Ecology: Nitrogen Cycle, Minerals And Eutrophication

Question 1

Plants and nitrogen

Answer 1

Plants absorb nitrogen in form of nitrates. They then convert into amino acids and then made into protein to help plant grow.

Nitrogen cycle relies on bacteria

Question 2

Decay

Answer 2

Feeds on dead organisms and waste materials releasing ammonia

Question 3

Nitrifying

Answer 3

Convert ammonia to nitrates

Question 4

Denitrifying

Answer 4

Convert nitrates to nitrogen gas

Question 5

Nitrogen fixing

Answer 5

Convert nitrogen gas into nitrates

Question 6

Decay, nitrifying and nitrogen fixing

Answer 6

bacteria all require oxygen to function efficiently.

This is why well aerated soils are important to farmer when growing crops

Question 7

Denitrification

Answer 7

Reduces amount of nitrate in soil. Denitrifying bacteria prefer anaerobic conditions(no oxygen)
Such as those created due to water logging following prolonged periods due to heavy rain

Question 8

Root hairs cells

Answer 8

All minerals are absorbed from the soil in solution via these roots

Question 9

Major adaptation in root hair cells

Answer 9

The adaptation is the presence of an extension of the cell that projects outwards from the cell into the soil.
This greatly increases the surface area of the cell improving the rate of water and mineral absorption

Question 10

Active uptake

Answer 10

The process of absorbing minerals from soil relies on active uptake.
This process moves substances against the concentration gradient.
Active uptake requires energy from respiration. This is why roots must have a sufficient supply of oxygen (glucose)

Question 11

Nitrates

Answer 11

Growth and development:Needed to make amino acids the building blocks of protein

Deficiency:stunted growth

Question 12

Calcium

Answer 12

Growth and development: a component of cell walls

Deficiency: no growth at all, new cells can’t form

Question 13

Magnesium

Answer 13

Growth and development: a compliment of the chlorophyll molecules

Deficiency: leaves appear yellowed

Question 14

Natural fertilisers advantages

Answer 14

• less soluble than artificial fertiliser so less will be lost by leaching and runoff into waterways
• improves soil quality by adding to the humus content of the soil

Question 15

Natural fertilisers disadvantages

Answer 15

• difficult to store and spread

- difficult to know the mineral composition exactly

Question 16

Artificial fertiliser advantages

Answer 16

• easier to stores

- can be applied in a more controlled manner

Question 17

Artificial fertiliser disadvantage

Answer 17

• soluble so can be easily washed away creating pollution problems
• has to be purchased

Question 18

Slurry

Answer 18

Faeces and urine from farm animals (usually cattle)

Question 19

Compost

Answer 19

Food waste (vegetable peelings)

Question 20

Manure

Answer 20

Animal faeces

Question 21

Eutrophication

Answer 21

This is where no life exist due to lack of oxygen. It is a common form of water pollution found close to agricultural land.
It often follows a sudden increase in concentration of minerals in water. ( fertiliser runoff due to heavy rain)

Question 22

Problem with the growth of algae

Answer 22

The presence of minerals lead to increase rate of growth.
These form a blanket like layer on the surface if the after preventing light from reaching plants beneath. These plants eventually die.
The decomposition of these plants uses up (DEPLETES) oxygen in the water and means fish and animals cannot survive in the water.

Question 23

How to reduce eutrophication

Answer 23

• use natural fertiliser
• apply when dry/don’t use it when heavy rain is forecast
• don’t apply close to river or ditch
• only use when necessary

Question 24

Other pollutants which has the same effect as fertiliser runoff

Answer 24

Household sewage

Question 25

Why is eutrophication more common in slow moving water (ponds)

Answer 25

The minerals become more concentrated