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 nutrition nutrients a plant may be lacking. Many plants engage in symbiosis with microorganisms. Two important types of these relationship are Though nitrogen is plentiful in the Earth's atmosphere, relatively few plants harbour nitrogen-fixing bacteria, so most plants rely on nitrogen compounds present in the soil to support their growth. These can be supplied by mineralization of soil organic matter or added plant residues, nitrogen fixing bacteria, animal waste, through the breaking of triple bonded N molecules by lightning strikes or through the application of fertilizers. At least 17 elements are known to be essential nutrients for plants. In relatively large