Biosphere: (Carbon And Oxygen Cycles)

Question 1

Nutrient cycling:

Answer 1

-nutrients travel through both biotic and abiotic parts of the environment.
-two types of biogeochemical cycles:
•1. Global: C, O, N and S can travel long distances (as gases in the atmosphere).
•2. Static: P, K, Ca and other trace elements are typically found in the soil so don’t travel as far.

Question 2

Rapid cycling of carbon:

Answer 2

•carbon moves from producer to consumer and decomposer, and back to the atmosphere through rapid cycling.
•plants take inorganic carbon (CO2) from the atmosphere during photosynthesis and convert it into organic compounds.
•carbon is returned to atmosphere through cellular respiration, forest fires and decomposition.

Question 3

Slow cycling of carbon:

Answer 3

•carbon can be stored in the deep ocean, earths crust (rocks), limestone (from shells of aquatic organisms) petroleum deposits (fossil fuels).
•carbon stored in reservoirs is unavailable until released.
•carbon is released during the combustion of fossil fuels, weathering of carbon from rocks, and carbon released as methane gas back to the atmosphere.

Question 4

Carbon reservoirs:

Answer 4

-atmosphere.
-formation of fossil fuels.
-weathering of limestone (CaCO3).
-bogs.
-growth and death of trees (deforestation = return of 2Gt of carbon to atmosphere each year).
-ocean is largest carbon sink (dissolved CO2).

Question 5

Oxygen reservoirs:

Answer 5

-atmosphere.
-rocks on land.
-dissolved in water.

Question 6

Processes:

Answer 6

-1. Fixing carbon.
•photosynthesis.
•dissolved CO2 in H2O makes carbonates which makes calcium carbonate (found in shells and forms ocean sediment) when crushed/heated it turns into rocks.
•releasing carbon.
•rocks broken down by volcanos, by decaying organisms, combustion of fossil fuels, respiration.

Question 7

Human impacts:

Answer 7

-burning wood and fossil fuels.
-deforestation.
-mining.
-overpopulation.
-forest fires. (Can happen naturally too).