Photosynthesis

The Big Picture

Carbon cycle

Process by which carbon moves from organic t inorganic compounds and back

Producers convert inorganic carbon (CO2) into organic carbon compounds (glucose)

Primary Consumers obtain organic compounds by eating producers

Secondary consumers obtain organic carbon by eating primary consumers

Cellular Respiration by producers and consumers return CO2 to atmosphere

In the natural carbon cycle, there are two main processes which occur Photosynthesis metabolism

 

Carbon in Ocean and Sediments

CO2 is slightly soluble Can be absorbed into water Some of the dissolved CO2 remains in the water, the warmer the water the

less carbon dioxide remains in the water Some CO2 is used by algae and phytoplankton through the process of

photosynthesis  Coral and shelled marine organisms take up CO2 from the water and

convert it into calcium carbonate When these organisms die pieces of shells/coral fall to ocean floor and make

sediments The carbonate sediments are constantly being formed and redissolved in

the bottom of the ocean Over long periods of time, the sediments may be raised up as dry land or

into mountains This type of sedimentary rock is called limestone The carbonates can redissolve releasing carbon dioxide back to the air or

water

Humans and the Carbon Cycle

Combustion of any type of fossil fuel, which may include oil, coal, or natural gas

Fossil Fuels formed thousands of years ago from plant or animal remains that were buried, compressed, and transformed into oil, coal, or natural gas

This carbon is said to be "fixed" in place and is essentially locked out of the natural carbon cycle

Humans intervene during by burning the fossil fuels During combustion in the presence of O2, CO2 and water

molecules are released into the atmosphere

Photosynthesis and Global Climate

CO2 makes up 0.03 percent of Earth’s atmosphere 300 parts per million

Greenhouse Effect CO2 traps heat from sun in Earth’s atmosphere (otherwise it would escape into space) Not a bad thing Keeps world climate warm enough to sustain life Keeps Earth 10% warmer than it would be without CO2

Currently CO2 in atmosphere is rising 360 parts per million

Burning fossil fuels Deforestation Natural Causes

Photosynthesis Cellular respiration Decomposition Volcanic eruptions Ocean/limestone

Global Warming Overall rise in Earth’s average temperature over a period of time