What Characteristic Is Used to Divide Aquatic Biomes into Three Zones? — Reading Comprehension

Aquatic biomes, such as oceans, lakes, and ponds, are divided into three main zones based on the amount of sunlight that reaches the water. Sunlight is a key factor because it affects how much photosynthesis can happen, which in turn affects what kinds of plants and animals can survive in each zone.

The sunlight zone, also called the photic zone, is the top layer of water where sunlight can easily reach. This zone supports a large variety of life because it has enough light for producers like algae and phytoplankton to grow. These tiny plants form the base of the food chain. Fish, sea turtles, and coral reefs are commonly found in this zone.

Below that is the twilight zone, or disphotic zone, where only a small amount of sunlight filters through. There is not enough light for most plants to perform photosynthesis. Animals that live here, such as squid and lanternfish, often have special adaptations like bioluminescence—the ability to produce light.

The deepest layer is called the midnight zone, or aphotic zone. In this zone, no sunlight reaches at all. It is cold, dark, and under great pressure. Only specially adapted organisms, like deep-sea fish and giant tube worms, can survive here. These creatures often rely on chemosynthesis, a process where energy is made from chemicals instead of sunlight.

Understanding these zones helps scientists study marine ecosystems and how energy moves through them. It also explains why different types of life are found at different depths in the water.

Fun Fact: The Mariana Trench, Earth's deepest ocean point, is part of the midnight zone—it's so deep that Mount Everest could fit inside it and still be underwater!

What main factor is used to divide aquatic biomes into zones?

What is another name for the sunlight zone?

Which aquatic zone receives no sunlight?

What kind of organisms live in the photic zone?

Why can plants not grow well in the twilight zone?

What special ability helps animals survive in the twilight zone?

What is the main idea of the passage?

How do some organisms in the midnight zone get energy?