The Carbon Cycle Flashcards
Carbon is the 4th most abundant element in the universe. Which 3 elements are more abundant than carbon?
Hydrogen, Oxygen, Helium
What % of our bodies is made up of water and carbon?
83%
What is carbon called when its a gas?
Carbon dioxide
Carbon can also exist as a solid, what are two examples of this?
Limestone, wood.
5 most important carbon compounds:
-Carbon dioxide
-Methane
-Calcium carbonate
-Hydrocarbons
-Bio-molecules
What is methane?
A gas found in the atmosphere, soils and oceans and sedimentary rocks.
What is calcium carbonate?
A solid compound found in calcareous rocks, oceans and in the skeletons and shells of ocean creatures.
What are hydrocarbons?
Solids, liquids or gases usually found in sedimentary rocks.
What are bio-molecules?
Complex carbon compounds produced in living things. Proteins. carbohydrates, fats and oils, and DNA are examples of bio-molecules.
Primary/ original source of carbon on earth:
Earth’s interior. It was stored in the earth’s mantle when earth was formed. It escapes here at destructive and constructive plate boundaries and volcanoes.
Co2 released at destructive margins is derived from what?
Metamorphism of carbonate rocks subducting with the ocean crust.
What unit is used by the United Nations climate change panel to measure carbon?
A gigatonne, 1Gt amounts to 1 billion tonnes.
How is transfer of carbon measured?
Gigatonnes of carbon per year.
Anthropogenic CO2 definition:
Carbon dioxide generated by human activity.
Biosphere definition:
The total sum of all living matter.
Carbon sequestration definition:
Capture of carbon dioxide from the atmosphere or capturing anthropogenic CO2 from stationary sources before it is released into the atmosphere. After it is captured it is put into long-term storage.
Carbon sink definition:
A store of carbon that absorbs more carbon than it releases.
Greenhouse gas definition:
Any gaseous compound in the atmosphere that is capable if absorbing infrared radiation, thereby trapping and holding heat in the atmosphere.
Lithosphere definition:
The crust and the uppermost mantle; this constitutes the hard and rigid outer layer of the earth.
Weathering definition:
The breakdown of rocks in situ by a combination of weather, plants and animals.
Inorganic deposits of carbon in the lithosphere:
Fossil fuels like coal, oil, and natural gas, oil shale and carbonate sedimentary deposits like limestones.
Four stores carbon is distributed between in the lithosphere:
Marine sediments/ sedimentary rocks- 100 million GtC
Soil organic matter- 1,500-1,600 GtC
Fossil fuel deposits of coal, oil and gas- 4,100 GtC
Peat- 250 GtC
What is peat?
Dead but undecayed organic matter found in boggy areas.
Hydrosphere- Ocean stores can be divided into 3:
-Surface layer where sunlight penetrates (photosynthesis)- 900 GtC
-Intermediate (twilight zone) and the deep layer of water- 37,100 GtC
-Living organic matter- 30 GtC and dissolved organic matter- 700 GtC
Total oceanic carbon:
37,000- 40,000 GtC
How is a sedimentary layer formed in the ocean?
Dead organisms decay releases carbon dioxide into deep water, some material sinks right to the bottom, forming carbon-rich sediments. Over millions of years chemical and physical processes may turn the sediments into rocks.
What is the estimated total amount of carbon in the terrestrial biosphere?
3,170 GtC.
What are the 5 main stores of carbon in the terrestrial biosphere?
-Living vegetation
-Plant litter
-Soil humus
-Peat
-Animals
What % of carbon in the Earth’s biosphere is in plants?
19%
Where in the plants is most carbon stored?
Directly in the tissue
What is the amount of carbon in the biomass and what affects this?
35-65%, varies depending on the location and vegetation type.
Which latitude forests hold the most carbon?
Half of carbon in forests is in high-latitude forests.
One third is in low-latitude forests.
What are the two largest forest reservoirs?
In Russia, holding 25% of the world’s forest carbon and the Amazon basin, containing 20%.
What is plant litter defined as?
Fresh, undecomposed, and easily recognisable plant debris.
What type of plant litter is most common in forests?
70% of litter in forests is leaf tissues.
What is soil humus?
Originates from litter decomposition, a thick brown substance that remains after most of the organic litter has decomposed.
How does soil humus get dispersed?
Throughout soil by soil organisms such as earth worms.
In all forests what % of carbon is stored in biomass and the soil?
31% in the biomass
69% in the soil
In tropical forests what % of carbon is stored in biomass and the soil?
50% in the biomass
50% in the soil
What holds more carbon in the world, soil or vegetation?
Soil!
What does inorganic carbon consist of?
Carbon and carbonate materials such as calcite, dolomite and gypsum.
How much larger is the soil carbon pool than the atmospheric pool?
3.1X larger than the atmospheric pool which is 800 GtC.
Where do peats form?
Wetland conditions, where almost permanent water saturation obstructs flows of oxygen from the atmosphere into the ground.
-Low oxygen anaerobic conditions slow down plant litter decomposition.
What % of the earths land and freshwater surface us peatlands?
3%
What is the peatland estimated carbon store?
More than 250 GtC worldwide.
What role do animals play in the storage of carbon?
A small role, however they are important in the generation of movement of carbon through the carbon cycle.
When was the earth’s atmospheric carbon the highest?
7,000 ppm in the Cambrian period around 500 million years ago.
When was the earth’s atmospheric carbon the lowest concentration?
Over the last 2 million years during the quaternary glaciation, it sank ti 180ppm (parts per million).
What is the estimated overall amount of carbon stored in the atmosphere today?
Varies from 720 GtC to 800 GtC, makes up around 0.04% of the atmosphere.
The Earths carbon is the highest it has been in ________?
800,000 years, likely the past 20 million years.
CO2 is a potent _______ ___?
Greenhouse gas
What has been the primary attribute to global warming?
Industrial CO2 emissions.
What is the Mauna Loa Observatory (MLO)?
Observatory measurements of carbon and monitoring atmospheric constituents.
Why is the MLO in Hawaii?
Undisturbed air, remote location, minimal influences of vegetation and human activity.
What do the MLO measurements show? Between when has it increased markedly and by how much?
Increased markedly since the Industrial Revolution, from 280ppm to 317.7ppm in March 1958, to 400.3 ppm as of February 2015.
What are human sources of carbon called?
Anthropogenic- burning fossil fuels and deforestation.
Who was Keeling Curve?
One of the first scientists to gather evidence that linked fossil fuel emissions to rising levels of carbon dioxide.
What the CO2 currently rising at a rate of?
2ppm/year and accelerating.
What is a net carbon sink?
If more carbon enters a store than leaves it.
What is a net carbon source?
More carbon leaves a store than enters it.
What is the geological component of the carbon cycle?
Where it interacts with the rock cycle in the processes of weathering, burial, subduction and volcanic eruptions.
How is carbon dioxide removed from the atmosphere ?
Dissolving in water and forming carbonic acid.
What is the equation for forming carbonic acid?
CO2 + H20 = H2CO3
How is calcium carbonate formed?
Acidic water reacting with minerals, dissolving them into their component ions through chemical weathering. They are then carried in surface waters to the ocean where they settle as minerals.
What do sea animals skeletons eventually form?
If they sink they collect as sediment where they can eventually layer over each other to form sedimentary limestone.
What does coral extract from seawater?
CaCO3
How does coral store carbon?
Dead coral is built upon by later generations of live coral so it becomes buried, carbon is now stored below the sea floor in layers of limestone.
What can expose carbon buried in limestone?
Tectonic uplift.
What process causes plate movement to push the sea floor under continental margins?
Subduction.
How does tectonic movement release the oceans carbon into the atmosphere?
Sea-floor deposits are pushed deep into the earth where they heat up, melt and rise up to the surface through volcanic eruptions, or seeps/vents.
What four processes control atmospheric carbon dioxide concentrations?
Weathering, burial, subduction, and volcanism.
What three oceanic plants (+bacteria) turn carbon into organic matter?
Tiny marine plants, all terrestrial plants, photosynthetic algae.
What process has plants turning carbon into organic matter?
Photosynthesis.
How does photosynthesis work?
Plants use energy from sunlight to combine atmospheric carbon dioxide with water to form carbohydrates.
What do carbohydrates store?
Energy
What by-product is released by photosynthesis?
Oxygen is released into the atmosphere.
The equation for photosynthesis:
CO2 + H2O + sunlight = CH20 + 02
What do photosynthetic algae and bacteria do with the stored carbohydrates?
Use it as an energy source to carry out their life functions by the process of respiration.
Consumers (bacteria and animals) get their energy from where?
The carbohydrates remaining in plants is stored as biomass which consumers gain their energy from.
What is the equation for respiration?
O2 + CH20 = energy + H20 + CO2
What two processes are opposites of each other that work together?
Photosynthesis and respiration.
What is decomposition?
Includes, physical, chemical and biological mechanisms that transform organic matter into increasingly stable forms.
Broad definition- Physical break-up of organic material by wet-dry, shrink-swell, hot-cold and other cycles.
How many trees and species does the Amazon contain?
300 billion trees and 15,000 species
How much of the Earth’s biomass stored carbon is in the Amazon?
One fifth.
How many people depend on the resources from the Amazon?
34 million people
How many tons of carbon did the Helmholtz Centre for Environmental Research estimate is store in th Amazon?
76 billion (in 2019)
How much do studies estimate above-ground biomass increases by in the Amazon a year?
0.3-0.5 %
Why is the above-ground biomass in the Amazon increasing?
Increasing CO2 concentrations in the atmosphere.
How much carbon did the UFZ estimate the Amazon absorbs per year?
600 million tonnes per year. In 1990 however it was estimated 2 billion tonnes a year.
What is the average discharge of water into the Atlantic Ocean by the Amazon?
175,000 m3/s or around 15% of the fresh water entering the oceans each day.
How much is the average rainfall across the who Amazon basin annually?
2,300mm, in the northern areas it can exceed 6,000.
What is the 2nd largest river in the world in terms of water flow?
The Rio Negro, a tributary of the Amazon, is 100m deep and 14km wide.
Why will half of the Amazon’s rainfall possibly never reach the ground?
It is intercepted by the forest canopy and re-evaporated into the atmosphere.
Of the rainfall that is evapotranspired back into the atmosphere, what % falls as rain again?
48%, only 30% of the rainfall reaches the sea.
Between 2000 and 2007 how much of the Brazilian Amazon was deforested?
At a rate of 19,368km per year. An area of forest larger than Greece was destroyed.
Where is the 4th largest climate polluter? What is 75% of its greenhouse gas emissions attributed to?
Brazil, attributed to deforestation and land change.
Amazon-Slash and burn technique results:
-Reduces retention of humidity in the soil’s top layer down to the depth of one meter.
-Facilitates sudden evaporation of water previously stored in forest canopy.
-Increases reflectiveness (albedo) and temp
-Reduces porosity of soil, causing faster rainfall drainage, erosion and silting of rivers and lakes.
Amazon- What clouds commonly form and how?
Any moisture that evaporates from deforested areas forms shallow cumulous clouds which usually do not produce rain.
Amazon- how do forests emitting salts and fibres assist clouds?
Forests emit salts and organic fibres along with water when they transpire. These act as condensation nuclei and assist in cloud and rain formation. The loss inhibits the formation of clouds and reduces rainfall.
Amazon- Differences between tropical rainforests (RF) and the pasture land it is replaced with:
-Forests absorb approx. 11% more solar radiation
-Avg temp in RF is approx. 24.1° C and 33 in pastures.
-Temp variation in forest soils at 20cm did not exceed 2.8°C, under pastures it was 8°C
-Moisture content in top 1m of soil in pasture is 15% less than nearby forest.
-Forest roots pump more soil moisture to the surface, producing 20-30% more air humididity and 5-20% more precipitation than pastures.
What % of South America is covered in the amazon rainforest? and how many countries?
40%, 8
Current statistics suggest we lost what % of the amazon rainforest?
20%
Are tropical rainforests a carbon sink or store?
Carbon sinks
What % of the global terrestrial vegetation carbon stock is help in the amazon?
17%
What does the amazon rainforest help reduce?
Global warming by lowering the planets’ greenhouse gas levels
How do we know tropical forests are becoming less effective at trapping carbon?
A study from 2015 found a long-term decreasing trend of carbon accumulation. Rates of net increase of above ground biomass declined by 1/3rd during the past decade.
What % does the WWF estimate of the amazon biome will be without trees by 2030?
27%
What is turning rainforest sinks into stores?
Deforestation and degradation.
What % of anthropogenic carbon emissions come from rainforests burning alone?
30%
How does deforestation effect soils?
Removing trees leads to more extreme temp swings that can be harmful to plants and animals as the canopy is no longer absorbing sun rays.
The top meter of soil hold 66.9PgC.
How does soil increase carbon in the waters?
When it rains soil erosion will wash away most of the carbon into rivers
