The gaseous shell that surrounds the Earth. Its major compo­nents are nitrogen and oxygen. The carbon dioxide content is only around 0.038 per cent. This gas, however, apart from water vapour, is the [..]

Microorganisms that produce energy for their metabolism from chemical compounds are called chemoautotrophic. Chemoautotrophic organisms are distinguished from photoautotrophic organisms such as plants [..]

The wearing away of fertile and humus-rich topsoil by the natural physical forces of water and wind. Human communities can worsen soil erosion through their farming activities. After harvesting, harro [..]

A large proportion of the carbon dioxide that enters the atmosphere through combustion processes is taken up by the ocean, causing the seawater to acidify. Strictly speaking the seawater remains basic [..]

A large proportion of the carbon dioxide that enters the atmosphere through combustion processes is taken up by the ocean, causing the seawater to acidify. Strictly speaking the seawater remains basic [..]

A massive reproduction event by algae and other single-celled organisms in rivers, lakes or the ocean triggered by an increased input of nutrients. Algal blooms are a natural phenomenon. As a result o [..]

A massive reproduction event by algae and other single-celled organisms in rivers, lakes or the ocean triggered by an increased input of nutrients. Algal blooms are a natural phenomenon. As a result o [..]

Oxygen-rich, highly saline ocean water that sinks to the bottom in the Antarctic and flows northward along the bottom around the globe, all the way to the North Atlantic.

Oxygen-rich, highly saline ocean water that sinks to the bottom in the Antarctic and flows northward along the bottom around the globe, all the way to the North Atlantic.

Changes in nature caused by humans, such as the increase of CO2 concentrations in the atmosphere, are referred to as anthropogenic.