The Carbon Cycle

Carbon Carbon (C) is a nutrient that is essential to all living things. Carbon moves through an ecosystem in a cycle called THE CARBON CYCLE.

The Carbon Cycle Carbon is found in carbon dioxide in the air. All producers undergo the process of PHOTOSYNTHESIS, whereby they use carbon dioxide and water and energy from the sun to produce food needed for their survival. 6 CO2 + 6 H2O + energy C6H12O6 + 6 O2 Carbon dioxide + water + energy produces glucose + oxygen

CELLULAR RESPIRATION The producers are then eaten by herbivores. Herbivores obtain glucose by eating the producers and use it in CELLULAR RESPIRATION. This process breaks down the glucose to give the herbivores energy they need for their life processes. C6H12O6 + 6 O2 6CO2 + 6H2O + energy glucose + oxygen produce Carbon dioxide + water + energy

Cellular respiration This process releases carbon dioxide back to the atmosphere. Both plants and animals undergo cellular respiration.

Decomposers Decomposers break down dead plant and animal matter and waste. In the decaying process, decomposers release carbon dioxide back into the atmosphere

Fossil Fuels organic (carbon-containing) wastes are not easily broken down. Over long periods of time, this matter builds up in the Earth’s crust and is converted to rock and FOSSIL FUELS. COAL, PETROLEUM AND NATURAL GAS Carbon is trapped in fossil fuels, but it is released through weathering and the burning of fossil fuels.

Carbon Cycle in the Oceans Oceans and lakes tend to hold 50 times more carbon dioxide than the atmosphere. Carbon dioxide from the air dissolves in water to form carbonic acid. Water plants use the carbonic acid, as a source of CO2 for photosynthesis. The aquatic producers are eaten by herbivores which return the carbon dioxide to the water through CELLULAR RESPIRATION

DECOMPOSERS Decomposers feed on waste and dead plants and animals. The decaying process will also return carbon dioxide to the water.

Calcium carbonate Some aquatic animals use dissolved carbon and calcium to form calcium carbonate, which is used to make shells. When these animals die, their shells sink to the bottom of the ocean and form layers of sediment, and eventually rock. The carbon is stored in the rock, until it gets broken down (weathered) and then returned to the water and atmosphere to restart the cycle.

The Carbon cycle Dissolved carbon dioxide in oceans can return to the atmosphere, and atmospheric carbon dioxide can be dissolved in the ocean.

Human Impact A perfect cycle is when carbon returns to the atmosphere as quickly as it is removed. Recently humans have been releasing carbon from reservoirs (through mining, and burning fossil fuels and forests) at a much faster rate than has ever occurred.

Human Impact Also, clearing of forests (clear cutting) eliminates the ability of producers (trees) to use the CO2 for photosynthesis More CO2 is being produced, and less is being consumed by the trees in photosynthesis The buildup of CO2 is thought to cause Global Warming