Eutrophication and development, pollution from septic systems and sewers, sewage sludge spreading, and other human-related activities increase the flow of both inorganic nutrients and organic substances into ecosystems. Elevated levels of atmospheric compounds of nitrogen can increase nitrogen availability. Phosphorus is often regarded as the main culprit in cases of eutrophication in lakes subjected to "point source" pollution from sewage pipes. The concentration of algae and the trophic state of lakes correspond well to phosphorus levels in water. Studies conducted in the Experimental Lakes Area in Ontario have shown a relationship between the addition of phosphorus and the rate of eutrophication.
Plant to plant communication via mycorrhizal networks Plant to plant communication via mycorrhizal networks Plant to plant communication via mycorrhizal networks refers to connections through mycorrhizal networks that facilitate communication between plants of the same or different species. Mycorrhizal networks allow for the transfers of signals and cues between plants which influence the behavior of the connected plants by inducing morphological or physiological changes. The chemical substances which act as these signals and cues are referred to as infochemicals. These can be allelochemicals, defensive chemicals or nutrients. Allelochemicals are used by plants to interfere with the growth or development of other plants or organisms, defensive chemicals can