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Ecology - Global Change Biology > Agriculture - Pollutants > Flashcards

Agriculture - Pollutants Flashcards

1
Q

Pollutants

A

These are chemicals with displaced concentration, with potential to damage the environment

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2
Q

What are the two categories of pollutants?

A

Primary
Secondary

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3
Q

Primary Pollutants

A

These are chemicals directly emitted into the atmosphere like NO, SO2 and VOC

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4
Q

Secondary Pollutants

A

These are those reacting with reacting with atmospheric particles forming toxic elements like O3 and NO2

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5
Q

NOX

A

This refers to NO with differing oxidation states, NO is rapidly oxidised to NO2 when produced almost instantly

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6
Q

What are the two origins of pollutants?

A

Natural Emissions like volcanoes, swamps and forest fires
Anthropogenic like fossil fuels and forest fires, either domestic or industrial

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7
Q

Where does SO2 come from mostly?

A

31% from energy production
29% from industry
25% from domesetic comubstion

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8
Q

Where does NOx come from mostly?

A

49% by Transport
20% Industry
20% Energy

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9
Q

What are the deposition mechanisms of pollution?

A

Dry or wet

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10
Q

What is the life cycle of NOx and SO2?

A

Introduced by dillution, dispersed into the atmosphere, returning depending on sollution

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11
Q

What physiological effects does SO2/NOx dry deposition have?

A

Inhibition of growth and photosynthesis

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12
Q

How does SO2 inhibit photosynthesis?

A

Action on Photosystem II

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13
Q

Photosystem II

A

This absorbs light energy and transfers electrons from water to plastoquinone

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14
Q

What is photosystem II important in?

A

Proton gradient generation and PS II disruption preventing ATP generation

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15
Q

How is O2 generated from H2O in plants?

A

Oxygen-Evolving Complex

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16
Q

What may SO2 inhibit?

A

Cytochrome BF

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17
Q

Cytochrome BF

A

This is a thylakoid membrane protein catalysing transfer of electrons from plastoquinol to plastocyanin.

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18
Q

How does intensity of light exposure effect extent of SO2 damage?

A

More pronounced in higher light due to increased photosynthetic demand as ETC operates at higher demands.

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19
Q

How might stroma acidification occur?

A

Acidic nature of SO2 and NOx decreasing pH

20
Q

How might ROS generated by SO2/NOx cause acidification?

A

Disruption of membrane proton pumps

21
Q

Why is acidification important?

A

Optima of enzyme to certain conditions

22
Q

Dark Reactions

A

These utilise NADPH and ATP generated by the light ETC within the thylakoid membranes

23
Q

Photophosphorylation

A

This is the process of ATP generation using light energy.

24
Q

How much can 0.5pH inhibit?

A

50% of photosynthesis

25
Q

How can Rubisco in Dark Reactions be affected?

A

Optimal alkaline pH of 9.0 so acidity disrupts.

26
Q

How much do both SO2/NOx both inhibit?

A

7.5-25% and 55%

27
Q

What does wet deposition affect?

A

Soils and plants

28
Q

How does wacid rain affect soils?

A

Increase acidity with loss of fertility and struggle for photosynthetic homeostasis.

29
Q

How does soil acidification affect plants?

A

Decrease nutrient availability essential for plant growth and development, like Ca, Mg and P, and also Al release.

30
Q

Why do acidic effects of soil damage plants?

A

Acidity reduces soil solubility, thus less availabile, as ions can bind soil particles more strongly with increased acidity.

31
Q

Cation Exchange Capacity

A

This is a measure of a soils ability to hold or store positively charged ions.

32
Q

How does CEC change?

A

Number of soil particle negative chages increase with decreasing pH, thus more cationic adsorption to soil

33
Q

How are microbial organisms affected with acidity?

A

Sensistive to pH changes like mycorrhizae, with reduced activity thus nutrient cycling.

34
Q

Why does solubiltiy change with pH?

A

Increaseing H+ from decreasing pH compete with negatively charged binding sites on soil particles with leaching occuring

35
Q

How might H+ decrease nutrient assimilation?

A

Binding to form inorganic compounds unable to be taken up.

36
Q

What are examples of tree damage by acid rain?

A

White pine and Loblolly pine in the UK due to coal burning.

37
Q

How does stratospheric O3 form?

A

Photochemical reactions of VOC, NOx and sunlight.

38
Q

What is the chemical pathway of O3 formaiton?

A

NO2 undergoes photolysis into NO and O, the O then reacting with O2 to form ozone.

39
Q

How does O3 affect plants?

A

ROS generation, lipid peroxidation, protein oxidation, stomatal closure and gene expression effects

40
Q

Lipid Peroxidation

A

This is the generation of reactive aldehydes like malondialdehyde which can damage proteins and NA

41
Q

What are structural effects of pollutants on plants?

A

Water Soaked Appearance
Chloritic Flecking
Stipple of Dead
Growth Suppression Early Abscission

42
Q

Water Soaked Appearnce

A

This is damage of the membrane and cell death due to O3 reactivity and oxidative stress induction

43
Q

Chloretic Flecking

A

This is chloroplast function disrupiton and ROS accumulation

44
Q

How does CHloretic Flecking occur?

A

Diffusion into mesophyll cells and thylakoid membrane damage, disruption PS

45
Q

What causes stipple of dead/pigmented cells?

A

FA reactions and aldehyde/peroxide production with cytoplasmic effects on pigments like anthocyanines

Ecology - Global Change Biology (8 decks)

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