booklet 1- water and carbon cycle as natural systems 3.4.1

Question 1

what are systems

Answer 1

simplify complex processes, interrelationships, situations

Question 2

what are 4 subsystems

Answer 2

• biosphere
• hydrosphere
• lithosphere
• atmosphere
• cryosphere

Question 3

subsystems- biosphere

Answer 3

• living things
• where life exists from above earth’s surface to below it
• humans, fungi, animals, plants

Question 4

subsystems- hydrosphere

Answer 4

• all water on earth in any state found in oceans, atmosphere, groundwater etc

Question 5

subsystems- lithosphere

Answer 5

• land
• earths relatively hard outer layer e.g. limestone (calcium carbonate), hydrocarbons (fossil fuels), marine sediments from shells + marine life

Question 6

subsystems- atmosphere

Answer 6

• layer of gases + suspended solids that surrounds earth

Question 7

subsystems- cryosphere

Answer 7

all frozen components of the earth e.g. frozen rivers, lakes, snow, glaciers, frozen soil (permafrost) etc

Question 8

what are components of a system

Answer 8

• transfers (flows–> movements of parts of the system
• stores (components)
• outputs (matter/energy moving from the system to outside to another system
• inputs (matter/energy moving into a system from outside)
• boundary (limits to the system e.g. watershed)

Question 9

types of systems

Answer 9

open
closed
cascading

Question 10

open system

Answer 10

where matter + energy are allowed to transfer across the system boundary and into the environment

input –> store -(flow)-> store –> output

Question 11

closed system

Answer 11

• where there may be a flow into/out of system but no matter flow takes place across the boundary
• fixed mass

input –> store –> output –> input –> store output

Question 12

cascading system

Answer 12

where energy + matter are transferred from one subsystem to another –> output of one subsystem= input of another subsystem
e.g. river debris cascades into coastal systems

Question 13

feedback loops what are they

Answer 13

try to maintain/restore equilibrium

Question 14

positive feedback

Answer 14

• amplifies (multiplies) the change
• change becomes bigger and moves the system further away from the balance

e.g. global warming –> increases permafrost thawing –> releases methane to atmosphere –> causes more warming

Question 15

negative feedback

Answer 15

• nullifies a change
• decreases the effects of the change keeping system closer to previous state

e.g rock has freeze thaw weathering –> debris covers rock –> debris acts as protection –> nullifies further weathering

Question 16

dynamic equilibrium

Answer 16

• whole system may change to another system
• when inputs = outputs in a system then it is in equilibrium
• flows and processes continue in same way at all times, there’s no overall change to the system

Question 17

dynamic equilibrium in reality

Answer 17

• lots of small variations in inputs + outputs of a system
• variations are usually small so inputs + outputs remain about balanced over a longer period
• BUT large, long term changes to balance of inputs + outputs can cause system to change
  –> it will then establish a new dynamic equilibrium
  –> changes can trigger positive/negative feedback

Question 18

siberia forest fires how do they cause a threat?

Answer 18

• they create positive feedback
• fires release greenhouse gases e.g. CO2 –> more carbon in atmosphere –> atmosphere warms –> more forest fires + more carbon released –> cycle continues

Question 19

albedo

Answer 19

• when snow + ice + vegetation reflects solar radiation
• snow has albedo 80%
• Arctic has a high albedo as it has lots of ice + snow
  –> this is decreasing due to melting ice –> means more solar radiation can reach ground –> this warms earths surface –> more ice melting + less albedo –> cycle continues

Question 20

negative feedback example

Answer 20

• high temps= more vegetation grows= captures more CO2

Question 21

siberias melting permafrost

Answer 21

• permafrost= stores carbon + when it melts releases methane. it is ground that remains below 0 degrees for at least 2 years. It’s found beneath 24% of exposed land area (Northern hemisphere)

how is it an issue?
-melting permafrost releases methane –> methane= greenhouse gas that traps more heat in atmosphere than CO2 –> leads to enhanced greenhouse effect (positive feedback) –> more heat in atmosphere= more permafrost melts, more methane in atmosphere, cycle continues