All of the following are commonly used to deal with the side effects of eutrophication in lakes EXCEPT applying herbicides to kill nuisance plants applying herbicides to kill nuisance plants A dredging out lakes to deepen them dredging out lakes to deepen them B pumping oxygen into the lowest layers of water pumping oxygen into the lowest layers of water C introducing insects that eat certain nuisance plants introducing insects that eat certain nuisance plants D adding nitrates