Topic 33 -Biogeochemical cycles

Question 1

Internal cycling of nutrients

Answer 1

primarily concerned with the flow of nutrients through the ecosystem dominated by the biological processes of primary production and decomposition

Question 2

many transformations take place in the

Answer 2

nonliving (abiotic) component -atmosphere, water, soil

Question 3

weathering

Answer 3

physical and chemical breakdown of rocks and minerals releases inorganic nutrients into the soil and water ->available for plant uptake

Question 4

Biochemical cycle

Answer 4

flow of nutrients from the nonliving to the living and back to the nonliving components of the ecosystem in a more or less cyclic path

Question 5

The processes of inputs and outputs of nutrients during biochemical cycles

Answer 5

link different ecosystems

Question 6

the output of ones system represents

Answer 6

inputs to another (ex terrestrial to aquatic)

Question 7

Carbon cycle for terrestrial ecosystems

Answer 7

Photosynthesis: -> CO2->organic form -> herbivores -> carnivores ->organic matter -> decomposers -> plant tissue
CO2 released back into atmosphere via respiration (plants, consumers, decomposers)

Question 8

Swamps and marshes carbon cycle

Answer 8

dead organic matter falls into water does not completely decompose
carbon stored as humus or peat
buildup of partially decomposed organic matter forms fossil fuels in the long term

Question 9

Fresh water and marine ecosystems carbon cycle

Answer 9

CO2 diffuses into the surface water from atmosphere -> carbonates
Phytoplankton uses carbonates -> plant tissue -> herbivores -> carnivores -> organic matter -> decomposers -> plant tissue
CO2 released via respiration (plants, consumers, decomposers) is either reused or released into the atmosphere (diffusion=high to low concentration)

Question 10

Earths carbon budget

Answer 10

most buried in sedimentary rocks (not involved in cycle) 99%
Oceans (major) 38 000 Gt 70%
Fossil Fuels (partially decomposed matter) 10 000 Gt (18%)
Atmosphere (750 Gt) (1%)
Terrestrial 2000 Gt (4%) -includes soil and organisms
Historically -exchanges of CO2 between terrestrial environments and the atmosphere were thought to be in equilibrium
recently CO2 in the atmosphere has increased

Question 11

Atmospheric Carbon

Answer 11

CO2 in atmosphere has increased 25% in last 100 years
historically CO2 is 280-290ppm
Industrial Revolution (mid-1800s) CO2 increased steadily -by mid-1900s increasing exponentially
1) Burning fossil fuels (coal, oil, gas) adding 6.4 Gt/yr (in 1900)
2) Deforestation -forested lands are typically cleared and burned for farming adding 2.2 Gt/yr (in 1990s)