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.

Comparing La Niña and El Niño atmosphere-ocean feedback patterns

El Niño and La Niña are Pacific Ocean climate patterns that affect global weather

View high-resolution maps of how El Niño and La Niña affect weather patterns around the world at different times of year.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

Because El Niño and La Niña affect the distribution of warm waters—a key ingredient in hurricane formation—they affect the intensity of the Atlantic and Pacific hurricane seasons.

El Niño, Spanish for 'the boy,' was named after Jesus Christ because the phenomenon resembled the weather changes observed around Christmastime.

Scientists anticipate the phases of the El Niño-Southern Oscillation by identifying differences between sea-surface temperatures in the equatorial Pacific and those elsewhere in the tropics.

Compare various El Niño-Southern Oscillations using maps of atmospheric and ocean variables

From 1877 to 1878, the deadliest super El Niño event in history contributed to a global famine that killed more than 50 million people.

The top several meters of the world's oceans can hold as much thermal energy as the entire atmosphere.

Understanding how the El Niño-Southern Oscillation is affected by climate change

Breaking down the health effects of the El Niño-Southern Oscillation

How jet streams and US weather are affected by the El Niño-Southern Oscillation

Learn about various ocean-atmosphere cycles impacting global weather patterns

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.

Kelvin waves are planetary-scale redistributions of warm water and energy deep beneath the ocean's surface that can raise sea levels by several inches for weeks.

Water is naturally tinted with a slight blue, but sediments and organics can alter its color

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

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.

The colors of auroras change with the intensity of solar activity and with altitude because of differences in atmospheric density and chemical composition.

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.

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 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.

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

Blood can be blue, green, magenta, or transparent due to differences in the oxygen-carrying molecules they contain.

Aerial photos of red tide off the Gulf Coast

Watch a visualization of how Earth's oceans impact its atmosphere, weather, and climate.

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

Surface ocean currents are primarily driven by wind, tides, and Earth's rotation, while deep-ocean currents are driven by differences in temperature and salt concentration.

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.

It's always snowing in Earth's oceans, but marine snow is predominantly made of decaying organic material, not ice crystals.

Corals sacrifice their food source and expel colorful microorganisms to protect themselves during coral bleaching—a phenomenon that resembles an organism's immune system attacking itself.

Watch underwater photosynthesis make water look like champagne

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

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

'Watermelon snow'—patches of pink, orange, and red in snow—is the result of extremophilic green algae that thrive in extremely frigid conditions and take the shape of red spheres in winter.

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

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

Leaves have orange and yellow pigments year-round, but they are masked until the fall, when shorter days reduce the production of chlorophyll, a green pigment.

Why 75% of ocean animals glow

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

Virtually all plants are biofluorescent because their photosynthesis is powered by chlorophyll, a pigment that glows red as a way to get rid of excess energy when exposed to ultraviolet light.

How salt, sunlight, and wind drive ocean currents

While published images have suggested that Neptune is much bluer than Uranus, the two ice giants are a similarly pale shade of greenish-blue.

Satellites can be used to measure photosynthetic activity worldwide by observing the red, biofluorescent light emitted by chlorophyll in plants.

The chlorophyll in plants captures energy in the form of red and blue light

Visualizing changes in ocean temperatures between 2016 and 2020

Copper is responsible for turning blonde hair green in swimming pools

A simple infographic explaining how coral bleaching works

Watch a time-lapse from space of photosynthesis across Earth