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.

Floating wetlands were first tested in retention ponds, the kind often located near developments to hold stormwater, to see if they filtered pollution. “The front end of it was, ‘Will they work? How well do they work? And what plants should we recommend?’” says Sarah White, an environmental toxicologist and horticulturalist at Clemson University who has worked on floating wetlands since 2006. Partnering with researchers at Virginia Tech, White found that the wetland plants she tested not only did well in ponds with lots of nutrient pollution, but the adaptable, resilient plants actually thrived. She did not always choose native plants, opting instead for those that would make the islands more attractive, so that more urban planners would use them.