For information on user permissions, please read our Terms of Service. Continental Slope Overview & Facts | What is Continental Slope? Depths below 6000 m occur within ocean trenches and this is often classified as the Hadal Zone (in both pelagic and benthic divisions). The Abyssal Zone is the ocean's fourth deepest and darkest layer. [ bth-p-ljk ] A layer of the oceanic zone lying below the mesopelagic zone and above the abyssopelagic zone, at depths generally between about 1,000 and 4,000 m (3,280-13,120 ft).The bathypelagic zone receives no sunlight and water pressure is considerable. Abyssopelagic Zone - The next layer is called the abyssopelagic zone, also known as the abyssal zone or simply as the abyss. Bacteria. Abyss derives from the Greek word , meaning bottomless. In the abyssal zone, life appears ill-adapted to survive in a strange, harsh world. 6. Among the species that we can find are: the giant squid that manages to measure between 17 and 19 meters long, the dragon fish, balloon fish, crystal squid, octopus Dumbo, anoplogaster brachycera, soccpharynx, melanocetus johnsonii and fish axe. 4. The life that is found in the Abyssal Zone includes chemosynthetic bacteria, tubeworms, and small fish that are dark in color or transparent. Explore these resources to teach students about marine organisms, their relationship with one another, and with their environment. Chemosynthesis is the energy-making method for the unique organisms that can tolerate the extreme temperatures of these underwater springs. The abyssopelagic zone is extremely reliant on the frigid polar . But life has found ways to thrive here, nonetheless. copyright 2003-2023 Study.com. Before the abyssal zone starts, we see the bathyal zone, a lot many animals live in this exact depth since not much pressure comes from the oceans covered in this zone. Some of them rely on it directly, while others eat organisms that eat detritus. This area does not extend along the ocean floor but exists only in the deepest ocean trenches. The concentration of nutrient salts of nitrogen, phosphorus, and silica in abyssal waters is much higher than in overlying waters. The temperatures of the exploding hot springs can rise over 750 degrees Fahrenheit or 400 degrees Celsius. Abyssopelagic zone (4,000-6,000m) - This is the zone past the continental slope - the deep water just over the ocean bottom. The two most common species are the swallower eel and the gulper eel. You. Up to 76 megapascals of water pressure can be achieved. Some organisms can live in this zone by using chemosynthesis, which is energy that is produced by chemical reactions. This surface layer is also called the sunlight zone and extends from the surface to 200 meters (660 feet). There is no primary production of plant life in the bathyal zone, so all creatures that live there are carnivorous, eating each other or feeding on carcasses that sink down from above. You cannot download interactives. Many of these bacteria, for example, convert hydrogen sulfide to sulfate and store the energy extracted from this reaction as chemical energy by synthesizing carbon-based compounds. How deep is the Abyssopelagic zone? Privacy Notice| The animals that live in this zone will eat anything since food is very scarce this deep down in the ocean. region between the high and low tide of an area. Fish that glow in the dark, gigantic sea worms, and explosive, hydrothermal vents. While there are a number of different fish species representing many different groups and classes, like Actinopterygii or ray-finned fish, there are no known members of the class Chondrichthyes, animals such as sharks, rays, and chimaeras, that make the abyssal zone their primary or constant habitat. Grenadiers, the Most Abundant Deep-Sea Fish. However, life has found ways to thrive here. The main sediment constituents below 4,000 m are brown clays and the siliceous remains of radiolarian zooplankton and phytoplankton such as diatoms. Bathypelagic Zone Both have large mouth lined with teeth that are capable of accommodating prey much larger than themselves. The ocean is divided into five zones: the epipelagic zone, or upper open ocean (surface to 650 feet deep); the mesopelagic zone, or middle open ocean (650-3,300 feet deep); the bathypelagic zone, or lower open ocean (3,300-13,000 feet deep); the abyssopelagic zone, or abyss (13,000-20,000 feet deep); and the hadopelagic zone, or deep ocean . Animals in this zone include anglerfish, deep sea jellyfish, deep sea shrimp, cookiecutter shark, tripod fish, and abyssal octopus also known as the dumbo octopus. Answer: Ok lets start with definitions. Compared to continental shelves, the deep sea is also very sparsely inhabited, largely because the availability of food is so limited. All rights reserved. Our goal is to make science relevant and fun for everyone. The abyssal zone retains several cubic centimeters of dissolved oxygen per liter because the sparse animal populations do not consume oxygen faster than it is introduced. Benthic ecosystems include coral reefs, seagrass beds, and other systems in shallow coastal areas and deep hydrothermal vents, the abyssal plain, and other systems in the deep sea. Lots of marine animals can be found in the sunlit zone including sharks, tuna, mackerel, jellyfish, sea turtles, seals and sea lions and stingrays. The upper. The next zone is the bathyal zone. While there are no plants in the abyssal zone, there are other living organisms that survive here. The organisms in the pelagic zone range from tiny planktons to large mammals like whales. New Zealand Ministry For Culture And Heritage: The Bathypelagic Zone. University of Southern California: Creatures of the Abyss. They have fat-filled swim bladders or lake them altogether. Even at the very bottom, life exists. Low energies are reflected in the character of abyssal sediments. These organisms migrate in massive number to the oceans surface at dusk in search of food. Scientists believe that this lure attracts other fish for its food or mating. The lowest form of the food chain would be like phytoplankton and . Tripod fish are an oddity that can be found in this zone. The long, pinkish-colored hagfish, for example, can go as long as seven months without eating because their metabolism is so slow. Other types of animals found in the abyssopelagic zone include deep-sea jellies, sea stars, deep-sea shrimp, and the dumbo octopus. It is the Hadalpelagic . The Epipelagic zone is the upper most part of the ocean, lying above the Mesopelagic zone. There are not a lot of places to hide in the sunlit zone! Invertebrates like jellyfish, squids, octopus and krill are . Types of animals that live in the Abyssopelagic zone include algae, anemones, anglerfish, arrow worm, cookie-cutter shark, copepods, crabs, and other crustaceans, ctenophores, dinoflagellates, fangtooth, lantern fish (Myctophids), mussels, nudibranchs, some squid, segmented worms, siphonophores, swallower fish, tubeworms, pelican eel, The Abyssal zone alone covers around 83% of the total area of the ocean! The depths from 1,000-4,000 meters (3,300 - 13,100 feet) comprise the bathypelagic zone. In this lesson, we learned that the abyssal zone is the layer of the ocean from 13,000 feet to the seafloor at 20,000 feet. The pressure in the bathypelagic zone is extreme and at depths of 4,000 meters (13,100 feet), reaches over 5850 pounds per square inch! No whale species live permanently in the bathyal zone, but sperm whales, with the large proportion of tissue in their heads protecting them from the immense pressures at depth, are capable of diving into the bathyal zone to hunt. The pelagic zone contains invertebrates such as squids, jellyfish, octopus, and krill. Abyssopelagic Zone Animals in this zone include anglerfish, deep sea jellyfish, deep sea shrimp, cookiecutter shark, tripod fish, and abyssal octopus also known as the dumbo octopus. A .gov What zone do most animals live in? . . In 2005, tiny single-celled organismscalled foraminifera, a type of plankton, were discovered in the Challenger Deep trench southwest of Guam in the Pacific Ocean. environment where an organism lives throughout the year or for shorter periods of time. A few of the organisms that live in this zone include zooplankton, shrimp, and other small fish. Official websites use .gov abyssal zone animals adaptations. It is the pitch-black bottom layer of the ocean. Explain that the abyssopelagic, or abyssal benthic, zone is the region that includes the ocean floor. It exists at approximately 13,000 ft to 20,000 ft of depth. Most fish that live in the bathyal zone are either black or red in color. The name (abyss) comes from a Greek word meaning "no bottom" because they thought the ocean was bottomless. This plume provides nutrients to the bacteria that live inside the worm. It truly is the abyss. Ocean zones are regions of the ocean that contain distinctive plant and animal life. Discuss the significance of the depths shown on this diagram. I would definitely recommend Study.com to my colleagues. The Abyss (Abyssal Zone) From 13,135 feet to 19,700 feet, the Abyssal zone (aka "the abyss") contains zero sunlight and crushing levels of water pressure. The conditions of the Abyssal Zone are almost constant. Many abyssal animals are bioluminescent, which means they can produce their own light. Get unlimited access to over 88,000 lessons. Some animals that live in the aphotic zone include the gulper eel, giant squid, smaller squids . . The animals that live in this zone will eat anything since food is very scarce this deep down in the ocean. Types of animals that live in the Abyssopelagic zone include algae, anemones, anglerfish, arrow worm, cookie-cutter shark, copepods, crabs, and other crustaceans, ctenophores, dinoflagellates, fangtooth, lantern fish (Myctophids), mussels, nudibranchs, some squid, segmented worms . The hadal zone is the deepest region of the ocean, extending from approximately 6,000 meters to 11,000 meters below the sea surface. This zone remains in perpetual darkness at depths of 4,000 to 6,000 meters (13,300 to 20,000 feet). In Honduras the depth is only about 550 meters and it is near to land. Absent photosynthesis at depth, abyssal waters oxygen content depends entirely on the amount dissolved into it at its polar origin and the amount dissolved into it at its polar source. deep pit in the ocean or other body of water. Ask: Why is the ocean divided into different zones? The ocean covers 83% of the worlds surface and 60% of the oceans area. ShopPress Center Employment OpportunitiesContactFinancialsPrivacy PolicyTerms of Use, United StatesEuropeChileCanadaBelizePhilippinesBrazilPeruMexico, A great way to get involved in protecting #oceans: Join Oceana as a Wavemaker & sound off on important issues! A microhabitat is a small area which differs somehow from the surrounding habitat. Caused by increasing water pressure, the abyssopelagic zone is much less explored than the shallower ocean zones, and it is frequent that scientists discover new species when exploring this area. The bathypelagic is much larger than the mesopelagic and 15 times the size of the epipelagic. The Epipelagic zone is the surface layer of the ocean that extends over 200 meters or 656 feet long. It is the pitch-black bottom layer of the ocean. The deepest known ocean depth is nearly 11,000 m (36,000 feet or almost 7 miles). The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. Some animals that live in the aphotic zone include the gulper eel, giant squid, smaller squids, anglerfish, vampire squid, and numerous jellyfish. Where is the bathyal zone? The depths of the ocean are ill-explored, so it's not currently known how many species inhabit the abyssal ecosystem. Most animals in the abyssal plain tend to be small, for example, but they usually have large, flexible stomachs and big mouths. Often they have special adaptations to help them reproduce, because finding mates in the dark and sparsely-populated world of the abyssal plain can be a challenging task. A few examples of these adaptations include blindness to semi-blindness due to the lack of light, bioluminescence, and slow metabolism. Neritic Zone Sediments & Organisms | What is the Neritic Zone? 2. The highest diversity of pelagic organisms is found in the baythypelagic zoneat depths between -3,000 and -8,000 ft. Fishes here are black and have tiny, simple eyes. Thousands of species of all shapes and sizes live in the pelagic zone. Oceans cover more than 70 percent of the Earths surface, and half of those waters are at least 1.86 miles (3 km) deep. Geologic Time and Earth Science: Tutoring Solution, Earth's Spheres and Internal Structure: Tutoring Solution, Weathering and Erosion: Tutoring Solution, Sedimentary Rocks - A Deeper Look: Tutoring Solution, Metamorphic Rocks - A Deeper Look: Tutoring Solution, Rock Deformation and Mountain Building: Tutoring Solution, Ocean Basins: Definition, Formation, Features & Types, Oceanic Ridge System: Formation & Distribution, Ocean Circulation: Patterns & Effect on Climate, Waves: Types, Features & Effect on Erosion, Contributing Factors of Longshore Transport: Beach Drift & Longshore Current, Environmental Science 101: Environment and Humanity, UExcel Pathophysiology: Study Guide & Test Prep, What is Alginic Acid? One example is the deep sea anglerfish, which uses a light attached to the end of its head to attract prey, as shown here in this image: Many organisms use bioluminescence, lighting up to attract prey and navigate the darkness. This is as a defense against predators -- with only minute amounts of blue-green light, red is not reflected and appears black. What is meant Bathypelagic zone? The ocean is divided into five zones: the epipelagic zone, or upper open ocean (surface to 650 feet deep); the mesopelagic zone, or middle open ocean (650-3,300 feet deep); the bathypelagic zone, or lower open ocean (3,300-13,000 feet deep); the abyssopelagic zone, or abyss (13,000-20,000 feet deep); and the hadopelagic zone, or deep ocean trenches (20,000 feet and deeper). Earth Ocean Formation Theories | How Did the Oceans Form? The abyssal zone is a frightening sight. Scientists are still researching this mysterious part of the deep sea, but what exactly do we already know about the Abyssal Zone of the ocean? I feel like its a lifeline. The animals that live in this zone will eat anything since food is very scarce this deep down in the ocean. The most common characteristics of species that live in this zone include slow metabolic rates, slow consumption, flexible stomachs, large mouths, and bioluminescence. We are restoring the worlds wild fish populations to serve as a sustainable source of protein for people. It is home to many organisms found nowhere else on earth, and most hadal animals are gigantobenthic scavengers adapted to extreme pressure and lack of light. The animals that live in this zone will eat anything since food is very scarce this deep down in the ocean. . It lies between the mesopelagic above, and the abyssopelagic below. 1. Temperatures here are frigid, and pressures are hundreds of times greater than at the surface of the ocean. Unique animals like the marine hatchet fish and giant squid live in this subzone, surviving mostly on the detritus that drifts down from the epipelagic zone. website belongs to an official government organization in the United States. Animals living in the bathypelagic zone or deeper never see sunlight.1 Some organisms living there, such as vampire squid and humpback anglerfish, produce their own light.2, 4. The long, thin bodies of eels are adaptable to the pressures of the bathyal zone. It is strongest in the tropics and decrease to non-existent in the polar winter season. When scientists collect abyssal specimens for study, they very frequently find species that are completely new to science. The animals of the abyssal plain, however, tend to have some adaptations that help them cope with their unusual environment. Code of Ethics| When you reach out to them, you will need the page title, URL, and the date you accessed the resource. Answer: There are many layers to the ocean floor but the one where 90% of all ocean life lives is the epipelagic, or euphotic zone. Abyssal animals do not need to worry about pressure because the pressures within their bodies are the same as that outside. The high pressure ranges from approximately 200 to 600 atmospheres (2,938- 8,817 pounds of pressure per square inch), which makes it very difficult for life to exist at these depths. The mesopelagic zone is much larger than the epipelagic, and the most numerous vertebrates on Earth (small bristlemouth fishes) live in this zone. The only light at this depth and lowercomes from the bioluminescence of the animals themselves. The most common characteristics of species that live in this zone include slow metabolic rates, slow consumption, flexible stomachs, large mouths, and . After these layers is the abyssal zone, the focus of this lesson. Of all the inhabited Earth environments, the pelagic zone has the largest volume, 1,370,000,000 cubic kilometres (330,000,000 cubic miles), and the greatest vertical range, 11,000 metres (36,000 feet). Located on the rift valleys are hydrothermal vents (see Figure 2,) which produce nutrient-rich waters for organisms to utilize through a process known as chemosynthesis. The viperfish, for example, has a hinged skull it can rotate upwards so it can eat large fish, an oversized stomach to store plenty of food, and a ferocious-looking set of fangs to chomp down on its prey. The only layer deeper than the abyssal zone is the hadalpelagic zone, which occurs from the seafloor into the deepest trenches, or vertical caverns, in the ocean. Organisms have adapted to the harsh environment of the abyssopelagic zone in order to survive. Organisms that live in the epipelagic zone may come into contact with the sea surface. The temperature never fluctuates far from a chilling 39F (4C). This zone starts at the bottom of the mesopelagic and stretches down to 4000 m (13,000 feet). Animals from the Hadal Zone. The epipelagic zone (or upper open ocean) is the part of the ocean where there is enough sunlight for algae to utilize photosynthesis (the process by which organisms use sunlight to convert carbon dioxide into food). We dont know how many species inhabit the abyssal ecosystem because the depths of the ocean are poorly explored. The water temperature is constantly near freezing, and only a few creatures can be found at these crushing depths. Megan has a Bachelor of Science in Marine Biology from the University of New Haven, and a Master of Science in Biology Adolescent Education from the CUNY- College of Staten Island. The animals that live here have very slow metabolic rates due to the frigid temperatures of the ocean water and they only eat occasionally -- sometimes as seldom as once every few months. Some animals that live in the aphotic zone include the gulper eel, giant squid, smaller squids, anglerfish, vampire squid, and numerous jellyfish. The vampire squid's tentacles are lined with sharp spines to catch it prey with. Male anglerfish, for example, literally attach themselves physically to the female, using her blood for food, like a parasite, and fertilizing her eggs in return. These animals include fish, shrimp, squid, snipe eels, jellyfish, and zooplankton. . A grenadier from the genus Coryphaenoides, one of the only genera of grenadiers with hadalpelagic members. . Some species have lost their ability to see anything at all. Sailors for the Sea developed the KELP (Kids Environmental Lesson Plans) program to create the next generation of ocean stewards. Sea surface temperatures over three years: 2012-14 (2.6 mb), Sea surface temperatures over six years: 2009-14 (5.4 mb), National Oceanic and Atmospheric Administration, The Positive and Negative Side of Lightning, Tsunami Preparedness and Mitigation: Individuals (You!). As far as we know, the ocean is 36,200 feet (11,000 m or almost 7 miles) deep at its deepest point. The primarily bathypelagic fish families Cetomimidae (whalefishes) and Chiasmodontidae (great swallowers) have some of the most highly developed acousticolateralis systems (lateral lines and associated pores and nerves) known of any fishes. Chemosynthesis vs. Photosynthesis | Differences, Equations & Processes, High School Physical Science: Help and Review, Study.com ACT® Test Prep: Tutoring Solution, NY Regents Exam - Earth Science: Help and Review, NY Regents Exam - Earth Science: Tutoring Solution, ILTS Science - Physics (116): Test Practice and Study Guide, ILTS Science - Environmental Science (112): Test Practice and Study Guide, Create an account to start this course today. This activity is made possible by a generous grant from the National Oceanic and Atmospheric Administration (NOAA) National Marine Sanctuary Program. The animals of the abyssal plain rely on this detritus for their food. What type of creatures live in the abyss? Hadalpelagic Zone Understanding Oceanic Zones: The layers of depth in the ocean help to define unique environments that create separate ecosystems in the sea. Elicit from students that each zone has unique characteristics and animal and plant life. Animals of the Abyssopelagic Zone Animals capable of living at these depths include some species of squid, such as the deep-water squid, and octopus. It is the pitch-black bottom layer of the ocean. What kind of animals live in the abyssal zone? His articles have appeared in "Plenty," "San Diego Reader," "Santa Barbara Independent" and "East Bay Monthly." 5. The name is Greek-based and means "bottomless". The brine sinks due to its high density and flows slowly toward the Equator along the bottom. The biome is shaped by a dark open ocean, flat plains, low hills, seamounts, and most importantly, rift valleys. The deepest a fish have ever been found, Abyssobrotula galatheae, was in the Puerto Rico Trench at 8,372 meters (27,460 feet). The mesopelagic zone (or middle open ocean) stretches from the bottom of the epipelagic down to the point where sunlight cannot reach. Among the types of abyssal fish, some of the most notable are: Angler fish (Ceratias holboelli) This fish (order Lophiiformes) inhabits the depths of all the oceans in our planet. They are sometimes referred to as ocean layers or environmental zones. About Us; View Products; Contact; Blog; Openweathermap Java Api Maven, Properties Of A Table In Database, Edreams Booking Reference, Kiwi Shoe Polish White, Cecily Strong This Will All Be Over Soon, Custom Thank You Bags With Logo, Cream And Beige Living Room Ideas, What are the conditions like in the abyssal zone? Promoting Physical Activity in School & the Community. What animals live in the abyssopelagic zone? Throughout the majority of its mass, the abyssal zone has temperatures between 2 and 3 C (36 and 37 F). She is also certified in secondary special education, biology, and physics in Massachusetts. These include the epipelagic zone (sunlight zone), mesopelagic zone (twilight zone), bathypelagic zone (midnight zone), abyssopelagic zone (abyssal zone), and the hadalpelagic zone. In addition, the food web down there is similar to food webs everywhere on Earth, with chemosynthetic bacteria creating energy for the rest of the food chain using hydrothermal vents, supporting giant tube worms and crustaceans. Elicit from students that each zone has unique characteristics and animal and plant . Text on this page is printable and can be used according to our Terms of Service. Ask: Why is the ocean divided into different zones? Immediately following the epipelagic zone is the mesopelagic zone, where sunlight is very faint and you can find creatures that glow in the dark or are bioluminescent. An adaptation is any heritable trait that helps an organism, such as a plant or animal, survive and reproduce in its environment. In these areas, some species of bacteria can harness chemical energy to make their own food, and in turn, become food for other abyssal animals like tube worms. Twilight zone (mesopelagic zone) 3. This water sinks to the seafloor, supplying oxygen to deep-sea life. The tube worms and bacteria can then support crustaceans, like crabs. It is the largest ecosystem on earth. It also includes sharks and invertebrates such as squid, shrimp, sea spiders, sea stars, and other crustaceans. It also. The monognathid eel has developed a single fang that is linked to a primitive venom gland, on which it impales prey. What are the conditions like in the abyssal zone? What fish lives in the abyssal zone? The Rights Holder for media is the person or group credited. But the animals of the abyssal plain tend to have special adaptations to help them cope with their unusual environment. However, it is believed that humans have impacted every part of the ocean with waste and chemical pollution.5. The Abyssopelagic Zone (or abyssal zone) extends from 13 100 feet (4 000 meters) to 19 700 feet (6 000 meters). Many open ocean organisms live out their existence without ever coming into contact with the shore, the seafloor, or the waters surface. The Epipelagic Zone is penetrated by sunlight which allows photosynthetic organisms like algae to undergo an energy-making process known as photosynthesis. To understand the abyssal zone, we need to get an idea of what the other layers of the ocean look like. Food is hard to find, so they must swallow as much as they can when they find it and store some of it, because their next meal may be a long time away. What kind of animals live in the Abyssopelagic zone? Algae that live in the epipelagic zone are responsible for much of the original food production for the entire ocean and create at least 50% of the oxygen in the atmosphere (both through photosynthesis). And then we also must consider that abyssopelagic means open ocean as opposed to the abyssal plain which is the ocean bottom at those depths. The communities are encased in perpetual darkness, and the temperatures are also cold, hovering near freezing, due to the lack of sunlight. We will discuss this in more detail as we progress through this article. Animals. Finally, organisms that live on the ocean floor (regardless of depth) are part of the benthos. They often have special adaptations to help them reproduce since finding mates in the dark and sparsely-populated world of the abyssal plain can be difficult. The physical characteristics of the seafloor in the Abyssal Biome influence the little life that inhabits or visits the region. What animals live in the abyssal zone? Deeper still is the abyssopelagic zone, which stretches from the bottom of the bathypelagic to the seafloor. Unfortunately, some habitats are threatened by pollution, extreme weather, or deforestation. As land mammals that breathe air, walk on land, and rely on our sense of sight for almost all functions, it is difficult for people (even experts) to comprehend that most of the organisms on the planet are never exposed to air, land, or sunlight. Sustainability Policy| Washington, DC 20036, Careers| Zooplanktons are also found in this zone. Abyssal life includes chemosynthetic bacteria, tubeworms, and small fish that are dark in color or transparent. The abyssal salinities are between 34.6 and 35.0 parts per thousand, and temperatures are between 0 and 4 C (32 and 39 F). Doing so under the cover of dark helps them to avoid daytime predators. The deepest zone of the ocean, the hadalpelagic zone extends from 6,000 meters (19,700 feet) to the very bottom,10,994 meters (36,070 feet) in the Mariana Trench off the coast of Japan. - Structure, Solubility & Products, Arrow Pushing Mechanism in Organic Chemistry, Topicity in Stereochemistry: Relationships & Examples, Antarafacial & Suprafacial Relationships in Organic Chemistry, Working Scholars Bringing Tuition-Free College to the Community. A layer deeper than the abyssal zone is the hadalpelagic zone, which extends from the seafloor to the deepest trenches, or vertical caverns, in the ocean. Share sensitive information only on official, secure websites.. Epipelagic Zone Phytoplanktons provide oxygen for humans and food for many animals. .ng-c-sponsor-logo { These characteristics are also paired with other adaptations which include enlarged teeth, fangs, extra fins, extra gills, and structures that function to attract prey. At depths of 3,000 to 6,000 metres (9,800 to . The bathyal zone is in permanent darkness, with only a tiny amount of sunlight at the blue end of the spectrum penetrating as far down as the bathyal zone. More than 70% of the Earths surface is covered by ocean, and it is important to remember that more than 50% of the Earths surface is covered by ocean that is at least two miles (3.2 km) deep. At depths of 3,000 to 6,000 meters (which is approximately 9,800 to 19,700 ft), this zone remains in acute darkness.