies at these depths.
aphotic zoneEvery depth below 1,000 meters, where no sunlight comes. The name means without light. The midnight zone, the abyss and the hadal zone are all parts of it.
bathypelagic zoneThe scientists' name for the midnight zone. Bathy is from the Greek for deep. The water stays close to 39 degrees Fahrenheit (4 degrees Celsius).
benthic zoneThe lowest living region of any sea, lake or river. The living things of this zone are called benthos, or bottom dwellers.
deep seaAll the ocean under about 200 meters, where light fades. It is cold and dark, and the pressure is high.
epipelagic zoneThe scientists' name for the sunlight zone. Wind keeps this layer mixed, which spreads the sun's heat downward.
intertidal zoneThe strip of shore that is wet at high tide, dry at low. Sea stars and sea urchins live there.
mesopelagic zoneThe scientists' name for the twilight zone. Meso is from the Greek for middle. Another name for it is the midwater zone.
neritic zoneThe shallow sea that lies over a continental shelf. It is well lit, and about 200 meters deep where the shelf drops off.
oceanic zoneThe open ocean out past the edge of the shelf. It holds deep basins, undersea volcanoes and trenches.
pelagic zoneThe open water of the sea, apart from the sea floor. The word is from the Greek for open sea. The five depth zones are layers of it.
thermoclineThe layer in which water turns colder fast with depth. It lies between the warm, mixed water at the top and the cold water of the deep.
Life and the sea floor 12
abyssal plainA wide, level stretch of ocean floor, far down. Abyssal plains are usually 3,000 to 6,000 meters down and are among the flattest places on Earth.
anglerfishA fish that fishes: it dangles a lure to draw prey. In some deep-sea kinds the lure gives off light.
Challenger DeepThe lowest spot yet measured on the ocean floor. It is in the western Pacific, where the Mariana Trench ends in the south, about 10,900 meters down.
continental shelfThe sea-covered rim of a landmass, before the drop-off. The shallow water over it is called a shelf sea.
continental slopeThe steep drop from the shelf toward the deep ocean. It is one of three parts of a continent's margin: the shelf, the slope and the rise.
hydrothermal ventAn opening in the sea floor that pours out heated water. Scientists first found them in 1977, near the Galapagos Islands. The water can be hotter than 700 degrees Fahrenheit.
lanternfishA small, glowing fish of the twilight zone. Most kinds swim up toward the surface at sundown to feed and are gone again by daybreak.
phytoplanktonTiny drifting plantlike life that feeds on light. They live in the sunlit top waters, because they need light as land plants do.
seamountAn undersea mountain whose top stays under water. Most seamounts are old volcanoes that no longer erupt.
submersibleA small underwater craft that a ship carries to sea. Some carry people. Others have no crew and are steered by remote control.
vertical migrationA daily swim up toward the surface and back down. Many small sea animals rise at night and sink again by day. The full name is diel vertical migration.
zooplanktonTiny drifting animals that eat other living things. The name joins the Greek words for animal and drifter.
How this list was compiled: Term list chosen for this site on 2026-10-11. Each meaning is written in our own words and was checked that day against the English Wikipedia article on the term (https://en.wikipedia.org/), whose text is under the Creative Commons Attribution-ShareAlike license: Photic zone, Mesopelagic zone, Bathypelagic zone, Abyssal zone, Hadal zone, Oceanic trench, Seabed, Photosynthesis, Pelagic zone, Bioluminescence, Marine snow, Water column, Benthic zone, Aphotic zone, Intertidal zone, Neritic zone, Oceanic zone, Thermocline, Deep sea, Phytoplankton, Zooplankton, Lanternfish, Anglerfish, Diel vertical migration, Hydrothermal vent, Continental shelf, Continental margin, Abyssal plain, Seamount, Challenger Deep, Mariana Trench and Submersible. The zones, their depths and the facts about light, temperature and pressure were checked a second time against pages of the U.S. National Oceanic and Atmospheric Administration: Layers of the Ocean (https://www.noaa.gov/jetstream/ocean/layers-of-ocean) and, on the National Ocean Service site (https://oceanservice.noaa.gov/facts/), How far does light travel in the ocean?, How deep is the ocean?, What is marine snow?, What is a hydrothermal vent?, What is bioluminescence? and What is a thermocline?. Water column was also checked in the glossary of NOAA's Aquatic food webs page (https://www.noaa.gov/education/resource-collections/marine-life/aquatic-food-webs). Depths are NOAA's, in meters. The fact after each meaning is from the same pages. Licence: own work
How it works
This ocean zones worksheet names the five zones in everyday words, sunlight zone down to hadal zone, and adds trench, water pressure, marine snow and four more terms to match to their meanings. It has no diagram to label.
Read the full guide
The scientific names of the ocean zones
Set opens on The five zones. Names and divisions prints the epipelagic, mesopelagic, bathypelagic and abyssopelagic zones with the pelagic, benthic, aphotic, intertidal, neritic and oceanic zones, thermocline and deep sea.
Life and the sea floor
The third set has what lives in the zones and what lies under them: phytoplankton, zooplankton, lanternfish, anglerfish, vertical migration, hydrothermal vent, continental shelf, continental slope, abyssal plain, seamount, Challenger Deep and submersible.
Depths on the sheet are in meters: 200, 1,000, 4,000 and 6,000.
Questions and answers
What are the 5 ocean zones in order?
From the top down: the sunlight zone (surface to 200 meters), the twilight zone (200 to 1,000 meters), the midnight zone (1,000 to 4,000 meters), the abyss (4,000 to 6,000 meters) and the hadal zone, in the trenches below 6,000 meters.
What are the scientific names of the ocean zones?
The sunlight zone is the epipelagic zone, the twilight zone the mesopelagic, the midnight zone the bathypelagic and the abyss the abyssopelagic. The hadal zone is also written hadalpelagic or hadopelagic.
How deep is the deepest part of the ocean?
The Challenger Deep, at the southern end of the Mariana Trench in the western Pacific, is about 10,900 meters deep, close to 36,000 feet. The average depth of the ocean is about 3,700 meters.
Is this an ocean zones worksheet for 5th grade?
No grade is printed on it. The set the page opens on names the zones in plain words, sunlight, twilight and midnight. The Greek names, such as epipelagic and bathypelagic, wait in the second set.