Rivers are made of multiple streams that have joined together. Streams and rivers provide spawning grounds for fish, hunting grounds for predators, and transportation for migrating animals.

Ponds and lakes are larger bodies of fresh water. Lakes are usually larger and deeper than ponds. They provide habitats for many living organisms, from algae to insects to fish and more.

Wetlands are lands covered by fresh water. Swamps, marshes, and floodplains are all examples. Wetlands filter pollution and sediment, reduce flooding, refill streams, and provide habitat to many organisms.

These are coastal lands covered with salt water. These include marshes, mangrove forests, and seagrass beds. Coastal wetlands maintain water quality by filtering sediment, pollution, and nutrients. They also provide food, habitat, and nursery grounds for many species.

These are places where a freshwater river meets the ocean. The water in these areas is brackish, or partially salt water and partially freshwater. Many animals use these areas for breeding because of how calm the water is.

The open ocean is divided into 3 layers:

• Euphotic Zone: brightly lit, photosynthesis occurs here, and major predators live in this zone (bluefin tuna, sharks, etc.)

• Bathyal Zone: dimly lit, small fish and zooplankton

• Abyssal Zone: no light, deepest, very cold, nutrients come from decaying matter as it falls to the ocean floor.