1.b. The carbon and water cycles are systems with inputs, outputs and stores. Flashcards
(36 cards)
what are the stores in the water cycle?
include: oceans, ice, groundwater, rivers, soil moisture, permafrost, the atmosphere.
what is the biggest store in the water cycle?
the OCEAN - 1,334,040 thousand km3. means 97% of the Earth’s water is saline. Residence time for water molecule in the ocean is avg 3600 years
what is the second largest store in the water cycle?
Ice - 26,350 km3 / residence time 15,000 years
what is a very small store in the water cycle?
the atmosphere very small store 12.7 thousand km3 however flows in and out of atmosphere are very rapid via precipitation + evaporation avg residence time - 9 days
how many countries hold the world’s available fresh water?
less than 10 countries hold 60% of the world’s AVAILABLE fresh water. fresh water is a tiny proportion of the water held in store and 3/4 of it is frozen in the ice caps.
what happens to water vapour when you move from equator to poles?
there is a decrease in the amount of water vapour in the atmosphere as you move from the equator to the poles. the greatest amount of water vapour found in equatorial regions - least at poles
how much water moves per year between water stores?
505,000 KM3 of water per year moves between water stores
what is precipitation (water cycle)?
water and ice that falls from clouds to the ground. when water vapour in the atmosphere cools to dew point and condenses –> changes state from gas to liquid water droplets –> droplets aggregate together until they reach a critical size –> then they fall from the could as precipitation
how does precipitation vary in the water cycle?
precipitation varies in type depending on the latitude in terms of intensity and duration, in some places there is a concentrated wet season
what is snowmelt/ablation (water cycle)?
loss of ice due to melting, evaporation and sublimation. globally, runoff from snowmelt is a major component of the global movement of water, particularly in colder climates where there is a spring snowmelt
- mountain snow is a natural store of water in the cold season –> in warm season is released into rivers up to 75% of water in western USA comes from snowmelt
evapotranspiration what is evaporation (water cycle)?
liquid water turning into water vapour. the main pathway by which water enters the atmosphere. heat is needed to break molecular bonds, this is released as latent heat during condensation –> this process allows huge quantities of heat to transfer around the planet
evapotranspiration what is transpiration? (water cycle)
diffusion of eater vapour into the atmosphere from leaf stomata - responsible for 10% of moisture in the atmosphere.
what is transpiration influenced by?
temperature, wind, speed and the amount of water available to the plants. deciduous trees shed their leaves in the winter to reduce water loss
what is the largest store of carbon?
carbonate rocks such as limestone and chalk + deep ocean sediment
what is the second largest store of carbon?
oceans - cold polar winds absorb most CO2 from the air (diffusion). Warm equatorial waters have a low diffusion rate –> ocean currents carry the CO2 - upwelling at the equator and downwelling at the poles
what big of a carbon store is the atmosphere?
atmosphere is small store of carbon BUT is crucial –> represents most of the carbon in circulation at any one time.
in northern hemisphere highest concs are focused around major emissions sources –> North america, Europe - but are dispersed by winds.
Spring and summer vegetation/leaf growth absorbs large quantities of C from atmosphere in northern hemisphere via photosynthesis
–> in winter when leaves fall –> slows the quantity of carbon in the atmospere + increases as result / in southern hemisphere large fluxes enter the atmosphere when there are forest fires
how is carbon stored on land?
is stored in living and dead organic matter above + below ground / most is stored in tropical forest - 86% of the world’s above ground carbon / deserts + tundra = poor stores of carbon on land
what is precipitation (carbon cycle) / include acidic rainfall?
atmospheric co2 dissolves in rain –> forming weak carbonic acid. increased carbon in the atmosphere due to anthropogenic (human) emissions is making rainfall more acidic.. in turn makes the oceans more acidic harmful to marine lif
what is photosynthesis in the carbon cycle? (phytoplankton)
plants on land and phytoplankton in the oceans use the sun’s energy, co2 from the atmosphere and water to convert light energy to chemical energy (glucose). plants use glucose to grow, reproduce, and release carbon through respiration
what is decomposition in the carbon cycle? what do rates of decomposition depend on?
decomposer organisms eg. bacteria, fungi breakdown dead organic matter - extracting energy and releasing co2 into the atmosphere and minerals into the soil. rates of D depend on the climate .. faster when it is warm and humid = opposite in cold
what is respiration in the carbon cycle?
the reverse of photosynthesis. carbohydrates eg. glucose fixed in photosynthesis are converted to co2 and water. carbon flows rapidly in and out of the atmosphere via photosynthesis and respiration
what is combustion in the carbon cycle?
when organic matter burns in the presence of oxygen. it releases co2, occurs naturally via wildfires caused by lightening and is essential to clear the log jam + free up nutrients from fallen leaves. fossil fuels are burnt for energy - carbon is released from the geological store into the atmosphere then makes way into oceans.
what is weathering in the carbon cycle?
the in-situ breakdown of rocks at the earth’s surface. rain contains dissolved co2 - weak carbonic acid, CARBONATION slowly dissolves limestone and chalk and release carbon into streams, rivers + ocean then atmosphere
where is weathering most effective? and how much chemical weathering is transferred into oceans + atmosphere per year?
weathering is most effective beneath soil cover as the co2 in soils adds to the acidity. chemical weathering transfers 0.3 billion tonnes of carbon into the atmosphere and oceans per year.
