For the history of modern humans, see History of the world. For the history of life on Earth, see Evolutionary history of life. The history of Earth concerns the development of the planet Earth from its formation to the present day. Nearly all branches of natural science have contributed to the understanding of the main events of the Earth's past. The age of Earth is approximately one-third of the age of the universe.
Eutrophication is one of the main problems caused by an overuse of fertilizers and an excess of manure and sewage. These wastes enter the ecosystem and generally leach away from residential, business, and agricultural sites. The first part of eutrophication is the hyper-acceleration of aquatic life growth.
Eutrophication arises from the oversupply of nutrients, which induces explosive growth of plants and algae which, when such organisms die, consume the oxygen in the body of water, thereby creating the state of hypoxia. According to Ullmann's Encyclopedia, the primary limiting factor for eutrophication is phosphate..ultural eutrophication also occurs when excessive fertilizers run into lakes and rivers. This encourages the growth of algae (algal bloom) and other aquatic plants. Following this, overcrowding occurs and plants compete for sunlight, space and oxygen.