a pale green mineral the major source of phosphorus
Phosphorus At 0.099%, phosphorus is the most abundant pnictogen in the Earth's crust but it is not found free in nature; it is widely distributed in many minerals, mainly phosphates.[7] Inorganic phosphate rock, which is partially made of apatite (a group of minerals being, generally, pentacalcium triorthophosphate fluoride (hydroxide)), is today the chief commercial source of this element. According to the US Geological Survey (USGS), about 50 percent of the global phosphorus reserves are in the Arab nations.[30] Large deposits of apatite are located in China, Russia, Morocco,[31] Florida, Idaho, Tennessee, Utah, and elsewhere.[32] Albright and Wilson in the UK and their Niagara Falls plant, for instance, were using phosphate rock in the 1890s and 1900s from Tennessee, Florida, and the Îles du Connétable (guano island sources of phosphate); by 1950 they were using phosphate rock mainly from Tennessee and North Africa.[33]
Everglades Further problems with the environment arose when a vast algal bloom appeared in one-fifth of Lake Okeechobee in 1986, the same year cattails were discovered overtaking sawgrass marshes in Loxahatchee National Wildlife Refuge. Scientists discovered that phosphorus, used as a fertilizer in the EAA, was flushed into canals and pumped back into the lake.[143] When the lake drained, the phosphorus entered the water in the marshes, changing the nutrient levels. It kept periphyton from forming marl, one of two soils in the Everglades. The arrival of phosphorus allowed cattails to spread quickly. The cattails grew in dense matsâ€”too thick for birds or alligators to nest in. It also dissolved oxygen in the peat, promoted algae, and prohibited growth of native invertebrates on the bottom of the food chain.[144]