ELSS L6 - Carbon exchange
- Created by: Hadley023
- Created on: 07-11-18 12:38
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- Carbon exchange
- Precipitation
- Atmospheric CO2 dissolves in rainwater to form carbonic acid.
- Human activities are increasing the acidity of rainfall (increase CO2 in the atmosphere) = ocean surface waters are becoming more acidic.
- Marine and ocean reservoirs. Rate at which CO2 dissolves into the ocean is dependent on the temperature.
- Temperature rise by the end of the century.
- P'synth
- Using the Sun's energy, CO2 from the atmosphere and water, green plants and marine phytoplankton convert light energy to chemical energy.
- Flux of carbon from the atmosphere to land plants and phytoplankton via p'synth average around 120 gigatonnes.
- Chemical weathering
- Most weathering involves rainwater which contains dissolved CO2.
- Dissolves limestone and chalk - carbonation.
- Transfers carbon to the atmosphere, streams, rivers and the ocean.
- Rate of process is influenced by geology.
- Biological weathering
- Rainwater mixed with dead and decaying organic material in the soil forms humid acids (important to tropical environments)
- Physical weathering
- Freeze thaw breaks rocks down into smaller particles but involves no chemical weathering.
- Dissolves into smaller pieces, increases surface area, increases chemical weathering.
- Respiration
- Process in which carbohydrates fixed in p'synth are converted to CO2 and water.
- Plants and animals use these carbohydrates to provide energy needed for metabolism and growth.
- Decomp.
- Decomposer organisms breakdown DOM, extracting energy and releasing CO2 into the atmosphere and mineral nutrients to the soil.
- Anaerobic decomposition in waterlogged soils releases methane. Contributes to GGC as methane is extremely potent.
- Rates of decomp depend on climatic conditions. Increase GGC due to increase temp = increase decomp.
- Combustion - natural
- Organic material reacts in the presence of oxygen. Combustion releases CO2 (natural combustion e.g. wildfires.
- Combustion - humans
- Human activities e.g. cleaeing of forests (slash and burn) and combustion of fossil fuels (due to increased affluence).
- Precipitation
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