1.C - the carbon cycle as a system Flashcards
1
Q
what is N.P.P?
A
- NET PRIMARY PRODUCTIVITY
- the amount of energy accumulated and stored in plants
- photosynthesis minus respiration = N.P.P
2
Q
what is N.P.P like in rainforest compared to grazing land?
A
- rainforest = high N.P.P
- stores 400 tonnes carbon per hectare
- grazing land = 30 tonnes carbon p h
3
Q
CARBON
A
- makes up organic compounds
- used as an economic resource
> fossil fuels, eg. coal, oil, natural gas
> oil used as a raw material in the manufacture of products - contained in multiple greenhouse gases
- stored in carbonate rocks in its largest store
- combustion = CO2 increasing sharply in atmospheric concentration
- 600 billion tonnes of carbon in atmosphere
- land use change decreases our ability to store carbon (e.g. deforestation)
4
Q
stores of global carbon: ATMOSPHERE
A
- 0.53%
- stored as the gas carbon dioxide and to a lesser extent methane
5
Q
stores of global carbon: BIOSPHERE
A
- plants: 0.42%
- soils: 1.12%
- stored in organic molecules in living and dead plants and animals.
- in the soil it is stored as organic matter from dead plant material and the activity of microorganisms
- the decay process releases carbon dioxide back into the atmosphere
6
Q
stores of global carbon: OCEAN
A
- 28%
- stored as dissolved carbon dioxide, but also as calcium carbonate in the shells of marine life, which can fall to the sea floor and become marine sediments.
- much of the oceanic carbon store is located at great depths
- only 4% is found near upper ocean surface
7
Q
stores of global carbon: LITHOSPHERE
A
- 70%
- stored as fossil fuels (coal, oil and gas) and also in sedimentary rocks such as chalk and limestone
- this is the largest store of carbon
8
Q
what are rainforests in terms of carbon?
A
REALLY EFFECTIVE CARBON SINKS
9
Q
how do levels of CO2 change throughout the year?
A
- spring and summer = photosynthesis ↑ = much less CO2 in atmosphere (trees are v. effective at soaking up CO2)
- winter = opposite
- temporal change over time
10
Q
what is TUNDRA’S NPP like?
A
- low NPP
- limited seasons
- soils in tundra = really important store of carbon
11
Q
what is NPP?
A
- Net primary productivity measures the amount of carbon that ecosystems sequester.
- it is the difference between what is taken in by photosynthesis and what is given out by respiration
12
Q
what is HOT DESERT’S NPP like?
A
- low NPP
- very little organic matter can survive the LACK OF WATER/NUTRIENTS (and the extreme temps)
- plants cant photosynthesis
13
Q
what is TROPICAL RAINFOREST’S NPP like?
A
- high NPP
- loads of plants and trees = photosynthesis is more than respiration = carbon accumulates
14
Q
how is the ocean a part of the carbon cycle?
A
- carbon dioxide can dissolve in sea water
- phytoplankton - basis of ocean food chain
15
Q
how do phytoplankton play a crucial role in the carbon cycle?
A
- through photosynthesis they absorb CO2 from the atmosphere and combine it w/ water to make carbohydrates (sugars/glucose)
- photosynthesis = foundation of food chain
- decomposition of dead organic material by microbial activity also returns CO2 to the atmosphere
16
Q
how is the LITHOSPHERE a part of the carbon cycle?
A
- long term store. typical residence time = 150 mill yrs
- the lithosphere contains by far the largest amount of carbon on earth, much of which is stored in sedimentary rocks within the planets crust