Water And Carbon Cycles

Question 1

What is an open system?

Answer 1

One which can exchange energy and matter with its surroundings, inputs and outputs eg. The coastal system

Question 2

What is a closed system?

Answer 2

One which cannot exchange matter with its surroundings, but can exchange energy eg the water cycle

Question 3

What is feedback?

Answer 3

When inputs or outputs suddenly change and stores are forced to change to restore equilibrium

Question 4

What is the role of oceans as a store and source of carbon dioxide?

Answer 4

-Oceans play a key role in carbon cycle
-Photosynthesis by plankton generates organic compounds of carbon dioxide
-Some of this material passes through the food chain and sinks to the ocean floor where it is decomposed into sediments, destroyed at subduction zones, where ocean crusts are subducted beneath the continental plates.
-Carbon dioxide is later released during volcanic activity
-The transfer of carbon dioxide from ocean to atmosphere involves a very long time scale

Question 5

What is meant by dynamic equilibrium?

Answer 5

Where a system tries to reach a continuous balance

Question 6

What is meant by positive feedback?

Answer 6

Feedback that tends to magnify a process or increase its output

Question 7

Water on or close to the earths surface is called?

Answer 7

The hydrosphere

Question 8

What % earths water is oceanic?

Answer 8

97%

Question 9

The area of land drained by a river and its tributaries is called?

Answer 9

Drainage basin

Question 10

What are the flows occurring in the drainage basin system?

Answer 10

-Groundwater flow
-Throughflow
-Overland flow
-Base flow
-Infiltration
-Percolation
-Throughfall

Question 11

What is water balance within a drainage basin system?

Answer 11

-Water balance budget refers to the balance between inputs and outputs of water in the drainage basin system
-Water balance graph show that the system is in a state of dynamic equilibrium over the year
-Changes in inputs and outputs effect soil moisture and river discharge

Question 12

The role of oceans as a carbon store/sink?

Answer 12

-Oceans are the largest CO2 sink on earth, more than 25% CO2 that humans release into the air is absorbed into the sea

Question 13

Why is the local drainage basin an open system?

Answer 13

A drainage basin is an example of an open system because it is open to inputs from the outside such as precipitation and is responsible for outputs out of the system of water into the sea and evaporation of water into the atmosphere.

Question 14

What is river discharge

Answer 14

The amount of water in a rover flowing past a particular point (cumecs)

Question 15

What is the river regime

Answer 15

Graph showing changes in river discharge over the course of a year in response to climatic changes with the seasons eg. Precipitation, temperature, evapotranspiration

Question 16

Is the hydrological cycle an open or closed system?

Answer 16

The global hydrological cycle is a closed system (local drainage basin=open), meaning that all the water within the cycle remains as such in one form or another- not created or destroyed.

Question 17

What is dynamic equilibrium

Answer 17

A state or act of balance between continuing processes eg. Inputs and outputs in a system. This means that when one changes, another is simultaneously altered within a system.

Question 18

Example of negative feedback loop

Answer 18

Increasing levels of cloud cover preventing increasing solar radiation on temperatures.

Question 19

What is the lithosphere

Answer 19

Earths upper mantle and crust- the rigid outer part closest to the surface.

Question 20

What is the biosphere?

Answer 20

Anything biotic which is in our world

Question 21

What is the hydrosphere

Answer 21

Stores within bodies of water- primarily the worlds oceans

Question 22

What is the cryosphere

Answer 22

Within ice, such as areas near the poles such as ice caps or sheets or glaciers

Question 23

What is the rising limb?

Answer 23

Indicates the amount of discharge and the speed at which it is increasing
Very steep in response to a flash flood or in small drainage basins where the response is rapid

Question 24

What is the discharge on flood hydrograph?

Answer 24

The volume of water flowing through rivers (cumecs) Higher in larger basins
Steep catchments have lower infiltration rates
Flat catchments have high infiltration rates so more throughflow and lower peaks

Question 25

What is the lag time on flood hydrographs?

Answer 25

Time interval between peak rainfall and discharge. Influenced by basin shape, steepness and stream order

Question 26

Characteristics of a flashy hydrograph?

Answer 26

Shorter lag time, steeper rising limb, higher peak discharge

Question 27

Physical factors affecting flood risk

Answer 27

-precipitation type and intensity
-temperature and evapotranspiration
-antecedent moisture
-drainage basin size and shape
-drainage density
-porosity and impermeability of rocks and soils
-slopes
-vegetation type
-land use

Question 28

How does urbanisation increase the magnitude and frequency of floods?

Answer 28

-creation of highly impermeable surfaces such as roads, roofs and pavements
-removal of trees means less interception
-agriculture can damage the soils, removing the top layer, make soil smears and reduce percolation and make them impermeable

Question 29

Bankfull

Answer 29

The maximum discharge a river channel is capable of carrying without flooding

Question 30

Carbon sink

Answer 30

A store of carbon that absorbs more carbon than it releases

Question 31

Example of positive feedback in the water cycle

Answer 31

Rising sea levels means ice shelves become unstable as they are in more contact with warmer ocean water. This leads to increased calving (breaking up of ice shelves). This leads to an increase in melting, causing sea levels to rise further.

Question 32

Example of positive feedback in the carbon cycle

Answer 32

Increased temperatures leads to an increase in evaporation from the oceans. This leads to more cloud cover. Clouds reflect radiation from the sun, resulting in a slight cooling of temperatures.

Question 33

Example of negative feedback in the carbon cycle

Answer 33

Increased atmospheric CO2 leads to increased temperatures, promoting plant growth and rates of photosynthesis. This in turn removes more CO2 from the atmosphere, counteracting the rise in temperatures.

Question 34

Distribution of freshwater stores

Answer 34

-97% in oceans (salt water), 3% earths water is freshwater, almost all of which is stored as snow and ice (70%) and groundwater (29%)
-Surface and other freshwater is only 1% of all freshwater
-Most freshwater sources can be found in the northern hemisphere, where there is greater land cover, and the mild climate means not all freshwater is locked up as snow or ice and evaporation remains low