But I thought nutrients are good things, right? We all need nutrients to survive. Nutrients such as nitrogen and phosphorus in lawn fertilizer can make your grass grow, but they also cause problems once they wash into local streams and waterways. These nutrients can cause algae to grow in the water, which reduces the amount of oxygen in the water. Less oxygen in the water makes it harder for fish and other aquatic organisms, like crayfish, to survive.
So how do ponds and wetlands improve water quality? Wetlands improve water quality by filtering out pollutants before they reach local streams. What kind of nasty toxic pollutants are we talking about? Oddly enough, the major pollutants affecting local streams and the Bay are nutrients, such as nitrogen and phosphorus, and sediments. Wetlands can filter as much as 91% of the phosphorus and 86% of the nitrogen out of the water.
Sediments that are suspended in running water can also be removed by wetlands. As the flowing water enters a wetland, the water slows and the sediments settle out. Some wetlands can retain as much as 94% of the sediment (dirt) that flows into the wetland. Clean sediments are important because they contain air pockets that aquatic life depend upon to exist. These spaces provide habitat for aquatic organisms to lay their eggs and contributes oxygen that is essential for their survival.
Wondering what you can do at home to reduce pollution getting into local streams? Check out the green gardening page.