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Deep Sea Habitats & Food Sources
Remember that the abyssal plain is the flat part of the ocean bottom. It is a cold and dark place that lies between 3,000 and 6,000 meters. It is home to squat lobsters, red prawns, and various species of sea cucumbers. For these creatures food is scarce most of the time. Bits of decaying matter and excretions from thousands of meters above must trickle down to the seafloor. Less than five percent of food produced at the surface will make its way to the abyssal plain.
Abyssal Plain
Snow crabs, brittle stars, and squat lobsters also arrive. Once the flesh has been stripped and consumed by predators, bone eaters like worms and snails arrive so that not even the skeleton will remain. In the months and years after a whale fall the site will become the home and food source for millions of creatures. No two whale fall communities are the same. The size of the whale, the depth of the seafloor, and the location all contribute to the types of animals that colonize the area and determinehow long it takes for the skeleton to disappear.
Whale falls occur when a whale dies in surface waters and sinks to the bottom of the ocean. The sudden arrival of food prompts creatures, such as sleeper sharks, rattail fish, and black hagfish, from afar to congregate and feast on the fleshy carcass.
Whale falls
water. A chemical reaction occurs and solid deposits are formed. Over time, the deposits create towers. Some spew water filled with black iron sulfide and are aptly named “black smokers,” while others spew white colored elements like barium, calcium, and silicon and are called “white smokers.” Clams, mussels, shrimp, and gigantic worms thrive in these habitats. Animal life here relies on the energy produced by symbiotic bacteria. The bacteria live either inside the bodies or on the surface of their hosts. These bacteria produce energy through a chemical reaction that uses minerals from the vents.
Hydrothermal vents exist in volcanically active areas. Seawater makes its way through cracks in earth’s crust until it reaches hot magma. As the water heats, it absorbs metals like iron, zinc, copper from the surrounding rocks. Hot water rises, carrying these minerals to the surface of the sea floor where it meets cool ocean
Hydrothermal vents
preserved, serves as a warning of the toxic landscape below. But for many creatures the risk is worth it. A brine lake is also an area high in methane and certain bacteria can use the methane in a chemical reaction to produce energy. Animals like mussels and crabs come to feed on the special bacteria by the lake’s edge, and often there are whole communities that live along the shore.
Brine lakes are super salty pools of water that sit on the ocean floor. The extreme saltiness causes significantly denser water than the average ocean water and, like water and air, the two do not mix. Brine lakes are deadly for ocean creatures. The salt content is so high that creatures that “fall in” often die. Their carcass, pickled and
Brine lakes
gas and liquid from deep underground where they formed over millions of years. These liquids and gases are made up of hydrogen and carbon molecules, like methane. It is from these chemicals that cold seep creatures get their energy. Microbes near cold seeps gain energy through chemical reactions, and then pass the energy to symbiotic partners like tubeworms, clams, or mussels. This draws larger predators like octopuses and crabs to the seeps.
A cold seep is a place on the ocean floor where fluids and gases trapped deep in the earth percolate up to the seafloor. A cold seep gets its name because they are cooler than the scalding temperature of the similar hydrothermal vent. Cold seeps form at cracks in the earth’s crust. The cracks release buried petroleum-based
cold seeps
A seamount is an underwater mountain. Seamounts are often found at the edges of tectonic plates where magma is able to rise through the surface crust. When dense, nutrient rich ocean currents hit the seamount they deflect up toward the surface, allowing marine life to thrive on the newly supplied food. Crabs, corals, anemones, sea stars, and many other creatures make the walls of seamounts their home. About 80 commercial species live on seamounts, and many are only found near this habitat.
seamounts
It may be the last place you’d expect to find corals—up to 6,000 m (20,000 ft) below the ocean’s surface where the water is icy cold and completely dark. Yet believe it or not, lush coral gardens thrive here. Deep sea corals are also known as cold-water corals. Deep sea creatures like sea stars and sharks can be found here. Unlike shallow-water corals, however, deep-sea corals don’t need sunlight. They obtain the energy and nutrients they need to survive by trapping tiny organisms in their polyps from passing currents.
deep sea reefs
The deep-sea anglerfish lures prey straight to its mouth with a dangling bioluminescent barbel, lit by glowing bacteria. In addition to feeding, creatures of the deep use light in flashy displays meant to attract mates. Or, animals use a strong flash of bioluminescence to scare off an impending predator. The bright signal can startle and distract the predator and cause confusion about the whereabouts of its target.
Creatures produce their own light to snag a meal or find a mate in a process called bioluminescence. Sometimes the prey being lured can be small plankton, like those attracted to the bioluminescence around the beak of the Stauroteuthis octopus. But the light can also fool larger animals. Whales and squid are attracted to the glowing underside of the cookie-cutter shark,which grabs a bite out of the animals once they are close.
bioluminescence
meters in just a few hours. Under the light of the moon they feast on the phytoplankton that grew during the day. Then, when the sun comes out and there is enough light for predators to see them again, the zooplankton return to the deep darkness. Some animals take advantage of the reliable movement of potential prey. Diel vertical migration is the largest animal migration on the planet, with trillions of animals participating every day.
Some creatures have adapted a way of life that takes advantage of both the plentiful surface waters and the safety of the deep. It’s called diel vertical migration. As the sun sets, fish and zooplankton make massive migrations from the depths up to the ocean’s surface. Despite their small size, these creatures can travel hundreds of
vertical migrations
column, but the journey to the bottom can take several weeks to years. Some particles don't make it to the bottom as they are often eaten by fish or marine mammals. Once the wastes land on the seafloor, it becomes a welcome food source for animals here, like the vampire squid, which has special feeding filaments to help them better catch and eat falling particles.
For much of the deep ocean, food rains down from above in the form of marine snow. The term "marine snow" is used for all sorts of things that slowly drift to the seafloor, like waste, poop, silt and other organic items washed into the sea from land. As this material drops deeper and deeper, the particles can grow in size as smaller flakes clump together. The larger size causes them to fall more quickly through the water
marine snow
