Carbon Cycling Flashcards
How is carbon present in aquatic ecosystems?
Carbon dioxide and hydrogen carbonate ions
What allows carbon dioxide to diffuse into plants?
Carbon dioxide is used in photosynthesis which creates a concentration gradient for more carbon dioxide to diffuse into the stomata
Some carbon dioxide produced by respiration in plants is used during the day for…
Photosynthesis
What are the seasonal changes in atmospheric carbon dioxide levels?
In the Northern Hemisphere in winter, most plants are dormant and produce little oxygen and take up little carbon dioxide due to shorter days. In cold winter, more fuel is burnt to heat houses and heterotrophs still respire to produce more carbon dioxide. In summer, more light levels and more photosynthesis and carbon taken from atmosphere
How is methane produced?
From organic matter under anaerobic conditions by methanogenic archaeans (bacteria)
What happens to methane when produced?
Diffuses into the atmosphere or accumulates into the ground
Where might you find methanogenic archaeans?
Gut bacteria, landfill sites, lakebeds, swamps, termites
Why have concentrations of methane in the atmosphere remained low?
Oxidised eventually into carbon dioxide
How is pear formed?
Partial digestion of organic matter by saprotrophs but is aerobic and stagnant water makes it anaerobic and acidic which kills saprotrophs. New layers of leaf litter fall on top and compress older material
What can peat be used for?
Substitute for firewood for cooking and heating, increase moisture holding capacity of soil for horticulture, acidify soils for pot plants, increase water infiltration rate of soils rich in clay
How does peat form coal and oil?
Sedimentation, partial digestion, anaerobic conditions, heat and high pressure
Are coal, oil and gas stable?
Yes
Where is coal found?
Beneath the surface
Where is oil and gas found?
In porous rock
Other than deliberate burning of fossil fuels, how else can carbon dioxide be released?
Forest fires
