Some scientists are now exploring how to optimise the design of floating islands – probing, for instance, which plants do the best job of removing pollutants. Gary Burtle, an aquaculture specialist at the University of Georgia, thinks we can get even more out of these artificial wetlands by seeding the rafts with plants that are of commercial value, such as lettuces and herbs. Burtle is screening a number of potential plant candidates – if he finds one that grows well on a floating island, we may soon see constructed wetland systems that “give us a little bit more return”, he says, producing saleable crops while purifying the water.
Meanwhile, the removal of contaminants not only improves the water itself, but also helps to foster a healthier ecosystem. Clearer water allows light to penetrate deeper, encouraging the growth of various aquatic plants, which produce oxygen and become part of the food chain, supporting larger populations of fish and other animals. “You end up with a waterway that can be abundant,” Kania says, “that can be verdant even at depth.” The organic debris that attaches itself to the underside of a floating island also becomes a source of food for fish and other aquatic organisms, and the island itself provides new habitat for birds.
“The concept of how to get back to a healthy waterway,” Kania says, “is very simple: nature’s wetland effect.” All we have to do is simulate it.