Carbon EQ1 Flashcards
Define what the Carbon Cycle is?
The bio - geo - chemical cycle is where carbon moves from one sphere to another. It is a closed system that is made up of linked subsystems.
What are the two types of carbon?
Geological - Carbon results from the formation of sedimentary carbonate rocks - limestone or chalk. - This cycle operates on a timescale of millions of years.
Biologically - derived carbon is stored as shale,coal,crude oil and other sedimentary rocks. - this cycle operates on a timescale of days to thousands of years.
What are the key processes in the carbon cycle (fluxes/transfers between stores)?
also include explanation of each.
Photosynthesis - removes CO2 from atmosphere for plant growth
Respiration - releases CO2 back into the atmosphere
Decomposition - breaking down organic matter containing carbon (reacts with air and soil to form CO2)
Combustion - Biomass and fossil fuels release CO2 into the atmosphere.
Diffusion - CO2 moves between the atmosphere and oceans, where it dissolves into seawater or is released back into the air.
Gas Exchange - The natural process where CO2 is transferred between the atmosphere and bodies of water.
Volcanic Outgassing - Volcanoes release CO2 and other gases from Earth’s interior into the atmosphere.
Rock Weathering - Carbon from the atmosphere reacts with minerals in rocks, forming compounds that eventually get stored in sediments.
What is the biggest store of carbon?
Sedimentary rocks
(high residency time - 150M years)
Lithosphere / pedosphere
What are the smaller stores of carbon?
Soil, Oceans, Atmosphere.
(lower residency time - 10s - 1000s of years)
4 overlying, core “spheres” (stores) of carbon
Atmosphere - as CO2 in compounds like methane (CH4)
Hydrosphere - as dissolved CO2
Lithosphere - as carbonates in limestone and fossil fuels.
Biosphere - in living and dead organisms
carbon can exist in almost every form (liquid,gas,solid,living,non living)
AND CYROSPHERE AS PERMAFROST
Explain the geological carbon cycle
Very slow - most of earths carbon is geological.
Carbon is released through chemical weathering and volcanic outgassing.
Summarise the carbonic geological cycle.
1) Co2 released at volcanoes
2) CO2 reacts with water in atmosphere to form acid rain.
3) Carbonic acid dissolves silica in rocks releasing calcium ions.
4) Calcium ions flow into rivers -> sea.
5) Sea creatures combine dissolved carbon with the calcium carbonate for shells.
6) Sea creatures die and their shells are deposited on the ocean floor eventually forming limestone.
How do sedimentary rocks contain carbon?
EG> LIMESTONE
formed through shells, skeletons and phytoplankton and these can absorb carbon through photosynthesis. Over long periods of time these accumlate at the sea bed to form organic limestone rock.
Explain chemical weathering as a geological process:
Water reacts with Atmospheric CO2 and carbonic acid forms. Once this carbonic acid reaches the surface as rain, it reacts with surface minerals found in rocks (e.g silica) slowly dissolving them into their compound ions. Calcium ions are transported by rivers to the sea. Organisms then use these calcium ions with dissolved carbon to form calcium carbonate for their shells. When they die, their shells are deposited and turned into rock.
Explain how volcanic outgassing is a geological process:
Volcanic eruptions or earthquake activity released CO2 into the atmosphere.
Pockets of CO2 exist within the crust.
Outgassing - when calcium carbonate is heated above 840C (deep in the mantle) it decomposes releasing CO2.
Outgassing occurs at active volcanic zones and fractures in the Earth’s crust.
How is coal/oil/gas formed?
Oil, gas, and coal form from ancient organic matter buried under sediment. Over millions of years, heat and pressure transform it into fossil fuels—coal from plants, oil and gas from marine organisms.
What is seuquestering?
The natural storage of carbon by physical or biological processes such as photosynthesis.
What are the carbon cycle pumps?
Processes in the oceans to circulate and store carbon. There are 3 different types of carbon cycle pumps: biological, carbonate and physical.
Explain the biological pump:
The biological pump is how the ocean moves carbon from the surface to the deep sea. Phytoplankton absorb CO₂ through photosynthesis, then die or get eaten (new animals respire or decompose the CO2).
Their carbon-rich waste sinks, storing CO₂ in deep ocean water and sediments for centuries.
Explain the (marine) carbonate pump:
The marine carbonate pump moves carbon as calcium carbonate (CaCO₃). Marine organisms like shellfish and corals use dissolved CO₂ to build shells. When they die, shells sink and become limestone, locking away carbon for millions of years.
Shells either disolve releasing the CaCO3 or form sedimentary rock like limestone.
Difference between biological and carbonate pump?
The biological pump moves carbon through organic processes—phytoplankton absorb CO₂, and when they die or are eaten, carbon sinks as organic matter.
The marine carbonate pump moves carbon through inorganic processes—marine organisms form calcium carbonate (CaCO₃) shells, which sink and become limestone, storing carbon long-term.
Both store carbon in the deep ocean, but the biological pump is organic, while the carbonate pump is mineral-based.
What is the physical pump?
The physical carbon pump moves CO₂ in the ocean through temperature and circulation. Cold water absorbs more CO₂ at the surface and sinks in deep ocean currents (downwelling), storing carbon for centuries. Warmer water releases CO₂ back into the atmosphere (upwelling). This cycle helps regulate global carbon levels.
Why is thermohaline circulation important for the carbon cycle?
Thermohaline circulation is crucial for the carbon cycle because it transports carbon-rich deep water to the surface (upwelling) and moves carbon-absorbing surface water to the deep ocean (downwelling). This process helps regulate atmospheric CO₂ levels and long-term carbon storage.
However - this is around the whole globe and is more “macro”
- think of this as the MACRO pump and the physical pump as the MICRO one.
Thermohaline conveyor belt - moves cold and warm water around the globe
What is terrestial sequestration?
Terrestrial sequestration is the process of capturing and storing carbon in land-based ecosystems
For instance - primary producers like plants or consumers like animals
also micro organisms like bacteria/fungi which faciclitate carbon sequestration by breaking down organic matter into SOIL. - decomposition.
What are the most productive biomes in sequestering the most carbon?
Tropical Rainforests
Savanahs
Grasslands
Temperate Forests
Explain how carbon fluxes vary daily and seasonally?
Diurnally - during the day there is more sunlight for photosynthesis - NET loss at night to respiration.
Seasonlly - Summer/Spint more plants and leaves + sunlight to photosynthesise - in winter atmospheric CO2 Levels rise as there is less plants etc to photosynthesise.
How does soil store carbon - and how much % worldwide does it?
20% - 30%
Soils store carbon primarily as organic matter. When plants and animals die, their residues are broken down by microbes, forming complex organic compounds (like humus) that bind to soil particles. This stabilization process protects the carbon from rapid decomposition.
What is a carbon balance?
What happens if it is disrupted?
SOURCES = SINKS
if balance is disrupted - Greenhouse effect - the CO2 traps the suns LONG wave radiation preventing it escaping to outer space- warming the planet.
The suns energy arrives in short wave radiation but once it reflects of the surface its infrared long wave (which is trapped by CO2)
What are the consequences of the greenhouse effect in the Carbon cycle?
Increase in solar radiation levels (trapped by CO2) - increases sunlight levels and temprature - enhancing photosynthesis. More UV converted to IR and atmosphere warms -> oceans warm -> sequester less carbon -> more carbon in atmosphere -> more IR trapped -> temp rises.
Increased CO₂ traps more infrared radiation, warming the atmosphere. Warmer oceans then absorb less CO₂, leaving more in the air to trap even more heat—a reinforcing feedback loop that intensifies global warming and disrupts the carbon cycle.
What impacts are humans having on the greenhouse effect?
Deforestation - carbon store reducing in size
Land use change - removal of vegetation
Fossil fuel extraction - releases CO2
Farming practices - ploughing can release CO2 in soils - methane from cows/rice.
ENHANCED GREENHOUSE EFFECT.
Explain what will happen if temprature increases?
- More solar raditation
- Temps rise
- Oceans warm and store less carbon
- Phytoplankton die - less photosynthesis
- Ice sheet melts - surface waters become saturated with CO2
- Tundra thaws and organic material decomposes anaerobically releasing methane.
Explain what will happen if temprature decreases?
- Less solar radiation
- Temps fall
- Oceans cool
- Phytoplankton grow = photosynthesis
- Sea water freezes
- Tundra freezes - organic material cant decompose
What are the implications of fossil fuel combustion:
Carbon imbalance as more CO2 is being sequestered than stored.
Increases temp - rainfall increases - extreme weather events likely to increase.
Arctic amplification - rapid warming melts ice - more UV is converted into IR (more absorbed by water than reflected by ice)
Increased rates of evaporation, condensation and precipitation.
What are the 5 Geological processes in the carbon cycle?
- Weathering - Mechanical, chemical and biological breakdown rocks.
- Decomposition - Plant and animal particles from decomposition after death store carbon.
- Transportation - Rivers can carry particles to the ocean where they will be deposited.
- Sedimnetation - Over time sediment builds up, burying older sediment like shale or limestone
- Metamorphosis - Pressure builds over time in the layers of sediment which eventually leads to deeper sediment changing to rock e.g. limestone becomes marble, shale becomes slate
How does carbon move in the ocean?
- The 3 carbon pumps (vertical)
- Thermohaline circulation (horizontal)
What is thermohaline circulation?
The thermohaline circulation is a global system of surface and deep ocean currents driven by differences in temperature and salinity
These ocean currents are responsible for circulating carbon
Thermo = temprature
Haline = salt content
Both of these determine the density of the water.
Implications of fossil fuel combustion on the climate
The IPCC report in 2014, explicitly linked gas concentrations to fossil fuel emissions, rising global temperatures and sea levels
Implications of fossil fuel combustion for ecosystems:
Ecosystems help regulate carbon and hydrological cycles as well as providing goods and services for humans and the planet
- Already, species with low population numbers, limited climatic ranges or restricted habitats are at risk
- Marine ecosystems are threatened by lower oxygen levels, higher rates of ocean acidification and food chain changes (resulting from rising temperatures)
- Coastal ecosystems are at risk from sea level rise
Although most species will be impacted negatively, there are some that may benefit
- Cool, moist regions (e.g., UK) could provide habitats for more species
Implications of fossil fuel combustion on the Hydrological Cycle
- Reduction in sea ice / glacier storage
- Changes in the capacity of terrestrial ecosystems to sequester carbon and store water.
- Increased evaporation rates.
- Changes in precipiation.
