A commonly held belief is that the Great Lakes ecosystem stops at the shoreline, when in actuality the shoreline itself, and the surrounding streams and wetlands are also an integral component of the system. Simply put, wetlands are a unique habitat that is not quite terrestrial and not quite aquatic. It is for this reason (and many others) that wetlands play such an important role in the Great Lakes ecosystem; they are the connection between two different habitats. There are also a variety of ways in which wetlands protect the Great Lakes ecosystem. Among many benefits to the ecosystem, wetlands filter sediment, control erosion, manage floods and filter nutrients, which are vital to the myriad of organisms that live there.
Sediment Filtering, Erosion Control and Flood Management:
Wetlands act as a catchment basin, able to hold the large volumes of water. This is particularly important during periods of increased run-off that are present during a storm event. The accomodatino of the initial influx of water slows the release of the run-off into the watershed (streams, rivers, lakes etc.) and has many implications for erosion control as well as sediment filtering and flooding management. Without wetlands, surges of high velocity water would be dumped directly into the aquatic system. This high velocity water would have picked up soils, debris, oils and other pollutants that would then enter the watershed*.
This containment system that the wetlands provide decreases the impact of erosion by slowing the flow of the run-off. High velocity water carves more out of stream banks and redistributes the sediments to the lakes. Additionally, the lower velocity water allows the particles to settle. It would be expected that large particles (e.g. rocks) are the first to drop down, but as the velocity continues to decrease, smaller and smaller particles settle. Erosion and sediment deposits are important because any increases in the cloudiness (or turbidity) of lakes can have wide-reaching implications: wetlands help to keep this from happening.
Nutrients are an important component of growth. All organisms need nutrients, but excessive nutrient concentrations in an aquatic system can do more harm than good. Organisms and particular conditions in wetlands utilize excessive nutrients present in run-off and prevent these nutrients from being introduced into an aquatic system, where it can cause excessive algal growth. The major nutrients that are removed by wetlands are nitrogen and phosphorus. These nutrients are removed from the system either by being transformed into another compound more easily utilized by organisms or by adhering to the sediments that are present.
Wetlands provide crucial habitat for a variety of organisms thanks to the plant diversity. Rooted and submerged plants provide different characteristics that are important to different species. Water fowl use wetlands to feed and rest during migration as well as nesting outside of winter. Some fish spawn in wetlands and others feed on the other organisms present. In addition to aquatic organisms, there are frogs, snakes, turtles and beautiful plants that create a unique habitat. Inland Seas Education Association has constructed wetland that offers a unique experience to take a walk through a natural wetlands habitat. Tours of the wetlands can be self-guided. For more information, visit their website or call 231.271.3077.
For further information on wetlands, check out these sources:
-Emily Shaw, Feature Writer
*This assumption is based on a modified landscape, i.e. an urbanized area. The delay and surge are much more gradual in places with large areas of permeable surfaces.