WCC: Carbon Cycle - Factors Driving Change in the Magnitude of Carbon Stores Over Time Flashcards
Factors driving change in the magnitude of carbon stores over time and space including flows and transfers at plant, sere and continental scales: photosynthesis, respiration, decomposition, combustion, carbon sequestration in oceans and sediments, weathering.
Chemical equation for photosynthesis
6CO2 + H2O -> 6O2 + C6H12O6
Chemical equation for respiration
C6H12O6 + 6O2 -> 6CO2 + 6H2O
Describe a lithosere
- Exposed rock is vulnerable to weathering
- Weathering releases carbon, often dissolved in water
- Lichen and mosses grow on the bare rock and a carbon exchange starts to take place
- As organic matter is added a soil develops that can support a wider range of plants
- Wildlife becomes abundant
- Climatic climax reached
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What have been the maximum and minimum amounts of carbon stored in the atmosphere throughout history? When did they occur?
Atmospheric CO2 possibly reached over 7,000 ppm in the Cambarian period around 500 million years ago. Its lowest concentration has been over the last 2 million years during the Quaternary glaciation when it sank to about 180 ppm.
Where is atmospheric carbon measured on Earth?
At the Mauna Loa Observatory on Hawaii
How has the magnitude of carbon stored in the atmosphere changed since the Industrial Revolution?
Global annual mean concentration of CO2 has increases from 280 ppm in 1958 to 400 ppm in 2015 - a percentage increase of 143% in 30 years
The present concentration of atmospheric CO2 is higher than is has been for how many years?
At least 800,000 years, buts it’s likely the highest that its been in the past 20 million years.
What sources is the recent rise in atmospheric CO2 being attributed to?
Anthropogenic sources, mainly burning fossil fuels and deforestation
What is the name of the graph showing changing concentration of atmospheric CO2?
the Keeling curve
As well as readings from MLO, name another method of measuring atmospheric CO2 over time. How does it work?
Studying the CO2 in trapped ice cores from Antarctica and Greenland can give a proxy measure of the CO2 in the atmosphere at the time is was laid down, allowing the change over time to be seen
When did the daily average of atmospheric CO2 at MLO first exceed 400 ppm?
May 2013
At what rate is atmospheric CO2 currently rising?
2 ppm/year
How is the rate of increase of atmospheric CO2 changing?
It is accelerating
Describe how the magnitude of soil carbon stores can change over time.
Carbon can remain in soils for hundreds of years, however deforestation, land use change and soil erosion can release the stored carbon very rapidly
How is carbon uptake from vegetation changing over space?
Carbon uptake is increasing in the middle and high latitudes of the northern hemisphere, but decreasing in the tropics and southern hemisphere
What is a major reason why less carbon is being absorbed in the tropics and southern hemispere?
Drought
What is photosynthesis?
The process whereby organisms use light energy from the sun to combine CO2 from the atmosphere with water to form carbohydrates which store energy.
Word equation for photosynthesis
Carbon dioxide + water + sunlight -> glucose + oxygen
Which organisms photosynthesise?
Terrestrial plants
Phytoplankton
Photosynthetic algae
Bacteria
What is respiration?
A chemical process that occurs in cells where oxygen from the atmosphere is used to convert glucose into energy to be used in an organism’s life functions
What are the by-products of respiration?
Carbon dioxide and water
Which organisms respire?
All organisms - animals, plants, photosynthetic algae and bacteria
Is there a balance between photosynthesis and respiration? How does this impact the carbon cycle?
No as not all organic matter is used in respiration. This means over time photosynthesis removes more CO2 from the atmosphere than respiration releases.
Word equation for respiration
Oxygen + glucose -> energy + water + carbon dioxide
What is decomposition?
Physical, chemical and biological mechanisms transforming organic matter into increasingly stable forms
What are the biological mechanisms resulting in decomposition of organisms?
Feeding and digestion aided by the catalytic effect of enzymes