Embedded Files
Click the photo to access the project site:
One of the most important issues affecting water quality in the Saginaw Bay Watershed is the presence of phosphorus. Excess phosphorus in water can lead to eutrophication, which begins with high growth rates of algae and other aquatic plants. Plant and algae decay then follows which causes a condition known as hypoxia (low dissolved oxygen). Muck formation can also be part of this process. Overall, this process leads topoor conditions for aquatic life and discourages recreational use of the water.
Phosphorus in the bay can come from several sources throughout the watershed including lawn and agricultural fertilizers, faulty septic systems, and large farm manure run-off. Phosphorus can be present as soluble reactive phosphorus(SRP). SRP is most typically in the form of hydrogen phosphate (HPO4-2), and it is available for direct use as a nutrient by plants and algae. Phosphorus can also be present in non-reactive forms that can be soluble in water or insoluble but suspended as particles in water. The sum of these forms of phosphorus is known as total phosphorus(TP). TP will convert to SRP over time as part of the natural phosphorus cycle. SRP and TP concentrations are commonly measured in water quality studies.
We need to understand more about sources of phosphorus, how it is transported, and where it may be stored in order to develop ways to solve the problem. There are two things that we don’t understand very well about phosphorus. It was once assumed that phosphorus would not move withgroundwater to field tiles because it would adsorb to clay and become immobile. However,some ecosystem models andpreliminary data suggest that phosphorus may now be seeping out throughfield tilesdue to changing soil conditions or increased tiling densities. Once phosphorus isinthe water causingan increase in algae and plant growth, we know little about how much is distributed in the plant and algae tissues. It has been suggested thatremoving the plants and algae will help restore the water by taking phosphorus away. Furthermore, it is thought that the tissues could be useful as a slow release field fertilizer that would minimize phosphorus in runoff or tile seepage.
The student researchers on this project will test the following two hypotheses:
1. Water draining by field tile contains a detectable amount of phosphorus (our detection limit is 0.005 mg/L) making it a potential concern.
2. The tissues of nuisance algae, muck, and invasive plants (such as phragmites) contain detectable amounts of phosphorus making removal a potentially beneficial activity.
This project will involve sampling in fields, rivers, and near-shore areas of Saginaw Bay followed by lab measurements of phosphorus (SRP and TP) in a variety of samples types (water, soil, and plant tissues). The results will be used to determine if the hypotheses are correct or if they need to be modified.The outcome of the project will be important knowledge that will inform resource managers on the effects of field tiling and also on potential mitigation methods for lowering phosphorus levels in the water.
The link to their site is:
Page updated
Report abuse