This company makes floating rafts using native wetland plants (unsure which species) to help soak up excess nutrients in various waterways and water bodies. Could work really well - the rafts are rented out. http://nelmac.co.nz/business/conservation-ecology/smartraft/
Hi Jesse, Rebecca Eivers did a PhD on this topic recently, I don't know a lot about it but here is a list of her publications: http://www.waikato.ac.nz/php/research.php?mode=show&author=3022374
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