This aquatic ecosystem has very low salt content or does not contain salt.

Freshwater ecosystems have water flowing over land or standing still. Lakes and ponds have ______ water, while rivers and streams have____________ water.

Only_______ of aquatic ecosystems is considered freshwater.

Lakes and ponds are divided into _______ zones determined by depth and distance from the shore.

The topmost or the shallow-water zones is called the _______________ zone.

The open-water zone away from the shore is called _______.

This is a well-lighted zone that is why producers, like algae and plankton, float near the surface.

Very deep lakes have an area known as the__________-, where light is limited or is not present at all.

The bottom part below the open water zone is called the ________________. This zone is much colder and denser because little light reaches the bottom.

The temperature of rivers and streams is cooler at the ______ than at the __________.

Many plants and animals adapt to stream and river habitats.

Slower-moving waters have less oxygen and less amount of light.

Saltwater ecosystems are also called _________ ecosystems.

The saltwater ecosystem covers three-fourths of Earth’s surface. It includes the oceans and the seas. Just like ponds and lakes, oceans are divided into _____________ zones

It is where the ocean meets the land. It is the shallowest part of the marine ecosystem.

It is either submerged in water or exposed to air depending on the tides and waves. Snails, crabs, sea urchins, seaweeds, sea anemones, sea stars, small fishes, barnacles, and shrimps, live in this zone.

The majority of marine animals live in this zone because it is where oxygen is high, and pressure is low.

It is basically the open ocean and begins when the water is over 200 meters deep.

Coral reefs that are home to aquatic animals and plants can be found here.

Producers, such as phytoplankton, kelp, and sea grass, grow here because sunlight can penetrate through the water.

It is also known as midnight zone, receives little to no sunlight. That is why producers, like aquatic plants, do not live here.

Examples of Nektons, animals that live in the midnight zone are:

It never receives daylight and is marked by its cold, dark conditions.

The zone that includes the entire ocean floor is called the ________zone. It begins at the intertidal zone and extends downward to the ocean. This zone is very cold and gets no sunlight.