The earthly cycles of water, nitrogen, phosphorus, sulphur and carbon
All elements of the periodic chart can be found on earth in many different forms. The elements may differ in physical form and be either solid, liquid or gaseous, or they may differ in their overall form as a result of chemical reactions they have undergone.
Water will circulate primarily between the oceans, the continents and the atmosphere. These are the main parts of the hydrological cycle, also known as the water cycle. As the water cycle takes place, water can be found on earth in different physical states: in solid, liquid and gaseous form.
Nitrogen is a substance that is essential for all life on earth. Most nitrogen can be found in air in the gaseous form, but nitrogen can also be found in water and soil in different forms. There, it will be decomposed by bacteria and absorbed by plants and animals.
Phosphorus is an element that can be found in the DNA structures of organisms. Phosphorus is the main limiting growth factor for ecosystems, because the phosphorus cycle is mainly concerned with the movement of phosphorus between continents and the ocean. Contrarily to the nitrogen cycle there is no gaseous phase found in air.
Sulfur is present within every organism in small quantities, mainly in the amino acids. It can be found in air as sulfur dioxide and in water sulfuric acid and in other forms. The sulfur cycle is not only concerned with natural processes, but also with human additions through industrial processes.
Carbon is a very important element, as it is a building block of all organic matter, including parts of the human body, such as proteins, fats, DNA and RNA. Carbon can mainly be found in air as carbon dioxide, but as a part of the carbon cycle it may also be dissolved in water or stored in sediments.
Also available: info on matter cycles and environmental problems