Biogeochemical cycles

Question 1

Carbon reservoir: atmosphere

Answer 1

CO2, CH4, CO

smallest store

Question 2

Carbon reservoir: hydrosphere

Answer 2

CO2 dissolves in water

Question 3

Carbon reservoir: lithosphere

Answer 3

carbonate rocks
hydrocarbons

largest store

Question 4

Carbon reservoir: biosphere

Answer 4

DOM
carbohydrates
proteins
lipids

Question 5

How carbon moves from one reservoir to another and in what form: photosynthesis

Answer 5

atmosphere to biosphere
CO2 to glucose

Question 6

How carbon moves from one reservoir to another and in what form: respiration

Answer 6

biosphere to atmosphere
glucose to CO2
produces energy from glucose by producing ATP

Question 7

How carbon moves from one reservoir to another and in what form: food chain transfer

Answer 7

biological molecules are transferred from one organism to another
energy decreases up each trophic level

Question 8

How carbon moves from one reservoir to another and in what form: fossilisation

Answer 8

biosphere to lithosphere
carbohydrates to hydrocarbons

layers of sediment build up around the DOM, it begins to compact and form rocks

Question 9

How carbon moves from one reservoir to another and in what form: combustion

Answer 9

biosphere/lithosphere to atmosphere
carbohydrates to CO2 and CO

fossil fuels are burned to release CO2 and CO

Question 10

How carbon moves from one reservoir to another and in what form: decomposition

Answer 10

biosphere to lithosphere/atmosphere

carbohydrates to hydrocarbons/CH4

Question 11

How carbon moves from one reservoir to another and in what form: volcanic activity

Answer 11

lithosphere to atmosphere
hydrocarbon to CO2

carbonated rocks are melted to magma, when magma reaches the surface CO2 is released

Question 12

How human activities impact the carbon cycle: deforestation

Answer 12

decreases photosynthesis, decomposition and food chain transfer

reduced amount of CO2 absorbed from atmosphere
land is used for agriculture and cattle ranching

Question 13

How human activities impact the carbon cycle: combustion of fossil fuels

Answer 13

increases CO2 in atmosphere

contributes to greenhouse effect
global temperature rise
anthropogenic climate change

Question 14

How human activities impact the carbon cycle: afforestation

Answer 14

increases photosynthesis, decomposition and food chain transfer

CO2 is absorbed from atmosphere

Question 15

How human activities impact the carbon cycle: intensive farming

Answer 15

increases CO2 in atmosphere and biosphere and combustion

contributes to greenhouse effect
increased combustion for machinery
ploughing of soil releases CO2

Question 16

How human activities impact the carbon cycle: cattle farming

Answer 16

increases CH4 in atmosphere and CO2 in biosphere
decreases photosynthesis

contributes to greenhouse effect
anaerobic conditions release CH4

Question 17

How human activities impact the carbon cycle: ocean pollution

Answer 17

increased CO2 in atmosphere and hydrosphere
decreased photosynthesis

reduces number of phytoplankton and algae
ocean acidification
less CO2 removed from atmosphere and oceans

Question 18

Nitrogen reservoir: atmosphere

Answer 18

N2 = 78%
NOXs

Question 19

Nitrogen reservoir: biosphere

Answer 19

DNA, proteins, amino acids, RNA

Question 20

Nitrogen reservoir: lithosphere

Answer 20

soil = ammonia, nitrates, nitrites

Question 21

Nitrogen reservoir: hydrosphere

Answer 21

dissolved nitrates
dissolved ammonia

Question 22

How nitrogen moves from one reservoir to another and in what form: ionisation

Answer 22

lightning provides energy for atmospheric nitrogen and oxygen to react

produces oxides of nitrogen

Question 23

How nitrogen moves from one reservoir to another and in what form: fixation

Answer 23

micro-organisms chemically reduce N2 to NH3

Question 24

How nitrogen moves from one reservoir to another and in what form: food chain transfer

Answer 24

nitrogen passes between organisms as amino acids and proteins in food

Question 25

How nitrogen moves from one reservoir to another and in what form: nitrification

Answer 25

involves oxidation of ammonium ions to nitrites then nitrates using nitrifying bacteria

Question 26

How nitrogen moves from one reservoir to another and in what form: denitrification

Answer 26

chemical reduction of nitrates in soil to nitrogen and nitrogen oxides requires anaerobic conditions

Question 27

How nitrogen moves from one reservoir to another and in what form: leaching

Answer 27

nitrates = highly soluble easily leached out of soil act as nutrients for aquatic plants and algae

Question 28

How nitrogen moves from one reservoir to another and in what form: absorption by roots

Answer 28

absorb nitrogen as soluble ions (ammonium and nitrates)

Question 29

How nitrogen moves from one reservoir to another and in what form: ammonification

Answer 29

amino groups in proteins released as ammonium ions when DOM decomposes

Question 30

How human activities impact the nitrogen cycle: haber process

Answer 30

iron catalyst, high temp and pressure uses lots of energy N2 + 3H2 ---> 2NH3 NH3 ---> NO3-

Question 31

How human activities impact the nitrogen cycle: agricultural activities - use of fertilisers

Answer 31

eutrophication

Question 32

How human activities impact the nitrogen cycle: agricultural activities - drainage systems

Answer 32

makes soil more aerobic increases nitrifying bacteria and decreases denitrifying bacteria

Question 33

How human activities impact the nitrogen cycle: agricultural activities - soil disturbance

Answer 33

ploughing releases NOXs into atmosphere increases rate of decomposition

Question 34

How human activities impact the nitrogen cycle: agricultural activities - choice of crop

Answer 34

legumes increase levels of nitrites and nitrates in the soil

Question 35

How human activities impact the nitrogen cycle: pollution

Answer 35

NOXs released into atmosphere by combustion increases quantity of nitrates added to the soil by rain

Question 36

Explain the process of eutrophication

Answer 36

farmers add fertiliser to soil excess nutrients runoff from field to water causes algal bloom algae blocks sunlight and uses up O2 algae dies and is decomposed by bacteria decomposition of algae = increased biological demand for O2 water becomes anoxic fish and other aquatic life dies

Question 37

Phosphorus reservoir: plants and animals

Answer 37

proteins, DNA, RNA, phospholipid, ATP

Question 38

Phosphorus reservoir: sediments and rocks

Answer 38

present in phosphate rocks

Question 39

Phosphorus reservoir: water

Answer 39

phosphate ions go into solution

Question 40

Why is phosphorus often a limiting factor in plant growth?

Answer 40

no gaseous reservoir so slower to cycle phosphate ions are less soluble than nitrate ions (low solubility)

Question 41

How phosphorus moves from reservoir to another and in what form: absorption by roots

Answer 41

phosphate ions in solution solution taken up by plant roots used in synthesis or organic molecules

Question 42

How phosphorus moves from reservoir to another and in what form: food chain transfer

Answer 42

moves through trophic levels when one organism eats another

Question 43

How phosphorus moves from reservoir to another and in what form: decomposition

Answer 43

microbes break down DOM phosphates returned to soil

Question 44

How phosphorus moves from reservoir to another and in what form: sedimentation

Answer 44

phosphates in sediments end up in rocks phosphate originates from DOM

Question 45

How phosphorus moves from reservoir to another and in what form: mountain building - uplift

Answer 45

plate tectonics move rocks from deep to surface

Question 46

How phosphorus moves from reservoir to another and in what form: weathering/erosion

Answer 46

rocks at surface are weathered and then eroded

Question 47

What human activity causes the most impact on the movement and storage of phosphorus? What problems can this cause?

Answer 47

production of fertiliser - eutrophication mining for phosphorus - pollution

Question 48

Sustainable management of the carbon cycle

Answer 48

reduce combustion of fossil fuels increase use of renewables afforestation carbon capture and storage protect existing carbon stores

Question 49

Sustainable management of the nitrogen cycle

Answer 49

reduce reliance on artificial fertiliser use fertiliser during dry spells educate farmers around eutrophication collect runoff and return to farmland reduce use of combustion engines catalytic convertors

Question 50

Sustainable management of the phosphorus cycle

Answer 50

use of natural fertilisers leave DOM to decay on soil breed crops to increase efficiency of phosphorus uptake