A habitat is the home of a living thing: the place that gives it water, food, shelter and space. An aquatic habitat is a water home. Standard 3 asks you to tell these apart: rivers, ponds, swamps and the sea.

A wetland is land that is wet for much of the year. Swamps are wetlands. Trinidad and Tobago has the Caroni Swamp, a mangrove wetland on the west coast, and the Nariva Swamp, a large freshwater wetland on the east. Both are delicate. Small changes can harm the animals that depend on them.

A river is flowing water moving toward the sea or another body of water. The water is usually fresh. Animals must cope with the current.

A pond is a small, still body of fresh water. It can warm up quickly and can dry smaller in the dry season. Frogs often use ponds.

A swamp is a wetland with trees or other plants standing in water. A mangrove swamp is salty or brackish, which means a mix of river water and sea water. The sea, or marine habitat, is salty and large. Waves, tides and depth matter there.

The Caroni Swamp has red mangroves. Prop roots hold the trees in soft mud and give young fish and crabs places to hide. Scarlet ibises roost there. Their long bills probe the mud for food. If the mud is poisoned or the trees are cut, the birds and the young sea animals lose that home.

The Nariva Swamp is mainly freshwater. It has palms, open water and a different community of animals from the salty Caroni mangroves. Protecting wetlands does not mean treating every swamp as the same place. You name the kind of water and the plants.

People visit with guides and leave the roots, nests and birds alone. A boat wake that is too fast, loud noise, and rubbish all disturb a roost.

Natural factors can stress a habitat. A drought lowers the water. A flood can change the saltiness or wash animals away. Water that is much hotter or colder than usual can harm eggs and young. If predators increase, or food runs short, or too many of one animal crowd the space, the balance shifts.

Human actions can do sharper harm. Pollution adds poison, oil, sewage or plastic. Over-exploitation means taking too many fish, crabs or trees. Using a place carelessly, with speeding boats or dumped waste, is indiscriminate use. Bringing in a species that did not belong there can eat the local young. You will study that idea again in the food-web lesson.

Protecting a wetland is a responsibility. It can mean using a bin, staying on the boat path, obeying closed seasons for fish and crabs, and telling an adult about a spill.