Slow Carbon Cycle

Question 1

How long is carbon in the slow cycle for ?

Answer 1

100-200 million years for carbon to move between rocks/ soils / ocean / atmosphere

Question 2

Chemical weathering

Answer 2

Movement of carbon from atmosphere to lithosphere.

Atmospheric carbon combines with water to create weak carbonic acid.
Falls to surface in precipitation.

Acid dissolves rock through chemical wearing and releases calcium / magnesium / potassium.

Ions get carried to river

Question 3

In the ocean.

Answer 3

Calcium ions combine with bicarbonate ions to form calcium carbonate.

Calcium carbonate is used in shell building for organisms like plankton.

When they die they sink to sea floor and over layers of sediment/ shells cement together and turn to rock storing the carbon in stone - carbon stored for millions of years

Question 4

How does the slow cycle return carbon to atmosphere?

Answer 4

Volcanoes.
Destructive Pb- subduction occurs, denser plate melts which includes gases and silica.
When erupt they vent has to atmosphere.

Question 5

How much co2 do volcanoes emit ?

Answer 5

130-380 million tonnes

Question 6

How much co2 do humans emit ?

Answer 6

30 billion tones

Burning fossil fuels

Question 7

How do volcanoes lead to positive feedback?

Answer 7

Co2 rises in atmosphere due to more eruptions.
Temps rise.
More rains.
This dissolved more rock.
More ions created which end up in ocean.
Fall to bottom of floor where they will store carbon for long period of time

Question 8

How has the slow cycle been disrupted by humans ?

Answer 8

Ocean used to vent carbon dioxide to atmosphere in balance with carbon the ocean received during weathering.
Since co2 concentrations in atmosphere have increased the ocean now takes more carbon from atmosphere than it releases.

Question 9

Ocean in the future

Answer 9

Over millennia the ocean will absorb up to 85% of extra co2 people have put in atmosphere by burning fossil fuels