From sunny reef to the midnight deep
Near the surface, coral reefs blaze with life in the sunlight; miles down it's black, freezing, and crushing, yet still full of strange creatures. The ocean is stacked in zones, each with its own light, pressure, and residents.
Down through the layers
Sunlight only reaches the top layer of the ocean, so that is where most plants and plankton live. Go deeper and it gets darker, colder, and the pressure climbs. In the midnight zone, animals make their own light to survive.
- Sunlight zone: warm, bright, full of life — reefs and plankton.
- Twilight zone: dim, cooler, home to squid and lanternfish.
- Midnight zone: pitch black, freezing, crushing pressure — creatures glow.
Lab · Build a reef food web
- Start with tiny plankton that make food from sunlight.
- Add a small fish that eats plankton, then a bigger fish that eats the small fish.
- Add a shark at the top. Draw arrows showing who eats whom.
- Explain what happens to the shark if the plankton disappear.
What you should see: You built a marine food web and saw how every animal depends on the sunlit base.