Have you seen part 1 of the Carbon Cycle? This IBDP Biology blog post is the continution of the first one regarding the carbon cycle.
Formation of Peat and Coal
Peat forms when organic matter is not fully decomposed because of acidic and/or anaerobic conditions in waterlogged soils
- In soil organic matter [dead leaves] are digested by Saprotrophs
- Saprotrophs digest some Carbon for growth and release Carbon Dioxide during Aerobic respiration
- BUT
water logged soils are an Anaeronic Environment therefore Saprotrophs and Methanogens are inhibited
- The organic matter is only partially decomposed
- Partial decomposition causes
Acidic conditions
- Large quantities of partially decomposed organic matter build up
- The organic matter is compressed to form Peat
Coal is formed when:
- Diposits of peat are buried under other sediments
- Peat is heated and compressed over millions of years eventually becoming coal
Oil and Gas Formation
- Sea plants and animals
died and buried on the ocean floor
- Over time the plants and animals were
covered by silt and sand
- In these Anaerobic conditions there is only
partial decomposition
- The remains were buried deeper and deeper
heat and pressure turned the remains into oil and gas
- Methane is the largest part of Natural Gas
CO2 produced from Combustion of Biomass and Fossil
Carbon Dioxide produced by the Combustion of Carbon Compounds is an non-biological process
BUT can happen naturally:
- Lightning sets fire to forest and burns the biomass and releasing Carbon Dioxide
Over time humans learned about Combustion
- Extracts coal oil and natural gas.
- energy is generated from the Combustion of Fossil Fuels. This releases a lot of Carbon Dioxide into the Atmosphere
- If heated dried biomass or fossil fuels will burn in the presence of Oxygen
Limestone in the Carbon Cycle
Limestone: Rock made from Calcium Carbonate
Some animals secrete calcium carbonate structures to protect themselves
- Hard shells
of Molluscs
- Exoskeletons
of hard Coral
When the animals die the body parts decompose but the calcium carbonate remains form deposits on the ocean floor
- The deposits are buried and compressed eventually forming limestone
- Imprints of the hard body parts remain in the rock as fossils
- Limestone is a huge Carbon Sink
- Carbon is released when
Limestone reacts with acid
- Rainwater contains
carbonic acid and can cause calcium carbonate to breakdown and release the carbon that it holds inside
Measuring Carbon Fluxes & Analysing CO2 Data
- It is not possible to measure carbon sinks and fluxes
. Estimates are based off of different measurements that are published with large uncertainties.
- Impossible to measure globally
- Estimates can be made based on Ecosystems and Mescosoms
- Global Fluxes estimates are made with
Gigatonnes
- Keeling Curve and other field stations show a
clear upward trend with annual cycles
- Historical Data can be collected from Ice Cores - analysing CO2 concentration of air bubbles trapped in the ice and determining the year from estimating the depth of the core
That's all for the Carbon Cycle! Well done!
References:
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fskepticalscience.com%2Fco2-measurements-uncertainty.htm&psig=AOvVaw24vKZoMc8RHW5UnyJHhrdJ&ust=1625918916065000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCLC-lo_61fECFQAAAAAdAAAAABAn
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fgeol105b.sitehost.iu.edu%2F1425chap8.htm&psig=AOvVaw1Wbpc7LaVrYbv8slynLGKF&ust=1625918981995000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCKD-2q761fECFQAAAAAdAAAAABAY
Drafted by Venetia (Biology)