1.9 Carbon Cycle

(Sec 4.2 pg 86-91)

VIDEO: http://www.youtube.com/watch?v=2D7hZpIYlCA

• Carbon (C) is the key element in all living organisms (our Earth is full of carbon-based life forms).

• Carbohydrates, lipids (fats) and protein are all organic compounds.

• The carbon cycle involves a lot of oxygen too; here are some important features of the cycle:– Carbon reservoirs = anything that has the ability to store

C for a long time. (forests, oceans, fossil fuels, etc)

• The carbon cycle involves a lot of oxygen too; here are some important features of the cycle:– Carbon sink = something that actively absorbs more C

than it releases. (growing forest, oceans, etc.)

• The carbon cycle involves a lot of oxygen too; here are some important features of the cycle:– Carbon source = something that releases stored C. (a

burning forest, decaying matter, burning fossil fuels, etc.)

• The carbon cycle involves a lot of oxygen too; here are some important features of the cycle:– Carbon cycle = cycling of carbon through the

environment (Fig. 2 p.87, and in your Data Pages) – Photosynthesis and respiration are responsible for most

C recycling.

• Oceans are very significant carbon reservoirs/sinks. They store C two ways: – CO2 from atmosphere is dissolved in the water and used

by aquatic producers in photosynthesis

• Oceans are very significant carbon reservoirs/sinks. They store C two ways: – Dissolved CO2 reacts with water to form calcium

carbonate (CaCO3), which is used to make shells and other structures by marine organisms (e.g. sponges, crabs)

• Fossil fuels represent a significant portion of global C reservoirs.

• They represent the decayed C from organisms that have died and were buried before they were fully decomposed.

• Fossil fuels include coal, oil, and gas

• Burning fossil fuels releases CO2, which is a greenhouse gas (GHG).

• GHG’s collect in the atmosphere and trap heat from the Sun inside the atmosphere, leading to the greenhouse effect (Fig.3 p.88).

• The greenhouse effect is responsible for life as we know it on Earth (it keeps the planet warm), but many believe increasing GHG levels is causing climate change.

• Respiration that occurs with oxygen present is called aerobic respiration.

• This is the most common type of respiration, and is another term for cellular respiration.

• Respiration that happens without oxygen is called anaerobic respiration or fermentation.

• It is carried out by some bacteria. These organisms release methane, ethyl alcohol, or acetic acid instead of CO2.