SB9 Material Cycles Flashcards

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1
Q

What are the two processes that allows water to enter the atmosphere as water vapour?

A
  • evaporation
  • transpiration
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2
Q

What is the importance of the water cycle?

A

It distributes fresh water globally providing us with clean water for drinking

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3
Q

Describe the water cycle

A
  1. Water enters the atmosphere through transpiration or evaporation
  2. The warmer air of the atmosphere rises, taking the water vapour with it
  3. Since moist air cools down as it rises, water vapour forms clouds
  4. Water returns to Earth in a form of precipitation
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4
Q

Name the forms of precipitation

A

Rain, hail, snow or sleet

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5
Q

Define potable

A

Drinkable water

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6
Q

How can we produce potable water?

A

Filteration or chemical removal

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7
Q

How do we provide potable water for regions experiencing droughts regularly?

A

Through desalination

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8
Q

What is desalination?

A

Removing excess mineral ions from salts to make it drinkable

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9
Q

What are the methods of desalination?

A
  • Distillation
  • Reverse osmosis
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10
Q

Describe what happens in distillation

A
  • saline water is boiled
  • water vapour is funnelled through a tube before it is condensed
  • pure water is collected
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11
Q

Describe what happens in reverse osmosis

A

Saline water is forced at a high pressure through a partially permeable membrane which filters out all the mineral ions leaving pure water

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12
Q

Give examples of materials that cycle through ecosystems

A
  • water
  • carbon
  • nitrogen
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13
Q

When is carbon removed from the atmosphere?

A

Photosynthesis by plants and algae - used to make carbs. When they are consumed, carbon moves up the food chain

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14
Q

When is carbon returned to the atmosphere?

A
  • When plants, animals and algae respire
  • When combustion occurs
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15
Q

What is the importance of the carbon cycle?

A
  • component of all organic molecules, many of which are responsible for sustaining life on Earth, such as glucose
  • since there is only a limited amount of carbon available, the carbon cycle is an essential way of recycling the carbon we have available to us
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16
Q

Describe the carbon cycle

A
  1. Carbon removed from atmosphere through photosynthesis
  2. passed onto animals and decomposers due to feeding
  3. returned through respiration; in plants, animals and decomposing microorganisms
  4. additionally, returned by the combustion of fossil fuels
17
Q

What are the four key processes of the nitrogen cycle?

A
  • nitrogen fixation
  • ammonification
  • nitrification
  • dentrification
18
Q

Describe nitrogen fixation

A

Atmospheric nitrogen gas is converted into nitrogen-containing compounds such as ammonia, which forms ammonium ions (in solution) that can then be used by plants

19
Q

What is nitrogen fixation carried out by?

A
  • Nitrogen fixing bacteria
  • Lightning
20
Q

Describe nitrogen fixing bacteria

A
  • found ‘free-living’ in soil and also in root nodules of certain plants (legumes)
  • take n2 gas and change it into nitrates in the soil
21
Q

How does lightning play a part in nitrogen fixing?

A

Splitting the bond between two atoms and turning them into nitrous oxides like N20 and NO2, which disolve in rainwater and ‘leach’ into the soil

22
Q

Describe ammonification

A

Nitrogen compounds in waste products and dead organisms are converted into ammonia by decomposers

23
Q

Describe nitrification

A

Ammonium ions in the soil are converted into nitrates by the nitrifying bacteria

24
Q

Describe dentrification

A

Dentrifying bacteria use nitrates in the soil during respiration which releases nitrogen gas back into the atmosphere

25
Q

Define decomposition

A

Breaking down and digestion of biological material by organisms called decomposers

25
Q

What affects the rate of decay?

A
  • temperature
  • water availability
  • oxygen availability
26
Q

Why is decomposition a crucial process?

A

It returns important materials back to the rnvironment, such as carbon and mineral ions

27
Q

How can decomposition be used in farming?

A

To make compost

28
Q

What is compost used as?

A

A natural fertiliser, as it recycles the previously used minerals

29
Q

What are the conditions required for decomposers to grow the best?

A
  • warm
  • moist
  • lots of oxygen
30
Q

How can we preserve food?

A
  • drying food: adding salt/sugar (removes water)
  • chilling/freezing (removes warmth required)
  • pickling (changes pH)
  • canning/ vacuum packing/ sealing in gases like N2 (prevents oxygen access)
  • irradiation: kills decomposers
31
Q

Define irradiation

A

Exposing something to radiation to kill microorganisms

32
Q

Stat the equation for the rate of decomposition

A

mass lost/ number of days

33
Q

What conditions ensure the best compost is produced?

A
  • high temperatures: increase rate of enzyme controlled reactions
  • water provided
  • heap is turned to get more oxygen for the decomposers to respire
34
Q

How can farmers increase soil fertility?

A
  • adding manure
  • adding artificial fertilisers
  • crop rotation
35
Q

How does manure increase soil fertility?

A

Increases the nitrates available in the soil

36
Q

How does crop rotation increase soil fertility?

A

Planting crops with nitrogen fixing bacteria and digging in the roots after the crop is harvested. Decomposers break roots down and release nitrates for the next crop