All biological organisms require certain nutrients to live. Plants require carbon, hydrogen, and oxygen from air and water, as well as nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, copper, zinc, nickel, chloride, boron, and molybdenum from soil. Animals require a few others. Conversions and transformations of nutrients in the environment result from chemical reactions, biological activity, or both.
The ocean is a “carbon sink,” which means that it removes CO2 (carbon dioxide) from the atmosphere. The ocean currently absorbs about one-third of the CO2 released by the burning of fossil fuels.
However, beyond a certain level of atmospheric CO2, the ocean can no longer act as a carbon sink without it having a negative impact on marine life. When CO2 dissolves in seawater, it leads to decreased pH levels. The ocean becomes less alkaline. This is referred to as ocean acidification.
Over Earth’s 4.5 billion-year history, tectonic upheavals and colliding plates formed mountain ranges and carved out basins. Forces of erosion and weathering have been at work to break down these landforms. Records of these processes are imprinted on the land and define distinctive landscapes around the United States and in its national parks.