The carbon cycle Flashcards
What type of cycle is the carbon cycle?
It is biogeochemical
Where is most of the carbon stored?
In rocks
What are the other stores of carbon?
Ocean, atmosphere, biosphere and lithosphere
What is the carbon cycle?
It is the movement of carbon between stores
How is the carbon cycle closed?
It is in balance over long time scales
There are sources and sinks of carbon
What are the two components that the carbon cycle can be divided into?
Geological
Biological
What is the geological component?
A long time scale of millions of years
What is the biological time scale?
Shorter such as days to thousands of years
What is the slow component of the carbon cycle like?
Carbon moves between the rocks, soil, ocean and atmosphere
How is carbon moved in the long term cycle?
Through chemical recations and tectonic activity
How many grams of carbon are passed through the slow carbon cycle every year?
10^13 to 10^14 grams
How many grams of carbon pass through the fast carbon cycle each year?
10^16 to 10^17
How many extra grams of carbon into the atmosphere do humans add each year?
10^15
In which gases does carbon feature in the atmosphere?
CH4
CO2
How do CO2 and CH4 act in the atmosphere?
They absorb and retain heat in the atmosphere
What is the fast carbon cycle mostly movement through?
The biosphere
Why does carbon play an essential role in biology?
It is able to chemically bond and is in living cells
What do chains of carbon bonds contain and how is this released?
They contain lots of energy which is released when the chains are broken. This acts as a source of fuel for all living things
What are short term carbon cycle changes dictated by?
Photosynthesis and respiration of plants and phytoplankton
What is the difference in the amount of carbon moving in the geological and biological timescales?
Amount of C moving between the atmosphere and biosphere each year is 1000x greater than the amount of C through the geological cycle
How is CO2 removed from the atmosphere?
Through photosynthesis by plants and plankton
What is the photosynthesis equation?
CO2 + H2O + energy = CH2O + O2
How is CO2 returned to the atmosphere?
By respiration through plants and soil
What is the respiration equation?
CH2O + O2 = CO2 + H2O + energy
What changes can photosynthesis and respiration cause?
Diurnal and seasonal changes
What happens during the day in growing season?
Leaves absorb sunlight and take up CO2 from the atmosphere whilst organisms consume the carbon in organic matter and return CO2 to the atmosphere
What happens at night?
Photosynthesis stops but respiration continues
What happens in winter in the Northern Hemisphere?
Photosynthesis ceases when many plants lose leaves but respiration increases leading to an increase in CO2
What happens in spring in the Northern Hemisphere?
Photosynthesis resumes and atmospheric CO2 concentrations are reduced
What is the rate of carbon accumulation in peat dictated by?
The balance between productivity and decay
How does temperature influence productivity?
Warmer temperatures increase productivity
How does temperature influence decay?
Warmer temperatures increase the rate of decay
How does moisture affect decomposition and decay?
Wet= limited decompostion
Too dry = limited accumulation
What is an issue with the peat carbon sink?
There are two competing processes and responses:
Projected warming is likely to cause substantial increases in decomposition, nutrient release and primary production
What are the projections for the present-day global sink?
The present day global sink will increase slightly until around AD2100 and then decline
How is carbon moved from the atmosphere to the land and ocean surface?
By dissolving into water bodies
How is carbon moved from the atmosphere to the lithosphere and ocean?
Through rain
What acid is formed when carbon combines with water?
Carbonic acid
What is released when carbonic acid dissolves rocks?
Calcium ions
What is one of the most important forms of carbon sequestration?
Oceaanic absorption of CO2
What occurs at the ocean surface?
Two way carbon exchange
What does photosynthesis within oceans allow?
For carbon to be passed through the food chain
Where can carbon be stored for centuries?
At ocean depths
