Hey, Is That A Marsh, Swamp, Bog, Fen or Bayou?

Fountainebleu State Park, Louisiana

On the shore of Lake Pontchartrain

November 22, 2019

I have arrived in Louisiana. The first thing I noticed crossing over from Mississippi was water - lots of water. And resulting humidity. It’s November 22 and the humidity here is 74 percent (The temperature coincidently is 74 degrees). I can feel the humidity. Summer must be brutal in these parts.

Not wanting to seem like too much of a tourist (although did ask someone the difference between jambalaya and gumbo - rice vs soup I was told), I investigated the difference between swamps and bayous. Turns out it’s not quite that easy. In order that you might know for future reference, here is what I learned.


One of the defining characteristics of a marsh is that it is consistently flooded with water from one source or another. Many marshes are freshwater, and exist in areas with poor drainage—along stream beds, lakes, and ponds. Because the soil is consistently wet from flooding, it is also extremely nutrient-rich, and can support a wide variety of plant and animal life.

Marshes may also be tidal; saltwater marshes can be found along the oceans, and are saturated every time the tide comes in.

While some marshes are also fed by groundwater, all receive most of their soil saturation from surface water like tides and rains. Some marshes, such as those that form when potholes and large depressions in the earth catch melting snow, can be temporary. Most of the vegetation in marshes are along Two the lines of cattails and reeds.


Swamps are defined by the trees which have adapted to live in standing water or constantly saturated dirt. This waterlogged dirt is high in nutrient content. Trees like the cypress and some varieties of maple and white oak can survive in these wet areas that would rot the roots of other trees. Wetlands that support woody plants like the buttonbush or the swamp rose are considered shrub swamps. Mangroves are shrubby trees that thrive in this wet environment, doing so well that there is a sub-type of swamp called the mangrove swamp.


Bogs are clearly defined by their lack of nutrients and their relative inability to support large plant life. A bog is created over hundreds or thousands of years, formed when plant matter decays in a lake and fills it. This creates layers and layers of peat, which is often drained before being harvested and burned as a heat source or used as insulation. Bogs are freshwater, and in spite of the large amounts of decaying plant matter, they are very poor in nutrients because of the slow rate of decay. Most of the plant life around a bog is along the lines of fungi, mosses, and small shrubs. Many carnivorous plants, such as the pitcher plant and the sundew, have evolved in bogs to combat the low nutrient levels in the soil. Bogs are infinitely valuable in their ability to store carbon, removing this greenhouse gas from the atmosphere.


Fens are very similar to bogs, and can contain much of the same decaying plant matter and peat. The difference is how they are formed. Fens are created by a water table that is very close to the surface and keeps the ground saturated. The water level in a fen can rise and fall slightly with changes to the water table, but fens are characterized by having flowing water year around. They tend to have a higher nutrient content than bogs and can support a wider variety of plant life. However, if the decaying plant matter reaches too high a level, it can strangle the nutrient levels of the fen and turn it into a bog.


Bayous are defined as relatively small, sluggish waterways through lowlands or swamps. They generally have a slow, almost imperceptible current flow. Bayous are sometimes also defined as slow moving streams crisscrossing Louisiana. They are marshy outlets of a lake or a river.  The word “bayou”  was first used by the English in Louisiana and is thought to originate from the Choctaw word “bayuk”, which means “small stream." The first settlements of Bayou Tech in Louisiana, and other bayous, were by the Cajuns, and that is why bayous are associated with Cajun culture.

You thought I wouldn’t include a music video? Wrong!

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