Eutrophication is the the scientific term for a dense growth of plant life& the lack of oxygen that coincides with it. It happens, usually when a run-off of land occurs, when the soil becomes so rich and fertile that the abundance of plant life restricts oxygen supplies, thus causing animals to suffocate around that dense area of plants. Matter can neither be, created nor destroyed, but our water is preserved with the water cycle. Although, I dont know how water replenishes itself, like when we drink it& it infuses with our body; all ice becomes water, all water becomes vapor, all vapor forms together into a cloud& then rain is released, this is when it either adds to our lakes\rivers or turns to ice in the mountains. At this point our mountains produce run-off, that is melted ice, that flows to our lacks and rivers& the water in those lakes and rivers have more liquid evaporated while the ice is melting. I know that the water's matter has no more created and the water we convert cant go back in the cycle.
