Stop P[ing] in the Lake

There are a lot of things I am learning about this summer, but all of them come down to one pesky, little letter. P. It is the symbol for the element phosphorous. Phosphorous is usually a good thing. It is used to make ATP, which powers cells, and it is used to make DNA, which powers life. However, the phosphorous in the Red Cedar Watershed is a perfect illustration of the phrase “too much of a good thing.” The huge amount of phosphorous in the lake is what leads to the toxic blooms of cyanobacteria every summer. This phosphorous gets into the lake because of people.

As many of you reading probably know, farmers and homeowners spend good money to fertilize their fields and lawns. This fertilizer contains lots of phosphorous because plants find it absolutely delicious. The problem is the soil does too. Soil particles grab onto as much phosphorous as they can. When the rain comes and the soil gets washed away it takes the phosphorus with it. So soil and phosphorous follow the rain down into the waterways. Bam! Money down the drain.

Our research this summer is looking at how we can get the phosphorous back out of the lake in a way the will be useful again. Our first experiment is setting up a hydroponics* system on the lake. We are trying to see if the lake will be able to provide enough phosphorous for the plants to grow, while still produce a product that is safe for humans to consume. There are a lot of complicating factors to this project not the least of which are whether or not the plants will uptake heavy metals found in the lake or the toxins produced by the cyanobacteria. If either of these things happen it will make the plant unsafe to consume. However, if this experiment is able to produce a safe product it could be a viable method of lowering the amount of phosphorous in the lake.

Our second experiment is looking at the sediment of the lakes and streams in the area. Remember those traitorous soil particles that stole all of the phosphorous? Well, we are looking at collecting those particles where they accumulate in large quantities after floods. Then we will determine the sediment’s viability as a fertilizer. This experiment involves using varying amounts of soil and collected sediment to grow plants to see if there is improved growth from adding the sediment. If plants get happier growing in the sediment, then collecting the sediment could be another means of taking back the phosphorous that ran off of our fields and lawns.   

*Hydroponics is when you grow plants in a nutrient solution rather than in soil.