Watch a time-lapse of hard coral growth, which forms coral reefs

Read about coral reef restoration efforts, from coral IVF and cryopreservation

Researchers have collected coral eggs and sperm from healthy reefs, grown baby corals in lab pools, and released them to help repopulate damaged or lost reefs. Devices such as Coralclip® help attach these corals to existing structures, promoting growth without the use of chemical bonding agents. Corals near extinction can be frozen using liquid nitrogen for future restoration efforts.

Artificial coral reefs have been 3D printed from nontoxic, biodegradable terracotta clay, which coral polyps have used as a foundation for rebuilding marine ecosystems.

Artificial coral reefs have been 3D printed from nontoxic, biodegradable terracotta clay, which coral polyps have used as a foundation for rebuilding marine ecosystems.

Corals are themselves not coral reefs—the term refers to the tiny marine invertebrates that build the rigid reef.

Learn about deep water corals and the coral gardens they slowly build in the dark

Found throughout the world's ocean basins at depths beyond 200 meters (660 feet), these corals do not rely on photosynthetic organisms for nutrients and instead rely on food that's fallen from the ocean surface. Beyond forming larger reefs over the course of thousands of years, smaller coral gardens are built with the aid of underwater worms.

View the three types of coral reefs, categorized by where they form

Fringing reefs—the most common type—are built from coral depositing calcium carbonate onto the seafloor closest to the shoreline. Barrier reefs grow further from and parallel to the shore, while atolls are the result of mid-ocean volcanoes or seamounts eroding away and leaving a lagoon surrounded by reefs.

Coral polyps reproduce via broadcast spawning, where entire reefs simultaneously release reproductive cells for about one hour, once a year.

Coral polyps reproduce via broadcast spawning, where entire reefs simultaneously release reproductive cells for about one hour, once a year.

Fish populations in the Great Barrier Reef have increased after installing waterproof speakers on the ocean floor that played recordings of sounds from healthy coral reefs.

Corals are themselves not coral reefs—the term refers to the tiny marine invertebrates that build the rigid reef.

Fish populations in the Great Barrier Reef have increased after installing waterproof speakers on the ocean floor that played recordings of sounds from healthy coral reefs.

The marine animals that rely on coral reefs for habitats, camouflage, and food

Parrotfish and surgeonfish feed on algae that grow on coral reefs to prevent overgrowth while serving as prey for larger fish across the food chain. Reefs also serve as structures for organisms like sea anemones, which provide shelter for clownfish, and homes for invertebrates such as crabs, lobsters, and shrimp, which help recycle nutrients.

Watch how coral bleaching resembles an organism's immune system attacking itself

Microorganisms called zooxanthellae are in a symbiotic relationship with coral polyps and provide them with food created through photosynthesis. When ocean temperatures or sunlight exceed an optimal range, zooxanthellae release harmful chemicals that irritate coral cells. To protect themselves, corals sacrifice their food source and expel the colorful microorganisms, becoming white.

Learn how humans can protect coral reefs

When diving and snorkeling in environments containing reefs, avoid touching reefs, anchoring on them, or using sunscreen with active ingredients harmful to marine life. Properly recycling and disposing of trash in bins helps reduce microplastics and chemicals that can run off into wastewater and into the oceans.

The origin of the symbiotic relationship between corals and the algae that feed them

An analysis of fossilized reefs from northern Africa and Germany suggests that shallow water corals and photosynthetic algae formed a mutualistic partnership between 419 and 359 million years ago. The discovery was made by analyzing nitrogen-isotope ratios in the fossils, which differ depending on whether algae are present, due to various chemical processes.

Why are coral reefs important?

Coral reefs are vital ecosystems that millions of people and countless species depend on. This two-minute video from London's Natural History Museum looks at the ecological and economic significance of coral reefs, including their biodiversity and...

Coral reefs get their colors from zooxanthellae—microorganisms that line corals' digestive tracts and provide them with sugars in exchange for a home within this protective tissue.

The world's largest coral, as seen from space

The world’s largest individual coral colony—measuring over 100 feet wide and 100 feet long—was discovered in the Solomon Islands. This coral is so large it can be seen from space, and is estimated to be between 300 and 500 years old. The coral's size and health provide hope amidst a global coral bleaching crisis, wherein three-quarters of coral reefs have experienced significant bleaching in recent decades. See the photos from space and learn more here.

Explore the history, structure, and species of Australia's Great Barrier Reef with this interactive journey narrated by Sir David Attenborough.

Niagara’s bedrock holds 440-million-year-old coral fossils

The Lockport Dolomite that caps Niagara Falls is composed of fossilized coral reefs from a tropical sea that once covered the region 440 million years ago.

Explore the history, structure, and species of Australia's Great Barrier Reef with this interactive journey narrated by Sir David Attenborough.

Watch a pinecone become a pine tree

Sometimes a closer look at an ordinary process can uncover its glory This timelapse video presents the wondrous natural process of a withering pinecone turning into a full sprouted tree. A nearly two year growth, watch the seed turn to seedling and rise over time.

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.

Hurricanes can grow by replacing their eyewall

A second outer eyewall can form around the primary eyewall surrounding a hurricane's eye. During an eyewall replacement cycle, the outer wall can weaken, collapse, and replace the inner wall, temporarily weakening the storm before it strengthens and grows.

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.

Watch how engineers salvaged almost every sunken ship at Pearl Harbor

This four-part video series explains the massive effort to raise, repair, and refloat the Pacific Fleet—detailing the engineering challenges, diving operations, and months of around-the-clock work that restored all but three damaged ships to active service.

Watch how deep-sea mining equipment collects and processes polymetallic nodules—metal-rich, potato-shaped rocks—from the ocean floor and creates environmentally damaging plumes of sediments.

Watch tardigrade samples under an optical microscope

Tardigrade samples can be collected by gathering moss and submerging it in tap water for 24 hours. The moss should then be cut and drained with a mesh sieve, and the water should be collected. Samples are observable in the water between 10x and 40x magnifications.

Watch the first-ever footage of a ghost shark

In 2009, the pointy-nosed blue chimaera was filmed swimming in the deep sea. That same year, researchers first observed them off the coast of California and Hawaii, after they had previously been found only in the Southern Hemisphere.

Symmetric patterns of magnetic stripes seen on either side of mid-ocean ridges

The symmetry provides evidence of seafloor spreading, where new oceanic crust is created at mid-ocean ridges, which pushes older ocean crust away on either side. Matching the pattern to magnetized material in rocks on Earth’s surface provided a timeline of ocean floor recycling.

In 2009, accidentally drilling into magma provided time capsules of volcanic glass

While drilling for geothermal energy in Iceland's Krafla Geothermal Field, magma encountered at a depth of 2,100 meters quickly formed glass upon making contact with drilling fluid. By trapping dissolved gases, volatile chemicals, and the physical characteristics of magma before cooling, the glass acts as a time capsule of ancient volcanic activity and magmatic conditions.

Watch the Arecibo Observatory collapse

Watch this remarkable footage of the Arecibo Observatory’s 900-ton platform falling into the 1,000-foot wide (305 meters) dish below, followed by footage from a drone coincidentally observing the cables at the time they snapped.

Stereolithography uses light to fabricate objects in layers via chemical reactions

Specific locations in a tank of light-sensitive liquid resin are exposed to projected light, causing them to cure onto a build platform. The resulting cross-section of hardened plastic is moved slightly away from the light source, exposing it to resin once more, and the process repeats to produce successive layers.

Scientists testing how climate change affects plants found, in a years-long simulation study, that poison ivy grew 70% faster with the resulting extra carbon dioxide.

See how fireworks are made and learn how metals like magnesium and copper are responsible for different colors.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

This real-time tracking of the hantavirus cruise ship outbreak in May 2026 offers a unique glimpse into the global reach of the outbreak and whether the virus sickened passengers and their communities around the world.

The animatronic shark from Steven Spielberg's 'Jaws,' the first modern blockbuster, was a complex underwater apparatus called 'Bruce.'

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Watch this video that uses Lego bricks to explain how venture capital works.

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens.

The first steps to rebuilding your credit score include getting to know exactly what's on your credit report and figuring out how far you are from the '700 club,' or 'good score' range.

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

Watch the cumbersome, but necessary, precautions healthcare workers must take to care for and protect themselves while caring for Ebola patients.

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.

Fast-casual restaurant Chili's is experiencing a resurgence, with its parent company recently reporting a nearly 32% increase in sales, thanks to passionate Gen Z fans on TikTok.

The first image of a black hole was captured by creating an Earth-sized virtual observatory from a network of eight radio telescopes.