The following experiment along with the previous one illustrate the adverse effects of only two of the many changes that have been made in the Lake Pontchartrain Basin. As your students perform these exercises, they will develop an appreciation of just how dramatically certain environmental changes can affect our precious natural resources. Saltwater intrusion, or the advancement of saltwater into formerly freshwater marshes and swamps, has been blamed for much of the wetland loss in the Lake Pontchartrain Basin. Quite often saltwater is allowed to enter interior marshes by way of straight canals dug by oil companies to facilitate travel during oil exploration or deepwater navigation channels designed to improve shipping traffic in the Port of New Orleans. While saltwater intrusion is not necessarily to blame for wetland loss in all parts of the Basin, it is certain that almost all plants accustomed to freshwater cannot tolerate saltwater for very long.
Some plants can, over time, adapt to changing salinity conditions.
These experiments will allow students to develop hypotheses like these concerning the effects of saltwater on various wetland plants. Be sure to keep the seeds separated and labeled if you know the plants. Ordinary plant seeds from your local hardware store will also demonstrate the effects of increasing salt levels. A plastic bottle for plant watering. Something with a sprinkler or spray top works best.