The world's largest algal bloom spans from the Caribbean to West Africa.

Satellite imagery of the massive seaweed blob in the Atlantic

Aerial photos of red tide off the Gulf Coast

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.

Harmful algal blooms can occur in warm, nutrient-rich, stagnant waters and are often associated with the rapid reproduction of blue-green algae—a misnomer for cyanobacteria, not algae.

Explore a map of coral reefs around the world and the extent of coral bleaching.

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

Massive blooms of microscopic algae called dinoflagellates produce the neon blue light seen in glowing tides.

The world's largest garbage patch, explained

The world's largest coral, as seen from space

To fight invasive species, some people have harvested them to produce useful materials that can be sold for a profit.

Algae produce about half of Earth's atmospheric oxygen and can capture carbon dioxide at rates up to 50 times faster than land-based plants.

From 2023 to 2025, coral reefs experienced their fourth global bleaching event and the largest such event through 2025.

Climate change threatens coral reefs by disrupting the symbiotic relationship between corals and algae due to rising ocean temperatures.

Plastic debris across the ocean aids the spread of invasive species

Alaska's Bristol Bay hosts the world's largest self-sustaining wild salmon runs

An analysis of fossilized reefs from northern Africa and Germany suggests that shallow water corals and photosynthetic algae formed the mutualistic partnership seen today between 419 and 359 million years ago.

About 76% of global coral species are found in the Coral Triangle—a region spanning the waters of Indonesia, Malaysia, Papua New Guinea, the Philippines, the Solomon Islands, and Timor-Leste.

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.

View the biggest threats to biodiversity, according to the World Wildlife Fund, led by changes to species' environments, species overexploitation, and invasive species.

Earth's oceans do mix, despite viral images and videos claiming to show boundaries between oceans that waters do not cross.

Known as the corpse flower for smelling like rotting meat, Rafflesia is the world's largest flower and a parasite that lives off a host vine.

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

The Amazon rainforest is considered the 'lungs of the Earth,' but it contributes less than a quarter of the oxygen of phytoplankton—microscopic plants, algae, and bacteria capable of photosynthesis.

Molecules derived from algae can be found in foods such as ice cream, salad dressings, brownie mix, and gravies, as well as in products such as toothpaste, multivitamins, and egg substitutes.

El Niño makes the equatorial Pacific Ocean bluer than usual as high temperatures kill off microscopic plants that normally give the waters a green hue.

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

Invasive species can harm infrastructure and threaten human health

The seafloor contains hundreds of brine pools—underwater lakes that are many times saltier than the surrounding ocean and lethal to most marine creatures.

How marine debris accumulates in giant garbage patches

Acetabularia jalakanyakae is one of the largest known single-celled organisms and is nicknamed the 'mermaid's wineglass' for its umbrella-shaped cap.

Some corals absorb harmful ultraviolet radiation and re-emit it as visible light, thereby protecting symbiotic algae within their tissues and providing them with energy for photosynthesis.

Despite being multicellular and photosynthetic, organisms such as kelp and sea moss are macroalgae, not plants, because they lack specialized roots and stems to pump water.

Some algae have helped remove microplastics from water after being bioengineered to clump together with these contaminants, forming an easily collectible microplastic-algae sludge.

How a polluted New York City waterway created extremophiles hungry for 'black mayonnaise'

Scientists have found that the Great Barrier Reef's microbiome includes an estimated 362,802 distinct viruses and 876 distinct bacterial and archaeal species—584 of which had never been documented before 2026.

Watch a visualization of global ocean currents from NASA's Estimating the Circulation and Climate of the Ocean project.

Take a 3D underwater trip near the Great Barrier Reef

Elysia chlorotica is a sea slug that can photosynthesize, making it an animal with the defining ability of a plant.

While major oil spills result from accidental pipeline ruptures or damage to transportation vessels or rigs, as much as half the oil that reaches coastlines has naturally leaked from the seafloor.

Gulf nations produce about 40% of the world's desalinated water

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.

Coral reefs get their colors from zooxanthellae—photosynthetic algae that line corals' digestive tracts and provide them with sugars in exchange for a home.

The 'humongous fungus' may be the largest organism on Earth at more than 2,300 acres

We're in the middle of a decadeslong cholera pandemic

The cells of spotted salamander embryos and early-stage larvae harbor algae that support embryonic development by increasing oxygen levels and removing waste.

From 1970 to 2017, invasive species have caused $1.28T in damage globally

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.

The Atlantic Ocean is home to the world's largest waterfall—the Denmark Strait cataract—which is more than three times the height of the largest land-based waterfall.

The harsh realities of the Great Pacific Garbage Patch

The biggest ocean waves in the world, which regularly reach between 80 and 100 feet, are primarily caused by a 140-mile-long submarine canyon that reaches a maximum depth of 16,000 feet.