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The beach shown here appears calm and unchanging. But in reality, the beach is always a work in progress. It is constantly being constructed and reshaped by strong forces of nature.
Dunes
The wind is the major sculptor of the beach. When it blows across the
smooth surface of Lake Michigan, there’s little to hinder its momentum.
It hits the shore with a fury, picking up grains of sand and pushing them
inland. As the wind velocity slows over land, sand drops to the earth,
and in time, a pile is formed. Gradually, the pile grows into a tall sand
dune, like the one in this picture. Long series of dunes like this one
have formed at the back of the beach at the Indiana Dunes
National Lakeshore.
If you’ve ever felt the sting of sand pelting your skin on a windy
day at the beach, it’s because you’ve been caught in the middle of this
sculpting process.
Indiana Dunes National Lakeshore
Over 14,000 acres of dune country are preserved at the National Lakeshore,
located in northern Indiana between Gary and Michigan City. The Visitor
Center is located on Kemil Road at U.S. Highway 12, three miles east of
Indiana Route 49. The public is welcome to swim, hike and explore.
Marram grass (Ammophila breviligulata)
Between the edge of the water and the beginning of the dunes, dry sand
is constantly in motion--dancing, shifting and floating. This makes the
beach a treacherous place for plants to take root. One kind of plant that
does live here is marram grass. It spreads its tuberous roots just under
the surface of the sand, and forms an underground web that helps hold the
sand in place.
Though marram grass stabilizes the soil for its own survival, an inadvertent side effect is that it makes it possible for other kinds of vegetation to begin to take hold. Other plants take advantage of the increased stability of the soil surface and start to colonize areas the marram grass helped make safe.
