Carbon Cycle

Carbon Cycle Overview

Movement of molecules that contain carbon (CO2, glucose, CH4) between sources and sinks

Short Carbon Cycle

cycle that has quick processes - like fossil fuel & combustion

Long carbon cycle

cycles that are slow processes - like sedimentation and burial

Carbon Sink

reservoir that takes in more carbon than is releases (ocean, plants, soil)

Carbon Source

reservoir that releases more carbon than it takes in (fossil fuels, animal agriculture, deforestation)

Threats of Carbon Cycle Imbalance

1) Short vs long C cycle can lead to imbalances in

which sinks are storing carbon.

2) Increasing levels of C in atmosphere leads to global warming

Photosynthesis

- Occurs in plants, algae, and phytoplankton

- Removes carbon dioxide from the atmosphere and converts it to

glucose

- quick process

- CO2 sink

Glucose

biological form of C and stored chemical energy in the form of sugar

Cellular Respiration

- Done by plants, animals, and microbes to release stored energy

- Uses O2 to break glucose down and release energy

- Releases CO2 into the atmosphere CO2 source

- Cycles C between biosphere and atmosphere in balanced amount (no net C increase in atmosphere)

Direct Exchange

CO2 moves directly between atmosphere and ocean by dissolving into and out of ocean water at the surface

- can go both ways, currently higher into ocean due to high atmospheric CO2, leading to ocean acidification

Algae and Phytoplankton

takes CO2 out of the ocean and atmosphere through photosynthesis

- coral and mollusks take CO2 out of ocean to make CaCO3 exoskeletons

Sedimentation

CaCO3 precipitates out as sediment and settles on ocean floor

Burial (long term carbon resevoir)

1) slow, geologic process that stores C in underground sinks like sedimentary rock or fossil fuels. Sediments are compressed by weight of overlying rock

or water

2) over long periods of time, pressure of water compresses C-containing sediments on ocean floor into sedimentary rock

- ex. limestone, sandstone

Fossil Fuels

formed from fossilized remains of organic matter into coal; their

decomposition produces natural gas (CH4)

Extraction & Combustion

- digging up or mining fossil fuels and burning them as an energy source, releases CO2 into atmosphere

- Burial takes far longer than extraction and combustion, which means they increase concentration of atmospheric CO2