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

Photoautotrophs, which include plants, algae, bacteria, and Euglena, are organisms at the base of the food web that convert light energy from the sun into chemical energy stored in sugars.

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.

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

'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.

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.

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

Instead of consuming water and carbon dioxide to produce oxygen and sugar, anoxygenic photosynthesis involves alternative reactants and products.

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

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.

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

Imagining if humans could perform photosynthesis and how it would change our anatomy

Green algae have lived on Earth for about 1 billion years, roughly twice as long as the first plants.

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.

Electrogenic animals generate their own electricity by changing the pattern of electrical charges in disc-shaped cells called electrocytes.

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.

Biofluorescent animals—those that absorb light, such as ultraviolet rays, and re-emit other types of light, such as neon green—include some flying squirrels, scorpions, sea turtles, and platypuses.

View a gallery of bioluminescent organisms, including snails, worms, fungi, jellyfish, and mushrooms.

Watch underwater photosynthesis make water look like champagne

View examples of luciferin, the light-emitting molecule behind bioluminescence

Why 75% of ocean animals glow

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

A Death Valley shrub optimizes its cells' organelles to photosynthesize in extreme heat

The term 'symbiosis' was coined during the study of lichens—composite organisms in which algae or cyanobacteria partner with a fungus, alongside bacteria.

Watch a time-lapse from space of photosynthesis across Earth

As of 2026, the Great Atlantic Sargassum Belt is the world's largest macroalgal bloom, with seaweed stretching from the Caribbean to West Africa.

Learn about endoliths, the polyextremophiles that thrive inside rocks

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

View colorful flowers that grow on cacti and succulents, popular xerophilic organisms

Bioluminescent organisms produce their own light through chemical reactions involving unstable, energetic molecules, while biofluorescent organisms almost immediately re-emit light shone on them, but at a different wavelength.

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.

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

Learn how chloroplasts—the photosynthesis factories—may have once been independent cells

About 1,500 species of tardigrades have been identified by their unique physiology

Bioluminescence provides organisms with a method of hunting, defense, or mating

The Turritopsis dohrnii jellyfish can reverse its life cycle

As part of the up to 15 pounds of seafood they consume daily, sea otters eat urchins that feed on kelp forests—sources of shelter and food to over 800 species—thereby making the marine mammal a keystone species.

Chameleons change color by altering the spacing of nanocrystals under their skin, which changes what colors of light are absorbed and reflected.

How slugs helped soldiers during WWI

View a sample of the bioluminescent tree of life

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.

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.

Astronauts on the International Space Station have tested an algae-powered bioreactor that converts carbon dioxide, water, and light into oxygen and edible, protein-rich biomass.

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.

How the pigments that absorb light for photosynthesis contribute to plants' green color

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

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

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.

An overview of oxygenic photosynthesis, which releases oxygen from breaking down water

How artificial photosynthesis can help make plastics and fuels using sunlight