The Dells:
The Dells area bedrock itself consists of a 1.4 billion year old precambrian Granite pluton. A pluton is a mass of igneous rock, typically several miles in size. The Dells pluton intruded at a depth of between one and two miles. The overlying rock has since been eroded away, along with areas of the pluton itself, creating depressions (valleys, gulleys, washes etc.). Granite Creek fed into, and out of, one of the major depressions. With the construction of a dam in the early 1900's, water flow was trapped and Lake Watson (a reservoir) was formed. As the water deepened and vegetation around the lake changed with the (almost) constant supply of water, a marsh formed at the shallower south end of the lake.
The Marsh:
Marshes provide habitat for many types of plants and animals. Plants found here must be able to survive in wet environs that contain low oxygen levels. Many of these plants therefore have tubes within their stems called aerenchymas. This allows air to move from the leaves down into the root zone. Most marsh plants have rhizomes "mass of roots" which are used for underground storage and reproduction. Examples of these types of plants include sedges, cattails, papyrus and sawgrass.
Many aquatic animals, from fish to salamanders, can generally survive with low oxygen amounts in the water, obtaining oxygen directly from air. Marshes are important for their water quality protection functions, including the trapping of sediments and transfer of nutrients, as well as stormwater and floodwater retention. They also provide some of the largest "natural" openings found in nature and form a transition zone between aquatic and upland communities. The pH in marshes tends to be neutral to alkaline, where as bogs, and their accumulation of peat, are typically more acidic.
Different marsh types are categorized mainly by their location and salinity. These 2 factors greatly influence the range of animal and plant life that can survive in these environments. The three main types of marshes are salt marshes, freshwater tidal marshes and freshwater marshes. Since this is an inland freshwater lake with no tidal forces at work here, we will deal with freshwater marshes only from now on.
Freshwater marshes make up the most common form of wetland in North America. Below are some examples of freshwater marsh types. They are listed in order of driest to wettest.
Shallow Emergent Marsh:
These marsh types have mineral and/or shallow organic soils that are moist to saturated and only seasonally flooded. Abundant species found in these marshes include reed canary grass, bluejoint grass, rice cutgrass, bulrushes and Joe-pye weed.
Sedge Meadow Marsh:
These types of open wetlands are permanently saturated and only seasonally flooded. Soils are typically a shallow organic muck, although mineral soils could also be present. Beaked sedge, tussock sedge, bladder sedge and bristly sedge are dominant plant types in these meadows.
Cattail Marsh:
Common cattail and/or narrow-leaved cattail dominate these types of marshes. The muck and/or mineral soils found here are typically flooded with extremely shallow standing water throughout the entire year.
Deep Broadleaf Marsh:
Water depth in this type of marsh is typically over one foot year round, although in dry summers, some marshes may have only saturated soils. These types of marshes contain organic type soils, which aid in the growth of broad-leaved arrowhead, pickerelweed and giant bur-reed.
Wild Rice Marsh:
This type of marsh is dominated by wild rice. It has an organic soil substrate that is flooded with one to two feet of water throughout the summer.
Deep Bulrush Marsh:
This type of marsh thrives in open water. Meaning that they are found along the shores of lakes and ponds. Water depths here range from one to six feet. Generally, soft-stem and hard-stem bulrushes dominate this type of marsh.
Animal Life:
Many species of birds including sandhill cranes, ring-necked pheasants, blackbirds, swamp sparrows, American and least bitterns, common snipes and sedge wrens live within the different marshes. An abundance of mammals such as beavers, muskrats, minks, foxes and many others consider the various marshes home. Reptiles and amphibians that use these communities include common garter snakes, leopard frogs, green frogs and more.
1. A marsh is an ever changing ecosystem. Snow cover, changing water levels, temperature, varying amounts of sun, pollution and many other factors can alter its appearance. Describe how the marsh appears on the day of your visit.
2. What type of marsh do you believe this to be? Read "ALL" of the following definitions carefully.
3. (Google Earth will not help you with this one.) From the coordinates given (solid ground), to solid ground on the other side, is a span of 50 to 75 feet. Is the marsh growth nearer to you, more to the other side, or does it stretch all the way across?
4. List any animal life encountered on your trek to the coordinates.
Email your answers to the questions, to me, using the link in my profile only. If your answers are not received by me, your log will be deleted. Photos are accepted and appreciated as long as the answers are not pictured. You do not have to wait for confirmation from me before logging this cache as completed. Most of all……learn……and enjoy the view.