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Descriptive Information A marl prairie is a wet prairie that has a short hydroperiod and shallow soil. Saw grass is the tall, dominate plant of this ecosystem. During the hydroperiod, a floating layer of algae forms called periphyton. When the water recedes, this layer of periphyton dries on top and retains moisture beneath. This acts as an evaporation barrier until the next hydroperiod. Observation of the Layers We measured off an area of the prairie to observe closely. We used my notebook that is 10 1/4 inches long to measure a 20 1/2 by 20 1/2 inch rhombus. We observed six different grasses growing within this area. There were old roots and dead stalks of saw grass in the middle with another kind of bulbous-rooted green grass that we could not identify. Along the edge was an orange stringy parasitic vine called the Love Vine. It looked a lot like silly string was sprayed over the grass. Four other plants we could not identify were within this area. After observing the plant growth we began to pull apart the top layer of the soil which was the dried periphyton. The top layer of periphyton was thin, dried out, hard, and blackened. The periphyton covered approximately 90% of the surface being studied. The bottom layer of periphyton was very moist and fibrous. It had the consistency similar to tofu and crumbled. We could squeeze it into a small ball and wring water out of it like a sponge. Fifty percent of this layer was green and very moist while the other fifty percent was almost beige and not as moist. We found that the green and more moist substance was more common around the roots of the plants while the drier, whiter substance was in areas without plants. Through both of these layers there seemed to be no odor from the periphyton. The third layer was calciferous soil that was a lot more like sandy mud and had an earthy smell. This layer was very moist and among the roots of the plants we found many tiny snail shells, larvae, and eggs. We also found black beetle wings and 3 little red worms. We speculated that they were mostly found around the plants roots because that was were there was the most moisture. As the water holes disappear and the periphyton dries up, the living organisms move to follow the moisture deeper into the soil. The fourth layer was limestone that had a knobby surface from pinnacle rocks ranging from 1/4Ó to 1Ó from the rock bed. This is the base layer of the the Marl prairie. We could tell it was limestone because of the calciferous soil above it. We noticed water pooling in one corner of the area so we scooped out more mud. We found a ridge in the limestone and then realized there was a solution hole. A solution hole is a place in the limestone base that was weaken and washed away or eaten out by an acid. Water pools in these holes and creates a reservoir that supports the life within the marl prairie. We could reach down this particular hole up to our elbow (app. 1 1/2 feet). We could tell that it went deeper but the angles of the limestone ridges did not allow us to reach further. This lead to the completion of our dissection of the layers. It was a very dirty experience! |
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