Cultural eutrophication found where rivers empty into oceans. Nutrient pollution is a major cause of algal blooming however, the excess nutrients also facilitate the growth of other aquatic plants. Following this, overcrowding occurs and plants compete for sunlight, space, and oxygen. Overgrowth of water plants also blocks sunlight and oxygen for aquatic life in the water, which threatens their survival. Increased competition for the added nutrients can cause potential disruption to entire ecosystems and food webs, as well as a loss of habitat, and biodiversity of species. The Experimental Lakes Area (ELA), Ontario, Canada is a fully equipped, year-round, permanent field station
Plant tolerance to herbivory Using simulated herbivory allows for the control of environmental variables, but replicating natural herbivory is difficult, causing plants to respond differently from imposed and natural herbivory (Tiffin and Inouye 2000). Growing plants in the control environment of the greenhouse may also affect their response as it is still a novel environment to the plants. Even if the plots are grown in natural settings, the methods of excluding or including herbivores, such as using cages or pesticides, may also affect plant tolerance (Tiffin and Inouye 2000). Lastly, models have predicted that manipulated herbivory may actually result in less precise estimates of