1b & 1c - The carbon and water cycles are systems with inputs, outputs and stores and have distinctive processes and pathways that operate within them.

Question 1

Photosynthesis-

Answer 1

light energy to chemical energy - light energy is captured and used to convert water, CO2 and minerals into O2 and glucose (AO2 - diurnal = day more light, location = equator increased PS, more in warm seasons) 6CO2 + 6H2O = C6H12O6 +6O2

Question 2

Respiration-

Answer 2

movement of O2 from the outside air to the cells within tissues, and the transport of CO2 in the opposite direction (AO2 - availability of O2, density of veg, steady flow)) resp = C6H12O6 + 602 = 6CO2 + 6H2O + energy

Question 3

Decomposition-

Answer 3

when micro-organisms eg bacteria and fungi breakdown dead organic matter, extracting energy and releasing CO2 into the atmosphere (AO2 - faster rates in host humid places) - recycle of nutrients/carbon from animals and plants

Question 4

Combustion-

Answer 4

when organic material containing carbon, reacts or burns in the presence of O2, releasing CO2 into the atmosphere. natural and human causes

Question 5

Natural sequestion in oceans/vegetation/sediments-

Answer 5

atmospheric CO2 dissolves in ocean surface waters while the oceans ventilate CO2 back into atmosphere - through this exchange, individual carbon atoms are stored in the oceans for about 350yrs

Question 6

Slow carbon cycle-

Answer 6

• carbon stored in rocks, sea floor sed and fossil fuels is lock away for millions of years
• total carbon circulated est. 10-100mill tonnes a yr
• dead organisms accumulate on sea floor - heat and pressure convert them into carbon rich sedimentary rocks (150mill yrs residence time)
• some sedimentary rocks get subducted into upper mantle at tectonic plate boundaries = vented to the atmosphere through volcano
• some exposed to surface by erosion and tectonic movement = chemical weathering
• carbonaceous rocks - formed by decomposed organic matter being buried under young sed eg coal/oil - act as carbon sinks for mill of yrs

(IRREVERSABLE CHANGES)

Question 7

Fast carbon cycle-

Answer 7

• circulates between atmosphere, oceans, living organisms, soil (biosphere, atmosphere and ocean)
• transfers 10-10000x faster than slow cycle
• land plants and phytoplankton (key components) - PS absorbs atmosphere CO2 and respiration release CO2, decomposition returns CO2 to atmosphere
• exchanges of CO2 between atmosphere and oceans

(REVERSABLE CHANGES)

Question 8

Physical (inorganic) carbon-

Answer 8

• mixing of surface and deep ocean waters by vertical currents creating a more even distribution of carbon
• CO2 enters the oceans from the atmosphere by diffusion
• Surface ocean currents then transport the water and its dissolved CO2 poleward where it cools, becomes dense and sinks
• downwelling occurs, carrying carbon to depths where carbon molecules can be stored for centuries
• upwelling occurs from deep ocean currents moving cold - carbon rich water towards the surface, warming and so less likely to hold carbon so CO2 diffuses back into the atmosphere

Question 9

Biological (organic) carbon-

Answer 9

• carbon is exchanged between oceans and atmosphere (around 50GT of carbon is drawn from atmosphere by the biological pump) through the actions of marine organisms
• phytoplankton, float near surface combines sunlight, water and dissolved CO2 to produce organic material
• death of carbon locked in phytoplankton decomposes and released CO2 or accumulates in sed (seafloor)- sedimented to form fossil fuels/rocks which are locked away for mill of yrs (slow carbon cycle)
• this can be exposed by tectonic processes and weathering = release CO2

Question 10

Evaporation-

Answer 10

the process by which liquid water is converted into a gaseous state

Question 11

Transpiration-

Answer 11

the evaporation of moisture from pores on the leaf surfaces of plants

Question 12

Condensation-

Answer 12

• the phase change of water vapour (gas) to water (liquid)
• when air is cooled so it reaches its dew point
• air rises upwards due to being warmer then surrounding air (convection). as air rise, pressure falls and it expands and cools to dew point (adiabatic expansion) - this can also happen if air is morced to rise over mountain barriers
• mass of air will cool if it moves across cooler surface (advection) eg from sea to land in winter

Question 13

Precipitation-

Answer 13

• moisture falling from clouds (atmosphere) to ground (biosphere)
• forms when atmosphere can no longer hold water as vapour and additional wv reaches dew point to form clouds which eventually form precipiation

Question 14

Interception-

Answer 14

rainwater stored temporarily on the leaves, stems and branches of vegetation which is evaporated and does not reach the ground surface

Question 15

Ablation-

Answer 15

the loss of ice and snow (especially glacier) through melting, evaporation and sublimation

Question 16

Runoff (overland flow vs saturated overland flow)-

Answer 16

movement of water across the land surface (ground is saturated or impermeable has increased runoff and flooding)

Question 17

infiltration-

Answer 17

vertical movement of rainfall through soil - more permeable rocks or soil = more infiltration and reduced flood risk

Question 18

percolation-

Answer 18

the movement of surface and soil water into underlying permeable rocks

Question 19

throughflow-

Answer 19

water flowing horizontally through the soil to stream and river channels

Question 20

groundwater flow-

Answer 20

the horizontal movement of water within aquifers

Question 21

cryospheric processes-

Answer 21

processes involving ice sheets and glaciers - rapid thawing of snow in upland Britain is common cause of flooding

Question 22

What can influence the relative significance of the different flows/stores?

Answer 22

• seasons
• permeability of rocks/soils - stores
• diurnal changes
• temperature
• climate
• geology