The carbon cycle, one of Earth's biogeochemical cycles Click on image for full size (191 Kb) University Corporation for Atmospheric Research

As a part of biogeochemical cycles, certain elements move through both living and non-living components of the Earth system. The living parts of the Earth system comprise the biosphere, while the non-living parts of the Earth include the hydrosphere, atmosphere, cryosphere, and geosphere. The same individual elements are recycled over and over in different parts of the Earth through biogeochemical cycles.

For example, carbon may be taken from the air (atmosphere) into the ocean surface (hydrosphere) where it is utilized by photosynthesizing plankton (biosphere). Carbon is also stored long-term in rocks (geosphere) and fossil fuels like oil, coal, and natural gas (biosphere). This long-term storage that sequesters an element from the rest of the cycle for some amount of time is called a “sink”. When fossil fuels are burned, carbon that had been sequestered underground is sent into the air (atmosphere) as carbon dioxide, a greenhouse gas.

All chemical elements that are found in living things are a part of biogeochemical cycles, the most common of these being carbon and nitrogen.

Find out more about two common biogeochemical cycles!

• The carbon cycle
• The nitrogen cycle

In recent decades these biogeochemical cycles have been changing because of how humans are changing the biosphere (see links below). Less forests, more factories and cars that burn fossil fuels - these changes to biogeochemical cycles are causing more greenhouse gases in our atmosphere and, thus, more global warming.

The carbon cycle, one of Earth's biogeochemical cycles NCAR

There are a few types of atoms that can be a part of a plant one day, an animal the next day, and then travel downstream as a part of a river’s water the following day. These atoms can be a part of both living things like plants and animals, as well as non-living things like water, air, and even rocks. The same atoms are recycled over and over in different parts of the Earth. This type of cycle of atoms between living and non-living things is known as a biogeochemical cycle.

All of the atoms that are building blocks of living things are a part of biogeochemical cycles. The most common of these are carbon and nitrogen.

• The carbon cycle
• The nitrogen cycle

Tiny atoms of carbon and nitrogen have no legs to walk, no bicycles, cars, or airplanes. Yet they can travel around the world as a part of biogeochemical cycles. So, how do these little things move around the planet? Here’s an example: An atom of carbon is absorbed from the air into the ocean water where it is used by little floating plankton doing photosynthesis to get the nutrition they need. There is the possibility that this little carbon atom becomes part of the plankton’s skeleton, or a part of the skeleton of the larger animal that eats it, and then part of a sedimentary rock when the living things die and only bones are left behind. Carbon that is a part of rocks and fossil fuels like oil, coal, and natural gas may be held away from the rest of the carbon cycle for a long time. These long-term storage places are called “sinks”. When fossil fuels are burned, carbon that had been underground is sent into the air as carbon dioxide, a greenhouse gas.

Recently, people have been causing these biogeochemical cycles to change (see links below). When we cut down forests, make more factories, and drive more cars that burn fossil fuels, the way that carbon and nitrogen move around the Earth changes. These changes add more greenhouse gases in our atmosphere and this causes more global warming.

The carbon cycle, one of Earth's biogeochemical cycles NCAR

There are a few types of atoms that can be a part of a plant one day, an animal the next day, and then travel downstream as a part of a river’s water the following day. These atoms are found in living things like plants and animals. They are also found in non-living things like water, air, and rocks. The same atoms are recycled over and over in different parts of the Earth.

All of the atoms that are building blocks of living things are a part of these cycles. The most common of these are carbon and nitrogen. Find out more about how carbon and nitrogen move around the Earth!

• The carbon cycle
• The nitrogen cycle

Tiny atoms of carbon and nitrogen have no legs to walk, no bicycles, cars, or airplanes. Yet they can travel around the world. So, how do these little things move around the planet? Here’s an example: An atom of carbon is absorbed from the air into sea water. There, it is used by little floating plankton as they get the nutrition they need using the Sun’s energy to make food. This little carbon atom might become part of the plankton’s skeleton, or a part of the skeleton of a fish who eats it. Then it may become part of a sedimentary rock when the living things die and their bones are left behind. Carbon that is a part of rocks and fossil fuels like oil, coal, and natural gas may be held away from the rest of the carbon cycle for a long time. When fossil fuels are burned, carbon that had been underground is sent into the air as carbon dioxide, a greenhouse gas.

Recently, people have been causing these cycles to change (see links below). When we cut down forests, make more factories, and drive more cars that burn fossil fuels, the way that carbon and nitrogen move around the Earth changes. These changes add more greenhouse gases in our atmosphere and this causes more global warming.