How Floating Wetlands Are Helping to Clean Up Urban Waters. As cities around the world look to rid their waterways of remaining pollution, researchers are installing artificial islands brimming with grasses and sedges. The islands’ surfaces attract wildlife, while the underwater plant roots absorb contaminants and support aquatic life. Three thousand square feet in total, these artificial wetlands are part of an effort to clean up a portion of a river that has long served the interests of industry. This floating wetland project is one of many proliferating around the world as cities increasingly look to green infrastructure to address toxic legacies. In the United States, researchers are conducting experiments in Boston and Baltimore as well as in Chicago, each team sharing best practices with the other to maximize the ecological benefits of their systems. The Canadian government and local municipalities are allotting more funding for innovative projects. Floating wetlands are also multiplying in the United Kingdom, and studies to quantify additional benefits continue in Australia and Brazil. Floating wetlands filter contaminants and take up excess agricultural nutrients that can lead to algal blooms and dead zones. Like natural wetlands, floating versions provide a range of ecosystem services. They filter sediment and contaminants from stormwater, and laboratory experiments show that some plants have the ability to lock up some chemicals and metals found in acid mine drainage. These systems take up excess agricultural nutrients that can lead to algal blooms and dead zones, and recent research suggests they could be used to reduce manmade contaminants that persist in the environment. Though it’s difficult to quantify the exact benefits these systems offer, and they have limitations as a tool in remediating polluted waterways, they could provide another option, researchers say.                     https://e360.yale.edu/features/floating-wetlands-cities-pollution