3.a&b How much change occurs over time in the water and carbon cycles?

Question 1

Uninfluenced by human activity, in what state are most natural systems?

Answer 1

dynamic equilibrium

Question 2

What type of feedback loop usually restores balance?

Answer 2

Negative feedback loops

Question 3

What is an example of a negative feedback loop in the carbon cycle?

Answer 3

The burning of fossils fuels increases atmospheric CO2 however this stimulates more photosynthesis, which removes CO2 from the atmosphere.

Question 4

How does urbanisation impact the water cycle?

Answer 4

Large artificial surfaces like tarmac and concrete are impermeable and so increase surface run-off. Urban areas also have drainage systems like gutters and pitch roofs so water flows off into rivers and streams.
Urbanisation also encroaches on floodplains with reduces storage capacity in drainage basins.

Question 5

How does farming impact the carbon cycle?

Answer 5

The clearance of forest for farming decreases both above and below ground storage in biomass. Soil carbon storage is also decreased by ploughing through oxidation. Harvesting of crops returns only small amounts of organic matter back to soils. Soil erosion increased with less vegetation cover.

Question 6

How does farming impact the water cycle?

Answer 6

Crop irrigation diverts surface water from rivers while some of this water is extract by crops, most is lost to evaporation.
interception is less by crops than natural forest and grassland ecosystems.
furrows made. by ploughs act as channels, surface run off is increased where heavy machinery compresses the ground.

Question 7

How does forestry impact the water cycle?

Answer 7

-Higher rates of interception
- increased evaporation; a large amount of rainfall is stored on leaf surfaces and goes back into the atmosphere.
-Reduced run-off and stream discharge high interception alter drainage basin hydrology. lag times are increased in streams draining plantations
-increased transpiration (Sitka spruce)
-timber harvest temporarily changes water cycle

Question 8

How does forestry impact the carbon cycle?
And how much carbon is stored on mature trees/ha?

Answer 8

Changing land from farmland to forestry increases carbon stores. In a typical plantation in the UK, mature trees contain between 170-200 tonnes of carbon/ha.
forest trees also sequester carbon.

Question 9

How many times higher is storage of carbon in mature trees than grasslands?

Answer 9

10

Question 10

Why do forestry plantations have a rotation of 80-100 years?

Answer 10

Forest trees only become a carbon sink for the first 100 years or so.

Question 11

Describe The river Kennet:

-biodiversity
-geology
-human activity

Answer 11

The upper catchment of the river Kennet mainly comprises of chalk which is high permeable. As a chalk stream , the river supports a lot of wildlife. Its water is filtered through chalk and so even clear.
Several urban areas rely on water from the river Kennet. Thames water abstracts water form the keen basin to Meet this supply. this has a significant impact on the regional water cycle.

Question 12

How has water abstraction impacted the river Kennet

Answer 12

-Rates of groundwater have exceeded rates of recharge, and falling of the water table has reduced flow by 10-14 percent
-In the dry conditions of the 1990s, flows fell by 40%
-lower flows have reduced flooding
- lower groundwater levels have caused springs to dry up and reduced saturated overland flow.

Question 13

What are Aquifers?

Answer 13

Porous water bearing rocks such as clay and red sandstone from which groundwater is extracted for public supply by wells and boreholes

Question 14

What is the upper surface saturated in aquifers called?

Answer 14

The water table

Question 15

What is an artesian basin or aquifer?

Answer 15

When sedimentary rocks form a syncline or basin like structure, an aquifer confined between impermeable rock layers may contain groundwater which is under artesian pressure. When this basin is accessed via a borehole or well, water will rise to the surface under its own pressure.

Question 16

By how much did the water table of the London artisan basin fall after overexploitation in the 19th century.

Answer 16

Nearly 90m, now (last 50 years) less extraction has allowed it to rise.

Question 17

How many tonnes of Co2 does fossil fuel consumption release annually to the atmosphere?

Answer 17

10 billion tonnes

Question 18

What percentage of the 1200 gt cumulative anthropogenic emissions from CO2 were from fossil fuels?

Answer 18

75

Question 19

What percent of the natural influx of carbon from the biosphere to atmosphere do human carbon emissions make up?

Answer 19

less than 10%

Question 20

Describe the process of CSS

Answer 20

CSS is the capture and storage of co2 released by power plants and industry. CO2is seperated from power stain emissions, it is then compressed and transported by pipeline to storage areas. It is injected into porous rocks underground, where it is stored permanently.

Question 21

Describe the Scottish Peterhead 2 project

Answer 21

peterhead power station in Aberdeenshire is plotting a CSS project and have submitted their requests to the energy consent unit.

Question 22

What failed CCS project did the government spend 100m on?

Answer 22

Peterhead powerstation, North Yorkshire, cancelled in 2015.

Question 23

What could CCS do if developed at scale?

Answer 23

1. allow safe removal and permanent storage of co2.

Question 24

what percentge of emmisons did power stations in the us account for? and by what percentage might css decrease this?

Answer 24

40% CCS could decrease this by 80-90 percent

Question 25

What are limitations of CCS

Answer 25

-expensive and requires idea geology
- uses a large amount of energy (around 20% of a power stations energy)

Question 26

What can a positive feedback loop be compared to?

Answer 26

A snowball effect; an initial change causes further change.

Question 27

How do rising temperatures create a positive feedback effect in the water cycle?

Answer 27

Rising temperatures increase evaporation and the atmosphere holds more vapour, this relates in more cloud cover and more precipitation. More cloud in the atmosphere creates more absorption of solar radiation, creating more warming.

Question 28

How do rising temperatures create a negative feedback effect in the water cycle?

Answer 28

Cloud cover also has an abedo effect, reflecting solar radiation back into the atmosphere causing global temperatures to fall.

Question 29

What are negative feedback loops in drainage basins?

Answer 29

The drainage basin is generally (on a longer time scale) in a state of equilibrium, inputs are balanced by evaporation and run-of ,however the basin responds to changes in precipitation. The system responds to lower precipitation by increasing river flow.

Question 30

Give an example of feedback loops in the water cycle on a smaller scale. (individual tree)

Answer 30

In. most years precipitation is sufficient for an individual trees water supply, but in drought years, shallow rooted trees become stressed, these trees responds to the lack of water uptake by shedding leaves to reduce transpiration losses. This is a negative feedback loop.

Question 31

Give an example of a negative feedback loop in the carbon cycle.

Answer 31

Negative feedback might neutralise rising levels of CO2 by stimulating photosynthesis. (carbon fertilisation)

Question 32

Why is carbon fertilisation likely not enough to counterbalance anthropogenic emissions?

Answer 32

Because it relies on the availability ion conditions for photosynthesis to occurs e.g. light.

Question 33

How does positive feedback in the carbon cycle create greater disequilibrium?

Answer 33

Global warming can intensity the global carbon cycle, increasing rate of decomposition and release more co2 into the atmosphere, amplifying the greenhouse effect.

Question 34

How can changes to the global carbon and water cycles be monitored? (4)

Answer 34

• sea surface temperatures
• global air temperatures
  -deforestation
  -sea ice thickness rates

Question 35

Ground based measuring techniques are unreliable, what is preferred?

Answer 35

Saltelite methods.

Question 36

Why is satellite monitory the best way to measure global changes in carbon and water cycles?

Answer 36

Using GIS these can be mapped and analysed over time and region and to find trends and anomalies.

Question 37

What is one way that fluxes of carbon can vary diurnally?

Answer 37

During the day, photosynthesis occurs in vegetation, at night this is revered. This can be observed in phytoplankton. At the flux is revered and carbon goes int the atmosphere.

Question 38

How can seasonal changes impact on the water cycle ?

Answer 38

Seasonal variation ultimately depends on the intensity of solar radiation, in the UK this is highest in mid-June an d therefore evapotranspiration is at its highest. In the driest parts of England, up to 80 percent of rainfall is lost to EVT.

Question 39

What is one way that fluxes of water can vary diurnally?

Answer 39

Lower temperatures at night reduce evt. Convectional precipitation also ceases (particularly significant in the tropics, where bulk of precipitation is from convectional storms)

Question 40

Monitoring changes: Ice caps/glaciers.

Answer 40

Measures surface height of ice sheets and glaciers using laser tech. Shows extent and volume of ice changes.

Question 41

Monitoring changes: sea surface temperatures

Answer 41

Radiometers measure the wave band of radiation emitted from the ocean surface.

Question 42

Monitoring changes: DEFORESTATION

Answer 42

Uses satellites to measure albedo, reflectivity of earth’s surface and land use changes.

Question 43

What happens to the water cycle during glacial periods?

Answer 43

There is a net transfer of water to storage in ice sheets and glaciers. Sea level falls. As ice sheets advance, negotiation is destroyed and the biosphere shrinks. Desserts and grasslands replace rainforests. The water cycle slows.

Question 44

What happens to the carbon cycle during glacial periods?

Answer 44

There is a dramatic reduction in atmospheric co2. The cause is unknown but there is a definite correlation, maybe because phytoplankton having fixed carbon die and carbon is foxed in sedimentary rocks.
Large amount of permafrost in tundra areas sequester carbon. there is an overall slowing of the carbon flux.