Enquiry 1 How Does The Carbon Cycle Operate To Maintain Planetary Health?

Question 1

Long term geological scale

Answer 1

Most of worlds carbon is locked n terrestrial stores

Question 2

Shorter timescale

Answer 2

Biological processes sequester carbon both on land in the oceans

Question 3

The carbon cycle

Answer 3

The cycle by which carbon moves from one earth sphere (atmos/ hydrosphere/ lithosphere/ biosphere) to another

Closed system

Made up of interlinked subsystems which are open and have inputs and outputs

Question 4

Carbon stores

Answer 4

Function as sources (adding carbon the atmos) and sinks (removing carbon from atmos)

Question 5

Carbon fluxes

Answer 5

Or flows

Are movements of carbon from one store to another

They provide the motion in the carbon cycle

Question 6

Carbon exists in different forms depending on the store

Answer 6

Atmosphere- as co2 and carbon compounds (methane)

Hydrosphere- dissolved co2

Lithosphere- carbonates in limestone, chalk and fossil fuels, as pure carbon in graphite/ diamonds

Biosphere- carbon atoms in living and dead organisms

Question 7

Major fluxes

Answer 7

Between oceans and atmos

Between land and atmos

Via biological processes of photosynthesis and respiration

Question 8

Measured

Answer 8

Pentagrams or gigatonnes of carbon per year

Question 9

Geological origins (oceans)

Answer 9

Results from:

1. Formation of sedimentary carbonate rocks in oceans. (Himalayas= one of largest carbon stores as mountains start as ocean sediments rich in calcium carbonate from crustaceans)

Sediments are up-folded and the carbon they contained has been weathered, eroded and transported back to oceans

Question 10

Geological origins( plants and animals)

Answer 10

Derived in plants and animals in shale, coal and other rocks

Rocks made up of remains of organisms

Sank to bottom of ocean and covered in silt/mud

Remains decayed anaerobically and were
compressed

Subsequent burning of fossil fuels released large amounts of carbon back into atmos

Question 11

Geological processes releasing carbon

Answer 11

Not just burning fossil fuels

1. Carbon dioxide in atmos rests with moisture to form weak carbonic acid

Falls as rain and reacts with sone surface mineral (chemical weathering)

2. Pockets of carbon dioxide exist in crust

Volcanic eruptions release gas (outgassing) mid oceanic ridges, subduction zones

Question 12

Biological pump

Answer 12

Moves co2 from surface to phytoplankton by photosynthesis

Converts co2 into food for zooplankton and their predators

30% co2 sinks into deep ocean and demons there as part of deep of currents

Then converted back into co2 by marine bacteria

Question 13

Physical pump

Answer 13

Moves carbon compounds around the ocean by upwelling and downwelling

Downwelling involves cold fender water sinking to bottom of ocean and takes dissolved co2 down with it

Moves in slow moving deep ocean currents

Becomes part of thermohaline circulation

Upwelling involves water warming as it rises to surface

Co2 is released back into atmos

Question 14

Carbonate pump

Answer 14

Form sediments from dead organisms that have fallen to bottom of ocean

Hard outer shells and skeletons of crustaceans are significant as they are rich in calcium carbonate

Question 15

Terrestrial sequestering

Answer 15

Primary producers (plants) sequester carbon by photosynthesis

Carbon enters terrestrial food chains and nutrient cycle

Animals eat plant and carbon becomes part of their fat and protein

Respiration releases some co2 back into atmos

Animals waste is eaten by micro organisms

When die their remains fall to round and carbon enters soil

Question 16

Biological carbon

Answer 16

Soil is biggest carbon store on land

Stays here for years until it’s broken down by soil microbes (BIOLOGICAL DECOMP)

Soils store 20%-30%

Question 17

Amount of carbon in soil depends on

Answer 17

Climate: rate of plant growth and decomp

Veg cover: supply of dead organic matter

Soil type: clay protects carbon from decomp

Land use: cultivation creates soil disruption

Question 18

Greenhouse effect

Answer 18

Increasing concentration in atmos

Co2 and methane are most important gases in GHGs

Increasing presence is upsetting earths natural temp control system

Question 19

Earths climate driven by incoming short wave solar radiation

Answer 19

31% is reflected back into space by clouds/GHG/ land surface

69% absorbed at earths surface (especially oceans)

Much of radiation absorbed at surface is re-radiated as long wave radiation

Large amount of long wave reverted from returning into space by clouds and GHGs

Trapped long wave is re radiated back into earth surface

Question 20

Trapped re radiated radiation

Answer 20

Determines distribution of precipitation and heat

Constitutes the nature greenhouse effect

Controls mean global temp