Bring in a crib for a doll or a bassinet. Ask the students what this has to do with an estuary. Many animals come to the estuary to have their young. The estuary with its tall grasses offers many hiding places to keep young animals and birds safe. Fish and shellfish also use the abundant kelp forest in the estuary as a nursery. The ocean tides and temperatures are not as volatile for the young fish and makes the estuary a protected place to grow bigger and stronger. Some fish, like salmon, use the estuary as a nursery then make their way out to the ocean.
Show the students an air conditioning filter. Ask them how this item helps them understand the role of an estuary. The mangrove forests and salt marshes of an estuary act as filters. "As water flows through a salt marsh, marsh grasses and peat -- a spongy matrix of live roots, decomposing organic material, and soil -- filter pollutants such as herbicides, pesticides, and heavy metals out of the water, as well as excess sediments and nutrients," according to National Oceanic and Atmospheric Administration.
Show students a big sponge -- the kind used to wash cars. The estuary acts like a sponge to protect fragile coastlines from flooding. A river's big runoff from extra rainfall and snowfall are buffered by the estuary. A hurricane's damage to shorelines is decreased because the estuary absorbs the extra surge of water.
Water from all rivers and creeks end up in the ocean. Map the route of a local river to the ocean.Take the children to the river for a clean-up day. Explain to them the importance of taking care of the river. The condition of the local river affects the plants and animals of the estuary and the ocean. Obtain the permission of your local government to stencil the storm drains around town. Storm drain stencils promote watershed awareness. Stencils educate the public about the importance of taking care of local watersheds -- "No Dumping -- Drains to Sea."