Part 2: WE HAVE A NUTRIENT PROBLEM
In our last article, we learned that our lakes are green because of algae but that is only part of the problem. While algae blooms can occur naturally, many scientists are now telling us that they are happening more and more, because of us. Algae blooms are caused by an excess of nutrients found in the lake, as well as the warm sunny summer days. While we cannot do much about the weather, and as much as we would like our summers longer, we can do a lot about the amount of nutrients going into our lakes.
More nutrients, like Phosphorus and Nitrogen, are not a good thing because lakes have a very delicate balance of nutrients that keep their particular residents well fed year round. Introducing excess nutrients disrupts this balance.
So where do all these excess nutrients come from? Sometimes it comes naturally from the soil or from decaying plant matter, but far too often, it is because of us. For example, think about those beautiful green lawns you see out there. Do you use fertilizer to keep yours looking nice? Well, if you do, that’s one place where excess nutrients could come from! The nutrients you are using to keep your lawn green can make the lakes green as well if it gets to the lake. It is hard to imagine that we can have an impact on a water body the size of a lake but we do.
Scientists at the University of Regina have shown that water runoff into our lakes has a lot to do with the excess nutrients getting there. The lake kind of acts as a collecting bed for these nutrients and chemicals, because water flows across the ground from snowmelt and heavy rains and collects in lakes. In the Lower Qu’Appelle Watershed what we do on the land influences what happens to our water. According to the “State of the Watershed” Report, the Lower Qu’Appelle Watershed is stressed.
But lawn fertilizer is just one of the many sources of nutrients. In the city, or at the cottage, wastewater-treatment facilities and sewage can send nutrients directly into our lakes. That’s why Regina upgraded their waste water treatment facility. For Agriculture, nitrogen and phosphorus are indispensable nutrients used for growing crops. Every year, farmers apply millions of tons of chemical fertilizers and manure rich in nitrogen and phosphorus on their soil to improve crop yields; these two nutrients are essential for food security but also part of the excess nutrient problem. Livestock and hog production wastes can also be a source. We all produce a lot of extra nutrients.
Mother Nature does have its own defences against nutrient runoff and they are called wetlands. Potholes and marshes not only provide habitat for wildlife and reduce drought and floods; they are an essential part of Earth’s water filtration system. Wetlands store water so that the excess nutrients can be removed by the growth of wetland plants. Draining wetlands releases all those nutrients and creates a path for more nutrients to flow into our lakes. Sadly, we are destroying a lot of wetlands, draining them for agriculture and urban development and removing nature’s filtration system.
The more wetlands we drain the more nutrients we send into our lakes. Controlling excess nutrient is challenging because the nutrients can come from many different sources and is affected by how we use the land. Identifying what the main sources are is key to fixing the problem and what we’ll be talking about in our next article....
Watch for Part 3 “Measuring the Source”.
