Louisiana has a wide variety of marshes. If you spend much time walking the wetlands, you will have experiences ranging from dry feet to sinking to your waist in smelly muck. Most are growing in soil, so the more consolidated it is, the easier it is to walk.
We have a special form of marsh that can be found in either freshwater or intermediate marsh. It is called flotant (flow tawnt=) by the locals (and often referred to as la prairie tremblante, or, trembling prairie), because it is a floating marsh that is not anchored to the ground beneath. It consists of tightly entangled plants and their roots, mixed with peat; typically there is water flowing below it, then some oozing soil, then clay. Patches of it may occur within normal marsh, and from the surface, it looks like any other marsh. It may be rather thin and not able to support a person, or it may be very thickly vegetated and solid enough for a human to actually walk about. If you step on flotant marsh, you will feel like you are standing on a water bed. As you step around, waves of grass spread around you. It is tempting to jump up and down, but the flotant is rarely thick enough and you usually end up falling through.
Though they may look the same, the overall ecology of flotant is very different from that of freshwater and intermediate marsh. By definition, flotant is floating, so it is never inundated with water and covered with sediments as the others are on occasion. However, some floating marshes don=t float all the time, lying on the bottom for part of the year - and maybe even being covered sometime by water.
When the water level drops and the floating marsh touches the bottom, there is danger that the roots will grow into the soil and, when the water rises again, the Afloating marsh@ stays attached and is drowned and may die.
Over time, as the floating marsh thickens, new and larger plants are able to grow on the mat. In some places, there comes a time when woody plants, especially Wax Myrtle (Myrica cerifera), can grow and be supported by the floating marsh. Even small cypress trees and the like can grow under some conditions. When this happens, the floating marsh is changing and will someday become swamp forest as the cypress and tupelo take over. Remember, this is a remarkable change since the area goes from being open marsh (water with no woody plants) to swamp (water with woody plants).
When Hurricane Andrew blew through south Louisiana, it passed over some of the best flotant marsh zones in the state. In some areas, terrible damage occurred. The flotant was ripped from the shore and the storm winds pushed it across the water where it bunched up in folds on the other shore. It looked like your bed spread does when you kick your covers off during the night and they bunch up at the foot of the bed. We thought that this would be devastating, but over the next couple of years the flotant spread back out and reunited with the other shore. Most of these marshes look today like they did before the hurricane.
However, there is danger when flood waters from rivers enter floating marshes. They may float the marsh, tear it into smaller pieces, and float it away until it enters estuaries and the Gulf. These conditions result is open expanses of water that may never, or will take decades to, become flotant again.
In order to have a truly balanced ecosystem in our coastal wetlands, we need to protect all its components - and flotant is a very important segment.