APS124 Papers Flashcards

1
Q

The primary source of carbon dioxide released to the atmosphere by human activities derives from..

A

fossil fuels fixed by prehistoric photosynthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Globally and annually, photosynthesis fixes an order of magnitude more CO2 than..

A

is released by human activities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Gross Primary Production (GPP) refers to the photosynthetic conversion of solar radiation to produce … and …

A

ATP, NADPH

  • rate of production of chemical energy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

NPP is taken as…

A

the energy remaining for CO2 fixation, after its use for photorespiration and the reduction of nitrate and sulphate

NPP = GPP - autotrophic respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Net ecosystem production (NEP) =

A

NPP - heterotrophic respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Net biome production (NBP) =

A

NEP - losses through disturbance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Biomass =

A

Sum of(NPP - losses through litterfall)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Per unit … or …

A

surface area, time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Over a year, only about … of GPP is fixed into …

A

half, biomass

  • the other half is lost by respiratory processes, which defines NPP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Biomass is the key product of NPP as…

A

this is now available for consumption by secondary consumers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The NPP of a single plant can be measured by..

A

enclosing the whole plant (including roots) in an airtight and air conditioned container, while constantly recording changes in CO2 concentration
(Daytime photosynthetic uptake of CO2 will be followed by nocturnal release of CO2 by respiration)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

On land, NPP can be calculated in the field for a larger sample of plants by measuring the biomass increment over a year. This approach may miss…

A

unaccounted losses of new biomass through litterfall, and other possible losses such as through herbivory or root exudates, and so would underestimate NPP.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

NPP =

A

photosynthetic biomass x growth efficiency x light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Photosynthetic biomass is made up of either green leaves or chlorophyll in algal cells and expressed per…

A

unit area of surface.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Light is solar radiation (mol day^-1) in…

A

the photosynthetically active waveband (400-700nm)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Radiometric measurements by satellites of radiation reflected from the earth’s surface can be used to quantify…

A

critical components of the NPP model

17
Q

Ocean light depth =

A

euphotic zone

18
Q

Terrestrial NPP per unit area is on average…

A

3 times that of the oceans

19
Q

However the total NPP by the 2 biospheres is … …

A

approximately equal

  • 60PgC.yr^-1 for terrestrial biosphere
  • 65PgC.yr^-1 for oceanic biosphere
20
Q

High oceanic NPP is observed in areas where there is…

A

coastal upwelling of nutrients, such as off the coasts of South America and Africa
(these regions account for about 14-30% of oceanic NPP)

21
Q

On land, NPP is highest…

A

in the rainforests between the tropics

22
Q

Seasonal variations of temperature or precipitation…

A

reduce NPP

23
Q

Over Europe NPP is reduced by about … for every 1C reduction in mean annual temperature

A

4%

24
Q

Accounting for heterotrophic respiration reduces global NPP considerably from 125PgC.yr^-1 to…

A

11 for oceans and 5 for the land - similar to the 9 from human derived emissions

25
Q

It is likely that carbon sequestration by the biological pump is a…

A

relatively small fraction of emissions

26
Q

CO2 solubility is greatest in..

A

the cold waters of high latitude oceans

- where the dense water sinks, removing CO2 to depth

27
Q

Rising atmospheric CO2 concentrations increase the dissolved CO2 concentration in sea water, but…

A

warming reduces this solubility

28
Q

It is estimated that the oceanic NPP by the biological pump has declined by about 6% over the last 20 years and this is strongly correlated with…

A

an increase in global sea surface temperatures of 0.2C

29
Q

The contemporary solubility pump is already working at a…

A

25-40% reduction in efficiency compared to before the industrial revolution

30
Q

Atmospheric carbon accumulation : atmospheric CO2 concentrations : Global warming

A

200:100:1

31
Q

Experiments have demonstrated that increasing CO2 concentrations stimulate…

A

NPP on land

- doubling CO2 concentration stimulates NPP by about 20%

32
Q

If the whole of the UK were reforested this would be equivalent to a C sequestration of about…

A

1PgC

33
Q

Global mitigation of climatic change can only be achieved by…

A

internationally concerted action to reduce carbon emissions

34
Q

The oceanic and terrestrial carbon sinks currently sequester … of anthropogenic emissions

A

60%

- likely to decline through the 21st century

35
Q

Brazil produces ethanol from sugar can that replaces 20-25%…

A

of petrol in fuel