Carbon cycle

Carbon Cycle

Carbon Cycle

The biogeochemical cycle by which carbon is exchanged among the biosphere, pedospher, geosphere, hydrosphere, and atmosphere of the Earth. Carbon is the main element in biological compounds and various minerals.

Pools

A location or system that can release or store carbon

Atmosphere

Carbon is found in carbon dioxide (CO2) and in small amounts of methane in the atmosphere. The atmosphere has the least amount of carbon, but the amount of carbon in the atmosphere is very important because it can influence and affect climate.

Atmosphere Pool

750 GT

Pedosphere

The Earth’s soil is a mixture of organic matter, minerals, gasses, liquids, and organisms that support life.

Pedosphere Pool

1580 GT

Biosphere

The portion of the Earth with living material that stores carbon within biological molecules. Includes: plants, animals, soil, and micro-organisms

Biosphere Terrestrial Pool

610 GT

Hydrosphere

Contains dissolved inorganic carbon, located in Earth’s water. (primarily the ocean)

Hydrosphere Surface Pool

970 GT

Biosphere Aquatic Pool

3 GT

Hydrosphere Deep Pool

38,000 GT

Litosphere

• Contains the largest amount of carbon on Earth, and is stored in sedimentary rocks within the planet’s crust.

• The rocks are produced in two ways:

  • Hardening of mud turns into shale (over geological time)

  • Collection of calcium carbonate particles (from shells and skeletons of marine organisms, in limestone)

Lithosphere Pool

1,000,000+ GT

Fossil Fuels

A "fossil" store of organic matter (coal, oil, and natural gas). Usually there is no flux of fossil fuels in the carbon cycle, but it is introduced in the cycle because of human actions (unnatural).

Lithosphere Pool

1200 GT

Flux

A signal carbon pool can often have several fluxes both adding and removing carbon simultaneously

Photosynthesis (from year 1 notes)

• Carbon dioxide diffuses through the atmosphere or water in autotrophs. The process of autotrophs harnessing light energy to help drive chemical processes of creating chemical energy in the form of glucose. Energy from light is ultimately stored in the chemical bonds found in glucose.

• CO2 is removed from the atmosphere (terrestrial plants and some bacteria) and hydrosphere (aquatic plants and phytoplankton), and moved into the biosphere.

• Respiration (Year 1 Notes)

  • All organisms of the biosphere and pedosphere release carbon during cellular respiration.

  • Terrestrial organisms release carbon to the atmosphere

  • Aquatic organisms release carbon to the hydrosphere.

  • Carbon dioxide produced by respiration is diffused out of organisms into water or the atmosphere.

Decomposition

• releases CO2 from the biosphere to the atmosphere during cellular respiration

• the breakdown of complex, organic compounds in dead organisms, urine and feces into simpler carbon compounds transfer carbon from the biosphere to the pedosphere.

Diffusion

• Inorganic carbon is absorbed and released at the interface of the hydrosphere and atmosphere.

• In its dissolved form, CO2 goes on to react with water in the carbonate reactions*. The formation of carbonate in seawater allows oceans to take up and store a much larger amount of carbon than would be possible if it remained as dissolved CO2.

Lithification

The process in which sediments compact under pressure, expel fluids and become solid rock. Lithification moves carbon from the biosphere to the lithosphere (limestone rock from calcium carbonate shells).

Combustion

HydroCarbon + Oxygen → Carbon Dioxide + Water

CH + O2 → CO2 + H2O

• A combustion reaction is a reaction in which a substance reacts with oxygen gas, releasing energy in the form of light and heat.

• Releases carbon gasses when organic hydrocarbons (wood, coal, oil, and gas) are burned as a fuel source. Combustion moves carbon from fossil fuels and the biosphere to the atmosphere.

Fossilization

In anaerobic conditions (little to no oxygen), dead organisms will sometimes slowly decay. Over millions of years, the organisms build up. If they are compressed together then they form fossil fuels (coal, oil, gas). Fossilization moves carbon from the pedosphere and biosphere to the geosphere.

Feeding

not technically a flux but carbon is reemerging within one pool (biosphere). The heterotrophs move carbon within biological molecules along the food chain.

Are pools

• atmosphere

• pedosphere

• biosphere

• hydrosphere

• lithosphere

• fossil fuels

Are fluxes

• photosynthesis

• Decomposition

• Diffusion

• Lithification

• Combustion

• Feeding

Fossil Fuels

Hydrocarbon molecules made from fossilized plant and animal remnants. The creation of fossil fuels is determined by the type of fossil fuel, the amount of heat, and the amount of pressure. Both plants and animals build their bodies using predominantly carbon and hydrogen atoms and it is the stored energy in the fossilized hydrocarbon compounds that act as fuel when it is burned.

Are examples of fossil fuels

• Coal

• Petroleum Oil & Natural Gas

• Methanogenic Archaea

Coal

• formed from peat

• formed from millions of years of heat and pressure, which compresses the peat

Peat

brown deposit resembling soil, formed by the partial decomposition of vegetable matter in wet acidic or anaerobic conditions, with lots of decomposers

Petroleum Oil and Natural Gas

• All of the available began as plankton living in oceans and lakes millions of years ago. As these microscopic plants and animals lived, they stored carbon molecules in their bodies. When they died, they sank to the bottom of the sea.

• Over millions of years, heat, and pressure compress sediment to form it. Multiple layers of sediment were formed.

Methanogenic Archaea

• prokaryotic cells, belong in Archaea domain

• produces methane (CH4) as a by product of anaerobic respiration

• methane is oxidized (loss of carbons) in the atmosphere to form CO2 and H2O

Prokaryotic Cells

• Unicellular organisms that lack a membrane-bound nucleus and mitochondria.

• Divided into two domains: Archaea and Bacteria

Domain Archaea

• Archaea and bacteria are both prokaryotes with similar cell structures and metabolic pathways, but archaea and eukaryotes are more similar genetically.

• Some archaea can produce methane as part of the carbon cycle—something no eukaryotes or bacteria can do.

Methane

The simplest hydrocarbon consists of one carbon atom and four hydrogen atoms (CH4). Methane is flammable, and is used as a fuel worldwide. Most of Earth’s methane is produced by methanogenic archaea.

Anaerobic Respiration

A type of cellular respiration, which occurs in the absence of oxygen. Methanogenic archaea converts the food molecules they absorb into methane during anaerobic respiration.

Oxidization

• Lose electrons (OIL RIG)

• In the carbon cycle, after being produced by the archaea, the methane diffuses into the atmosphere where it is oxidized in the presence of oxygen to form carbon dioxide and water.

Seasonal CO2

• Seasonal fluctuations in CO2 is a result of photosynthetic activity by plants. Plants photosynthesize in the spring and summer, they use CO2 from the atmosphere as the main source or carbon for growth and reproduction. Causes a decrease in CO2 levels.

• In the winter, plants save energy by decreasing photosynthesis. Without photosynthesis, the dominant process in the rel;ease of CO2 from respiration by the total ecosystem, including bacteria, plants, and animals.

• a lot of cellular respiration (to make ATP to fuel the growth) - releasing lots of CO2 to the atmosphere.

Carbon in Water

• Ocean holds about 50 times more CO2 than the atmosphere

• Coccolithophores are microscopic phytoplankton that live in the upper layers of the world's oceans. They are part of the base of the marine food web, because they perform photosynthesis using CO2 dissolved in the water. They also use calcium carbonate to build tiny plates on their exterior.

• When these organisms die, the soft parts of their body decompose, but their calcium carbonate parts sink to the bottom of the ocean forming deposits.

  • These deposits are buried by sediment. Pressure changes the deposits into limestone.

  • Fossils of these organisms can often be found in limestone.

  • Limestone is a significant carbon sink.

• Sand is mostly made of particles of calcium carbonate shells and skeletons that have been broken down by waves.

• Limestone

  • A sedimentary rock composed primarily of calcium carbonate (CaCO3) from the accumulation of shell and coral debris. It most commonly forms in clear, warm, shallow marine waters. Through the lithification flux, carbon has moved from the marine biosphere to the lithosphere.