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Observe · understand · progress

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Understand marine biodiversity and underwater environments

What is hidden in the sand, around a wreck or among the algae? Dive.Explo360 articles build on your underwater observations to help you understand marine habitats, species’ ways of life and their relationships within ecosystems.

Develop your knowledge of marine life while diving: discover the features of different environments, learn to observe their inhabitants and connect your discoveries with the marine species guides and the dive videos. These readings accompany divers and anyone curious about underwater life, before or after exploring.

Your marine region: Red Sea. Choose a marine region, then search for a subject or filter articles by category and topic. Each publication shows its availability and access conditions.

An open marine life magazine showing an octopus, its eye and its suckers.
From observations to explanations

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Region labels show where the topic applies. Articles that cover several seas may use tropical examples, even in the Mediterranean catalogue.

32 articles

Striped lionfish beneath a rocky overhang. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Biotope · Environment

How do fish from the Red Sea reach the Mediterranean?

A lionfish peeks out from under a rock off Cyprus. It opens its wide striped fins and moves towards a smaller fish. Its ancestors came from the Red Sea. How did they get from one sea to the other?

UnderstandingPublic 4 min · Lic. 8 min Read the article
A ray and several fish over a sandy seabed Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Way of life · Behaviour

Why do fish tag along?

A ray digs for dinner and sends up a puff of sand. A fish swims closer. The digging might turn up something for that fish to eat, too.

UnderstandingPublic 4 min · Lic. 8 min Read the article
Artist’s view of a tropical reef with coral rubble in the foreground. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaRaja Ampat

Ecology · Science

WHAT DIVERS DON’T SEE ON A CORAL REEF

Look into a crack in the reef. A little crab might live there. Other tiny animals hide under pieces of coral.

UnderstandingPublic 2 min · Lic. 4 min Read the article
Artist’s view of fish in the sunlit shallows of a tropical reef. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaRaja Ampat

Ecology · Science

HOW DO FISH PROTECT THEMSELVES FROM THE SUN?

Sunlight reaches the fish on a shallow reef. Some fish swim into shade. Others carry a kind of sunscreen right on their skin.

UnderstandingPublic 2 min · Lic. 5 min Read the article
Artist’s view of a reef slope in the Gulf of Aqaba. Available1/3 public · licence required for the rest

Article region: Red Sea

Red Sea

Ecology · Science

RED SEA: WHY DO SOME CORALS WITHSTAND HIGH TEMPERATURES?

When the sea gets too hot, some corals turn pale. Others keep their colours. In the Red Sea, you can see both responses.

UnderstandingPublic 2 min · Lic. 5 min Read the article
A translucent young fish above a tropical reef at dusk. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaRaja Ampat

Way of life · Science

Does the reef have a voice?

Listen to a reef after dark. Tiny shrimp snap from their hiding places and fish grunt among the corals. Some young fish can pick up these sounds as they look for a place to live.

UnderstandingPublic 2 min · Lic. 5 min Read the article
Two neighbouring coral colonies, one golden and the other bleached. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaRaja Ampat

Way of life · Science

What happens when a coral bleaches?

Two neighbouring corals live in the same water. Why does one turn white?

UnderstandingPublic 2 min · Lic. 3 min Read the article
A moray with its mouth ajar in a reef crevice. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Way of life · Behaviour

Why do morays keep opening their mouths?

A moray peeks out from a crack in the reef. Its mouth opens, closes, then opens again. All those teeth come into view every time it takes a breath.

UnderstandingPublic 2 min · Lic. 5 min Read the article
Shark resting beneath a reef ledge. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Way of life · Behaviour

Do sharks sleep?

A shark can lie on the sand with its eyes wide open. It’s still breathing. Could it be asleep?

UnderstandingPublic 2 min · Lic. 4 min Read the article
Clownfish among the tentacles of an anemone. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaRaja Ampat

Way of life · Behaviour

How do clownfish avoid anemone stings?

An orange fish disappears into a sea anemone. Its tentacles can sting a little shrimp, yet the clownfish swims right between them. A slippery coat on the fish’s skin helps it do this.

UnderstandingPublic 2 min · Lic. 4 min Read the article
A crown-of-thorns sea star on branching coral beside a pale feeding scar. AvailableFree access

Multiple marine regions

Red SeaRaja Ampat

Way of life · Behaviour

How can a sea star devour a reef?

A spiny sea star climbs over a coral. When it moves away, a white patch shows where it has eaten.

Understanding4 min Read the article
Reef-building corals spawn at night. Gamete bundles rise above the reef. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaRaja Ampat

Way of life · Behaviour

How do corals reproduce?

On some nights, tiny pink bundles rise from the corals on a reef. Inside each bundle are eggs and sperm. If they meet in the water, a tiny swimmer can begin to grow.

UnderstandingPublic 2 min · Lic. 5 min Read the article
A white sand beach and the reef that supplies some of its grains. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaRaja Ampat

Biotope · Environment

Who makes the white sand on tropical islands?

Imagine holding a handful of white sand. Look through a magnifying glass and you might spot a piece of coral, a flake of algae or even a tiny star. How did they get to the beach?

UnderstandingPublic 3 min · Lic. 5 min Read the article
Nassau groupers (Epinephelus striatus) converge above a Caribbean reef. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaRaja Ampat

Way of life · Behaviour

Spawning gatherings under the sea

One grouper appears at the edge of a reef. Then another swims in, and soon there are hundreds. On some winter evenings, these fish make the same journey to breed.

UnderstandingPublic 2 min · Lic. 5 min Read the article
A veined octopus (Amphioctopus marginatus) carries a shell across the sand. AvailableFree access

Multiple marine regions

Red SeaMediterranean

Way of life · Behaviour

Clever moves underwater

A crab moves inside a glass jar. The octopus can see it, but the jar is shut. How will those eight arms get past the stopper?

Understanding6 min Read the article
Two mandarinfish (Synchiropus splendidus) begin to rise above the reef. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Way of life · Behaviour

How animals meet underwater

As the light fades, two little fish come out from the reef. Soon they’ll swim upwards side by side. What does swimming together help them do?

UnderstandingPublic 3 min · Lic. 6 min Read the article
A sea star over a mussel. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

Swallow, filter, suck in: surprising ways to feed

A mussel snaps its shell shut. A sea star settles over it. All it needs is a tiny gap. Elsewhere, a fish uses rushing water to catch a shrimp, and a sea cucumber finds food between grains of sand.

UnderstandingPublic 3 min · Lic. 5 min Read the article
A motionless fish on the seabed. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

What happens when an animal dies in the sea?

A dead fish can sink all the way to the seabed. Small animals may gather to feed, and other fish may come to catch them. Where does the dead fish go once there’s nothing left to see?

UnderstandingPublic 2 min · Lic. 5 min Read the article
A damselfish above a Caribbean reef. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

Why do reef fish chase their neighbours?

A little reef fish darts towards a much bigger one. What makes it give chase? Watch where the fish lives and what it guards.

UnderstandingPublic 2 min · Lic. 5 min Read the article
A red scorpionfish on a rocky Mediterranean seabed. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

Venoms, poisons and chemical weapons: the invisible battle

A scorpionfish can be hard to spot among the rocks. An anemone leaves its tentacles out in the open. Look closely at both animals to see how they catch food and protect themselves.

UnderstandingPublic 3 min · Lic. 5 min Read the article
A parrotfish resting in a reef cavity. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

Do Fish Really Sleep?

Imagine a fish sleeping with its eyes open. How could you tell? From a reef to a research tank, several animals give us clues.

UnderstandingPublic 3 min · Lic. 7 min Read the article
A camouflaged frogfish faces a small fish on the reef. AvailableFree access

Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

Eat or Be Eaten: Hunting Strategies Underwater

Imagine a little fish spotting what looks like a worm. It swims closer. The wriggling thing is a lure, and it belongs to a frogfish hiding on the seabed.

Getting started7 min Read the article
Fish gathering over a reef in moonlight. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Way of life · Natural history

Born in the Sea: The Perils of Early Life

Imagine an egg smaller than a grain of rice drifting in a current. When it hatches, a tiny larva must find food and, in some species, reach a shelter. Follow its journey and discover how other parents protect their…

Getting startedPublic 4 min · Lic. 8 min Read the article
A parrotfish in shelter and squirrelfish on a reef at dusk. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Ecology · Natural history

When the Sea Comes Alive at Night

As the sun sets, some reef fish slip into hiding. Others come out to feed. Farther out at sea, tiny animals are already swimming up towards the surface.

UnderstandingPublic 3 min · Lic. 6 min Read the article
A grouper approaches an octopus at a rocky crevice. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Anatomy · Natural history

How marine animals regrow lost body parts

Picture an octopus slipping between rocks to escape a fish. If it loses part of an arm and survives, the arm can grow back. A sea star can also regrow an arm. A sea cucumber can even rebuild its intestine.

UnderstandingPublic 3 min · Lic. 7 min Read the article
A blue glowing wave breaking on a beach at night. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Ecology · Natural history

Who Turns on the Light Underwater?

Picture a wave breaking after dark. A blue line runs along it and fades. Tiny living things in the water make those flashes. Deeper down, some fish and jellyfish can make light too.

UnderstandingPublic 4 min · Lic. 6 min Read the article
A striped wrasse approaches the head of a stationary grouper. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaMediterranean

Ecology · Natural history

Who Helps Whom in the Sea?

Imagine a large grouper opening its mouth beside a tiny fish. The little fish comes closer and looks for parasites on its skin. What could each fish gain from the encounter?

UnderstandingPublic 3 min · Lic. 5 min Read the article
White polyps of red coral connected along a branch. AvailableFree access

Multiple marine regions

Red SeaMediterranean

Anatomy · Science

The Hidden Life of Polyps: How Does a Colony Work?

The white crowns on a branch of red coral may look like flowers. Look closer and you’ll find a mouth at the centre of each one. Each crown belongs to a tiny animal called a polyp.

Understanding6 min Read the article
Comparison of three habitats: tropical reef, Mediterranean coralligenous habitat and temperate Atlantic coast. Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaRaja Ampat

Ecology · Behaviour

Why are reef fish so colourful?

Imagine a bright yellow fish swimming past a beige coral. You spot it straight away. Could its colours help another fish recognise it too?

UnderstandingPublic 2 min · Lic. 5 min Read the article
Tropical reef: stony coral colonies and shelters between the reef structures Available1/3 public · licence required for the rest

Multiple marine regions

Red SeaRaja Ampat

Biotope · Environment

THE SECRETS OF CORAL REEFS

A small fish slips between two coral branches and disappears. Those branches were built by tiny animals called polyps. Look closely and you can see how their work gives other animals places to hide and find food.

Getting startedPublic 3 min · Lic. 5 min Read the article
Mediterranean seagrass and rocky seabed with organisms whose functions are connected. AvailableFree access

Multiple marine regions

Red SeaMediterranean

Ecology · Natural history

What marine animals do and why it matters

A fish can eat a leaf or hide among leaves. A mussel catches food that drifts past in the water. These are examples from the Mediterranean. Look for the same kinds of links between living things in other seas.

Understanding8 min Read the article
SCHOOLS OF FISH AvailableFree access

Multiple marine regions

Red SeaMediterranean

Way of life · Behaviour

SCHOOLS OF FISH

Hundreds of fish can turn almost at once. They swim closer together, then spread out again. This group is called a **school of fish**. Each fish pays attention to the ones nearby. That helps the whole school move…

Understanding9 min Read the article