Carbon Flashcards
(102 cards)
what is the fast/biological carbon cycle
the movement of carbon from living things up into the atmosphere
What processes occur in the fast/biological carbon cycle
- photosynthesis
- respiration
- digestion
- decomposition
- combustion
- gas exchange
what is digestion
the release of carbon compounds by terrestrial and marine animals after feeding on carbon-rich materials
what is decomposition
the breakdown of animals and plant structures by bacteria, and the release of carbon compounds into the atmosphere, soil, and to the ocean floor
what is released in decomposition
- CO2 when oxygen is present
- CH4 when oxygen is absent
what is gas exhange
the mutual transfer of CO2 between the lower atmosphere and ocean surfaces
what are key features of the terrestrial carbon cycle
- dominated by photosynthesis
- carbon stored in biomass
- part of the fast carbon cycle
- bacteria in decomposition releases CO2
How is carbon transferred to the soil in the terrestrial carbon cycle
leaf litter, roots, and plant debris upon decomposition
What are the human impacts on the terrestrial carbon cycle
- urbanisation and deforestation affect the biomass and carbon exchange between soil and atmosphere
- clearing vegetation through combustion
what are the key features of the marine carbon cycle
- carbon stored as dissolved CO2, bicarbonate ions in solution, tissue of marine organisms
- phytoplankton perform photosynthesis and are eaten by zooplankton
what are the human impacts on the marine carbon cycle
warmer oceans = less CO2 absorption from atmosphere = reduction in phytoplankton activity
What are the key features of the carbon cycle in the atmosphere
- usually in the form of CO2 or CH4
- carbonic acid, formed when CO2 combines with H2O in clouds
- acid rain contributes to weathering and ocean acidification
What natural factors are causing an increase in atmospheric CO2
- periods of increased volcanicity
- glacial periods mean less vegetation
- interglacial periods cause warmer oceans
- winter in the north shuts down biomass
What natural factors are causing a reduction in atmospheric CO2
- long-term reduciton of volcanicity
- glacial periods create cooler oceans
- interglacial periods have more vegetation
- summers in the Northern Hemisphere have increased biomass activity
What human factors are causing an increase in atmospheric CO2
- burning fossil fuels
- causing more wildfires
- an increasing meat-based diet
- melting tundra releasing CO2 and CH4
- clearing natural vegetation for urban/agricultural/industrial use
What human factors are causing a reduction in atmospheric CO2
- CCS schemes
- re/afforestation projects
what is combustion
natural fires release carbon compounds from vegetation to the atmosphere
What happens in stage 1 of the slow/geological carbon cycle: the transfer of CO2 into the oceans from the atmosphere and land surface
carbonic acid rain dissolves surface rocks and transfers soluble bicarbonate compounds to the sea via rivers
What happens in stage 2 of the slow/geological carbon cycle: the deposition of carbon compunds on the ocean floor
- marine plants absorb CO2, while marine animals take in carbon to construct skeletons and shells
- phytoplankton are eaten by zooplankton and carbon-rich excrement falls to the ocean floor
- skeletal and shell remains of marine animals fall to ocean floor
What happens in stage 3 of the slow/geological carbon cycle: the conversion of ocean sediments into carbon-rich rock
- carbon-rich accumulations of deposits may be converted into carbon-rich rocks or become contained as concentrations in sandstones and shales to form organic deposits (lithification) (some become fossil-fuel reserves)
What happens in stage 4 of the slow/geological carbon cycle: the transfer of carbon rocks to tectonic margins
- as sedimentary rocks move in the direction their crustal plate is moving
- if they end up at collision margins, they may be uplifted to become surface mountain ranges
- carbon rich strata may be exposed to weathering (restarting the cycle)
What happens in stage 5 of the slow/geological carbon cycle: the return of carbon compounds to the atmosphere in volcanic eruptions
if carbon-rich rocks move near subduction zones, they could be ejected by volcanic eruptions
What is the physical carbon pump
when carbon compounds are transported to different parts of the ocean through downwelling and upwelling currents
How does CO2 enter the ocean carbon cycle once it is dissolved in surface sea water
- physical carbon pump
- biological carbon pump
- carbonate carbon pump