4c + d - Human Impacts/Cycles

Question 1

What are the two ways nitrogen can be taken out of the air and converted?

Answer 1

• nitrogen fixing bacteria

- lightning

Question 2

Where is nitrogen fixing bacteria found?

Answer 2

In soil and in the root nodules of plants

Question 3

How does a lightning convert nitrogen gas?

Answer 3

Splits the bond between the two atoms and turns them into nitrous oxide that dissolve in rainwater

Question 4

Why do plants absorb the nitrates

Answer 4

To make proteins

Question 5

How does the nitrogen go back into the soil?

Answer 5

As ammonium compounds in animal faeces

Question 6

What does nitrifying bacteria do?

Answer 6

Converts the ammonium compounds to nitrites then to nitrates

Question 7

What does denitrifying bacteria do?

Answer 7

Takes the nitrates out the soil and converts them back into nitrogen gas

Question 8

Where is denitrifying bacteria found?

Answer 8

Poorly aerated soil

Question 9

How can famers reduce unhelpful bacteria

Answer 9

Ploughing and turning over soil

Question 10

Name 3 sources of water pollution?

Answer 10

• toxic chemicals
• untreated sewage
• fertilisers

Question 11

What’s the conditions for decomposition?

Answer 11

Warmth, moisture and air

Question 12

What are detritus feeders’ role?

Answer 12

To start the decay process

Question 13

What is eutrophication?

Answer 13

Water pollution caused by sewage or fertiliser

Question 14

What is the effect of fertilisers in water?

Answer 14

• causes increased plant growth (algal bloom)
• which blocks sunlight so plants die
• bacteria eats the dead plants using up o2

Question 15

What is the effect of sewage in water?

Answer 15

provides food for bacteria which use up o2 therefore fish die

Question 16

What pollutes the air?

Answer 16

Sulphur dioxide and nitrogen oxides

Question 17

How can acid rain effect plants?

Answer 17

damages leaves, buds, flowers and roots of trees

Question 18

How can acid rain effect fish?

Answer 18

• Makes rivers too acidic

- causes leaching of toxic minerals eg aluminium

Question 19

What’s leaching?

Answer 19

The washing of chemicals into the soil or water by rain.

Question 20

What is a greenhouse gas?

Answer 20

A gas that absorbs infrared radiation from the sun

Question 21

What are the most important greenhouse gases?

Answer 21

Water vapour
Carbon dioxide  
Methane 
Nitrous oxides 
CFCs

Question 22

How is carbon dioxide produced?

Answer 22

Combustion of fossil fuels

Question 23

How is methane produced?

Answer 23

• by cattle
• fermentation in rice fields
• decomposition of waste In landfill sites

Question 24

What is the greenhouse effect?

Answer 24

• sun emits rays to the earth
• some heat bounces back to space
• some heat is absorbed by green house gases
• which is within earths atmosphere

Question 25

What is global warming?

Answer 25

An enhanced greenhouse effect

Question 26

What are the consequences of global warming?

Answer 26

• decreases in biodiversity
• loss of Habitats
• ocean temperatures increase

Question 27

What are the effects of deforestation?

Answer 27

• soil erosion
• increased CO2 levels
• flooding