Nitrogen

?
  • Created by: ppogba
  • Created on: 13-08-19 18:41
What is Anthropogenic atmospheric N deposition?
deposition from the atmosphere of man made nitrogen compounds to the biosphere.
1 of 19
What is the difference between wet and dry deposition?
Wet deposition = in rain. Dry deposition = as gas or aerosols.
2 of 19
Wet and dry deposition occurs in what 2 forms?
reduced and oxidised.
3 of 19
Give examples of oxidised N (NOx) forms from wet and dry deposition?
Wet = NO3 (nitrate). Dry = nitrous oxide (N2O).
4 of 19
Give examples of reduced N (NH4) forms from wet and dry deposition?
wet = NH4+ (ammonium). dry = NH3 (ammonia).
5 of 19
What is the main source of NOx (oxidised N)?
Fossil fuel combustion (eg. power stations, cars)
6 of 19
What is the main source of NHy (reduced N)
Agriculture (ammonia, NH3, from livestock manure)
7 of 19
How much kt-N yr-1 does the UK emit and how much is returned as wet and dry deposition?
Emissions = 723 kt-N yr-1. Wet + dry deposition = 402 kt-N yr-1.
8 of 19
What factors affect the deposition of Nitrogen?
distance from source, surface roughness and rainfall.
9 of 19
How does distance from source affect deposition of N, in terms of NOx and NHy?
Less important for NOx, since has long distance dispersal. More important for NHy, since deposited close to source- especially NH3- ammonia gas.
10 of 19
How does surface roughness affect deposition of N?
deposition velocities are faster on rougher surfaces (ie. more deposition occurs in forests than grasslands as forests are rougher surfaces.
11 of 19
How does rainfall affect deposition of N?
greater rainfall = increase wet deposition. Also, seeder-feeder effect can occur.
12 of 19
Describe the seeder-feeder effect?
An Orographic (feeder) club sits at the top of a hill and already contains pollutants. It can scavenge aerosols and gases blown up the hill. A seeder cloud can then go above the feeder cloud and rain onto it, adding to the wet pollution hitting hill.
13 of 19
Name 4 mechanism of N deposition being an ecological threat
Eutrophication. Soil acidification. Increased susceptibility of plants to secondary stress. Direct toxicity to plants.
14 of 19
Describe how Eutrophication is an ecological threat?
N accumulates in soils allowing expansion of nitrophilous species, resulting in competitive exclusion of others and decline in biodiversity.
15 of 19
What is a nitrophilous species?
nitrogen-loving plants.
16 of 19
How is soil acidification an ecological threat?
can reuse plant health and productivity. Also, fewer species can tolerate acidic levels, so can cause decline in species richness .
17 of 19
N deposition can increase susceptibility of plants to secondary stress. What are these stresses?
greater herbivory, reduced resistance to pathogen attack, increase susceptibility to drought or freezing.
18 of 19
To see if N accumulation affected clean groundwater, an experiment was done where Calcareous and acidic grasslands each had nitrogen put through it. What were the results.
The calcareous grasslands retained much more nitrogen than the acidic grasslands, maintaining provision of clean groundwater. (however does still result in species decline in both grassland types).
19 of 19

Other cards in this set

Card 2

Front

What is the difference between wet and dry deposition?

Back

Wet deposition = in rain. Dry deposition = as gas or aerosols.

Card 3

Front

Wet and dry deposition occurs in what 2 forms?

Back

Preview of the front of card 3

Card 4

Front

Give examples of oxidised N (NOx) forms from wet and dry deposition?

Back

Preview of the front of card 4

Card 5

Front

Give examples of reduced N (NH4) forms from wet and dry deposition?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all nitrogen resources »