ECEC - 7

Question 1

what are the 2 types of atmospheric nitrogen deposition?

Answer 1

wet = in rain 
dry = in aerosols or gases

Question 2

what are the 2 forms wet and dry deposition can come in?

Answer 2

1) Oxidised N (NOx). e.g.
• Wet: NO3 - (nitrate)
• Dry: nitrous oxide (N2O)
2)  Reduced N (NHy). e.g.
• Wet: NH4+ (ammonium)
• Dry: NH3 (ammonia)

Question 3

what are anthropogenic nitrogen sources?

Answer 3

1) fossil fuel combustion = NOx

2) agriculture = NHy

Question 4

describe the distribution of NOx and NHy

Answer 4

NOx mainly distributed around roads and industrial areas

NHy mainly distributed around livestock

Question 5

where are half of nitrogen emission deposited?

Answer 5

back to Earth

Question 6

where are a lot of our nitrogen emissions exported too?

Answer 6

europe

Question 7

what are 3 factors affecting nitrogen deposition?

Answer 7

1) distance from source (NOx has long distance dispersal compared to NHy)
2) surface roughness - faster to rougher surfaces eg forests
3) rainfall - greater rainfall increases wet deposition

Question 8

what is the seeder feeder effect?

Answer 8

one cloud (seeder) is above another orographic cloud (feeder) when the seeder precipitates it then goes through the feeder causing an increased amount of rain and activates the aerosol droplets in the base of the feeder cloud - this happens at the top of mountains

Question 9

what areas of the UK have high N deposition?

Answer 9

1) upland areas (seeder feeder effect)
2) areas near industrial centres and agriculture
3) forests (high surface roughness)
- peak district and pennines - combination of all these

Question 10

what are 4 mechanisms of N deposition that are a threat?

Answer 10

1) eutrophication
2) soil acidification
3) increases susceptibility of plants to secondary stress e.g. reduced resistance to pathogen attack
4) direct toxicity to plants

Question 11

whats an example of a fast growing N loving species which outcompete others?

Answer 11

Dutch chalk grasslands -Concurrent expansion of the competitive grass (Brachypodium pinnatum)

Question 12

what are the though effects of current N deposition in the UK on species richness?

Answer 12

reducing species richness by 4-5 species

Question 13

what does N deposition do to soil PH and ammonium and nitrate levels?

Answer 13

decreases soil PH

increases ammonium and nitrate levels

Question 14

what is the affect of N accumulation on clean ground water?

Answer 14

grasslands accumulate up to 75% of the pollutant N deposition but still manages to maintain clean ground water - its removed by leaching and gaseous losses

Question 15

why is industrialisation of developing countries thought to be a big issue?

Answer 15

because developing countries contain much of our global diversity but have few legislations on pollution as they are increasing in industrialisation

Question 16

what are biodiversity hotspots and how many are there?

Answer 16

regions on conservation priority - contain 50% of the worlds vascular species and 42% of terrestrial vertebrate species - 35/36 of them

Question 17

what affect does soil N and decreasing soil PH have on florisitic diversity?

Answer 17

• Floristic diversity can decline with increasing soil N (e.g. competitive exclusion by Brachypodium)
• Floristic diversity can decline with
  decreasing soil pH

Question 18

describe the experiments at wardlow?

Answer 18

Experimental plots at the Wardlow acidic and calcareous grasslands
• “Monoliths” removed and N fluxes quantified
– Leaching, gaseous losses, “grazing”

Question 19

how much greater is the global N deposition estimated to be in 2050 compared to 1990?

Answer 19

2 fold greater