Biogeochemical Cycles

Biogeochemical Cycles

Carbon Cycle • Carbon moves from the atmosphere to plants.With the help of the Sun, through the process of photosynthesis, carbon dioxide is pulled from the air to make plant food. • Carbon moves from plants to animals as the herbivores eat the plants.. Animals that eat other animals get the carbon from their food too. • Carbon moves from plants and animals to the ground.When plants and animals die, their bodies, wood and leaves decay bringing the carbon into the ground. 1 2 3

Carbon Cycle 4) Carbon moves from living things to the atmosphere.Each time you exhale, you are releasing carbon dioxide gas (CO2) into the atmosphere. 5) Carbon moves from fossil fuels to the atmosphere when fuels are burned. 6) Carbon moves from the atmosphere to the oceans. The oceans, and other bodies of water, soak up some carbon from the atmosphere. 6 1 5 4 2 3

The Nitrogen Cycle Nitrogen enters the food chain by means of nitrogen-fixing bacteria and algae in the soil. This nitrogen which has been 'fixed' is now available for plants to absorbAmmonium Ions. The nitrogen-fixing bacteria form nitrates out of the atmospheric nitrogen which can be taken up and dissolved in soil water by the roots of plants. 1 2

The Nitrogen Cycle 3) Some bacteria convert nitrates into atmospheric nitrogen through a process called denitrification. This nitrogen can then be used again by nitrifying bacteria to fix nitrogen for the plants. 3 1 2

The Water Cycle The Sun's heat provides energy to evaporate water from the Earth's surface (oceans, lakes, etc.). The water vapor eventually condenses, forming tiny droplets in clouds. The water vapor eventually condenses, forming tiny droplets in clouds. When the clouds meet cool air over land, precipitation (rain, sleet, or snow) is triggered, and water returns to the land (or sea). 2 3 1

The Water Cycle 4) Some of the precipitation soaks into the ground.Some of the underground water is trapped between rock or clay layers; this is called groundwater. 5) But most of the water flows downhill as runoff (above ground or underground), eventually returning to the seas as slightly salty water. 6) As the sun heats up the ocean, water evaporated and condenses into clouds. 2 3 6 1 4 5

The Phosphorous Cycle 1 In living organisms, phosphorous is an essential component of cells. It forms parts of the chemical backbone of DNA and RNA, and makes up our cell membranes. With weathering, rocks release phosphorous in the form of phosphate. Phosphate enters the soil, where plants take it into their roots. 2

The Phosphorous Cycle 1 3) When animals eat plants, they incorporate the plants’ phosphorous into their own bodies. 4) When these animals die or release wastes, phosphorous becomes available to decomposers like fungi or bacteria. 5) The decomposers break down the tissues and release phosphate into the soil. 3 2 5 4

The Phosphorous Cycle 1 6) From the land, phosphorous enters rivers and streams by runoff, leaching, or in the cells of living organisms. 7) A single phosphorus atom might cycle between the water and bodies of organisms for an average of 100,000 years before it forms sediment. 3 2 6 7 5 4

Biogeochemical Cycles