Carbon Flashcards
What is the carbon cycle?
The carbon cycle is the cycle by which carbon moves from one Earth sphere to another. It is a closed system but made up of interlinked subsystems which are open and have inputs and outputs
What are the two components of the carbon cycle?
Stores: function as sources and sinks
Fluxes: movements of carbon from one source to another ; provide the motion in the carbon cycle
How does carbon exist in different forms ?
Stores: carbon exists in different forms, depending on the store:
- atmosphere: carbon dioxide and carbon compounds
-hydrosphere: dissolved carbon dioxide
-lithosphere: carbonate in limestones, chalk and fossil fuels as pure carbon in graphite and diamonds
-biosphere: as carbon atoms in living and dead organisms
What are the main fluxes?
- between oceans and the atmosphere, and between land and atmosphere via the biological processes of photosynthesis and respiration
Why is most of the earth’s carbon geological?
-Most carbon in the world is geological in rocks, coming from carbonate rocks. This is mainly limestone formed in oceans as well as shale and clay which are created biologically
What is the formation process of sedimentary carbonate rocks?
Sediment is deposited in layers in a low-energy environment (lake, sea bed)
- Further layers are deposited and sediment undergoes diagenesis (the physical and chemical changes that occur ensuring the conversion of sediment to sedimentary rock)
- The lower layers become compressed and chemical reactions cement particles together
- The conversion of loose, unconsolidated sediment into solid rock is known as lithification
How do geological processes release carbon into the atmosphere?
- Carbon dioxide in the atmosphere reacts with moisture to form weak carbonic acid. When it falls as rain, it reacts with some of the surface minerals and slowly dissolves them. This is chemical weathering.
- Pockets of carbon dioxide exist in the Earth’s crust. Volcanic eruptions and earthquakes can release these gas pockets. Outgassing is the release of gas, previously dissolved, trapped, frozen or absorbed in some material. It occurs mainly along mid-ocean ridges, subduction zones and at magma hotspots.
What are the 3 types of oceanic carbon pump?
- biological pumps
- physical pumps
- carbonate pumps
What is phytoplankton?
phytoplankton are microscopic plants and plant-like organisms drifting or floating in the sea/ freshwater
How do biological pumps sequester carbon?
- These move carbon dioxide from the ocean surface to marine plants called phytoplankton through photosynthesis.
- This effectively converts carbon dioxide into food for zooplankton and their predators
- Most of the carbon dioxide taken up by phytoplankton is recycled near the surface.
How do physical pumps sequester carbon?
- Move carbon compounds to different parts of the ocean in downwelling and upwelling currents
- Downwelling occurs in parts of the ocean where cold, dense water sinks
These currents bring dissolved carbon dioxide down to the deep ocean - Once there, it moves in a slow-moving deep ocean current, staying there for hundreds of years
- Eventually, these deep ocean currents, part of the thermohaline circulation return to the surface by upwelling
- The cold deep ocean water warms as it rises towards the ocean surface and some of the dissolved carbon dioxide is released back into the atmosphere
How do carbonate pumps sequester carbon?
- These form sediment from dead organisms that fall to the ocean floor, especially the hard outer shells and skeletons of fish, crustaceans and corals, all rich in calcium carbonate
What is the thermohaline circulation?
The thermohaline circulation is the global system of surface and deep ocean currents driven by temperature and salinity differences between different parts of the ocean; it can be seen as a giant conveyor belt, which plays a vital part in the carbon cycle.
How do terrestrial primary producers sequester carbon during photosynthesis?
- Plants sequester carbon out of the atmosphere during photosynthesis, In this way, carbon enters the food chains and nutrients cycle of terrestrial ecosystems
- When animals consume plant matter, the carbon sequestered in the plant becomes part of their fat and protein. Respiration, particularly by consumer animals, returns some of the carbon back to the atmosphere
- Waste from animals is eaten by microorganisms and detritus feeders
As a consequence, carbon becomes part of these creatures. When plants and animals die and their remains fall to the ground, carbon is released into the soil
On what two timescales do carbon fluxes vary?
- Diurnally: during the day, fluxes are positive - from the atmosphere into the ecosystem. This reverse applies at night when respiration occurs but not photosynthesis
- Seasonally: during the winter, carbon dioxide concentrations increase because of the low levels of plant growth. However, as soon as spring arrives and plants grow, these concentrations begin to decrease until the onset of autumn
How can biological carbon be stored as dead organic matter?
The actual amount of carbon stored in some soil depends on:
- climate: dictates the rates of plant growth
-vegetation cover: affects supply of dead organic matter
-soil type: clay protects carbon from decomposition
-land use: cultivation and other forms of soil disturbance increase the rate of carbon loss
How do ocean and terrestrial photosynthesis play an important role in regulating the composition of the atmosphere?
- Photosyntheis by terrestrial and oceanic organisms plays an essential role in keeping carbon dioxide levels relatively constant and thereby helping to regulate the Earth’s mean temperature
-The amount of photosynthesis varies spatially, particularly with net primary productivity (NPP)- the highest in the warm and wet parts of the world, particularly in the tropical rainforests and in shallow ocean waters.
How is soil health influenced by stored carbon and why this is important for ecosystem productivity?
- Soil health is an important aspect of ecosystems and a key element in the normal functioning of the carbon cycle. Soil health depends on the amount of organic carbon stored in the soil.
- Carbon is the main component of soil organic matter and helps to give soil its moisture-retention capacity, its structure and fertility.
What is energy security?
Energy security is achieved whenever there is an uninterrupted availability of energy at a national level and at an affordable price.
What are the 4 key aspects of energy security?
- availability
- accessibility
- affordability
-reliability
How is consumption measured?
- in per capita terms
- By a measure known as energy intensity, which is assessed by calculating the units of energy used per unit GDP. The fewer the units of energy, the more efficiently a country is using its energy supply.
What is the energy mix?
The energy mix is a combination of different energy sources used to meet a country’s total energy consumption - varies from country to country
What are factors affecting per capita energy consumption?
- physical availability
-cost
-standard of living
-environmental priorities
-climate
-public perception - economic development
-technology
What is an energy pathway
An energy pathway is a route taken by any form of energy from its source to its point of consumption. The routes involve different forms of transport, such as tanker ships, pipelines and electricity transmission grids
