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 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.

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

An atmospheric high-pressure area that regularly forms in the central North Atlantic near the latitude of the Azores. Cold air sinks here, is warmed by the Gulf Stream, and is transported eastward tow [..]

Water that is pumped into special ballast water tanks in ships’ hulls for stabilization. Ballast water is transported over large distances, particularly by cargo vessels. Organisms in the water such a [..]

The biological variety of the Earth. This includes not only the species as such, but also the genetic variability present within the individuals of a species, or the variability of habitats in a regio [..]

Substances produced by living organisms such as plants, animals, fungi or bacteria are referred to as biogenic.