Some marine life can survive the extreme pressure of the deep ocean because of specialized molecules that strengthen proteins, enzymes, and cellular membranes.

How water pressure affects the body

The extreme conditions of the deep sea include increasing amounts of pressure as explorers and organisms descend into its depths. The major danger for both fish and humans is the way pressure changes how body tissues absorb chemical molecules...

Although consuming saltwater can dehydrate and kill organisms, some fish survive by using specialized gills that leach excess salt from their bodies back into the surrounding water.

How specialized oxygen mixtures like heliox enable deep diving without feeling drunk

Beyond a depth of about 30 meters (98 feet), if divers are breathing surface air, which is about 78% nitrogen, underwater pressure forces more nitrogen into the bloodstream and induces nitrogen narcosis, whose symptoms resemble alcohol intoxication. Through saturation diving, where nitrogen is replaced with helium—an inert gas—deep divers can maintain cognitive function while working for extended periods.

View a gallery of animals found on abyssal plains, hydrothermal vents, seamounts, and other deep-sea habitats.

An overview of extremophiles and the biochemical adaptations employed by various types

These organisms thrive in environments that would normally be inhospitable to most living things by using molecules that help counter deadly environmental factors. These include antifreeze-like proteins that prevent psychrophiles from freezing and rupturing in polar regions, and osmoprotectants that prevent some extremophiles from losing water to salty environments.

The deep-sea fangtooth has the largest teeth of any marine species relative to body size

From transparent fish to the heaviest worms on the planet, these seven creepy creatures lurk in the deep sea. Learn all about them and the unique traits that help them survive and hunt.

Read a technical review of extremophile categories, including the habitats of each

Acidophiles can survive in environments with acidity greater than that of the human stomach, and some radiophiles can live in places with radiation exposure hundreds of times higher than what is lethal to humans. Piezophiles—formerly known as barophiles—have been found in the Mariana Trench, where pressures are over 1,000 times larger than those on Earth's surface.

Fish in polar waters contain proteins in their blood that act as antifreeze, and some manufacturers have used lab-grown versions of these proteins to help keep ice cream smooth.

NASA explores Earth's deepest oceans to prepare for space

By studying extreme environments in Earth's hadal zone—the deepest part of the ocean —NASA tests technologies, probes life under crushing pressure, and gathers clues about potential oceans and possible life on worlds like Europa and Enceladus.

As immobile animals, corals and the organisms that live on them have evolved a suite of chemical compounds to prevent disease and ward off predators they cannot outrun.

Explore the deepest parts of the ocean

The deeps of the Earth's oceans are some of the most extreme environments on the planet. Take a trip 36,000 feet to the deepest parts of the sea in this informative, 10-minute animated video.

The warmest waters in the ocean are found at hydrothermal vents—hot springs on the seafloor that discharge plumes of mineral-rich water.

Earth's oceans, which have an average depth of 3.7 kilometers (2.3 miles), may be divided into zones based on depth or the abundance of light.

To survive underwater hibernation, some freshwater turtles perform cloacal breathing—blood vessels absorb dissolved oxygen from water drawn into the organism's cloaca, or rear orifice.

Breaking down the challenges of alkaline environments and how extremophiles survive them

These areas are far less acidic than the interiors of most organisms' cells, and this imbalance draws protons that are needed for various metabolic processes, including energy production, out of cells. To counter these effects, some alkaliphiles have developed stronger proton regulation across their cellular membranes and proteins that drive these processes with greater stability amid such acidity imbalances.

A look at how fish less than two inches long climb up 50-foot waterfalls

Shellears use tiny hooks on their front pectoral fins to grip rock like Velcro and take many pauses to recover energy between bursts of movement. Their pectoral girdle—an arch of bone—supports the muscle system needed for the roughly ten-hour climb.

Bioluminescence became common in the ocean to support survival in dark environments

Despite seeming like a rare ability in land animals and unseen in plants, bioluminescence has evolved at least 29 times across marine species, indicating its necessity for survival where hiding spots are rare and highlighting how environments provide evolutionary pressure.

A look at hydrothermal vents, where barophiles and hyperthermophiles survive boiling water

Discovered in 1977 during an exploration of the Galapagos Rift, these seafloor openings spew hot magma and chemicals that heat seawater to hundreds of degrees. Without the sunlight found at depths of less than 1,000 meters (3,281 feet), extremophiles in these environments convert released chemicals into energy to survive, alongside surviving extreme pressures.

Europa's deep ocean may hold the conditions needed to support alien life

Beneath its frozen crust, Europa hides a salty ocean heated by tidal forces from Jupiter. This environment may resemble Earth's deep-sea hydrothermal vents and have allowed for the development of life over billions of years.

While nearly all fish are cold-blooded—their body temperatures match their surroundings—the opah, or moonfish, is fully warm-blooded, with a body temperature about 5 degrees Celsius (9 degrees Fahrenheit) warmer than its environment.

The 10 most amazing deep sea creatures

In this video, researchers from the world-renowned Monterey Bay Aquarium discuss the most fascinating deep sea creatures, and how they developed some of their strangest features.

Why 75% of ocean animals glow

About 75% of ocean creatures can make their own light. It's called bioluminescence—and it all comes down to a special chemical reaction happening inside their bodies.

Whale falls—dead whales that have fallen to the ocean's floor—can provide enough food to spawn a local ecosystem of deep-sea organisms that lasts for decades.

Extremophiles were likely to have been Earth's first, and are expected to be its last, organisms

Their ability to survive in an enormous range of environmental conditions, including some resembling what has been modeled to have existed relatively shortly after Earth's formation, makes them the leading candidates for enduring the increasing solar intensity and the subsequent effects (e.g., zero-oxygen atmosphere, evaporated oceans) expected in the coming billions of years.

Explaining deep-sea mining, including its economic benefits and potential biomedical risks

Extraction via machines sweeping the ocean floor would reduce child labor and human rights violations currently occurring in land-based operations that collect the minerals needed for modern-day electronics. However, these sweeps may kill undiscovered organisms that possess biologies from which antibiotics could be derived and destabilize deep-sea ecosystems.

The weight of Earth's atmosphere is equivalent to a 33-foot deep, global ocean

Because air is made up of gas molecules with mass, it is not weightless. On the planet's surface, we are effectively living in what is the equivalent of the bottom of an invisible ocean of these particles pressing against us, just as water molecules do when we are submerged.

Can coral live in cold water?

Dive deep beyond the sunlit coral reefs, and you'll discover a world of deep-sea corals. This article from the National Oceanic and Atmospheric Administration (NOAA) explores the ecosystems of deep-sea corals found way below the water's surface....

Although an estimated 99.999% of the deep ocean has not been explored, techniques such as sonar have been used to identify the deepest known point in each of Earth's five oceans.

Starting with red, colorful objects will appear to lose their colors the deeper they are submerged because water scatters light, reducing the amount available to reflect off objects and be observed.

How the loss of Earth's atmosphere would cause oceans to boil at freezing temperatures

Many phenomena requiring air pressure, from the flight of birds and aircraft to the act of breathing, would no longer be possible. Because sound travels through vibrating air molecules, the loss of the planet's atmosphere would also create a silent environment. Even during daytime hours, the sky would resemble a clear night sky.

Since the Industrial Revolution, surface ocean waters have become 30% more acidic due to the absorption of carbon dioxide.

An interactive of the deep sea

Why extremophiles may play an important role in terraforming Mars

Possessing unique biochemicals that can detoxify extreme environments and resilience against the Martian surface that is lethal to humans, scientists are exploring whether colonies of these organisms can transform small areas of the Red Planet into future habitats for humans. Extremophiles may also be best equipped to serve as microscopic factories for the fabrication of essential polymers.

Learn about endoliths, the polyextremophiles that thrive inside rocks

These organisms include species that live in Antarctica, where they perform photosynthesis using light and water that makes it through pores in sandstone. Others residing in Earth's crust can survive temperatures reaching 60 degrees Celsius (140 degrees Fahrenheit) while generating energy through chemical reactions involving nutrients and gases trapped in rocks.

The ocean's ability to store carbon long-term is being hindered by marine heatwaves

More than 4,000 robotic floats with biogeochemical data sensors, including oxygen, pH, nitrate, suspended particles, chlorophyll, temperature, and conductivity, have been deployed as part of the Global Ocean Biogeochemical Array. They have identified changes to ecosystem structure affecting the ocean's ability to transport carbon from surface waters into the deep.

The Southern Ocean features the Antarctic Circumpolar Current—the largest ocean current on Earth—which encircles Antarctica and creates a unique biogeographical zone.

What animals live in the ocean?

The oceans host an incredible diversity of fascinating species. Oceana's Marine Life Encyclopedia beautifully presents facts and photos of ocean animals from Atlantic Cod to Zebra Sharks.

Scientists have collected critical minerals from ocean water using seaweed, a type of algae that leaves behind a mineral-rich powder called bio-ore after being processed into biofuels.

Deep water corals—located throughout the world's ocean basins at depths beyond 200 meters (660 feet)—slowly build small coral gardens in the dark with the help of underwater worms.

Why the existence of extremophiles greatly improves the odds of life beyond Earth

The conditions for life have long been thought to include liquid water, an energy source, and the essential elements for organic molecules within environments on or near Earth's surface. However, because extremophiles thrive in far more inhospitable environments, astronomers now analyze exoplanets whose characteristics indicate environments that fall within a broader range of possibilities when searching for signs of extraterrestrial life.

Sea stars are invertebrates—they lack a backbone—and while most exhibit pentametric radial symmetry due to having five arms radiating from a central disk, some can possess more than 40.

Over 1 million fish, marine mammals, and invertebrate species depend on coral reefs for habitats, camouflage, and food.

Listen to recordings of different fish species

Scientists have captured and curated this collection of species-specific recordings, helping us gain a deeper understanding of underwater ecosystems. Uncover their sounds, which include a lot of thumps, burps, and grunts.

The ocean gets its salt from runoff carrying fragments of eroded rock and from seawater dissolving salts and minerals from magma at seafloor spreading centers.

Located in the Pacific Ocean, the Challenger Deep is the deepest point on Earth, extending to depths a mile deeper than Mount Everest is tall.

The world's largest species of marine algae is giant kelp, which can grow as much as two feet per day from depths of about 100 feet up to the ocean surface.

View the industrial applications of extremozymes, from food safety to antibiotic production

Extremophiles possess unique enzymes and organic molecules that have enabled them to adapt to and thrive in otherwise lethal environments. Because these conditions resemble those found in various areas of manufacturing and production plants, these organisms and their macromolecules can optimize industrial processes where conventional catalysts would lose their ability to speed up reactions.

A chemical overview of water, whose uncommon properties help sustain life on Earth

The uneven distribution of charge in water molecules allows them to bond to each other and to surfaces, enabling them to move against gravity, including up plants through roots and stems. These bonds also keep water in a liquid state over a wider temperature range and make it less dense as it freezes. This causes ice to float and form an insulating layer for underwater ecosystems, from which all life originated.

Beyond a certain pressure and temperature, matter can become a supercritical fluid—an exotic state of matter that simultaneously exhibits properties of gases and liquids.

The hormone that spreads love and helps fish share fear

Scientists consider emotions like fear and empathy to be among the oldest evolutionary behaviors observed in mammals. Yet to date, how these reactions are processed in the brain, regardless of species, is not well understood. A new study reveals how the chemical oxytocin—known as the "love hormone" in humans—helps let fish know when their friends are in danger.