🤿 Exploring the deep

Yes, take a big breath and hold it for a moment, just like a diver does before going underwater.

Sunlight only manages to travel a certain distance down through water before it gets absorbed and scattered away completely, which means less and less light reaches you the deeper underwater you travel. Within roughly the first two hundred metres, called the sunlight zone, there is usually still enough light for plants and colourful reef life to grow and thrive, but much deeper than that, sunlight fades away almost entirely. Below about a thousand metres, the ocean becomes permanently pitch black, with absolutely no sunlight at all reaching that deep, no matter how bright or clear the day might be up on the surface.

A shark has a long, smooth body, sharp teeth, and a tall fin that can stick up out of the water.

Even in the deepest, darkest, coldest parts of the ocean, where sunlight never reaches at all, scientists have still found surprising creatures living and surviving, including strange fish, giant worms, and creatures clustered around hot vents in the seafloor. Many deep sea creatures have unusual adaptations for their extreme environment, like huge eyes to catch the faintest scraps of light, or bodies built to withstand crushing water pressure many times stronger than at the surface. Some deep sea creatures near hot underwater vents actually get their energy from chemicals in the water instead of sunlight, forming a food chain that works completely differently from almost anywhere else on Earth.

Yes, crawl under a table or into a dim corner, the deep ocean is dark just like that, only much colder.

Whales, like dolphins, are mammals that breathe air, but their bodies are specially built to use oxygen far more efficiently than ours, storing extra oxygen directly in their blood and muscles instead of mostly in their lungs. Before diving, a whale can also slow down its own heart rate and reduce blood flow to parts of its body that do not need oxygen urgently, saving its limited oxygen supply for its brain and most essential organs. These adaptations let some whale species dive for well over an hour at a time on a single breath, diving deep down to hunt before eventually returning to the surface for fresh air.

A tide pool is a small pocket of seawater left behind in rocky dips and hollows along the shore after the tide goes back out, trapping a miniature world of ocean life until the tide returns and refills it again. Creatures living in tide pools, like small crabs, sea anemones, and tiny fish, have to survive constant change, since the water inside can heat up in the sun, get pounded by waves, or nearly dry out entirely between each tide. Because tide pools sit right at the boundary between land and sea, they let curious visitors get an up-close look at ocean creatures without ever needing to swim or dive at all.

A whale makes long, low sounds that can travel far through the water, almost like singing.